Initial prototype of ActionData.

examples/pokedex/app/Fetcher/Route/Signup.elm

@@ -0,0 +1,49 @@
+module Fetcher.Route.Signup exposing (load, submit)
+
+import Bytes.Decode
+import Effect exposing (Effect)
+import FormDecoder
+import Http
+import Route.Signup
+
+
+load : Effect (Result Http.Error Route.Signup.Data)
+load =
+    Http.request
+        { expect = Http.expectBytes identity decodeData
+        , tracker = Nothing
+        , body = Http.emptyBody
+        , headers = []
+        , url = "/signup"
+        , method = "GET"
+        , timeout = Nothing
+        }
+        |> Effect.fromCmd
+
+
+submit : { headers : List ( String, String ), formFields : List ( String, String ) } -> Effect (Result Http.Error Route.Signup.ActionData)
+submit options =
+    let
+        { contentType, body } =
+            FormDecoder.encodeFormData options.formFields
+    in
+    Http.request
+        { expect = Http.expectBytes identity decodeActionData
+        , tracker = Nothing
+        , body = Http.stringBody contentType body
+        , headers = options.headers |> List.map (\( key, value ) -> Http.header key value)
+        , url = "/signup/content.dat"
+        , method = "POST"
+        , timeout = Nothing
+        }
+        |> Effect.fromCmd
+
+
+decodeData : Bytes.Decode.Decoder Route.Signup.Data
+decodeData =
+    Route.Signup.w3_decode_Data
+
+
+decodeActionData : Bytes.Decode.Decoder Route.Signup.ActionData
+decodeActionData =
+    Route.Signup.w3_decode_ActionData

examples/pokedex/app/Route/Hello.elm

@@ -0,0 +1,139 @@
+module Route.Hello exposing (ActionData, Data, Model, Msg, route)
+
+import DataSource exposing (DataSource)
+import Effect exposing (Effect)
+import ErrorPage exposing (ErrorPage)
+import Fetcher.Route.Signup
+import Head
+import Head.Seo as Seo
+import Html
+import Http
+import Pages.PageUrl exposing (PageUrl)
+import Pages.Url
+import Path exposing (Path)
+import Route.Signup
+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
+    | GotResponse (Result Http.Error Route.Signup.ActionData)
+
+
+type alias RouteParams =
+    {}
+
+
+route : StatefulRoute RouteParams Data ActionData Model Msg
+route =
+    RouteBuilder.serverRender
+        { head = head
+        , data = data
+        , action = \_ -> Request.succeed (DataSource.succeed (Response.render {}))
+        }
+        |> 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 =
+    ( {}
+    , Fetcher.Route.Signup.submit
+        { headers = []
+        , formFields =
+            [ ( "first", "Jane" )
+            , ( "email", "jane@example.com" )
+            ]
+        }
+        |> Effect.map GotResponse
+    )
+
+
+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 =
+    {}
+
+
+type alias ActionData =
+    {}
+
+
+data : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+data routeParams =
+    Request.succeed (DataSource.succeed (Response.render Data))
+
+
+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 Msg
+view maybeUrl sharedModel model static =
+    { title = "Hello!"
+    , body = [ Html.text "Hello" ]
+    }

examples/pokedex/app/Route/Index.elm

@@ -1,4 +1,4 @@
-module Route.Index exposing (Data, Model, Msg, route)
+module Route.Index exposing (ActionData, Data, Model, Msg, route)
 
 import DataSource exposing (DataSource)
 import DataSource.Env as Env
@@ -28,7 +28,7 @@ type alias RouteParams =
     {}
 
 
-route : StatelessRoute RouteParams Data
+route : StatelessRoute RouteParams Data ActionData
 route =
     RouteBuilder.single
         { head = head
@@ -41,6 +41,10 @@ type alias Data =
     { pokemon : List String, envValue : Maybe String }
 
 
+type alias ActionData =
+    {}
+
+
 data : DataSource Data
 data =
     DataSource.map2 Data
@@ -54,7 +58,7 @@ data =
 
 
 head :
-    StaticPayload Data RouteParams
+    StaticPayload Data RouteParams ActionData
     -> List Head.Tag
 head static =
     Seo.summary
@@ -76,7 +80,7 @@ head static =
 view :
     Maybe PageUrl
     -> Shared.Model
-    -> StaticPayload Data RouteParams
+    -> StaticPayload Data RouteParams ActionData
     -> View Msg
 view maybeUrl sharedModel static =
     { title = "Pokedex"

examples/pokedex/app/Route/Signup.elm

@@ -0,0 +1,127 @@
+module Route.Signup 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 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
+            }
+
+
+action : RouteParams -> Request.Parser (DataSource (Response ActionData ErrorPage))
+action _ =
+    Request.expectFormPost
+        (\{ field } ->
+            Request.map2 Tuple.pair
+                (field "first")
+                (field "email")
+                |> Request.map
+                    (\( first, email ) ->
+                        Success
+                            { email = email
+                            , first = first
+                            }
+                            |> Response.render
+                            |> DataSource.succeed
+                    )
+        )
+
+
+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 ActionData
+    = Success { email : String, first : String }
+    | ValidationErrors
+        { errors : List String
+        , fields : List ( String, String )
+        }
+
+
+actionData : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+actionData routeParams =
+    Debug.todo ""
+
+
+data : RouteParams -> Request.Parser (DataSource (Response Data ErrorPage))
+data routeParams =
+    Request.succeed (DataSource.succeed (Response.render Data))
+
+
+head :
+    StaticPayload Data ActionData RouteParams
+    -> List Head.Tag
+head static =
+    []
+
+
+view :
+    Maybe PageUrl
+    -> Shared.Model
+    -> Model
+    -> StaticPayload Data ActionData RouteParams
+    -> View Msg
+view maybeUrl sharedModel model static =
+    View.placeholder "Signup"

examples/pokedex/src/ColorHelpers.elm

@@ -27,7 +27,7 @@ data _ =
         |> DataSource.map Server.Response.render
 
 
-head : (routeParams -> String) -> StaticPayload Data routeParams -> List Head.Tag
+head : (routeParams -> String) -> StaticPayload Data {} routeParams -> List Head.Tag
 head toCssValue static =
     Seo.summary
         { canonicalUrlOverride = Nothing
@@ -53,7 +53,7 @@ view :
     (routeParams -> String)
     -> Maybe PageUrl
     -> Shared.Model
-    -> StaticPayload Data routeParams
+    -> StaticPayload Data {} routeParams
     -> View msg
 view toCssVal maybeUrl sharedModel static =
     let

generator/src/RouteBuilder.elm

@@ -98,20 +98,21 @@ import View exposing (View)
 
