Add starting point for trails demo.

2024-09-11 09:05:28 +03:00 · 2022-05-17 16:07:07 -07:00 · 2022-05-17 16:07:07 -07:00 · 31265b4979
commit 31265b4979
parent c5ad2c5e40
39 changed files with 8962 additions and 0 deletions
--- a/examples/pokedex/app/Route/HelloForm.elm
+++ b/examples/pokedex/app/Route/HelloForm.elm
@ -0,0 +1,150 @@
+module Route.HelloForm exposing (ActionData, Data, Model, Msg, route)
+
+import DataSource exposing (DataSource)
+import Effect exposing (Effect)
+import ErrorPage exposing (ErrorPage)
+import Head
+import Head.Seo as Seo
+import Html
+import Html.Attributes as Attr
+import Pages.Msg
+import Pages.PageUrl exposing (PageUrl)
+import Pages.Url
+import Path exposing (Path)
+import RouteBuilder exposing (StatefulRoute, StatelessRoute, StaticPayload)
+import Server.Request as Request
+import Server.Response as Response exposing (Response)
+import Shared
+import View exposing (View)
+
+
+type alias Model =
+    {}
+
+
+type Msg
+    = NoOp
+
+
+type alias RouteParams =
+    {}
+
+
+route : StatefulRoute RouteParams Data ActionData Model Msg
+route =
+    RouteBuilder.serverRender
+        { head = head
+        , data = data
+        , action = action
+        }
+        |> RouteBuilder.buildWithLocalState
+            { view = view
+            , update = update
+            , subscriptions = subscriptions
+            , init = init
+            }
+
+
+init :
+    Maybe PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> ( Model, Effect Msg )
+init maybePageUrl sharedModel static =
+    ( {}, Effect.none )
+
+
+update :
+    PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> Msg
+    -> Model
+    -> ( Model, Effect Msg )
+update pageUrl sharedModel static msg model =
+    case msg of
+        NoOp ->
+            ( model, Effect.none )
+
+
+subscriptions : Maybe PageUrl -> RouteParams -> Path -> Shared.Model -> Model -> Sub Msg
+subscriptions maybePageUrl routeParams path sharedModel model =
+    Sub.none
+
+
+type alias Data =
+    {}
+
+
+type alias ActionData =
+    {}
+
+
+data : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+data routeParams =
+    Request.succeed (DataSource.succeed (Response.render Data))
+
+
+action : RouteParams -> Request.Parser (DataSource (Response ActionData ErrorPage))
+action routeParams =
+    Request.skip "No action."
+
+
+
+--Request.expectFormPost
+--    (\{ field } ->
+--        Request.map
+--            (\first ->
+--                DataSource.succeed (Response.render {})
+--            )
+--            (field "first")
+--    )
+
+
+head :
+    StaticPayload Data ActionData RouteParams
+    -> List Head.Tag
+head static =
+    Seo.summary
+        { canonicalUrlOverride = Nothing
+        , siteName = "elm-pages"
+        , image =
+            { url = Pages.Url.external "TODO"
+            , alt = "elm-pages logo"
+            , dimensions = Nothing
+            , mimeType = Nothing
+            }
+        , description = "TODO"
+        , locale = Nothing
+        , title = "TODO title" -- metadata.title -- TODO
+        }
+        |> Seo.website
+
+
+view :
+    Maybe PageUrl
+    -> Shared.Model
+    -> Model
+    -> StaticPayload Data ActionData RouteParams
+    -> View (Pages.Msg.Msg Msg)
+view maybeUrl sharedModel model static =
+    { title = "Placeholder"
+    , body =
+        [ Html.form
+            [ Attr.method "POST"
+            ]
+            [ Html.label []
+                [ Html.text "First "
+                , Html.input
+                    [ Attr.name "first"
+                    ]
+                    []
+                ]
+            , Html.input
+                [ Attr.type_ "submit"
+                , Attr.value "Sign up"
+                ]
+                []
+            ]
+        ]
+    }
--- a/examples/pokedex/app/Route/Search.elm
+++ b/examples/pokedex/app/Route/Search.elm
@ -0,0 +1,166 @@
+module Route.Search exposing (ActionData, Data, Model, Msg, route)
+
+import DataSource exposing (DataSource)
+import Effect exposing (Effect)
+import ErrorPage exposing (ErrorPage)
+import Head
+import Head.Seo as Seo
+import Html exposing (Html)
+import Html.Attributes as Attr
+import Pages.Msg
+import Pages.PageUrl exposing (PageUrl)
+import Pages.Url
+import Path exposing (Path)
+import RouteBuilder exposing (StatefulRoute, StatelessRoute, StaticPayload)
+import Server.Request as Request
+import Server.Response as Response exposing (Response)
+import Shared
+import View exposing (View)
+
+
+type alias Model =
+    {}
+
+
+type Msg
+    = NoOp
+
+
+type alias RouteParams =
+    {}
+
+
+route : StatefulRoute RouteParams Data ActionData Model Msg
+route =
+    RouteBuilder.serverRender
+        { head = head
+        , data = data
+        , action = action
+        }
+        |> RouteBuilder.buildWithLocalState
+            { view = view
+            , update = update
+            , subscriptions = subscriptions
+            , init = init
+            }
+
+
+init :
+    Maybe PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> ( Model, Effect Msg )
+init maybePageUrl sharedModel static =
+    ( {}, Effect.none )
+
+
+update :
+    PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> Msg
+    -> Model
+    -> ( Model, Effect Msg )
+update pageUrl sharedModel static msg model =
+    case msg of
+        NoOp ->
+            ( model, Effect.none )
+
+
+subscriptions : Maybe PageUrl -> RouteParams -> Path -> Shared.Model -> Model -> Sub Msg
+subscriptions maybePageUrl routeParams path sharedModel model =
+    Sub.none
+
+
+type alias SearchResults =
+    { query : String
+    , results : List String
+    }
+
+
+type alias Data =
+    { results : Maybe SearchResults
+    }
+
+
+type alias ActionData =
+    {}
+
+
+data : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+data routeParams =
+    Request.oneOf
+        [ Request.expectForm
+            (\{ field, optionalField } ->
+                field "q"
+                    |> Request.map
+                        (\query ->
+                            DataSource.succeed
+                                (Response.render
+                                    { results =
+                                        Just
+                                            { query = query
+                                            , results = [ "Hello" ]
+                                            }
+                                    }
+                                )
+                        )
+            )
+        , Request.succeed (DataSource.succeed (Response.render { results = Nothing }))
+        ]
+
+
+action : RouteParams -> Request.Parser (DataSource (Response ActionData ErrorPage))
+action routeParams =
+    Request.skip "No action."
+
+
+head :
+    StaticPayload Data ActionData RouteParams
+    -> List Head.Tag
+head static =
+    Seo.summary
+        { canonicalUrlOverride = Nothing
+        , siteName = "elm-pages"
+        , image =
+            { url = Pages.Url.external "TODO"
+            , alt = "elm-pages logo"
+            , dimensions = Nothing
+            , mimeType = Nothing
+            }
+        , description = "TODO"
+        , locale = Nothing
+        , title = "TODO title" -- metadata.title -- TODO
+        }
+        |> Seo.website
+
+
+view :
+    Maybe PageUrl
+    -> Shared.Model
+    -> Model
+    -> StaticPayload Data ActionData RouteParams
+    -> View (Pages.Msg.Msg Msg)
+view maybeUrl sharedModel model static =
+    { title = "Search"
+    , body =
+        [ Html.h2 [] [ Html.text "Search" ]
+        , Html.form []
+            [ Html.label []
+                [ Html.text "Query "
+                , Html.input [ Attr.name "q" ] []
+                ]
+            , Html.input [ Attr.type_ "submit", Attr.value "Search" ] []
+            ]
+        , static.data.results
+            |> Maybe.map resultsView
+            |> Maybe.withDefault (Html.div [] [])
+        ]
+    }
+
+
+resultsView : SearchResults -> Html msg
+resultsView results =
+    Html.div []
+        [ Html.h2 [] [ Html.text <| "Results matching " ++ results.query ]
+        ]
--- a/examples/trails/.gitignore
+++ b/examples/trails/.gitignore
@ -0,0 +1,8 @@
+node_modules/
+elm-stuff/
+dist/
+.cache/
+.elm-pages/
+functions/render/
+functions/server-render/
+gen/
--- a/examples/trails/.nvmrc
+++ b/examples/trails/.nvmrc
@ -0,0 +1,2 @@
+v17.2.0
+
--- a/examples/trails/README.md
+++ b/examples/trails/README.md
@ -0,0 +1 @@
+# README
--- a/examples/trails/adapter.mjs
+++ b/examples/trails/adapter.mjs
@ -0,0 +1,312 @@
+import fs from "fs";
+
+export default async function run({
+  renderFunctionFilePath,
+  routePatterns,
+  apiRoutePatterns,
+  portsFilePath,
+  htmlTemplate,
+}) {
+  console.log("Running adapter script");
+  ensureDirSync("functions/render");
+  ensureDirSync("functions/server-render");
+
+  fs.copyFileSync(
+    renderFunctionFilePath,
+    "./functions/render/elm-pages-cli.js"
+  );
+  fs.copyFileSync(
+    renderFunctionFilePath,
+    "./functions/server-render/elm-pages-cli.js"
+  );
+  fs.copyFileSync(portsFilePath, "./functions/render/port-data-source.mjs");
+  fs.copyFileSync(
+    portsFilePath,
+    "./functions/server-render/port-data-source.mjs"
+  );
+
+  fs.writeFileSync(
+    "./functions/render/index.js",
+    rendererCode(true, htmlTemplate)
+  );
+  fs.writeFileSync(
+    "./functions/server-render/index.js",
+    rendererCode(false, htmlTemplate)
+  );
+  // TODO rename functions/render to functions/fallback-render
+  // TODO prepend instead of writing file
+
+  const apiServerRoutes = apiRoutePatterns.filter(isServerSide);
+
+  ensureValidRoutePatternsForNetlify(apiServerRoutes);
+
+  // TODO filter apiRoutePatterns on is server side
+  // TODO need information on whether api route is odb or serverless
+  const apiRouteRedirects = apiServerRoutes
+    .map((apiRoute) => {
+      if (apiRoute.kind === "prerender-with-fallback") {
+        return `${apiPatternToRedirectPattern(
+          apiRoute.pathPattern
+        )} /.netlify/builders/render 200`;
+      } else if (apiRoute.kind === "serverless") {
