Use esbuild to transpile port-data-source file, and watch for changes.

examples/end-to-end/port-data-source.ts

@@ -0,0 +1,24 @@
+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) {
+  await waitFor(1000);
+  return `147 ${name}!!`;
+}
+
+function waitFor(ms) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}

generator/src/dev-server.js

@@ -24,6 +24,7 @@ const cookie = require("cookie");
 const busboy = require("busboy");
 const { createServer: createViteServer } = require("vite");
 const cliVersion = require("../../package.json").version;
+const esbuild = require("esbuild");
 
 /**
  * @param {{ port: string; base: string; https: boolean; debug: boolean; }} options
@@ -137,6 +138,40 @@ async function start(options) {
     base: options.base,
     ...viteConfig,
   });
+  esbuild
+    .build({
+      entryPoints: ["./port-data-source"],
+      entryNames: "[dir]/[name]-[hash]",
+
+      outdir: ".elm-pages/compiled-ports",
+      assetNames: "[name]-[hash]",
+      chunkNames: "chunks/[name]-[hash]",
+      outExtension: { ".js": ".mjs" },
+
+      metafile: true,
+      bundle: false,
+      watch: true,
+      plugins: [
+        {
+          name: "example",
+          setup(build) {
+            build.onEnd((result) => {
+              global.portsFilePath = Object.keys(result.metafile.outputs)[0];
+
+              clients.forEach((client) => {
+                client.response.write(`data: content.dat\n\n`);
+              });
+            });
+          },
+        },
+      ],
+    })
+    .then((result) => {
+      console.log("Watching port-data-source...");
+    })
+    .catch((error) => {
+      console.error("Failed to start port-data-source watcher", error);
+    });
 
   const app = connect()
     .use(timeMiddleware())
@@ -288,6 +323,7 @@ async function start(options) {
         mode: "dev-server",
         pathname,
         serverRequest,
+        portsFilePath: global.portsFilePath,
       });
       readyThread.worker.on("message", (message) => {
         if (message.tag === "done") {
@@ -379,6 +415,7 @@ async function start(options) {
     });
 
     req.on("end", async function () {
+      // TODO run render directly instead of in worker thread
       await runRenderThread(
         await reqToJson(req, body, requestTime),
         pathname,

generator/src/hello.ts

@@ -0,0 +1,5 @@
+export function hello(): string {
+  console.log("HELLLO!!!!");
+
+  return "Hello World!";
+}

generator/src/render-worker.js

@@ -7,10 +7,11 @@ let Elm;
 
 global.staticHttpCache = {};
 
-async function run({ mode, pathname, serverRequest }) {
+async function run({ mode, pathname, serverRequest, portsFilePath }) {
   console.time(`${threadId} ${pathname}`);
   try {
     const renderResult = await renderer(
+      portsFilePath,
       workerData.basePath,
       requireElm(mode),
       mode,

generator/src/render.js

@@ -30,6 +30,7 @@ module.exports =
    * @returns
    */
   async function run(
+    portsFile,
     basePath,
     elmModule,
     mode,
@@ -49,6 +50,7 @@ module.exports =
     // we can provide a fake HTTP instead of xhr2 (which is otherwise needed for Elm HTTP requests from Node)
     XMLHttpRequest = {};
     const result = await runElmApp(
+      portsFile,
       basePath,
       elmModule,
       mode,
@@ -71,6 +73,7 @@ module.exports =
  * @returns {Promise<({is404: boolean} & ( { kind: 'json'; contentJson: string} | { kind: 'html'; htmlString: string } | { kind: 'api-response'; body: string; }) )>}
  */
 function runElmApp(
+  portsFile,
   basePath,
   elmModule,
   mode,
@@ -161,7 +164,10 @@ function runElmApp(
         }
       } else if (fromElm.tag === "DoHttp") {
         const requestToPerform = fromElm.args[0];
-        if (requestToPerform.url.startsWith("elm-pages-internal://")) {
+        if (
+          requestToPerform.url !== "elm-pages-internal://port" &&
+          requestToPerform.url.startsWith("elm-pages-internal://")
+        ) {
           runInternalJob(
             app,
             mode,
@@ -171,7 +177,7 @@ function runElmApp(
             patternsToWatch
           );
         } else {
-          runHttpJob(app, mode, requestToPerform, fs, hasFsAccess);
+          runHttpJob(portsFile, app, mode, requestToPerform, fs, hasFsAccess);
         }
       } else if (fromElm.tag === "Errors") {
         foundErrors = true;
@@ -229,10 +235,18 @@ async function outputString(
 
 /** @typedef { { head: any[]; errors: any[]; contentJson: any[]; html: string; route: string; title: string; } } Arg */
 
-async function runHttpJob(app, mode, requestToPerform, fs, hasFsAccess) {
+async function runHttpJob(
+  portsFile,
+  app,
+  mode,
+  requestToPerform,
+  fs,
+  hasFsAccess
+) {
   pendingDataSourceCount += 1;
   try {
     const responseFilePath = await lookupOrPerform(
+      portsFile,
       mode,
       requestToPerform,
       hasFsAccess

generator/src/request-cache.js

@@ -16,29 +16,36 @@ function requestToString(request) {
 /**
  * @param {Object} request
  */
-function fullPath(request, hasFsAccess) {
+function fullPath(portsHash, request, hasFsAccess) {
+  const requestWithPortHash =
+    request.url === "elm-pages-internal://port"
+      ? { portsHash, ...request }
+      : request;
   if (hasFsAccess) {
     return path.join(
       process.cwd(),
       ".elm-pages",
       "http-response-cache",
-      requestToString(request)
+      requestToString(requestWithPortHash)
     );
   } else {
-    return path.join("/", requestToString(request));
+    return path.join("/", requestToString(requestWithPortHash));
   }
 }
 