 
 {-| -}
-type alias StatefulRoute routeParams data model msg =
+type alias StatefulRoute routeParams data action model msg =
     { data : routeParams -> DataSource (Server.Response.Response data ErrorPage)
+    , action : routeParams -> DataSource (Server.Response.Response action ErrorPage)
     , staticRoutes : DataSource (List routeParams)
     , view :
         Maybe PageUrl
         -> Shared.Model
         -> model
-        -> StaticPayload data routeParams
+        -> StaticPayload data action routeParams
         -> View msg
     , head :
-        StaticPayload data routeParams
+        StaticPayload data action routeParams
         -> List Head.Tag
-    , init : Maybe PageUrl -> Shared.Model -> StaticPayload data routeParams -> ( model, Effect msg )
-    , update : PageUrl -> StaticPayload data routeParams -> msg -> model -> Shared.Model -> ( model, Effect msg, Maybe Shared.Msg )
+    , init : Maybe PageUrl -> Shared.Model -> StaticPayload data action routeParams -> ( model, Effect msg )
+    , update : PageUrl -> StaticPayload data action routeParams -> msg -> model -> Shared.Model -> ( model, Effect msg, Maybe Shared.Msg )
     , subscriptions : Maybe PageUrl -> routeParams -> Path -> model -> Shared.Model -> Sub msg
     , handleRoute : { moduleName : List String, routePattern : RoutePattern } -> (routeParams -> List ( String, String )) -> routeParams -> DataSource (Maybe NotFoundReason)
     , kind : String
@@ -119,26 +120,28 @@ type alias StatefulRoute routeParams data model msg =
 
 
 {-| -}
-type alias StatelessRoute routeParams data =
-    StatefulRoute routeParams data {} ()
+type alias StatelessRoute routeParams data action =
+    StatefulRoute routeParams data action {} ()
 
 
 {-| -}
-type alias StaticPayload data routeParams =
+type alias StaticPayload data action routeParams =
     { data : data
     , sharedData : Shared.Data
     , routeParams : routeParams
     , path : Path
+    , action : Maybe action
     }
 
 
 {-| -}
-type Builder routeParams data
+type Builder routeParams data action
     = WithData
         { data : routeParams -> DataSource (Server.Response.Response data ErrorPage)
+        , action : routeParams -> DataSource (Server.Response.Response action ErrorPage)
         , staticRoutes : DataSource (List routeParams)
         , head :
-            StaticPayload data routeParams
+            StaticPayload data action routeParams
             -> List Head.Tag
         , serverless : Bool
         , handleRoute :
@@ -155,17 +158,18 @@ buildNoState :
     { view :
         Maybe PageUrl
         -> Shared.Model
-        -> StaticPayload data routeParams
+        -> StaticPayload data action routeParams
         -> View ()
     }
-    -> Builder routeParams data
-    -> StatefulRoute routeParams data {} ()
+    -> Builder routeParams data action
+    -> StatefulRoute routeParams data action {} ()
 buildNoState { view } builderState =
     case builderState of
         WithData record ->
             { view = \maybePageUrl sharedModel _ -> view maybePageUrl sharedModel
             , head = record.head
             , data = record.data
+            , action = record.action
             , staticRoutes = record.staticRoutes
             , init = \_ _ _ -> ( {}, Effect.none )
             , update = \_ _ _ _ _ -> ( {}, Effect.none, Nothing )
@@ -181,14 +185,14 @@ buildWithLocalState :
         Maybe PageUrl
         -> Shared.Model
         -> model
-        -> StaticPayload data routeParams
+        -> StaticPayload data action routeParams
         -> View msg
-    , init : Maybe PageUrl -> Shared.Model -> StaticPayload data routeParams -> ( model, Effect msg )
-    , update : PageUrl -> Shared.Model -> StaticPayload data routeParams -> msg -> model -> ( model, Effect msg )
+    , init : Maybe PageUrl -> Shared.Model -> StaticPayload data action routeParams -> ( model, Effect msg )
+    , update : PageUrl -> Shared.Model -> StaticPayload data action routeParams -> msg -> model -> ( model, Effect msg )
     , subscriptions : Maybe PageUrl -> routeParams -> Path -> Shared.Model -> model -> Sub msg
     }
-    -> Builder routeParams data
-    -> StatefulRoute routeParams data model msg
+    -> Builder routeParams data action
+    -> StatefulRoute routeParams data action model msg
 buildWithLocalState config builderState =
     case builderState of
         WithData record ->
@@ -197,6 +201,7 @@ buildWithLocalState config builderState =
                     config.view model sharedModel staticPayload
             , head = record.head
             , data = record.data
+            , action = record.action
             , staticRoutes = record.staticRoutes
             , init = config.init
             , update =
@@ -225,20 +230,21 @@ buildWithSharedState :
         Maybe PageUrl
         -> Shared.Model
         -> model
-        -> StaticPayload data routeParams
+        -> StaticPayload data action routeParams
         -> View msg
-    , init : Maybe PageUrl -> Shared.Model -> StaticPayload data routeParams -> ( model, Effect msg )
-    , update : PageUrl -> Shared.Model -> StaticPayload data routeParams -> msg -> model -> ( model, Effect msg, Maybe Shared.Msg )
+    , init : Maybe PageUrl -> Shared.Model -> StaticPayload data action routeParams -> ( model, Effect msg )
+    , update : PageUrl -> Shared.Model -> StaticPayload data action routeParams -> msg -> model -> ( model, Effect msg, Maybe Shared.Msg )
     , subscriptions : Maybe PageUrl -> routeParams -> Path -> Shared.Model -> model -> Sub msg
     }
-    -> Builder routeParams data
-    -> StatefulRoute routeParams data model msg
+    -> Builder routeParams data action
+    -> StatefulRoute routeParams data action model msg
 buildWithSharedState config builderState =
     case builderState of
         WithData record ->
             { view = config.view
             , head = record.head
             , data = record.data
+            , action = record.action
             , staticRoutes = record.staticRoutes
             , init = config.init
             , update =
@@ -259,12 +265,13 @@ buildWithSharedState config builderState =
 {-| -}
 single :
     { data : DataSource data
-    , head : StaticPayload data {} -> List Head.Tag
+    , head : StaticPayload data action {} -> List Head.Tag
     }
-    -> Builder {} data
+    -> Builder {} data action
 single { data, head } =
     WithData
         { data = \_ -> data |> DataSource.map Server.Response.render
+        , action = \_ -> DataSource.fail "Internal Error - actions should never be called for statically generated pages."
         , staticRoutes = DataSource.succeed [ {} ]
         , head = head
         , serverless = False
@@ -277,12 +284,13 @@ single { data, head } =
 preRender :
     { data : routeParams -> DataSource data
     , pages : DataSource (List routeParams)
-    , head : StaticPayload data routeParams -> List Head.Tag
+    , head : StaticPayload data action routeParams -> List Head.Tag
     }
-    -> Builder routeParams data
+    -> Builder routeParams data action
 preRender { data, head, pages } =
     WithData
         { data = data >> DataSource.map Server.Response.render
+        , action = \_ -> DataSource.fail "Internal Error - actions should never be called for statically generated pages."
         , staticRoutes = pages
         , head = head
         , serverless = False
@@ -314,12 +322,13 @@ preRender { data, head, pages } =
 preRenderWithFallback :
     { data : routeParams -> DataSource (Server.Response.Response data ErrorPage)
     , pages : DataSource (List routeParams)
-    , head : StaticPayload data routeParams -> List Head.Tag
+    , head : StaticPayload data action routeParams -> List Head.Tag
     }
-    -> Builder routeParams data
+    -> Builder routeParams data action
 preRenderWithFallback { data, head, pages } =
     WithData
         { data = data
+        , action = \_ -> DataSource.fail "Internal Error - actions should never be called for statically generated pages."
         , staticRoutes = pages
         , head = head
         , serverless = False
@@ -333,10 +342,11 @@ preRenderWithFallback { data, head, pages } =
 {-| -}
 serverRender :
     { data : routeParams -> Server.Request.Parser (DataSource (Server.Response.Response data ErrorPage))
-    , head : StaticPayload data routeParams -> List Head.Tag
+    , action : routeParams -> Server.Request.Parser (DataSource (Server.Response.Response action ErrorPage))
+    , head : StaticPayload data action routeParams -> List Head.Tag
     }
-    -> Builder routeParams data
-serverRender { data, head } =
+    -> Builder routeParams data action
+serverRender { data, action, head } =
     WithData
         { data =
             \routeParams ->
@@ -355,6 +365,23 @@ serverRender { data, head } =
                                 Err error ->
                                     Server.Request.errorsToString error |> DataSource.fail
                         )
+        , action =
+            \routeParams ->
+                DataSource.Http.get
+                    "$$elm-pages$$headers"
+                    (routeParams
+                        |> action
+                        |> Server.Request.getDecoder
+                    )
+                    |> DataSource.andThen
+                        (\rendered ->
+                            case rendered of
+                                Ok okRendered ->
+                                    okRendered
+
+                                Err error ->
+                                    Server.Request.errorsToString error |> DataSource.fail
+                        )
         , staticRoutes = DataSource.succeed []
         , head = head
         , serverless = True