+        return `${apiPatternToRedirectPattern(
+          apiRoute.pathPattern
+        )} /.netlify/functions/server-render 200`;
+      } else {
+        throw "Unhandled 2";
+      }
+    })
+    .join("\n");
+
+  const redirectsFile =
+    routePatterns
+      .filter(isServerSide)
+      .map((route) => {
+        if (route.kind === "prerender-with-fallback") {
+          return `${route.pathPattern} /.netlify/builders/render 200
+${route.pathPattern}/content.dat /.netlify/builders/render 200`;
+        } else {
+          return `${route.pathPattern} /.netlify/functions/server-render 200
+${route.pathPattern}/content.dat /.netlify/functions/server-render 200`;
+        }
+      })
+      .join("\n") +
+    "\n" +
+    apiRouteRedirects +
+    "\n";
+
+  fs.writeFileSync("dist/_redirects", redirectsFile);
+}
+
+function ensureValidRoutePatternsForNetlify(apiRoutePatterns) {
+  const invalidNetlifyRoutes = apiRoutePatterns.filter((apiRoute) =>
+    apiRoute.pathPattern.some(({ kind }) => kind === "hybrid")
+  );
+  if (invalidNetlifyRoutes.length > 0) {
+    throw (
+      "Invalid Netlify routes!\n" +
+      invalidNetlifyRoutes
+        .map((value) => JSON.stringify(value, null, 2))
+        .join(", ")
+    );
+  }
+}
+
+function isServerSide(route) {
+  return (
+    route.kind === "prerender-with-fallback" || route.kind === "serverless"
+  );
+}
+
+/**
+ * @param {boolean} isOnDemand
+ * @param {string} htmlTemplate
+ */
+function rendererCode(isOnDemand, htmlTemplate) {
+  return `const path = require("path");
+const busboy = require("busboy");
+const htmlTemplate = ${JSON.stringify(htmlTemplate)};
+
+${
+  isOnDemand
+    ? `const { builder } = require("@netlify/functions");
+
+exports.handler = builder(render);`
+    : `
+
+exports.handler = render;`
+}
+
+
+/**
+ * @param {import('aws-lambda').APIGatewayProxyEvent} event
+ * @param {any} context
+ */
+async function render(event, context) {
+  const requestTime = new Date();
+  console.log(JSON.stringify(event));
+  global.staticHttpCache = {};
+
+  const compiledElmPath = path.join(__dirname, "elm-pages-cli.js");
+  const compiledPortsFile = path.join(__dirname, "port-data-source.mjs");
+  const renderer = require("../../../../generator/src/render");
+  const preRenderHtml = require("../../../../generator/src/pre-render-html");
+  try {
+    const basePath = "/";
+    const mode = "build";
+    const addWatcher = () => {};
+
+    const renderResult = await renderer(
+      compiledPortsFile,
+      basePath,
+      require(compiledElmPath),
+      mode,
+      event.path,
+      await reqToJson(event, requestTime),
+      addWatcher,
+      false
+    );
+    console.log("@@@renderResult", JSON.stringify(renderResult, null, 2));
+
+    const statusCode = renderResult.is404 ? 404 : renderResult.statusCode;
+
+    if (renderResult.kind === "bytes") {
+      return {
+        body: Buffer.from(renderResult.contentDatPayload.buffer).toString("base64"),
+        isBase64Encoded: true,
+        headers: {
+          "Content-Type": "application/octet-stream",
+          "x-powered-by": "elm-pages",
+          ...renderResult.headers,
+        },
+        statusCode,
+      };
+    } else if (renderResult.kind === "api-response") {
+      const serverResponse = renderResult.body;
+      return {
+        body: serverResponse.body,
+        multiValueHeaders: serverResponse.headers,
+        statusCode: serverResponse.statusCode,
+        isBase64Encoded: serverResponse.isBase64Encoded,
+      };
+    } else {
+      console.log('@rendering', preRenderHtml.replaceTemplate(htmlTemplate, renderResult.htmlString))
+      return {
+        body: preRenderHtml.replaceTemplate(htmlTemplate, renderResult.htmlString),
+        headers: {
+          "Content-Type": "text/html",
+          "x-powered-by": "elm-pages",
+          ...renderResult.headers,
+        },
+        statusCode,
+      };
+    }
+  } catch (error) {
+    console.error(error);
+    return {
+      body: \`<body><h1>Error</h1><pre>\${error.toString()}</pre></body>\`,
+      statusCode: 500,
+      headers: {
+        "Content-Type": "text/html",
+        "x-powered-by": "elm-pages",
+      },
+    };
+  }
+}
+
+/**
+ * @param {import('aws-lambda').APIGatewayProxyEvent} req
+ * @param {Date} requestTime
+ * @returns {Promise<{ method: string; hostname: string; query: Record<string, string | undefined>; headers: Record<string, string>; host: string; pathname: string; port: number | null; protocol: string; rawUrl: string; }>}
+ */
+function reqToJson(req, requestTime) {
+  return new Promise((resolve, reject) => {
+    if (
+      req.httpMethod && req.httpMethod.toUpperCase() === "POST" &&
+      req.headers["content-type"] &&
+      req.headers["content-type"].includes("multipart/form-data") &&
+      req.body
+    ) {
+      try {
+        console.log('@@@1');
+        const bb = busboy({
+          headers: req.headers,
+        });
+        let fields = {};
+
+        bb.on("file", (fieldname, file, info) => {
+          console.log('@@@2');
+          const { filename, encoding, mimeType } = info;
+
+          file.on("data", (data) => {
+            fields[fieldname] = {
+              filename,
+              mimeType,
+              body: data.toString(),
+            };
+          });
+        });
+
+        bb.on("field", (fieldName, value) => {
+          console.log("@@@field", fieldName, value);
+          fields[fieldName] = value;
+        });
+
+        // TODO skip parsing JSON and form data body if busboy doesn't run
+        bb.on("close", () => {
+          console.log('@@@3');
+          console.log("@@@close", fields);
+          resolve(toJsonHelper(req, requestTime, fields));
+        });
+        console.log('@@@4');
+        
+        if (req.isBase64Encoded) {
+          bb.write(Buffer.from(req.body, 'base64').toString('utf8'));
+        } else {
+          bb.write(req.body);
+        }
+      } catch (error) {
+        console.error('@@@5', error);
+        resolve(toJsonHelper(req, requestTime, null));
+      }
+    } else {
+      console.log('@@@6');
+      resolve(toJsonHelper(req, requestTime, null));
+    }
+  });
+}
+
+/**
+ * @param {import('aws-lambda').APIGatewayProxyEvent} req
+ * @param {Date} requestTime
+ * @returns {{method: string; rawUrl: string; body: string?; headers: Record<string, string>; requestTime: number; multiPartFormData: unknown }}
+ */
+function toJsonHelper(req, requestTime, multiPartFormData) {
+  return {
+    method: req.httpMethod,
+    headers: req.headers,
+    rawUrl: req.rawUrl,
+    body: req.body,
+    requestTime: Math.round(requestTime.getTime()),
+    multiPartFormData: multiPartFormData,
+  };
+}
+`;
+}
+
+/**
+ * @param {fs.PathLike} dirpath
+ */
+function ensureDirSync(dirpath) {
+  try {
+    fs.mkdirSync(dirpath, { recursive: true });
+  } catch (err) {
+    if (err.code !== "EEXIST") throw err;
+  }
+}
+
+/** @typedef {{kind: 'dynamic'} | {kind: 'literal', value: string}} ApiSegment */
+
+/**
+ * @param {ApiSegment[]} pathPattern
+ */
+function apiPatternToRedirectPattern(pathPattern) {
+  return (
+    "/" +
+    pathPattern
+      .map((segment, index) => {
+        switch (segment.kind) {
+          case "literal": {
+            return segment.value;
+          }
+          case "dynamic": {
+            return `:dynamic${index}`;
+          }
+          default: {
+            throw "Unhandled segment: " + JSON.stringify(segment);
+          }
+        }
+      })
+      .join("/")
+  );
+}
--- a/examples/trails/app/Api.elm
+++ b/examples/trails/app/Api.elm
@ -0,0 +1,262 @@
+module Api exposing (routes)
+
+import ApiRoute exposing (ApiRoute)
+import DataSource exposing (DataSource)
+import DataSource.Http
+import Html exposing (Html)
+import Json.Decode
+import Json.Encode
+import MySession
+import Pages.Manifest as Manifest
+import Route exposing (Route)
+import Server.Request
+import Server.Response
+import Server.Session as Session
+import Site
+
+
+routes :
+    DataSource (List Route)
+    -> (Html Never -> String)
+    -> List (ApiRoute.ApiRoute ApiRoute.Response)
+routes getStaticRoutes htmlToString =
+    [ --nonHybridRoute
+      --, noArgs
+      redirectRoute
+
+    --, repoStars
+    --, repoStars2
+    , logout
+    , greet
+    , fileLength
+    , DataSource.succeed manifest |> Manifest.generator Site.canonicalUrl
+    ]
+
+
+greet : ApiRoute ApiRoute.Response
+greet =
+    ApiRoute.succeed
+        (Server.Request.oneOf
+            [ Server.Request.expectFormPost
+                (\{ field, optionalField } ->
+                    field "first"
+                )
+            , Server.Request.expectJsonBody (Json.Decode.field "first" Json.Decode.string)
+            , Server.Request.expectQueryParam "first"
+            , Server.Request.expectMultiPartFormPost
+                (\{ field, optionalField } ->
+                    field "first"
+                )
+            ]
+            |> Server.Request.map
+                (\firstName ->
+                    Server.Response.plainText ("Hello " ++ firstName)
+                        |> DataSource.succeed
+                )
+        )
+        |> ApiRoute.literal "api"
+        |> ApiRoute.slash
+        |> ApiRoute.literal "greet"
+        |> ApiRoute.serverRender
+
+
+fileLength : ApiRoute ApiRoute.Response
+fileLength =
+    ApiRoute.succeed
+        (Server.Request.expectMultiPartFormPost
+            (\{ field, optionalField, fileField } ->
+                fileField "file"
+            )
+            |> Server.Request.map
+                (\file ->
+                    Server.Response.json
+                        (Json.Encode.object
+                            [ ( "File name: ", Json.Encode.string file.name )
+                            , ( "Length", Json.Encode.int (String.length file.body) )
+                            , ( "mime-type", Json.Encode.string file.mimeType )
+                            , ( "First line"
+                              , Json.Encode.string
+                                    (file.body
+                                        |> String.split "\n"
