fix reconnection and example

Author: GrosSacASac

js/network/onewaydata/changelog.md

@@ -8,10 +8,12 @@
  * Add possibility to change reconnection time with reconnectionTime
  * Replaced path option with general purpose condition
  * Use the following to keep using path
+ * Removed a weird condition
+ * Simplify code with optional chaining
+ * Fix reconnection
 
 ```js
-const path = ...
 const condition = (request) => {
-    request.url === path;
+    return request.url === `/sse`;
 };
 ```

js/network/onewaydata/examples/client.html

@@ -8,10 +8,10 @@
 <div>
   <h1>EventSource</h1>
 
-  <h2>Last message on default channel</h2>
+  <h2>Last message without explicit event type</h2>
   <p id="lastmessage"></p>
 
-  <h2>Goals</h2>
+  <h2>Message sent with event type football/goal</h2>
   <ol id="goals"></ol>
 </div>
 
@@ -31,4 +31,4 @@ <h2>Goals</h2>
 });     
 </script>
 </body>
-</html>
+</html>

js/network/onewaydata/examples/server.js

@@ -5,8 +5,8 @@ import url from "node:url";
 import path from "node:path";
 import {
     createEventStream,
+    RECONNECT,
     sendOne,
-    defaultChannel,
 } from "../source/onewaydata.js";
 import {
     useDefaultLogging
@@ -22,24 +22,42 @@ const PORT = 8080;
 const server = http.createServer((req, res) => {
     if (req.url === `/`) {
         fs.createReadStream(`${__dirname}/client.html`).pipe(res);
+    } else {
+        console.log(req.headers);
     }
 });
 
-const path = `/sse`;
+
 const condition = (request) => {
-    request.url === path;
+    return request.url === `/sse`;
 };
 const eventStream = createEventStream({ server, condition });
 useDefaultLogging({ eventStream });
 
+eventStream.on(RECONNECT, ({lastId, response}) => {
+    if (lastId) {
+        // opportunity to resume with sendOne
+        let dateString = ``;
+        let numberId = Number(lastId);
+        if (Number.isFinite(numberId)) {
+            const d = new Date();
+            d.setTime(numberId);
+            dateString = d.toTimeString();
+        }
+        sendOne(response, {
+            event: `football/goal`,
+            data: `Welcome back, you missed some goals since ${dateString}`,
+        });
+    }
+});
 
 server.listen(PORT);
 console.log(`open http:localhost:${PORT}/`);
 
 let i = 0;
 setInterval(() => {
     eventStream.send({ data: ++i });
-}, 3000);
+}, 1000);
 
 setInterval(() => {
     eventStream.send({

js/network/onewaydata/readme.md

@@ -19,15 +19,13 @@ import {
     RECONNECT,
     CONNECT,
     DISCONNECT,
-    defaultChannel,
 } from "onewaydata";
 import { useDefaultLogging } from "onewaydata/source/defaultLogging.js";
 
 
 const server = ...
-const path = `/sse`;
 const condition = (request) => {
-    request.url === path;
+    return request.url === `/sse`;
 };
 const eventStream = createEventStream({server, condition, reconnectionTime: 5000 });
 useDefaultLogging({ eventStream });
@@ -38,9 +36,9 @@ eventStream.send({ data: `something`,  event: `eventName`, id: String(Date.now()
 eventStream.on(RECONNECT, ({lastId, response}) => {
     if (lastId) {
         // opportunity to resume with sendOne
-        sendOne(response, `here is what you missed since last disconnection`)
+        sendOne(response, `here is what you missed since last disconnection`);
     }
-})
+});
 ```
 
 ### with express/polka

js/network/onewaydata/source/onewaydata.js

@@ -4,14 +4,12 @@ export {
     RECONNECT,
     CONNECT,
     DISCONNECT,
-    defaultChannel,
 };
 import Emitter from "event-e3/event-e3.js";
 
 
 const MIME = `text/event-stream`;
-const LAST_ID = `Last-Event-ID`;
-const defaultChannel = `message`;
+const LAST_ID = (`Last-Event-ID`).toLowerCase(); // node request.headers is lower cased
 const HTTP_OK = 200;
 const HTTP_PROBLEM = 400;
 
@@ -47,15 +45,15 @@ const formatEvent = (x) => {
     if (event) {
         message = `${message}${EVENT}:${event}\n`;
     }
-    if (data && data !== defaultChannel) {
+    if (data) {
         message = `${message}${DATA}:${data}\n`;
     }
     message = `${message}\n`;
     return message;
 };
 
-const sendOne = (response, x) => {
-    const message = formatEvent(x);
+const sendOne = (response, messageObject) => {
+    const message = formatEvent(messageObject);
     response.write(message);
 };
 
@@ -64,7 +62,7 @@ const isValidRequestForServerSentEvents = (request) => {
         return;
     }
 
-    if (request.headers.accept && !request.headers.accept.includes(MIME)) {
+    if (!request.headers?.accept.includes(MIME)) {
         return;
     }
     return true;
@@ -135,8 +133,8 @@ const createEventStream = (options) => {
         });
     };
 
-    const send = (x) => {
-        const message = formatEvent(x);
+    const send = (messageObject) => {
+        const message = formatEvent(messageObject);
         responses.forEach(response => {
             response.write(message);
         });