generator/src/generate-template-module-connector.js

@@ -142,6 +142,17 @@ type PageData
       .join("    | ")}
 
 
+type ActionData
+    = 
+    ${templates
+      .map(
+        (name) =>
+          `ActionData${pathNormalizedName(name)} Route.${moduleName(
+            name
+          )}.ActionData\n`
+      )
+      .join("    | ")}
+
 
 view :
     { path : Path
@@ -201,6 +212,7 @@ view page maybePageUrl globalData pageData =
                                       , routeParams = ${
                                         emptyRouteParams(name) ? "{}" : "s"
                                       }
+                                      , action = Nothing
                                       , path = page.path
                                       }
                                       |> View.map Msg${pathNormalizedName(name)}
@@ -215,6 +227,7 @@ view page maybePageUrl globalData pageData =
                       { data = data
                       , sharedData = globalData
                       , routeParams = ${emptyRouteParams(name) ? "{}" : "s"}
+                      , action = Nothing
                       , path = page.path
                       }
                       `
@@ -278,6 +291,7 @@ init currentGlobalModel userFlags sharedData pageData navigationKey maybePagePat
                         sharedModel
                         { data = thisPageData
                         , sharedData = sharedData
+                        , action = Nothing
                         , routeParams = ${
                           emptyRouteParams(name) ? "{}" : "routeParams"
                         }
@@ -414,6 +428,7 @@ update sharedData pageData navigationKey msg model =
                                 pageUrl
                                 { data = thisPageData
                                 , sharedData = sharedData
+                                , action = Nothing
                                 , routeParams = ${routeHelpers.referenceRouteParams(
                                   name,
                                   "routeParams"
@@ -476,7 +491,7 @@ templateSubscriptions route path model =
 
 main : ${
       phase === "browser"
-        ? "Pages.Internal.Platform.Program Model Msg PageData Shared.Data ErrorPage"
+        ? "Pages.Internal.Platform.Program Model Msg PageData ActionData Shared.Data ErrorPage"
         : "Pages.Internal.Platform.Cli.Program (Maybe Route)"
     }
 main =
@@ -515,6 +530,7 @@ config =
           phase === "browser" ? "Sub.none" : "gotBatchSub identity"
         }
         , data = dataForRoute
+        , action = action
         , sharedData = Shared.template.data
         , apiRoutes = ${
           phase === "browser"
@@ -533,6 +549,7 @@ config =
         , hotReloadData = hotReloadData identity
         , encodeResponse = encodeResponse
         , decodeResponse = decodeResponse
+        , encodeAction = encodeActionData
         , cmdToEffect = Effect.fromCmd
         , perform = Effect.perform
         , errorStatusCode = ErrorPage.statusCode
@@ -553,14 +570,14 @@ globalHeadTags =
         |> DataSource.map List.concat
 