+                                        |> List.head
+                                        |> Maybe.withDefault ""
+                                    )
+                              )
+                            ]
+                        )
+                        |> DataSource.succeed
+                )
+        )
+        |> ApiRoute.literal "api"
+        |> ApiRoute.slash
+        |> ApiRoute.literal "file"
+        |> ApiRoute.serverRender
+
+
+redirectRoute : ApiRoute ApiRoute.Response
+redirectRoute =
+    ApiRoute.succeed
+        (Server.Request.succeed
+            (DataSource.succeed
+                (Route.redirectTo Route.Index)
+            )
+        )
+        |> ApiRoute.literal "api"
+        |> ApiRoute.slash
+        |> ApiRoute.literal "redirect"
+        |> ApiRoute.serverRender
+
+
+noArgs : ApiRoute ApiRoute.Response
+noArgs =
+    ApiRoute.succeed
+        (Server.Request.succeed
+            (DataSource.Http.get
+                "https://api.github.com/repos/dillonkearns/elm-pages"
+                (Json.Decode.field "stargazers_count" Json.Decode.int)
+                |> DataSource.map
+                    (\stars ->
+                        Json.Encode.object
+                            [ ( "repo", Json.Encode.string "elm-pages" )
+                            , ( "stars", Json.Encode.int stars )
+                            ]
+                            |> Server.Response.json
+                    )
+            )
+        )
+        |> ApiRoute.literal "api"
+        |> ApiRoute.slash
+        |> ApiRoute.literal "stars"
+        |> ApiRoute.serverRender
+
+
+nonHybridRoute =
+    ApiRoute.succeed
+        (\repoName ->
+            DataSource.Http.get
+                ("https://api.github.com/repos/dillonkearns/" ++ repoName)
+                (Json.Decode.field "stargazers_count" Json.Decode.int)
+                |> DataSource.map
+                    (\stars ->
+                        Json.Encode.object
+                            [ ( "repo", Json.Encode.string repoName )
+                            , ( "stars", Json.Encode.int stars )
+                            ]
+                            |> Json.Encode.encode 2
+                    )
+        )
+        |> ApiRoute.literal "repo"
+        |> ApiRoute.slash
+        |> ApiRoute.capture
+        |> ApiRoute.preRender
+            (\route ->
+                DataSource.succeed
+                    [ route "elm-graphql"
+                    ]
+            )
+
+
+logout : ApiRoute ApiRoute.Response
+logout =
+    ApiRoute.succeed
+        (MySession.withSession
+            (Server.Request.succeed ())
+            (\() sessionResult ->
+                DataSource.succeed
+                    ( Session.empty
+                    , Route.redirectTo Route.Login
+                    )
+            )
+        )
+        |> ApiRoute.literal "api"
+        |> ApiRoute.slash
+        |> ApiRoute.literal "logout"
+        |> ApiRoute.serverRender
+
+
+repoStars : ApiRoute ApiRoute.Response
+repoStars =
+    ApiRoute.succeed
+        (\repoName ->
+            Server.Request.succeed
+                (DataSource.Http.get
+                    ("https://api.github.com/repos/dillonkearns/" ++ repoName)
+                    (Json.Decode.field "stargazers_count" Json.Decode.int)
+                    |> DataSource.map
+                        (\stars ->
+                            Json.Encode.object
+                                [ ( "repo", Json.Encode.string repoName )
+                                , ( "stars", Json.Encode.int stars )
+                                ]
+                                |> Server.Response.json
+                        )
+                )
+        )
+        |> ApiRoute.literal "api"
+        |> ApiRoute.slash
+        |> ApiRoute.literal "repo"
+        |> ApiRoute.slash
+        |> ApiRoute.capture
+        --|> ApiRoute.literal ".json"
+        |> ApiRoute.serverRender
+
+
+repoStars2 : ApiRoute ApiRoute.Response
+repoStars2 =
+    ApiRoute.succeed
+        (\repoName ->
+            DataSource.Http.get
+                ("https://api.github.com/repos/dillonkearns/" ++ repoName)
+                (Json.Decode.field "stargazers_count" Json.Decode.int)
+                |> DataSource.map
+                    (\stars ->
+                        Json.Encode.object
+                            [ ( "repo", Json.Encode.string repoName )
+                            , ( "stars", Json.Encode.int stars )
+                            ]
+                            |> Server.Response.json
+                    )
+        )
+        |> ApiRoute.literal "api2"
+        |> ApiRoute.slash
+        |> ApiRoute.literal "repo"
+        |> ApiRoute.slash
+        |> ApiRoute.capture
+        |> ApiRoute.preRenderWithFallback
+            (\route ->
+                DataSource.succeed
+                    [ route "elm-graphql"
+                    , route "elm-pages"
+                    ]
+            )
+
+
+route1 =
+    ApiRoute.succeed
+        (\repoName ->
+            DataSource.Http.get
+                ("https://api.github.com/repos/dillonkearns/" ++ repoName)
+                (Json.Decode.field "stargazers_count" Json.Decode.int)
+                |> DataSource.map
+                    (\stars ->
+                        Json.Encode.object
+                            [ ( "repo", Json.Encode.string repoName )
+                            , ( "stars", Json.Encode.int stars )
+                            ]
+                            |> Json.Encode.encode 2
+                    )
+        )
+        |> ApiRoute.literal "repo"
+        |> ApiRoute.slash
+        |> ApiRoute.capture
+        |> ApiRoute.literal ".json"
+
+
+manifest : Manifest.Config
+manifest =
+    Manifest.init
+        { name = "Site Name"
+        , description = "Description"
+        , startUrl = Route.Index |> Route.toPath
+        , icons = []
+        }
--- a/examples/trails/app/Effect.elm
+++ b/examples/trails/app/Effect.elm
@ -0,0 +1,147 @@
+module Effect exposing (Effect(..), batch, fromCmd, map, none, perform)
+
+import Browser.Navigation
+import Bytes exposing (Bytes)
+import Bytes.Decode
+import FormDecoder
+import Http
+import Json.Decode as Decode
+import Pages.Fetcher
+import Url exposing (Url)
+
+
+type Effect msg
+    = None
+    | Cmd (Cmd msg)
+    | Batch (List (Effect msg))
+    | GetStargazers (Result Http.Error Int -> msg)
+    | FetchRouteData
+        { body : Maybe { contentType : String, body : String }
+        , path : Maybe String
+        , toMsg : Result Http.Error Url -> msg
+        }
+    | Submit
+        { values : FormDecoder.FormData
+        , path : Maybe (List String)
+        , method : Maybe String
+        , toMsg : Result Http.Error Url -> msg
+        }
+    | SubmitFetcher (Pages.Fetcher.Fetcher msg)
+
+
+type alias RequestInfo =
+    { contentType : String
+    , body : String
+    }
+
+
+none : Effect msg
+none =
+    None
+
+
+batch : List (Effect msg) -> Effect msg
+batch =
+    Batch
+
+
+fromCmd : Cmd msg -> Effect msg
+fromCmd =
+    Cmd
+
+
+map : (a -> b) -> Effect a -> Effect b
+map fn effect =
+    case effect of
+        None ->
+            None
+
+        Cmd cmd ->
+            Cmd (Cmd.map fn cmd)
+
+        Batch list ->
+            Batch (List.map (map fn) list)
+
+        GetStargazers toMsg ->
+            GetStargazers (toMsg >> fn)
+
+        FetchRouteData fetchInfo ->
+            FetchRouteData
+                { body = fetchInfo.body
+                , path = fetchInfo.path
+                , toMsg = fetchInfo.toMsg >> fn
+                }
+
+        Submit fetchInfo ->
+            Submit
+                { values = fetchInfo.values
+                , path = fetchInfo.path
+                , method = fetchInfo.method
+                , toMsg = fetchInfo.toMsg >> fn
+                }
+
+        SubmitFetcher fetcher ->
+            fetcher
+                |> Pages.Fetcher.map fn
+                |> SubmitFetcher
+
+
+perform :
+    { fetchRouteData :
+        { body : Maybe { contentType : String, body : String }
+        , path : Maybe String
+        , toMsg : Result Http.Error Url -> pageMsg
+        }
+        -> Cmd msg
+    , submit :
+        { values : FormDecoder.FormData
+        , encType : Maybe String
+        , method : Maybe String
+        , path : Maybe String
+        , toMsg : Result Http.Error Url -> pageMsg
+        }
+        -> Cmd msg
+    , runFetcher :
+        Pages.Fetcher.Fetcher pageMsg
+        -> Cmd msg
+    , fromPageMsg : pageMsg -> msg
+    , key : Browser.Navigation.Key
+    }
+    -> Effect pageMsg
+    -> Cmd msg
+perform ({ fromPageMsg, key } as helpers) effect =
+    case effect of
+        None ->
+            Cmd.none
+
+        Cmd cmd ->
+            Cmd.map fromPageMsg cmd
+
+        Batch list ->
+            Cmd.batch (List.map (perform helpers) list)
+
+        GetStargazers toMsg ->
+            Http.get
+                { url =
+                    "https://api.github.com/repos/dillonkearns/elm-pages"
+                , expect = Http.expectJson (toMsg >> fromPageMsg) (Decode.field "stargazers_count" Decode.int)
+                }
+
+        FetchRouteData fetchInfo ->
+            helpers.fetchRouteData
+                { body = fetchInfo.body
+                , path = fetchInfo.path
+                , toMsg = fetchInfo.toMsg
+                }
+
+        Submit record ->
+            helpers.submit
+                { values = record.values
+                , path = Nothing --fetchInfo.path
+                , method = record.method
+                , encType = Nothing -- TODO
+                , toMsg = record.toMsg
+                }
+
+        SubmitFetcher record ->
+            helpers.runFetcher record
--- a/examples/trails/app/ErrorPage.elm
+++ b/examples/trails/app/ErrorPage.elm
@ -0,0 +1,74 @@
+module ErrorPage exposing (ErrorPage(..), Model, Msg, head, init, internalError, notFound, statusCode, update, view)
+
+import Effect exposing (Effect)
+import Head
+import Html exposing (Html)
