sse.js/demo.html at main · mpetazzoni/sse.js · GitHub

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<!DOCTYPE html>
<html>
  <head>
    <title>sse.js test</title>
    <style type="text/css">
      body {
        width: 60%;
        margin: 2em auto;
        font-family: monospace;
      }
      #content {
        display: flex;
        flex-direction: column-reverse;
      }
      #content div {
        border: 1px #eee solid;
        background: #f5f5f5;
        padding: 1em;
        margin: 1em 0;
      }
      #content span {
        display: block;
        text-align: right;
        color: #ccc;
        font-size: small;
      }
      #content pre {
        margin: 0;
      }
      .error {
        background-color: #fee !important;
        color: #900;
      }
      .info {
        background-color: #eef !important;
        color: #009;
      }
      .controls {
        margin: 1em 0;
        display: flex;
        gap: 1em;
        align-items: center;
      }
      .controls label {
        display: flex;
        align-items: center;
        gap: 0.5em;
      }
      .controls input[type="number"] {
        width: 6em;
      }
      .controls-group {
        border: 1px solid #eee;
        padding: 1em;
        margin: 1em 0;
        border-radius: 4px;
      }
      .controls-group h3 {
        margin: 0 0 1em 0;
        color: #666;
        font-size: 0.9em;
      }
    </style>
  </head>
  <body>
    <header>
      <h1>sse.js streaming demo</h1>
    </header>

    <main>
      <section>
        <label for="url">Enter a SSE source URL:</label>
        <input type="url" id="url" size="40" required />
        <input type="button" id="go" value="Start" />

        <div class="controls-group">
          <h3>Connection Settings</h3>
          <div class="controls">
            <label>
              <input type="checkbox" id="auto-reconnect" checked />
              Auto-reconnect
            </label>
            <label>
              <input
                type="number"
                id="reconnect-delay"
                value="3000"
                min="500"
                step="500"
              />
              ms delay
            </label>
          </div>
          <div class="controls">
            <label>
              <input type="checkbox" id="use-last-event-id" />
              Use Last-Event-ID header
            </label>
          </div>
          <div class="controls">
            <label>
              <input
                type="number"
                id="max-retries"
                value=""
                min="1"
                placeholder="∞"
              />
              max retries (empty = unlimited)
            </label>
          </div>
        </div>
      </section>
      <section id="content"></section>
    </main>

    <script type="module">
      import { SSE } from "./lib/sse.js";

      var url = document.getElementById("url");
      var button = document.getElementById("go");
      var content = document.getElementById("content");
      var autoReconnect = document.getElementById("auto-reconnect");
      var reconnectDelay = document.getElementById("reconnect-delay");
      var useLastEventId = document.getElementById("use-last-event-id");
      var maxRetries = document.getElementById("max-retries");
      var source;

      function addMessage(data, type = "") {
        var el = document.createElement("div");
        if (type) {
          el.className = type;
        }

        var span = document.createElement("span");
        span.appendChild(document.createTextNode(new Date().toString()));
        el.appendChild(span);

        var pre = document.createElement("pre");
        pre.appendChild(
          document.createTextNode(
            typeof data === "object"
              ? JSON.stringify(data, null, 2)
              : String(data)
          )
        );
        el.appendChild(pre);

        content.append(el);
      }

      function show(e) {
        console.log("Received SSE message:", e);

        let data = e.data;
        try {
          if (
            typeof data === "string" &&
            (data.startsWith("{") || data.startsWith("["))
          ) {
            data = JSON.parse(data);
            if (data.time && typeof data.time === "number") {
              data.time = new Date(data.time * 1000);
            }
          }
        } catch (err) {
          console.warn("Failed to parse message data as JSON:", err);
        }

        addMessage(data);
      }

      function start() {
        if (!url.value) {
          addMessage("Please enter a valid SSE URL", "error");
          return;
        }

        content.innerHTML = "";
        addMessage("Connecting to " + url.value, "info");

        const options = {
          start: false,
          debug: true,
          autoReconnect: autoReconnect.checked,
          reconnectDelay: parseInt(reconnectDelay.value, 10),
          useLastEventId: useLastEventId.checked,
          maxRetries: maxRetries.value ? parseInt(maxRetries.value, 10) : null,
        };

        if (options.autoReconnect) {
          const retryMsg = options.maxRetries
            ? `Auto-reconnect enabled (${options.reconnectDelay}ms delay, max ${options.maxRetries} retries)`
            : `Auto-reconnect enabled (${options.reconnectDelay}ms delay, unlimited retries)`;
          addMessage(retryMsg, "info");
        }

        source = new SSE(url.value, options);

        source.addEventListener("message", show);

        source.addEventListener("open", function (e) {
          addMessage("Connection opened", "info");
        });

        source.addEventListener("error", (e) => {
          const msg = e.data
            ? `Error: ${e.data}`
            : "Error: Unknown error occurred";
          addMessage(msg, "error");

          const nextAttempt = source.retryCount + 1;
          if (source.maxRetries && nextAttempt > source.maxRetries) {
            // Max retries reached, reset button
            button.value = "Start";
            button.onclick = start;
            addMessage(
              `Max retries (${source.maxRetries}) reached, connection permanently closed`,
              "info"
            );
          } else if (!source.autoReconnect) {
            // No auto-reconnect, reset button
            button.value = "Start";
            button.onclick = start;
          } else {
            // Still retrying
            addMessage(
              `Will attempt to reconnect in ${
                options.reconnectDelay
              }ms (attempt ${nextAttempt}${
                source.maxRetries ? "/" + source.maxRetries : ""
              })`,
              "info"
            );
          }
        });

        source.stream();

        button.value = "Stop";
        button.onclick = reset;
      }

      function reset() {
        if (source) {
          source.close();
          addMessage("Connection closed", "info");
        }

        button.value = "Start";
        button.onclick = start;
      }

      reset();
    </script>
  </body>
</html>