 
-encodeResponse : ResponseSketch PageData Shared.Data -> Bytes.Encode.Encoder
+encodeResponse : ResponseSketch PageData ActionData Shared.Data -> Bytes.Encode.Encoder
 encodeResponse =
-    Pages.Internal.ResponseSketch.w3_encode_ResponseSketch w3_encode_PageData Shared.w3_encode_Data
+    Pages.Internal.ResponseSketch.w3_encode_ResponseSketch w3_encode_PageData w3_encode_ActionData Shared.w3_encode_Data
 
 
-decodeResponse : Bytes.Decode.Decoder (ResponseSketch PageData Shared.Data)
+decodeResponse : Bytes.Decode.Decoder (ResponseSketch PageData ActionData Shared.Data)
 decodeResponse =
-    Pages.Internal.ResponseSketch.w3_decode_ResponseSketch w3_decode_PageData Shared.w3_decode_Data
+    Pages.Internal.ResponseSketch.w3_decode_ResponseSketch w3_decode_PageData w3_decode_ActionData Shared.w3_decode_Data
 
 
 port hotReloadData : (Bytes -> msg) -> Sub msg
@@ -584,6 +601,18 @@ ${templates
   )
   .join("\n")}
 
+encodeActionData : ActionData -> Bytes.Encode.Encoder
+encodeActionData actionData =
+    case actionData of
+${templates
+  .map(
+    (name) => `        ActionData${pathNormalizedName(name)} thisActionData ->
+            Route.${name.join(".")}.w3_encode_ActionData thisActionData
+`
+  )
+  .join("\n")}
+
+
 port sendPageData : Pages.Internal.Platform.ToJsPayload.NewThingForPort -> Cmd msg
 
 
@@ -607,6 +636,9 @@ ${templates
   )
   .join("\n")}
 
+
+
+
 dataForRoute : Maybe Route -> DataSource (Server.Response.Response PageData ErrorPage)
 dataForRoute route =
     case route of
@@ -633,6 +665,34 @@ dataForRoute route =
           )
           .join("\n        ")}
 
+action : Maybe Route -> DataSource (Server.Response.Response ActionData ErrorPage)
+action route =
+    case route of
+        Nothing ->
+            DataSource.succeed ( Server.Response.plainText "TODO" )
+
+        ${templates
+          .map(
+            (name) =>
+              `Just ${
+                emptyRouteParams(name)
+                  ? `Route.${routeHelpers.routeVariant(name)}`
+                  : `(Route.${routeHelpers.routeVariant(name)} routeParams)`
+              } ->\n            Route.${name.join(
+                "."
+              )}.route.action ${routeHelpers.referenceRouteParams(
+                name,
+                "routeParams"
+              )} 
+                 |> DataSource.map (Server.Response.map ActionData${routeHelpers.routeVariant(
+                   name
+                 )})
+              `
+          )
+          .join("\n        ")}
+
+
+
 handleRoute : Maybe Route -> DataSource (Maybe Pages.Internal.NotFoundReason.NotFoundReason)
 handleRoute maybeRoute =
     case maybeRoute of

src/Pages/Internal/Platform.elm

@@ -46,12 +46,12 @@ type Transition
 
 
 {-| -}
-type alias Program userModel userMsg pageData sharedData errorPage =
-    Platform.Program Flags (Model userModel pageData sharedData) (Msg userMsg pageData sharedData errorPage)
+type alias Program userModel userMsg pageData actionData sharedData errorPage =
+    Platform.Program Flags (Model userModel pageData sharedData) (Msg userMsg pageData actionData sharedData errorPage)
 
 
 mainView :
-    ProgramConfig userMsg userModel route pageData sharedData effect (Msg userMsg pageData sharedData errorPage) errorPage
+    ProgramConfig userMsg userModel route pageData actionData sharedData effect (Msg userMsg pageData actionData sharedData errorPage) errorPage
     -> Model userModel pageData sharedData
     -> { title : String, body : Html userMsg }
 mainView config model =
@@ -100,9 +100,9 @@ urlsToPagePath urls =
 
 
 view :
-    ProgramConfig userMsg userModel route pageData sharedData effect (Msg userMsg pageData sharedData errorPage) errorPage
+    ProgramConfig userMsg userModel route pageData actionData sharedData effect (Msg userMsg pageData actionData sharedData errorPage) errorPage
     -> Model userModel pageData sharedData
-    -> Browser.Document (Msg userMsg pageData sharedData errorPage)
+    -> Browser.Document (Msg userMsg pageData actionData sharedData errorPage)
 view config model =
     let
         { title, body } =
@@ -142,11 +142,11 @@ type InitKind shared page errorPage
 
 {-| -}
 init :
-    ProgramConfig userMsg userModel route pageData sharedData userEffect (Msg userMsg pageData sharedData errorPage) errorPage
+    ProgramConfig userMsg userModel route pageData actionData sharedData userEffect (Msg userMsg pageData actionData sharedData errorPage) errorPage
     -> Flags
     -> Url
     -> Maybe Browser.Navigation.Key
-    -> ( Model userModel pageData sharedData, Effect userMsg pageData sharedData userEffect errorPage )
+    -> ( Model userModel pageData sharedData, Effect userMsg pageData actionData sharedData userEffect errorPage )
 init config flags url key =
     let
         pageDataResult : Result BuildError (InitKind sharedData pageData errorPage)
@@ -163,10 +163,10 @@ init config flags url key =
                                 config.decodeResponse
                                 justBytes
                         of
-                            Just (ResponseSketch.RenderPage _) ->
+                            Just (ResponseSketch.RenderPage _ _) ->
                                 Nothing
 
-                            Just (ResponseSketch.HotUpdate pageData shared) ->
+                            Just (ResponseSketch.HotUpdate pageData shared _) ->
                                 OkPage shared pageData
                                     |> Just
 
@@ -223,7 +223,7 @@ init config flags url key =
                         }
                         |> config.init userFlags sharedData pageData key
 
-                cmd : Effect userMsg pageData sharedData userEffect errorPage
+                cmd : Effect userMsg pageData actionData sharedData userEffect errorPage
                 cmd =
                     UserCmd userCmd
 