+import Html.Events exposing (onClick)
+import View exposing (View)
+
+
+type Msg
+    = Increment
+
+
+type alias Model =
+    { count : Int
+    }
+
+
+init : ErrorPage -> ( Model, Effect Msg )
+init errorPage =
+    ( { count = 0 }
+    , Effect.none
+    )
+
+
+update : ErrorPage -> Msg -> Model -> ( Model, Effect Msg )
+update errorPage msg model =
+    case msg of
+        Increment ->
+            ( { model | count = model.count + 1 }, Effect.none )
+
+
+head : ErrorPage -> List Head.Tag
+head errorPage =
+    []
+
+
+type ErrorPage
+    = NotFound
+    | InternalError String
+
+
+notFound : ErrorPage
+notFound =
+    NotFound
+
+
+internalError : String -> ErrorPage
+internalError =
+    InternalError
+
+
+view : ErrorPage -> Model -> View Msg
+view error model =
+    case error of
+        _ ->
+            { body =
+                [ Html.div []
+                    [ Html.p [] [ Html.text "Looks like you've wandered off the trail. Try finding a new path." ]
+                    , Html.div [] []
+                    ]
+                ]
+            , title = "This is a NotFound Error"
+            }
+
+
+statusCode : ErrorPage -> number
+statusCode error =
+    case error of
+        NotFound ->
+            404
+
+        InternalError _ ->
+            500
--- a/examples/trails/app/Route/Index.elm
+++ b/examples/trails/app/Route/Index.elm
@ -0,0 +1,83 @@
+module Route.Index exposing (ActionData, Data, Model, Msg, route)
+
+import DataSource exposing (DataSource)
+import DataSource.Env as Env
+import DataSource.Http
+import Head
+import Head.Seo as Seo
+import Html exposing (..)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Encode
+import Pages.Msg
+import Pages.PageUrl exposing (PageUrl)
+import Pages.Url
+import Route
+import RouteBuilder exposing (StatelessRoute, StaticPayload)
+import Shared
+import View exposing (View)
+
+
+type alias Model =
+    {}
+
+
+type alias Msg =
+    ()
+
+
+type alias RouteParams =
+    {}
+
+
+route : StatelessRoute RouteParams Data ActionData
+route =
+    RouteBuilder.single
+        { head = head
+        , data = data
+        }
+        |> RouteBuilder.buildNoState { view = view }
+
+
+type alias Data =
+    {}
+
+
+type alias ActionData =
+    {}
+
+
+data : DataSource Data
+data =
+    DataSource.succeed {}
+
+
+head :
+    StaticPayload Data RouteParams ActionData
+    -> List Head.Tag
+head static =
+    Seo.summary
+        { canonicalUrlOverride = Nothing
+        , siteName = "elm-pages Pokedex"
+        , image =
+            { url = Pages.Url.external ""
+            , alt = "elm-pages logo"
+            , dimensions = Nothing
+            , mimeType = Nothing
+            }
+        , description = "This is a simple app to showcase server-rendering with elm-pages."
+        , locale = Nothing
+        , title = "Elm Pages Pokedex Example"
+        }
+        |> Seo.website
+
+
+view :
+    Maybe PageUrl
+    -> Shared.Model
+    -> StaticPayload Data RouteParams ActionData
+    -> View (Pages.Msg.Msg Msg)
+view maybeUrl sharedModel static =
+    { title = "Pokedex"
+    , body =
+        []
+    }
--- a/examples/trails/app/Route/Login.elm
+++ b/examples/trails/app/Route/Login.elm
@ -0,0 +1,147 @@
+module Route.Login exposing (ActionData, Data, Model, Msg, route)
+
+import DataSource exposing (DataSource)
+import Dict exposing (Dict)
+import ErrorPage exposing (ErrorPage)
+import Head
+import Head.Seo as Seo
+import Html
+import Html.Attributes as Attr
+import MySession
+import Pages.Msg
+import Pages.PageUrl exposing (PageUrl)
+import Pages.Url
+import Route
+import RouteBuilder exposing (StatefulRoute, StatelessRoute, StaticPayload)
+import Server.Request as Request
+import Server.Response exposing (Response)
+import Server.Session as Session
+import Shared
+import View exposing (View)
+
+
+type alias Model =
+    {}
+
+
+type alias Msg =
+    ()
+
+
+type alias RouteParams =
+    {}
+
+
+route : StatelessRoute RouteParams Data ActionData
+route =
+    RouteBuilder.serverRender
+        { head = head
+        , data = data
+        , action = \_ -> Request.skip "No action."
+        }
+        |> RouteBuilder.buildNoState { view = view }
+
+
+type alias Request =
+    { cookies : Dict String String
+    , maybeFormData : Maybe (Dict String ( String, List String ))
+    }
+
+
+data : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+data routeParams =
+    Request.oneOf
+        [ MySession.withSession
+            (Request.expectFormPost (\{ field } -> field "name"))
+            (\name session ->
+                ( session
+                    |> Result.withDefault Nothing
+                    |> Maybe.withDefault Session.empty
+                    |> Session.insert "name" name
+                    |> Session.withFlash "message" ("Welcome " ++ name ++ "!")
+                , Route.redirectTo Route.Index
+                )
+                    |> DataSource.succeed
+            )
+        , MySession.withSession
+            (Request.succeed ())
+            (\() session ->
+                case session of
+                    Ok (Just okSession) ->
+                        ( okSession
+                        , okSession
+                            |> Session.get "name"
+                            |> Data
+                            |> Server.Response.render
+                        )
+                            |> DataSource.succeed
+
+                    _ ->
+                        ( Session.empty
+                        , { username = Nothing }
+                            |> Server.Response.render
+                        )
+                            |> DataSource.succeed
+            )
+        ]
+
+
+head :
+    StaticPayload Data ActionData RouteParams
+    -> List Head.Tag
+head static =
+    Seo.summary
+        { canonicalUrlOverride = Nothing
+        , siteName = "elm-pages"
+        , image =
+            { url = Pages.Url.external "TODO"
+            , alt = "elm-pages logo"
+            , dimensions = Nothing
+            , mimeType = Nothing
+            }
+        , description = "TODO"
+        , locale = Nothing
+        , title = "TODO title" -- metadata.title -- TODO
+        }
+        |> Seo.website
+
+
+type alias Data =
+    { username : Maybe String
+    }
+
+
+type alias ActionData =
+    {}
+
+
+view :
+    Maybe PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> View (Pages.Msg.Msg Msg)
+view maybeUrl sharedModel static =
+    { title = "Login"
+    , body =
+        [ Html.p []
+            [ Html.text
+                (case static.data.username of
+                    Just username ->
+                        "Hello " ++ username ++ "!"
+
+                    Nothing ->
+                        "You aren't logged in yet."
+                )
+            ]
+        , Html.form
+            [ Attr.method "post"
+            , Attr.action "/login"
+            ]
+            [ Html.label [] [ Html.input [ Attr.name "name", Attr.type_ "text" ] [] ]
+            , Html.button
+                [ Attr.type_ "submit"
+                ]
+                [ Html.text "Login" ]
+            ]
+        ]
+    }
--- a/examples/trails/app/Route/Search.elm
+++ b/examples/trails/app/Route/Search.elm
@ -0,0 +1,166 @@
+module Route.Search exposing (ActionData, Data, Model, Msg, route)
+
+import DataSource exposing (DataSource)
+import Effect exposing (Effect)
+import ErrorPage exposing (ErrorPage)
+import Head
+import Head.Seo as Seo
+import Html exposing (Html)
+import Html.Attributes as Attr
+import Pages.Msg
+import Pages.PageUrl exposing (PageUrl)
+import Pages.Url
+import Path exposing (Path)
+import RouteBuilder exposing (StatefulRoute, StatelessRoute, StaticPayload)
+import Server.Request as Request
+import Server.Response as Response exposing (Response)
+import Shared
+import View exposing (View)
+
+
+type alias Model =
+    {}
+
+
+type Msg
+    = NoOp
+
+
+type alias RouteParams =
+    {}
+
+
+route : StatefulRoute RouteParams Data ActionData Model Msg
+route =
+    RouteBuilder.serverRender
+        { head = head
+        , data = data
+        , action = action
+        }
+        |> RouteBuilder.buildWithLocalState
+            { view = view
+            , update = update
+            , subscriptions = subscriptions
+            , init = init
+            }
+
+
+init :
+    Maybe PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> ( Model, Effect Msg )
+init maybePageUrl sharedModel static =
+    ( {}, Effect.none )
+
+
+update :
+    PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> Msg
+    -> Model
+    -> ( Model, Effect Msg )
+update pageUrl sharedModel static msg model =
+    case msg of
+        NoOp ->
+            ( model, Effect.none )
+
+
+subscriptions : Maybe PageUrl -> RouteParams -> Path -> Shared.Model -> Model -> Sub Msg
+subscriptions maybePageUrl routeParams path sharedModel model =
+    Sub.none
+
+
+type alias SearchResults =
+    { query : String
+    , results : List String
+    }
+
+
+type alias Data =
+    { results : Maybe SearchResults
+    }
+
+
+type alias ActionData =
+    {}
+
+
+data : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+data routeParams =
+    Request.oneOf
+        [ Request.expectForm
+            (\{ field, optionalField } ->
+                field "q"
+                    |> Request.map
+                        (\query ->
+                            DataSource.succeed
+                                (Response.render
+                                    { results =
+                                        Just
+                                            { query = query
+                                            , results = [ "Hello" ]
+                                            }
+                                    }
+                                )
+                        )
+            )
+        , Request.succeed (DataSource.succeed (Response.render { results = Nothing }))
+        ]
+
+
+action : RouteParams -> Request.Parser (DataSource (Response ActionData ErrorPage))
+action routeParams =
+    Request.skip "No action."