 /**
  * @param {string} mode
- * @param {{url: string; headers: {[x: string]: string}; method: string; body: Body } } rawRequest
+ * @param {{url: string;headers: {[x: string]: string;};method: string;body: Body;}} rawRequest
  * @returns {Promise<string>}
+ * @param {string} portsFile
+ * @param {boolean} hasFsAccess
  */
-function lookupOrPerform(mode, rawRequest, hasFsAccess) {
+function lookupOrPerform(portsFile, mode, rawRequest, hasFsAccess) {
   const { fs } = require("./request-cache-fs.js")(hasFsAccess);
   return new Promise(async (resolve, reject) => {
     const request = toRequest(rawRequest);
-    const responsePath = fullPath(request, hasFsAccess);
+    const portsHash = portsFile.match(/-([^-]+)\.mjs$/)[1];
+    const responsePath = fullPath(portsHash, request, hasFsAccess);
 
     // TODO check cache expiration time and delete and go to else if expired
     if (await checkFileExists(fs, responsePath)) {
@@ -48,17 +55,14 @@ function lookupOrPerform(mode, rawRequest, hasFsAccess) {
       let portDataSource = {};
       let portDataSourceFound = false;
       try {
-        portDataSource = requireUncached(
+        portDataSource = await import(path.join(process.cwd(), portsFile));
-          mode,
-          path.join(process.cwd(), "port-data-source.js")
-        );
         portDataSourceFound = true;
       } catch (e) {}
 
-      if (request.url.startsWith("port://")) {
+      if (request.url === "elm-pages-internal://port") {
         try {
-          const portName = request.url.replace(/^port:\/\//, "");
+          const { input, portName } = rawRequest.body.args[0];
-          // console.time(JSON.stringify(request.url));
+
           if (!portDataSource[portName]) {
             if (portDataSourceFound) {
               throw `DataSource.Port.send "${portName}" is not defined. Be sure to export a function with that name from port-data-source.js`;
@@ -70,9 +74,7 @@ function lookupOrPerform(mode, rawRequest, hasFsAccess) {
           }
           await fs.promises.writeFile(
             responsePath,
-            JSON.stringify(
+            JSON.stringify(jsonResponse(await portDataSource[portName](input)))
-              await portDataSource[portName](rawRequest.body.args[0])
-            )
           );
           resolve(responsePath);
         } catch (error) {
@@ -228,4 +230,11 @@ function requireUncached(mode, filePath) {
   return require(filePath);
 }
 
+/**
+ * @param {unknown} json
+ */
+function jsonResponse(json) {
+  return { bodyKind: "json", body: json };
+}
+
 module.exports = { lookupOrPerform };

package-lock.json

@@ -19,6 +19,7 @@
         "devcert": "^1.2.0",
         "elm-doc-preview": "^5.0.5",
         "elm-hot": "^1.1.6",
+        "esbuild": "^0.14.23",
         "fs-extra": "^10.0.0",
         "globby": "11.0.4",
         "gray-matter": "^4.0.3",

package.json

@@ -33,6 +33,7 @@
     "devcert": "^1.2.0",
     "elm-doc-preview": "^5.0.5",
     "elm-hot": "^1.1.6",
+    "esbuild": "^0.14.23",
     "fs-extra": "^10.0.0",
     "globby": "11.0.4",
     "gray-matter": "^4.0.3",
@@ -73,4 +74,4 @@
   "bin": {
     "elm-pages": "generator/src/cli.js"
   }
-}
+}

src/DataSource/Port.elm

@@ -8,8 +8,9 @@ module DataSource.Port exposing (get)
 
 import DataSource
 import DataSource.Http
+import DataSource.Internal.Request
 import Json.Decode exposing (Decoder)
-import Json.Encode
+import Json.Encode as Encode
 
 
 {-| In a vanilla Elm application, ports let you either send or receive JSON data between your Elm application and the JavaScript context in the user's browser at runtime.
@@ -73,12 +74,17 @@ prefer to add ANSI color codes within the error string in an exception and it wi
 As with any JavaScript or NodeJS code, avoid doing blocking IO operations. For example, avoid using `fs.readFileSync`, because blocking IO can slow down your elm-pages builds and dev server.
 
 -}
-get : String -> Json.Encode.Value -> Decoder b -> DataSource.DataSource b
+get : String -> Encode.Value -> Decoder b -> DataSource.DataSource b
 get portName input decoder =
-    DataSource.Http.request
+    DataSource.Internal.Request.request
-        { url = "port://" ++ portName
+        { name = "port"
-        , method = "GET"
+        , body =
-        , headers = []
+            Encode.object
-        , body = DataSource.Http.jsonBody input
+                [ ( "input", input )
+                , ( "portName", Encode.string portName )
+                ]
+                |> DataSource.Http.jsonBody
+        , expect =
+            decoder
+                |> DataSource.Http.expectJson
         }
-        (DataSource.Http.expectJson decoder)