@@ -281,14 +281,14 @@ init config flags url key =
 
 
 {-| -}
-type Msg userMsg pageData sharedData errorPage
+type Msg userMsg pageData actionData sharedData errorPage
     = LinkClicked Browser.UrlRequest
     | UrlChanged Url
     | UserMsg userMsg
-    | UpdateCacheAndUrlNew Bool Url (Maybe userMsg) (Result Http.Error ( Url, ResponseSketch pageData sharedData ))
+    | UpdateCacheAndUrlNew Bool Url (Maybe userMsg) (Result Http.Error ( Url, ResponseSketch pageData actionData sharedData ))
     | PageScrollComplete
     | HotReloadCompleteNew Bytes
-    | ProcessFetchResponse (Result Http.Error ( Url, ResponseSketch pageData sharedData )) (Result Http.Error ( Url, ResponseSketch pageData sharedData ) -> Msg userMsg pageData sharedData errorPage)
+    | ProcessFetchResponse (Result Http.Error ( Url, ResponseSketch pageData actionData sharedData )) (Result Http.Error ( Url, ResponseSketch pageData actionData sharedData ) -> Msg userMsg pageData actionData sharedData errorPage)
 
 
 {-| -}
@@ -310,23 +310,23 @@ type alias Model userModel pageData sharedData =
     }
 
 
-type Effect userMsg pageData sharedData userEffect errorPage
+type Effect userMsg pageData actionData sharedData userEffect errorPage
     = ScrollToTop
     | NoEffect
     | BrowserLoadUrl String
     | BrowserPushUrl String
-    | FetchPageData Int (Maybe RequestInfo) Url (Result Http.Error ( Url, ResponseSketch pageData sharedData ) -> Msg userMsg pageData sharedData errorPage)
-    | Batch (List (Effect userMsg pageData sharedData userEffect errorPage))
+    | FetchPageData Int (Maybe RequestInfo) Url (Result Http.Error ( Url, ResponseSketch pageData actionData sharedData ) -> Msg userMsg pageData actionData sharedData errorPage)
+    | Batch (List (Effect userMsg pageData actionData sharedData userEffect errorPage))
     | UserCmd userEffect
     | CancelRequest Int
 
 
 {-| -}
 update :
-    ProgramConfig userMsg userModel route pageData sharedData userEffect (Msg userMsg pageData sharedData errorPage) errorPage
-    -> Msg userMsg pageData sharedData errorPage
+    ProgramConfig userMsg userModel route pageData actionData sharedData userEffect (Msg userMsg pageData actionData sharedData errorPage) errorPage
+    -> Msg userMsg pageData actionData sharedData errorPage
     -> Model userModel pageData sharedData
-    -> ( Model userModel pageData sharedData, Effect userMsg pageData sharedData userEffect errorPage )
+    -> ( Model userModel pageData sharedData, Effect userMsg pageData actionData sharedData userEffect errorPage )
 update config appMsg model =
     case appMsg of
         LinkClicked urlRequest ->
@@ -462,10 +462,10 @@ update config appMsg model =
                     let
                         ( newPageData, newSharedData ) =
                             case newData of
-                                ResponseSketch.RenderPage pageData ->
+                                ResponseSketch.RenderPage pageData _ ->
                                     ( pageData, previousPageData.sharedData )
 
-                                ResponseSketch.HotUpdate pageData sharedData ->
+                                ResponseSketch.HotUpdate pageData sharedData _ ->
                                     ( pageData, sharedData )
 
                                 _ ->
@@ -563,14 +563,14 @@ update config appMsg model =
                 |> Result.map
                     (\pageData ->
                         let
-                            newThing : Maybe (ResponseSketch pageData sharedData)
+                            newThing : Maybe (ResponseSketch pageData actionData sharedData)
                             newThing =
                                 -- TODO if ErrorPage, call ErrorPage.init to get appropriate Model?
                                 pageDataBytes
                                     |> Bytes.Decode.decode config.decodeResponse
                         in
                         case newThing of
-                            Just (ResponseSketch.RenderPage newPageData) ->
+                            Just (ResponseSketch.RenderPage newPageData _) ->
                                 ( { model
                                     | pageData =
                                         Ok
@@ -583,7 +583,7 @@ update config appMsg model =
                                 , NoEffect
                                 )
 
-                            Just (ResponseSketch.HotUpdate newPageData newSharedData) ->
+                            Just (ResponseSketch.HotUpdate newPageData newSharedData _) ->
                                 ( { model
                                     | pageData =
                                         Ok
@@ -605,7 +605,7 @@ update config appMsg model =
                 |> Result.withDefault ( model, NoEffect )
 
 
-perform : ProgramConfig userMsg userModel route pageData sharedData userEffect (Msg userMsg pageData sharedData errorPage) errorPage -> Url -> Maybe Browser.Navigation.Key -> Effect userMsg pageData sharedData userEffect errorPage -> Cmd (Msg userMsg pageData sharedData errorPage)
+perform : ProgramConfig userMsg userModel route pageData actionData sharedData userEffect (Msg userMsg pageData actionData sharedData errorPage) errorPage -> Url -> Maybe Browser.Navigation.Key -> Effect userMsg pageData actionData sharedData userEffect errorPage -> Cmd (Msg userMsg pageData actionData sharedData errorPage)
 perform config currentUrl maybeKey effect =
     -- elm-review: known-unoptimized-recursion
     case effect of
@@ -640,8 +640,8 @@ perform config currentUrl maybeKey effect =
                     let
                         prepare :
                             (Result Http.Error Url -> userMsg)
-                            -> Result Http.Error ( Url, ResponseSketch pageData sharedData )
-                            -> Msg userMsg pageData sharedData errorPage
+                            -> Result Http.Error ( Url, ResponseSketch pageData actionData sharedData )
+                            -> Msg userMsg pageData actionData sharedData errorPage
                         prepare toMsg info =
                             UpdateCacheAndUrlNew True currentUrl (info |> Result.map Tuple.first |> toMsg |> Just) info
                     in
@@ -683,8 +683,8 @@ perform config currentUrl maybeKey effect =
 