+
+
+head :
+    StaticPayload Data ActionData RouteParams
+    -> List Head.Tag
+head static =
+    Seo.summary
+        { canonicalUrlOverride = Nothing
+        , siteName = "elm-pages"
+        , image =
+            { url = Pages.Url.external "TODO"
+            , alt = "elm-pages logo"
+            , dimensions = Nothing
+            , mimeType = Nothing
+            }
+        , description = "TODO"
+        , locale = Nothing
+        , title = "TODO title" -- metadata.title -- TODO
+        }
+        |> Seo.website
+
+
+view :
+    Maybe PageUrl
+    -> Shared.Model
+    -> Model
+    -> StaticPayload Data ActionData RouteParams
+    -> View (Pages.Msg.Msg Msg)
+view maybeUrl sharedModel model static =
+    { title = "Search"
+    , body =
+        [ Html.h2 [] [ Html.text "Search" ]
+        , Html.form []
+            [ Html.label []
+                [ Html.text "Query "
+                , Html.input [ Attr.name "q" ] []
+                ]
+            , Html.input [ Attr.type_ "submit", Attr.value "Search" ] []
+            ]
+        , static.data.results
+            |> Maybe.map resultsView
+            |> Maybe.withDefault (Html.div [] [])
+        ]
+    }
+
+
+resultsView : SearchResults -> Html msg
+resultsView results =
+    Html.div []
+        [ Html.h2 [] [ Html.text <| "Results matching " ++ results.query ]
+        ]
--- a/examples/trails/app/Route/Signup.elm
+++ b/examples/trails/app/Route/Signup.elm
@ -0,0 +1,226 @@
+module Route.Signup exposing (ActionData, Data, Model, Msg, route)
+
+import DataSource exposing (DataSource)
+import Dict
+import Effect exposing (Effect)
+import ErrorPage exposing (ErrorPage)
+import Head
+import Head.Seo as Seo
+import Html exposing (Html)
+import Html.Attributes as Attr
+import Http
+import MySession
+import Pages.Msg
+import Pages.PageUrl exposing (PageUrl)
+import Pages.Url
+import Path exposing (Path)
+import Route
+import RouteBuilder exposing (StatefulRoute, StatelessRoute, StaticPayload)
+import Server.Request as Request
+import Server.Response as Response exposing (Response)
+import Server.Session as Session exposing (Session)
+import Shared
+import View exposing (View)
+
+
+type alias Model =
+    {}
+
+
+type Msg
+    = NoOp
+    | GotResponse (Result Http.Error ActionData)
+
+
+type alias RouteParams =
+    {}
+
+
+route : StatefulRoute RouteParams Data ActionData Model Msg
+route =
+    RouteBuilder.serverRender
+        { head = head
+        , data = data
+        , action = action
+        }
+        |> RouteBuilder.buildWithLocalState
+            { view = view
+            , update = update
+            , subscriptions = subscriptions
+            , init = init
+            }
+
+
+action : RouteParams -> Request.Parser (DataSource (Response ActionData ErrorPage))
+action _ =
+    MySession.withSession
+        (Request.expectFormPost
+            (\{ field } ->
+                Request.map2 Tuple.pair
+                    (field "first")
+                    (field "email")
+            )
+        )
+        (\( first, email ) maybeSession ->
+            let
+                session : Session
+                session =
+                    maybeSession |> Result.toMaybe |> Maybe.andThen identity |> Maybe.withDefault Session.empty
+            in
+            validate session
+                { email = email
+                , first = first
+                }
+                |> DataSource.succeed
+        )
+
+
+validate : Session -> { first : String, email : String } -> ( Session, Response ActionData ErrorPage )
+validate session { first, email } =
+    if first /= "" && email /= "" then
+        ( session
+            |> Session.withFlash "message" ("Success! You're all signed up " ++ first)
+        , Route.redirectTo Route.Signup
+        )
+
+    else
+        ( session
+        , ValidationErrors
+            { errors = [ "Cannot be blank?" ]
+            , fields =
+                [ ( "first", first )
+                , ( "email", email )
+                ]
+            }
+            |> Response.render
+        )
+
+
+init :
+    Maybe PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> ( Model, Effect Msg )
+init maybePageUrl sharedModel static =
+    ( {}
+    , Effect.none
+    )
+
+
+update :
+    PageUrl
+    -> Shared.Model
+    -> StaticPayload Data ActionData RouteParams
+    -> Msg
+    -> Model
+    -> ( Model, Effect Msg )
+update pageUrl sharedModel static msg model =
+    case msg of
+        NoOp ->
+            ( model, Effect.none )
+
+        GotResponse result ->
+            let
+                _ =
+                    Debug.log "GotResponse" result
+            in
+            ( model, Effect.none )
+
+
+subscriptions : Maybe PageUrl -> RouteParams -> Path -> Shared.Model -> Model -> Sub Msg
+subscriptions maybePageUrl routeParams path sharedModel model =
+    Sub.none
+
+
+type alias Data =
+    { flashMessage : Maybe (Result String String)
+    }
+
+
+type ActionData
+    = Success { email : String, first : String }
+    | ValidationErrors
+        { errors : List String
+        , fields : List ( String, String )
+        }
+
+
+data : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+data routeParams =
+    MySession.withSession
+        (Request.succeed ())
+        (\() sessionResult ->
+            let
+                session : Session
+                session =
+                    sessionResult |> Result.toMaybe |> Maybe.andThen identity |> Maybe.withDefault Session.empty
+
+                flashMessage : Maybe String
+                flashMessage =
+                    session |> Session.get "message"
+            in
+            ( Session.empty
+            , Response.render
+                { flashMessage = flashMessage |> Maybe.map Ok }
+            )
+                |> DataSource.succeed
+        )
+
+
+head :
+    StaticPayload Data ActionData RouteParams
+    -> List Head.Tag
+head static =
+    []
+
+
+view :
+    Maybe PageUrl
+    -> Shared.Model
+    -> Model
+    -> StaticPayload Data ActionData RouteParams
+    -> View (Pages.Msg.Msg Msg)
+view maybeUrl sharedModel model static =
+    { title = "Signup"
+    , body =
+        [ Html.p []
+            [ case static.action of
+                Just (Success { email, first }) ->
+                    Html.text <| "Hello " ++ first ++ "!"
+
+                Just (ValidationErrors { errors }) ->
+                    errors
+                        |> List.map (\error -> Html.li [] [ Html.text error ])
+                        |> Html.ul []
+
+                _ ->
+                    Html.text ""
+            ]
+        , flashView static.data.flashMessage
+        , Html.form
+            [ Attr.method "POST"
+            ]
+            [ Html.label [] [ Html.text "First", Html.input [ Attr.name "first" ] [] ]
+            , Html.label [] [ Html.text "Email", Html.input [ Attr.name "email" ] [] ]
+            , Html.input [ Attr.type_ "submit", Attr.value "Signup" ] []
+            ]
+        ]
+    }
+
+
+flashView : Maybe (Result String String) -> Html msg
+flashView message =
+    Html.p
+        [ Attr.style "background-color" "rgb(163 251 163)"
+        ]
+        [ Html.text <|
+            case message of
+                Nothing ->
+                    ""
+
+                Just (Ok okMessage) ->
+                    okMessage
+
+                Just (Err error) ->
+                    "Something went wrong: " ++ error
+        ]
--- a/examples/trails/app/Shared.elm
+++ b/examples/trails/app/Shared.elm
@ -0,0 +1,116 @@
+module Shared exposing (Data, Model, Msg(..), SharedMsg(..), template)
+
+import DataSource
+import Effect exposing (Effect)
+import Html exposing (Html)
+import Html.Attributes as Attr
+import Pages.Flags
+import Pages.PageUrl exposing (PageUrl)
+import Path exposing (Path)
+import Route exposing (Route)
+import SharedTemplate exposing (SharedTemplate)
+import View exposing (View)
+
+
+template : SharedTemplate Msg Model Data msg
+template =
+    { init = init
+    , update = update
+    , view = view
+    , data = data
+    , subscriptions = subscriptions
+    , onPageChange = Just OnPageChange
+    }
+
+
+type Msg
+    = OnPageChange
+        { path : Path