 {-| -}
 application :
-    ProgramConfig userMsg userModel route pageData sharedData effect (Msg userMsg pageData sharedData errorPage) errorPage
-    -> Platform.Program Flags (Model userModel pageData sharedData) (Msg userMsg pageData sharedData errorPage)
+    ProgramConfig userMsg userModel route pageData actionData sharedData effect (Msg userMsg pageData actionData sharedData errorPage) errorPage
+    -> Platform.Program Flags (Model userModel pageData sharedData) (Msg userMsg pageData actionData sharedData errorPage)
 application config =
     Browser.application
         { init =
@@ -728,10 +728,10 @@ type alias RequestInfo =
 
 
 withUserMsg :
-    ProgramConfig userMsg userModel route pageData sharedData userEffect (Msg userMsg pageData sharedData errorPage) errorPage
+    ProgramConfig userMsg userModel route pageData actionData sharedData userEffect (Msg userMsg pageData actionData sharedData errorPage) errorPage
     -> userMsg
-    -> ( Model userModel pageData sharedData, Effect userMsg pageData sharedData userEffect errorPage )
-    -> ( Model userModel pageData sharedData, Effect userMsg pageData sharedData userEffect errorPage )
+    -> ( Model userModel pageData sharedData, Effect userMsg pageData actionData sharedData userEffect errorPage )
+    -> ( Model userModel pageData sharedData, Effect userMsg pageData actionData sharedData userEffect errorPage )
 withUserMsg config userMsg ( model, effect ) =
     case model.pageData of
         Ok pageData ->
@@ -761,11 +761,11 @@ urlPathToPath urls =
 
 fetchRouteData :
     Int
-    -> (Result Http.Error ( Url, ResponseSketch pageData sharedData ) -> Msg userMsg pageData sharedData errorPage)
-    -> ProgramConfig userMsg userModel route pageData sharedData effect (Msg userMsg pageData sharedData errorPage) errorPage
+    -> (Result Http.Error ( Url, ResponseSketch pageData actionData sharedData ) -> Msg userMsg pageData actionData sharedData errorPage)
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect (Msg userMsg pageData actionData sharedData errorPage) errorPage
     -> Url
     -> Maybe { contentType : String, body : String }
-    -> Cmd (Msg userMsg pageData sharedData errorPage)
+    -> Cmd (Msg userMsg pageData actionData sharedData errorPage)
 fetchRouteData transitionKey toMsg config url details =
     {-
        TODO:
@@ -844,16 +844,16 @@ chopEnd needle string =
 
 startNewGetLoad :
     String
-    -> (Result Http.Error ( Url, ResponseSketch pageData sharedData ) -> Msg userMsg pageData sharedData errorPage)
-    -> ( Model userModel pageData sharedData, Effect userMsg pageData sharedData userEffect errorPage )
-    -> ( Model userModel pageData sharedData, Effect userMsg pageData sharedData userEffect errorPage )
+    -> (Result Http.Error ( Url, ResponseSketch pageData actionData sharedData ) -> Msg userMsg pageData actionData sharedData errorPage)
+    -> ( Model userModel pageData sharedData, Effect userMsg pageData actionData sharedData userEffect errorPage )
+    -> ( Model userModel pageData sharedData, Effect userMsg pageData actionData sharedData userEffect errorPage )
 startNewGetLoad pathToGet toMsg ( model, effect ) =
     let
         currentUrl : Url
         currentUrl =
             model.url
 
-        cancelIfStale : Effect userMsg pageData sharedData userEffect errorPage
+        cancelIfStale : Effect userMsg pageData actionData sharedData userEffect errorPage
         cancelIfStale =
             case model.transition of
                 Just (Loading transitionKey path) ->

src/Pages/Internal/Platform/Cli.elm

@@ -76,7 +76,7 @@ type alias Program route =
 
 {-| -}
 cliApplication :
-    ProgramConfig userMsg userModel (Maybe route) pageData sharedData effect mappedMsg errorPage
+    ProgramConfig userMsg userModel (Maybe route) pageData actionData sharedData effect mappedMsg errorPage
     -> Program (Maybe route)
 cliApplication config =
     let
@@ -84,7 +84,7 @@ cliApplication config =
         site =
             getSiteConfig config
 
-        getSiteConfig : ProgramConfig userMsg userModel (Maybe route) pageData sharedData effect mappedMsg errorPage -> SiteConfig
+        getSiteConfig : ProgramConfig userMsg userModel (Maybe route) pageData actionData sharedData effect mappedMsg errorPage -> SiteConfig
         getSiteConfig fullConfig =
             case fullConfig.site of
                 Just mySite ->
@@ -199,12 +199,12 @@ requestDecoder =
         |> Codec.decoder
 
 
-flatten : SiteConfig -> RenderRequest route -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage -> List Effect -> Cmd Msg
+flatten : SiteConfig -> RenderRequest route -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage -> List Effect -> Cmd Msg
 flatten site renderRequest config list =
     Cmd.batch (flattenHelp [] site renderRequest config list)
 
 
-flattenHelp : List (Cmd Msg) -> SiteConfig -> RenderRequest route -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage -> List Effect -> List (Cmd Msg)
+flattenHelp : List (Cmd Msg) -> SiteConfig -> RenderRequest route -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage -> List Effect -> List (Cmd Msg)
 flattenHelp soFar site renderRequest config list =
     case list of
         first :: rest ->
@@ -222,7 +222,7 @@ flattenHelp soFar site renderRequest config list =
 perform :
     SiteConfig
     -> RenderRequest route
-    -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> Effect
     -> Cmd Msg
 perform site renderRequest config effect =
@@ -361,7 +361,7 @@ flagsDecoder =
 init :
     SiteConfig
     -> RenderRequest route
-    -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> Decode.Value
     -> ( Model route, Effect )
 init site renderRequest config flags =
@@ -388,14 +388,40 @@ init site renderRequest config flags =
                 }
 
 
+isActionDecoder : Decode.Decoder Bool
+isActionDecoder =
+    Decode.field "method" Decode.string
+        |> Decode.map
+            (\method ->
+                case method |> String.toUpper of
+                    "GET" ->
+                        False
+
+                    "OPTIONS" ->
+                        False
+
+                    _ ->
+                        True
+            )
+
+
 initLegacy :
     SiteConfig
     -> RenderRequest route
     -> { staticHttpCache : RequestsAndPending, isDevServer : Bool }
-    -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> ( Model route, Effect )
 initLegacy site renderRequest { staticHttpCache, isDevServer } config =
     let
+        isAction : Bool
+        isAction =
+            renderRequest
+                |> RenderRequest.maybeRequestPayload
+                |> Maybe.map (Decode.decodeValue isActionDecoder)
+                |> Maybe.withDefault (Ok False)
+                |> Result.withDefault False
+                |> Debug.log "@@@isAction"
+
         staticResponses : StaticResponses
         staticResponses =
             case renderRequest of
@@ -403,10 +429,16 @@ initLegacy site renderRequest { staticHttpCache, isDevServer } config =
                     case singleRequest of
                         RenderRequest.Page serverRequestPayload ->
                             StaticResponses.renderSingleRoute
-                                (DataSource.map3 (\_ _ _ -> ())
-                                    (config.data serverRequestPayload.frontmatter)
-                                    config.sharedData
-                                    (config.globalHeadTags |> Maybe.withDefault (DataSource.succeed []))
+                                (if isAction then
+                                    config.action serverRequestPayload.frontmatter
+                                        |> DataSource.map (\_ -> ())
+                                    -- TODO do loader or action based on METHOD
+
+                                 else
+                                    DataSource.map3 (\_ _ _ -> ())
+                                        (config.data serverRequestPayload.frontmatter)
+                                        config.sharedData
+                                        (config.globalHeadTags |> Maybe.withDefault (DataSource.succeed []))
                                 )
                                 (if isDevServer then
                                     config.handleRoute serverRequestPayload.frontmatter
@@ -461,7 +493,7 @@ initLegacy site renderRequest { staticHttpCache, isDevServer } config =
 
 updateAndSendPortIfDone :
     SiteConfig
-    -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> Model route
     -> ( Model route, Effect )
 updateAndSendPortIfDone site config model =
@@ -474,7 +506,7 @@ updateAndSendPortIfDone site config model =
 {-| -}
 update :
     SiteConfig
-    -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> Msg
     -> Model route
     -> ( Model route, Effect )
@@ -520,7 +552,7 @@ update site config msg model =
 
 nextStepToEffect :
     SiteConfig
-    -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> Model route
     -> ( StaticResponses, StaticResponses.NextStep route )
     -> ( Model route, Effect )
@@ -578,6 +610,7 @@ nextStepToEffect site config model ( updatedStaticResponsesModel, nextStep ) =
                                 config.sharedData
                                 model.allRawResponses
                                 |> Result.mapError (StaticHttpRequest.toBuildError "")
+                                |> Debug.log "@@@sharedData"
 
                         apiResponse : Effect
                         apiResponse =
@@ -666,7 +699,7 @@ nextStepToEffect site config model ( updatedStaticResponsesModel, nextStep ) =
 sendSinglePageProgress :
     SiteConfig
     -> RequestsAndPending
-    -> ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    -> ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> Model route
     -> { path : Path, frontmatter : route }
     -> Effect
@@ -674,6 +707,15 @@ sendSinglePageProgress site contentJson config model info =
     let
         ( page, route ) =
             ( info.path, info.frontmatter )
+
+        isAction : Bool
+        isAction =
+            model.maybeRequestJson
+                |> RenderRequest.maybeRequestPayload
+                |> Maybe.map (Decode.decodeValue isActionDecoder)
+                |> Maybe.withDefault (Ok False)
+                |> Result.withDefault False
+                |> Debug.log "@@@isAction sendSingle"
     in
     case model.maybeRequestJson of
         RenderRequest.SinglePage includeHtml _ _ ->
@@ -696,6 +738,7 @@ sendSinglePageProgress site contentJson config model info =
                     case includeHtml of
                         RenderRequest.OnlyJson ->
                             pageDataResult
+                                |> Debug.log "pageDataResult"
                                 |> Result.map
                                     (\okPageData ->
                                         case okPageData of
@@ -802,6 +845,7 @@ sendSinglePageProgress site contentJson config model info =
                                                     }
                                     )
 
+                --Debug.todo ""
                 currentUrl : Url
                 currentUrl =
                     { protocol = Url.Https
@@ -820,6 +864,14 @@ sendSinglePageProgress site contentJson config model info =
                         contentJson
                         |> Result.mapError (StaticHttpRequest.toBuildError currentUrl.path)
 
+                actionDataResult : Result BuildError (PageServerResponse actionData errorPage)
+                actionDataResult =
+                    -- TODO OPTIMIZATION can these three be included in StaticResponses.Finish?
+                    StaticHttpRequest.resolve
+                        (config.action (urlToRoute config currentUrl))
+                        contentJson
+                        |> Result.mapError (StaticHttpRequest.toBuildError currentUrl.path)
+
                 sharedDataResult : Result BuildError sharedData
                 sharedDataResult =
                     StaticHttpRequest.resolve
@@ -848,19 +900,34 @@ sendSinglePageProgress site contentJson config model info =
                                                     -- TODO want to encode both shared and page data in dev server and HTML-embedded data
                                                     -- but not for writing out the content.dat files - would be good to optimize this redundant data out
                                                     --if model.isDevServer then
-                                                    if True then
-                                                        sharedDataResult
-                                                            |> Result.map (ResponseSketch.HotUpdate pageData)
-                                                            |> Result.withDefault (ResponseSketch.RenderPage pageData)
-                                                            |> config.encodeResponse
-                                                            |> Bytes.Encode.encode
+                                                    if isAction then
+                                                        case actionDataResult of
+                                                            Ok (PageServerResponse.RenderPage _ actionData) ->
+                                                                --actionData
+                                                                --    |> ResponseSketch.Action
+                                                                --    -- TODO remove hardcoded actionData
+                                                                --    |> config.encodeResponse
+                                                                --    |> Bytes.Encode.encode
+                                                                actionData
+                                                                    -- TODO remove hardcoded actionData
+                                                                    |> config.encodeAction
+                                                                    |> Bytes.Encode.encode
+
+                                                            _ ->
+                                                                Bytes.Encode.encode (Bytes.Encode.unsignedInt8 0)
 