+        , query : Maybe String
+        , fragment : Maybe String
+        }
+    | SharedMsg SharedMsg
+
+
+type alias Data =
+    ()
+
+
+type SharedMsg
+    = NoOp
+
+
+type alias Model =
+    { showMobileMenu : Bool
+    }
+
+
+init :
+    Pages.Flags.Flags
+    ->
+        Maybe
+            { path :
+                { path : Path
+                , query : Maybe String
+                , fragment : Maybe String
+                }
+            , metadata : route
+            , pageUrl : Maybe PageUrl
+            }
+    -> ( Model, Effect Msg )
+init flags maybePagePath =
+    ( { showMobileMenu = False }
+    , Effect.none
+    )
+
+
+update : Msg -> Model -> ( Model, Effect Msg )
+update msg model =
+    case msg of
+        OnPageChange _ ->
+            ( { model | showMobileMenu = False }, Effect.none )
+
+        SharedMsg globalMsg ->
+            ( model, Effect.none )
+
+
+subscriptions : Path -> Model -> Sub Msg
+subscriptions _ _ =
+    Sub.none
+
+
+data : DataSource.DataSource Data
+data =
+    DataSource.succeed ()
+
+
+view :
+    Data
+    ->
+        { path : Path
+        , route : Maybe Route
+        }
+    -> Model
+    -> (Msg -> msg)
+    -> View msg
+    -> { body : Html msg, title : String }
+view sharedData page model toMsg pageView =
+    { body =
+        Html.div
+            []
+            [ Html.nav
+                [ Attr.style "display" "flex"
+                , Attr.style "justify-content" "space-evenly"
+                ]
+                [ Route.Index
+                    |> Route.link
+                        []
+                        [ Html.text "Home" ]
+                ]
+            , Html.div
+                [ Attr.style "padding" "40px"
+                ]
+                pageView.body
+            ]
+    , title = pageView.title
+    }
--- a/examples/trails/app/Site.elm
+++ b/examples/trails/app/Site.elm
@ -0,0 +1,46 @@
+module Site exposing (canonicalUrl, config)
+
+import DataSource exposing (DataSource)
+import Head
+import Route exposing (Route)
+import SiteConfig exposing (SiteConfig)
+import Sitemap
+
+
+type alias Data =
+    ()
+
+
+config : SiteConfig
+config =
+    { canonicalUrl = canonicalUrl
+    , head = head
+    }
+
+
+canonicalUrl : String
+canonicalUrl =
+    "https://elm-pages.com"
+
+
+head : DataSource (List Head.Tag)
+head =
+    [ Head.sitemapLink "/sitemap.xml"
+    ]
+        |> DataSource.succeed
+
+
+siteMap :
+    List (Maybe Route)
+    -> { path : List String, content : String }
+siteMap allRoutes =
+    allRoutes
+        |> List.filterMap identity
+        |> List.map
+            (\route ->
+                { path = Route.routeToPath route |> String.join "/"
+                , lastMod = Nothing
+                }
+            )
+        |> Sitemap.build { siteUrl = "https://elm-pages.com" }
+        |> (\sitemapXmlString -> { path = [ "sitemap.xml" ], content = sitemapXmlString })
--- a/examples/trails/app/View.elm
+++ b/examples/trails/app/View.elm
@ -0,0 +1,23 @@
+module View exposing (View, map, placeholder)
+
+import Html exposing (Html)
+
+
+type alias View msg =
+    { title : String
+    , body : List (Html msg)
+    }
+
+
+map : (msg1 -> msg2) -> View msg1 -> View msg2
+map fn doc =
+    { title = doc.title
+    , body = List.map (Html.map fn) doc.body
+    }
+
+
+placeholder : String -> View msg
+placeholder moduleName =
+    { title = "Placeholder - " ++ moduleName
+    , body = [ Html.text moduleName ]
+    }
--- a/examples/trails/elm-application.json
+++ b/examples/trails/elm-application.json
@ -0,0 +1,8 @@
+{
+    "name": "dmy/elm-doc-preview",
+    "summary": "Offline documentation previewer",
+    "version": "5.0.0",
+    "exposed-modules": [
+        "Page"
+    ]
+}
--- a/examples/trails/elm-pages.config.mjs
+++ b/examples/trails/elm-pages.config.mjs
@ -0,0 +1,8 @@
+import { defineConfig } from "vite";
+
+import adapter from "./adapter.mjs";
+
+export default {
+  vite: defineConfig({}),
+  adapter,
+};
--- a/examples/trails/elm-tooling.json
+++ b/examples/trails/elm-tooling.json
@ -0,0 +1,8 @@
+{
+    "tools": {
+        "elm": "0.19.1",
+        "elm-format": "0.8.4",
+        "elm-json": "0.2.10",
+        "elm-test-rs": "1.0.0"
+    }
+}
--- a/examples/trails/elm.json
+++ b/examples/trails/elm.json
@ -0,0 +1,66 @@
+{
+    "type": "application",
+    "source-directories": [
+        "src",
+        "app",
+        "../../src",
+        ".elm-pages",
+        "../../plugins",
+        "gen"
+    ],
+    "elm-version": "0.19.1",
+    "dependencies": {
+        "direct": {
+            "MartinSStewart/elm-serialize": "1.2.5",
+            "avh4/elm-color": "1.0.0",
+            "danfishgold/base64-bytes": "1.1.0",
+            "danyx23/elm-mimetype": "4.0.1",
+            "dillonkearns/elm-bcp47-language-tag": "1.0.1",
+            "dillonkearns/elm-graphql": "5.0.9",
+            "dillonkearns/elm-markdown": "6.0.1",
+            "dillonkearns/elm-sitemap": "1.0.1",
+            "elm/browser": "1.0.2",
+            "elm/bytes": "1.0.8",
+            "elm/core": "1.0.5",
+            "elm/html": "1.0.0",
+            "elm/http": "2.0.0",
+            "elm/json": "1.1.3",
+            "elm/parser": "1.1.0",
+            "elm/regex": "1.0.0",
+            "elm/time": "1.0.0",
+            "elm/url": "1.0.0",
+            "elm/virtual-dom": "1.0.2",
+            "elm-community/dict-extra": "2.4.0",
+            "elm-community/list-extra": "8.3.0",
+            "jluckyiv/elm-utc-date-strings": "1.0.0",
+            "justinmimbs/date": "4.0.0",
+            "lamdera/codecs": "1.0.0",
+            "lamdera/core": "1.0.0",
+            "miniBill/elm-codec": "1.2.0",
+            "noahzgordon/elm-color-extra": "1.0.2",
+            "pablohirafuji/elm-syntax-highlight": "3.4.0",
+            "robinheghan/fnv1a": "1.0.0",
+            "robinheghan/murmur3": "1.0.0",
+            "rtfeldman/elm-css": "16.1.1",
+            "tripokey/elm-fuzzy": "5.2.1",
+            "turboMaCk/non-empty-list-alias": "1.2.0",
+            "vito/elm-ansi": "10.0.1",
+            "zwilias/json-decode-exploration": "6.0.0"
+        },
+        "indirect": {
+            "bburdette/toop": "1.0.1",
+            "billstclair/elm-xml-eeue56": "1.0.3",
+            "elm/file": "1.0.5",
+            "elm/random": "1.0.0",
+            "fredcy/elm-parseint": "2.0.1",
+            "j-maas/elm-ordered-containers": "1.0.0",
+            "lukewestby/elm-string-interpolate": "1.0.4",
+            "mgold/elm-nonempty-list": "4.2.0",
+            "rtfeldman/elm-hex": "1.0.0"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}
--- a/examples/trails/functions/time.js
+++ b/examples/trails/functions/time.js
@ -0,0 +1,14 @@
+exports.handler =
+  /**
+   * @param {import('aws-lambda').APIGatewayProxyEvent} event
+   * @param {any} context
+   */
+  async function (event, context) {
+    return {
+      body: JSON.stringify(new Date().toTimeString()),
+      headers: {
+        "Content-Type": "application/json",
+      },
+      statusCode: 200,
+    };
+  };
--- a/examples/trails/index.js
+++ b/examples/trails/index.js
@ -0,0 +1,6 @@
+export default {
+  load: function (elmLoaded) {},
+  flags: function () {
+    return null;
+  },
+};
--- a/examples/trails/netlify.toml
+++ b/examples/trails/netlify.toml
@ -0,0 +1,13 @@
+[build]
+  functions = "functions/"
+  publish = "dist/"
+  command = "mkdir bin && export PATH=\"/opt/build/repo/examples/pokedex/bin:$PATH\" && echo $PATH && curl https://static.lamdera.com/bin/linux/lamdera -o bin/lamdera && chmod a+x bin/lamdera && export ELM_HOME=\"$NETLIFY_BUILD_BASE/cache/elm\" && (cd ../../ && npm install --no-optional && npx --no-install elm-tooling install) && npm install && npm run generate:tailwind && npm run generate:graphql && npm run build && cp secret-note.txt functions/server-render/"
+
+[dev]
+  command = "npm start"
+  targetPort = 1234
+  autoLaunch = true
+  framework = "#custom"
+
+[functions]
+  included_files = ["content/**"]
--- a/examples/trails/package-lock.json
+++ b/examples/trails/package-lock.json
--- a/examples/trails/package.json
+++ b/examples/trails/package.json
@ -0,0 +1,26 @@
+{
+  "name": "elm-pages-example",
+  "version": "1.0.0",
+  "description": "Example site built with elm-pages.",
+  "scripts": {
+    "start": "elm-pages dev",
+    "serve": "npm run build && http-server ./dist -a localhost -p 3000 -c-1",
+    "build": "elm-pages build --debug --keep-cache",
+    "generate:tailwind": "elm-tailwind-modules --dir ./gen --tailwind-config tailwind.config.js",
+    "generate:graphql": "elm-graphql https://striking-mutt-82.hasura.app/v1/graphql --header 'x-hasura-admin-secret: $TRAILS_HASURA_SECRET' --output gen"
+  },
+  "author": "Dillon Kearns",
+  "license": "BSD-3",
+  "devDependencies": {
+    "@dillonkearns/elm-graphql": "^4.2.3",
+    "@netlify/functions": "^0.7.2",
+    "@tailwindcss/forms": "^0.3.4",
+    "busboy": "^1.1.0",
+    "elm-pages": "file:../..",
+    "elm-review": "^2.7.0",
+    "elm-tailwind-modules": "^0.3.2",
+    "elm-tooling": "^1.3.0",
+    "postcss": "^8.4.5",
+    "tailwindcss": "^2.2.19"
+  }
+}
--- a/examples/trails/port-data-source.ts
+++ b/examples/trails/port-data-source.ts
@ -0,0 +1,23 @@
+import kleur from "kleur";
+kleur.enabled = true;
+
+export async function environmentVariable(name) {
+  const result = process.env[name];
+  if (result) {
+    return result;
+  } else {
+    throw `No environment variable called ${kleur
+      .yellow()
+      .underline(name)}\n\nAvailable:\n\n${Object.keys(process.env)
+      .slice(0, 5)
+      .join("\n")}`;
+  }
+}
+
+export async function hello(name) {
+  return `147 ${name}!!`;
+}
+
+function waitFor(ms) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
--- a/examples/trails/public/favicon.ico
+++ b/examples/trails/public/favicon.ico
--- a/examples/trails/public/images/elm-logo.svg
+++ b/examples/trails/public/images/elm-logo.svg
@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Generator: Adobe Illustrator 17.1.0, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
+   viewBox="0 0 323.141 322.95" enable-background="new 0 0 323.141 322.95" xml:space="preserve">
+<g>
+  <polygon
+    fill="#F0AD00"
+    points="161.649,152.782 231.514,82.916 91.783,82.916"/>
+
+  <polygon
+    fill="#7FD13B"
+    points="8.867,0 79.241,70.375 232.213,70.375 161.838,0"/>
+
+  <rect
+    fill="#7FD13B"
+    x="192.99"
+    y="107.392"
+    transform="matrix(0.7071 0.7071 -0.7071 0.7071 186.4727 -127.2386)"
+    width="107.676"
+    height="108.167"/>
+
+  <polygon
+    fill="#60B5CC"
+    points="323.298,143.724 323.298,0 179.573,0"/>
+
+  <polygon
+    fill="#5A6378"
+    points="152.781,161.649 0,8.868 0,314.432"/>
+
+  <polygon
+    fill="#F0AD00"
+    points="255.522,246.655 323.298,314.432 323.298,178.879"/>
+
+  <polygon
+    fill="#60B5CC"
+    points="161.649,170.517 8.869,323.298 314.43,323.298"/>
+</g>
+</svg>
--- a/examples/trails/public/images/github.svg
+++ b/examples/trails/public/images/github.svg
@ -0,0 +1 @@
+<svg role="img" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><title>GitHub icon</title><path d="M12 .297c-6.63 0-12 5.373-12 12 0 5.303 3.438 9.8 8.205 11.385.6.113.82-.258.82-.577 0-.285-.01-1.04-.015-2.04-3.338.724-4.042-1.61-4.042-1.61C4.422 18.07 3.633 17.7 3.633 17.7c-1.087-.744.084-.729.084-.729 1.205.084 1.838 1.236 1.838 1.236 1.07 1.835 2.809 1.305 3.495.998.108-.776.417-1.305.76-1.605-2.665-.3-5.466-1.332-5.466-5.93 0-1.31.465-2.38 1.235-3.22-.135-.303-.54-1.523.105-3.176 0 0 1.005-.322 3.3 1.23.96-.267 1.98-.399 3-.405 1.02.006 2.04.138 3 .405 2.28-1.552 3.285-1.23 3.285-1.23.645 1.653.24 2.873.12 3.176.765.84 1.23 1.91 1.23 3.22 0 4.61-2.805 5.625-5.475 5.92.42.36.81 1.096.81 2.22 0 1.606-.015 2.896-.015 3.286 0 .315.21.69.825.57C20.565 22.092 24 17.592 24 12.297c0-6.627-5.373-12-12-12"/></svg>
--- a/examples/trails/public/images/icon-png.png
+++ b/examples/trails/public/images/icon-png.png
--- a/examples/trails/public/images/icon.svg
+++ b/examples/trails/public/images/icon.svg
@ -0,0 +1,2 @@
+<svg version="1.1" viewBox="251.0485 144.52063 56.114286 74.5" width="50px" height="74.5"><defs><linearGradient id="grad1" x1="0%" y1="0%" x2="100%" y2="0%"><stop offset="10%" style="stop-color:rgba(1.96%,45.88%,90.2%,1);stop-opacity:1"></stop><stop offset="100%" style="stop-color:rgba(0%,94.9%,37.65%,1);stop-opacity:1"></stop></linearGradient></defs><metadata></metadata><g id="Canvas_11" stroke="none" fill="url(#grad1)" stroke-opacity="1" fill-opacity="1" stroke-dasharray="none"><g id="Canvas_11: Layer 1"><g id="Group_38"><g id="Graphic_32"><path d="M 252.5485 146.02063 L 252.5485 217.52063 L 305.66277 217.52063 L 305.66277 161.68254 L 290.00087 146.02063 Z" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="3"></path></g><g id="Line_34"><line x1="266.07286" y1="182.8279" x2="290.75465" y2="183.00997" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"></line></g><g id="Line_35"><line x1="266.07286" y1="191.84156" x2="290.75465" y2="192.02363" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"></line></g><g id="Line_36"><line x1="266.07286" y1="200.85522" x2="290.75465" y2="201.0373" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"></line></g><g id="Line_37"><line x1="266.07286" y1="164.80058" x2="278.3874" y2="164.94049" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"></line></g></g></g></g></svg>
+
--- a/examples/trails/public/syntax.css
+++ b/examples/trails/public/syntax.css
@ -0,0 +1,43 @@
+pre.elmsh {
+  padding: 10px;
+  margin: 0;
+  text-align: left;
+  overflow: auto;
+  padding: 20px !important;
+}
+
+code.elmsh {
+  padding: 0;
+}
+
+code {
+  font-family: 'Roboto Mono' !important;
+  font-size: 20px !important;
+  line-height: 28px;
+}
+
+.elmsh-line:before {
+  /* content: attr(data-elmsh-lc); */
+  display: inline-block;
+  text-align: right;
+  width: 40px;
+  padding: 0 20px 0 0;
+  opacity: 0.3;
+}
+
+.elmsh {
+    color: #f8f8f2;
+    background: #000;
+}
+.elmsh-hl {background: #343434;}
+.elmsh-add {background: #003800;}
+.elmsh-del {background: #380000;}
+.elmsh-comm {color: #75715e;}
+.elmsh1 {color: #ae81ff;}
+.elmsh2 {color: #e6db74;}
+.elmsh3 {color: #66d9ef;}
+.elmsh4 {color: #f92672;}
+.elmsh5 {color: #a6e22e;}
+.elmsh6 {color: #ae81ff;}
+.elmsh7 {color: #fd971f;}
+
--- a/examples/trails/src/Icon.elm
+++ b/examples/trails/src/Icon.elm
@ -0,0 +1,65 @@
+module Icon exposing (error, icon2, icon3)
+
+import Html.Styled exposing (Html)
+import Svg.Styled exposing (path, svg)
+import Svg.Styled.Attributes as SvgAttr
+import Tailwind.Utilities as Tw
+
+
+error : Html msg
+error =
+    svg
+        [ SvgAttr.css
+            [ Tw.h_5
+            , Tw.w_5
+            , Tw.text_red_500
+            ]
+        , SvgAttr.viewBox "0 0 20 20"
+        , SvgAttr.fill "currentColor"
+        ]
+        [ path
+            [ SvgAttr.fillRule "evenodd"
+            , SvgAttr.d "M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z"
+            , SvgAttr.clipRule "evenodd"
+            ]
+            []
+        ]
+
+
+icon2 =
+    svg
+        [ SvgAttr.css
+            [ Tw.h_full
+            , Tw.w_full
+            , Tw.text_gray_300
+            ]
+        , SvgAttr.fill "currentColor"
+        , SvgAttr.viewBox "0 0 24 24"
+        ]
+        [ path
+            [ SvgAttr.d "M24 20.993V24H0v-2.996A14.977 14.977 0 0112.004 15c4.904 0 9.26 2.354 11.996 5.993zM16.002 8.999a4 4 0 11-8 0 4 4 0 018 0z"
+            ]
+            []
+        ]
+
+
+icon3 =
+    svg
+        [ SvgAttr.css
+            [ Tw.mx_auto
+            , Tw.h_12
+            , Tw.w_12
+            , Tw.text_gray_400
+            ]
+        , SvgAttr.stroke "currentColor"
+        , SvgAttr.fill "none"
+        , SvgAttr.viewBox "0 0 48 48"
+        ]
+        [ path
+            [ SvgAttr.d "M28 8H12a4 4 0 00-4 4v20m32-12v8m0 0v8a4 4 0 01-4 4H12a4 4 0 01-4-4v-4m32-4l-3.172-3.172a4 4 0 00-5.656 0L28 28M8 32l9.172-9.172a4 4 0 015.656 0L28 28m0 0l4 4m4-24h8m-4-4v8m-12 4h.02"
+            , SvgAttr.strokeWidth "2"
+            , SvgAttr.strokeLinecap "round"
+            , SvgAttr.strokeLinejoin "round"
+            ]
+            []
+        ]
--- a/examples/trails/src/MarkdownRenderer.elm
+++ b/examples/trails/src/MarkdownRenderer.elm
@ -0,0 +1,233 @@
+module MarkdownRenderer exposing (renderer)
+
+import Html.Styled as Html
+import Html.Styled.Attributes as Attr exposing (css)
+import Markdown.Block as Block exposing (ListItem(..), Task(..))