                                                     else
-                                                        pageData
-                                                            |> ResponseSketch.RenderPage
+                                                        sharedDataResult
+                                                            |> Result.map (\something -> ResponseSketch.HotUpdate pageData something Nothing)
+                                                            |> Result.withDefault (ResponseSketch.RenderPage pageData Nothing)
                                                             |> config.encodeResponse
                                                             |> Bytes.Encode.encode
 
+                                                --else
+                                                --    pageData
+                                                --        |> ResponseSketch.RenderPage
+                                                --        |> config.encodeResponse
+                                                --        |> Bytes.Encode.encode
                                                 PageServerResponse.ServerResponse serverResponse ->
                                                     -- TODO handle error?
                                                     PageServerResponse.toRedirect serverResponse
@@ -877,7 +944,13 @@ sendSinglePageProgress site contentJson config model info =
                                                 PageServerResponse.ErrorPage error record ->
                                                     -- TODO this case should never happen
                                                     sharedDataResult
-                                                        |> Result.map (ResponseSketch.HotUpdate (config.errorPageToData error))
+                                                        |> Result.map
+                                                            (\sharedData ->
+                                                                ResponseSketch.HotUpdate (config.errorPageToData error)
+                                                                    sharedData
+                                                                    -- TODO remove hardcoded action data
+                                                                    Nothing
+                                                            )
                                                         |> Result.map config.encodeResponse
                                                         |> Result.map Bytes.Encode.encode
                                                         |> Result.withDefault (Bytes.Encode.encode (Bytes.Encode.unsignedInt8 0))
@@ -962,7 +1035,7 @@ sendSinglePageProgress site contentJson config model info =
 
 
 render404Page :
-    ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage
+    ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage
     -> Maybe sharedData
     -> Model route
     -> Path
@@ -974,8 +1047,11 @@ render404Page config sharedData model path notFoundReason =
             let
                 byteEncodedPageData : Bytes
                 byteEncodedPageData =
-                    justSharedData
-                        |> ResponseSketch.HotUpdate (config.errorPageToData config.notFoundPage)
+                    ResponseSketch.HotUpdate
+                        (config.errorPageToData config.notFoundPage)
+                        justSharedData
+                        -- TODO remove shared action data
+                        Nothing
                         |> config.encodeResponse
                         |> Bytes.Encode.encode
 
@@ -1054,7 +1130,7 @@ render404Page config sharedData model path notFoundReason =
                 |> Effect.SendSinglePageNew byteEncodedPageData
 
 
-urlToRoute : ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage -> Url -> route
+urlToRoute : ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage -> Url -> route
 urlToRoute config url =
     if url.path |> String.startsWith "/____elm-pages-internal____" then
         config.notFoundRoute

src/Pages/Internal/ResponseSketch.elm

@@ -1,11 +1,13 @@
 module Pages.Internal.ResponseSketch exposing (ResponseSketch(..))
 
+import Bytes exposing (Bytes)
 import Pages.Internal.NotFoundReason exposing (NotFoundReason)
 import Path exposing (Path)
 
 
-type ResponseSketch data shared
-    = RenderPage data
-    | HotUpdate data shared
+type ResponseSketch data action shared
+    = RenderPage data (Maybe action)
+    | HotUpdate data shared (Maybe action)
     | Redirect String
     | NotFound { reason : NotFoundReason, path : Path }
+    | Action action

src/Pages/ProgramConfig.elm

@@ -20,11 +20,10 @@ import Pages.Internal.RoutePattern exposing (RoutePattern)
 import Pages.PageUrl exposing (PageUrl)
 import Pages.SiteConfig exposing (SiteConfig)
 import Path exposing (Path)
-import Task exposing (Task)
 import Url exposing (Url)
 
 
-type alias ProgramConfig userMsg userModel route pageData sharedData effect mappedMsg errorPage =
+type alias ProgramConfig userMsg userModel route pageData actionData sharedData effect mappedMsg errorPage =
     { init :
         Pages.Flags.Flags
         -> sharedData
@@ -45,6 +44,7 @@ type alias ProgramConfig userMsg userModel route pageData sharedData effect mapp
     , subscriptions : route -> Path -> userModel -> Sub userMsg
     , sharedData : DataSource sharedData
     , data : route -> DataSource (PageServerResponse pageData errorPage)
+    , action : route -> DataSource (PageServerResponse actionData errorPage)
     , view :
         { path : Path
         , route : route
@@ -83,8 +83,9 @@ type alias ProgramConfig userMsg userModel route pageData sharedData effect mapp
     , sendPageData : Pages.Internal.Platform.ToJsPayload.NewThingForPort -> Cmd Never
     , byteEncodePageData : pageData -> Bytes.Encode.Encoder
     , byteDecodePageData : route -> Bytes.Decode.Decoder pageData
-    , encodeResponse : ResponseSketch pageData sharedData -> Bytes.Encode.Encoder
-    , decodeResponse : Bytes.Decode.Decoder (ResponseSketch pageData sharedData)
+    , encodeResponse : ResponseSketch pageData actionData sharedData -> Bytes.Encode.Encoder
+    , encodeAction : actionData -> Bytes.Encode.Encoder
+    , decodeResponse : Bytes.Decode.Decoder (ResponseSketch pageData actionData sharedData)
     , globalHeadTags : Maybe (DataSource (List Head.Tag))
     , cmdToEffect : Cmd userMsg -> effect
     , perform :

src/RenderRequest.elm

@@ -49,7 +49,7 @@ type IncludeHtml
 
 
 decoder :
-    ProgramConfig userMsg userModel (Maybe route) pageData sharedData effect mappedMsg errorPage
+    ProgramConfig userMsg userModel (Maybe route) pageData actionData sharedData effect mappedMsg errorPage
     -> Decode.Decoder (RenderRequest (Maybe route))
 decoder config =
     Decode.field "request"
@@ -90,7 +90,7 @@ decoder config =
 
 
 requestPayloadDecoder :
-    ProgramConfig userMsg userModel (Maybe route) pageData sharedData effect mappedMsg errorPage
+    ProgramConfig userMsg userModel (Maybe route) pageData actionData sharedData effect mappedMsg errorPage
     -> Decode.Decoder (RequestPayload (Maybe route))
 requestPayloadDecoder config =
     (Decode.string