+import Markdown.Html
+import Markdown.Renderer
+import SyntaxHighlight
+import Tailwind.Utilities as Tw
+
+
+renderer : Markdown.Renderer.Renderer (Html.Html msg)
+renderer =
+    { heading = heading
+    , paragraph = Html.p []
+    , thematicBreak = Html.hr [] []
+    , text = Html.text
+    , strong = \content -> Html.strong [ css [ Tw.font_bold ] ] content
+    , emphasis = \content -> Html.em [ css [ Tw.italic ] ] content
+    , blockQuote = Html.blockquote []
+    , codeSpan =
+        \content ->
+            Html.code
+                [ css
+                    [ Tw.font_semibold
+                    , Tw.font_medium
+                    ]
+                ]
+                [ Html.text content ]
+
+    --, codeSpan = code
+    , link =
+        \{ destination } body ->
+            Html.a
+                [ Attr.href destination
+                , css
+                    [ Tw.underline
+                    ]
+                ]
+                body
+    , hardLineBreak = Html.br [] []
+    , image =
+        \image ->
+            case image.title of
+                Just _ ->
+                    Html.img [ Attr.src image.src, Attr.alt image.alt ] []
+
+                Nothing ->
+                    Html.img [ Attr.src image.src, Attr.alt image.alt ] []
+    , unorderedList =
+        \items ->
+            Html.ul []
+                (items
+                    |> List.map
+                        (\item ->
+                            case item of
+                                Block.ListItem task children ->
+                                    let
+                                        checkbox =
+                                            case task of
+                                                Block.NoTask ->
+                                                    Html.text ""
+
+                                                Block.IncompleteTask ->
+                                                    Html.input
+                                                        [ Attr.disabled True
+                                                        , Attr.checked False
+                                                        , Attr.type_ "checkbox"
+                                                        ]
+                                                        []
+
+                                                Block.CompletedTask ->
+                                                    Html.input
+                                                        [ Attr.disabled True
+                                                        , Attr.checked True
+                                                        , Attr.type_ "checkbox"
+                                                        ]
+                                                        []
+                                    in
+                                    Html.li [] (checkbox :: children)
+                        )
+                )
+    , orderedList =
+        \startingIndex items ->
+            Html.ol
+                (case startingIndex of
+                    1 ->
+                        [ Attr.start startingIndex ]
+
+                    _ ->
+                        []
+                )
+                (items
+                    |> List.map
+                        (\itemBlocks ->
+                            Html.li []
+                                itemBlocks
+                        )
+                )
+    , html = Markdown.Html.oneOf []
+    , codeBlock = codeBlock
+
+    --\{ body, language } ->
+    --    let
+    --        classes =
+    --            -- Only the first word is used in the class
+    --            case Maybe.map String.words language of
+    --                Just (actualLanguage :: _) ->
+    --                    [ Attr.class <| "language-" ++ actualLanguage ]
+    --
+    --                _ ->
+    --                    []
+    --    in
+    --    Html.pre []
+    --        [ Html.code classes
+    --            [ Html.text body
+    --            ]
+    --        ]
+    , table = Html.table []
+    , tableHeader = Html.thead []
+    , tableBody = Html.tbody []
+    , tableRow = Html.tr []
+    , strikethrough =
+        \children -> Html.del [] children
+    , tableHeaderCell =
+        \maybeAlignment ->
+            let
+                attrs =
+                    maybeAlignment
+                        |> Maybe.map
+                            (\alignment ->
+                                case alignment of
+                                    Block.AlignLeft ->
+                                        "left"
+
+                                    Block.AlignCenter ->
+                                        "center"
+
+                                    Block.AlignRight ->
+                                        "right"
+                            )
+                        |> Maybe.map Attr.align
+                        |> Maybe.map List.singleton
+                        |> Maybe.withDefault []
+            in
+            Html.th attrs
+    , tableCell =
+        \maybeAlignment ->
+            let
+                attrs =
+                    maybeAlignment
+                        |> Maybe.map
+                            (\alignment ->
+                                case alignment of
+                                    Block.AlignLeft ->
+                                        "left"
+
+                                    Block.AlignCenter ->
+                                        "center"
+
+                                    Block.AlignRight ->
+                                        "right"
+                            )
+                        |> Maybe.map Attr.align
+                        |> Maybe.map List.singleton
+                        |> Maybe.withDefault []
+            in
+            Html.td attrs
+    }
+
+
+rawTextToId : String -> String
+rawTextToId rawText =
+    rawText
+        |> String.split " "
+        |> String.join "-"
+        |> String.toLower
+
+
+heading : { level : Block.HeadingLevel, rawText : String, children : List (Html.Html msg) } -> Html.Html msg
+heading { level, rawText, children } =
+    (case level of
+        Block.H1 ->
+            Html.h1
+
+        Block.H2 ->
+            Html.h2
+
+        Block.H3 ->
+            Html.h3
+
+        Block.H4 ->
+            Html.h4
+
+        Block.H5 ->
+            Html.h5
+
+        Block.H6 ->
+            Html.h6
+    )
+        [ Attr.id (rawTextToId rawText)
+        , Attr.attribute "name" (rawTextToId rawText)
+        , css
+            [ Tw.font_bold
+            , Tw.text_2xl
+            , Tw.mt_8
+            , Tw.mb_4
+            ]
+        ]
+        children
+
+
+
+--code : String -> Element msg
+--code snippet =
+--    Element.el
+--        [ Element.Background.color
+--            (Element.rgba255 50 50 50 0.07)
+--        , Element.Border.rounded 2
+--        , Element.paddingXY 5 3
+--        , Font.family [ Font.typeface "Roboto Mono", Font.monospace ]
+--        ]
+--        (Element.text snippet)
+--
+--
+
+
+codeBlock : { body : String, language : Maybe String } -> Html.Html msg
+codeBlock details =
+    SyntaxHighlight.elm details.body
+        |> Result.map (SyntaxHighlight.toBlockHtml (Just 1))
+        |> Result.map Html.fromUnstyled
+        |> Result.withDefault (Html.pre [] [ Html.code [] [ Html.text details.body ] ])
--- a/examples/trails/src/MySession.elm
+++ b/examples/trails/src/MySession.elm
@ -0,0 +1,85 @@
+module MySession exposing (..)
+
+import Codec
+import DataSource exposing (DataSource)
+import DataSource.Env as Env
+import Route
+import Server.Request exposing (Parser)
+import Server.Response as Response exposing (Response)
+import Server.Session as Session
+
+
+withSession :
+    Parser request
+    -> (request -> Result () (Maybe Session.Session) -> DataSource ( Session.Session, Response data errorPage ))
+    -> Parser (DataSource (Response data errorPage))
+withSession =
+    Session.withSession
+        { name = "mysession"
+        , secrets = Env.expect "SESSION_SECRET" |> DataSource.map List.singleton
+        , sameSite = "lax"
+        }
+
+
+withSessionOrRedirect :
+    Parser request
+    -> (request -> Maybe Session.Session -> DataSource ( Session.Session, Response data errorPage ))
+    -> Parser (DataSource (Response data errorPage))
+withSessionOrRedirect handler toRequest =
+    Session.withSession
+        { name = "mysession"
+        , secrets = Env.expect "SESSION_SECRET" |> DataSource.map List.singleton
+        , sameSite = "lax"
+        }
+        handler
+        (\request sessionResult ->
+            sessionResult
+                |> Result.map (toRequest request)
+                |> Result.withDefault
+                    (DataSource.succeed
+                        ( Session.empty
+                        , Route.redirectTo Route.Login
+                        )
+                    )
+        )
+
+
+expectSessionOrRedirect :
+    (request -> Session.Session -> DataSource ( Session.Session, Response data errorPage ))
+    -> Parser request
+    -> Parser (DataSource (Response data errorPage))
+expectSessionOrRedirect toRequest handler =
+    Session.withSession
+        { name = "mysession"
+        , secrets = Env.expect "SESSION_SECRET" |> DataSource.map List.singleton
+        , sameSite = "lax"
+        }
+        handler
+        (\request sessionResult ->
+            sessionResult
+                |> Result.map (Maybe.map (toRequest request))
+                |> Result.withDefault Nothing
+                |> Maybe.withDefault
+                    (DataSource.succeed
+                        ( Session.empty
+                        , Route.redirectTo Route.Login
+                        )
+                    )
+        )
+
+
+schema =
+    { name = ( "name", Codec.string )
+    , message = ( "message", Codec.string )
+    , user =
+        ( "user"
+        , Codec.object User
+            |> Codec.field "id" .id Codec.int
+            |> Codec.buildObject
+        )
+    }
+
+
+type alias User =
+    { id : Int
+    }
--- a/examples/trails/src/Request/Fauna.elm
+++ b/examples/trails/src/Request/Fauna.elm
@ -0,0 +1,70 @@
+module Request.Fauna exposing (dataSource, mutationDataSource)
+
+import DataSource exposing (DataSource)
+import DataSource.Http
+import Graphql.Document
+import Graphql.Operation exposing (RootMutation, RootQuery)
+import Graphql.SelectionSet exposing (SelectionSet)
+import Json.Encode as Encode
+
+
+dataSource : String -> SelectionSet value RootQuery -> DataSource value
+dataSource timeStamp selectionSet =
+    DataSource.Http.request
+        { url =
+            faunaUrl
+                -- for now, this timestamp invalidates the dev server cache
+                -- it would be helpful to have a way to mark a DataSource as uncached. Maybe only allow
+                -- from server-rendered pages?
+                ++ "?time="
+                ++ timeStamp
+        , method = "POST"
+        , headers = [ ( "authorization", faunaAuthValue ) ]
+        , body =
+            DataSource.Http.jsonBody
+                (Encode.object
+                    [ ( "query"
+                      , selectionSet
+                            |> Graphql.Document.serializeQuery
+                            |> Encode.string
+                      )
+                    ]
+                )
+        }
+        (selectionSet
+            |> Graphql.Document.decoder
+            |> DataSource.Http.expectJson
+        )
+
+
+mutationDataSource : String -> SelectionSet value RootMutation -> DataSource value
+mutationDataSource timeStamp selectionSet =
+    DataSource.Http.request
+        { url = faunaUrl ++ "?time=" ++ timeStamp
+        , method = "POST"
+        , headers = [ ( "authorization", faunaAuthValue ) ]
+        , body =
+            DataSource.Http.jsonBody
+                (Encode.object
+                    [ ( "query"
+                      , selectionSet
+                            |> Graphql.Document.serializeMutation
+                            |> Encode.string
+                      )
+                    ]
+                )
+        }
+        (selectionSet
+            |> Graphql.Document.decoder
+            |> DataSource.Http.expectJson
+        )
+
+
+faunaUrl : String
+faunaUrl =
+    "https://graphql.us.fauna.com/graphql"
+
+
+faunaAuthValue : String
+faunaAuthValue =
+    "Bearer fnAEdqJ_JdAAST7wRrjZj7NKSw-vCfE9_W8RyshZ"
--- a/examples/trails/src/Types.elm
+++ b/examples/trails/src/Types.elm
@ -0,0 +1,5 @@
+module Types exposing (..)
+
+
+type alias Data =
+    List String
--- a/examples/trails/style.css
+++ b/examples/trails/style.css
@ -0,0 +1,80 @@
+@import url("https://rsms.me/inter/inter.css");
+@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Mono&display=swap");
+
+body {
+  font-family: "Inter var" !important;
+}
+
+/*
+
+input:invalid {
+  border: 2px dashed red;
+}
+
+input:valid {
+  border: 2px solid black;
+}
+
+*/
+
+
+input[type=password], input[type=text], input[type=date], input[type=email] {
+  border-radius: 10px !important;
+  border-color: #ccc !important;
+}
+
+input[type=checkbox] {
+  border-radius: 4px !important;
+  border-color: #ccc !important;
+}
+
+main.color-app {
+  align-items: center;
+  display: flex;
+  justify-content: center;
+  min-height: 100vh;
+  box-sizing: border-box;
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
+    Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
+  font-size: 18px;
+  margin: 0;
+  padding: 0;
+}
+
+main.color-app {
+  background: rgba(0, 0, 0, 0.15);
+  border-radius: 0.8em;
+  padding: 0.8em;
+}
+
+main.color-app .content {
+  background: rgba(255, 255, 255, 0.9);
+  border-radius: 0.5em;
+  max-width: 90vw;
+  padding: 2rem 3rem;
+  width: 475px;
+  color: var(--selected-color);
+}
+
+main.color-app .content h1 {
+  margin: 0;
+}
+
+main.color-app .content ul {
+  list-style: none;
+  padding: 0;
+}
+
+main.color-app .content li {
+  margin-left: -1rem;
+  margin-right: -1rem;
+  padding: 1rem;
+}
+
+main.color-app .content li:nth-child(odd) {
+  background: rgb(100 10 80 / 0.1);
+}
+
+.timestamp {
+  font-size: 0.75rem;
+}
--- a/examples/trails/tailwind.config.js
+++ b/examples/trails/tailwind.config.js
@ -0,0 +1,5 @@
+module.exports = {
+  theme: {},
+  variants: [],
+  plugins: [require("@tailwindcss/forms")],
+};
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