Add live captions stream endpoints and test sender

routes/liveCaptions.js

@@ -0,0 +1,129 @@
+var express = require('express');
+var router = express.Router();
+
+const sessionChecker = require("../middleware/sessionChecker.js");
+
+const MAX_BUFFER_SIZE = 300;
+const DEFAULT_INITIAL_LIMIT = 40;
+const MAX_INITIAL_LIMIT = 120;
+
+const liveCaptionState = {
+    startedAt: Date.now(),
+    latestSequence: 0,
+    captions: [],
+};
+
+const normalizeLang = (lang = "") => {
+    const value = String(lang || "").trim().toLowerCase();
+    if (!value) return "";
+    const base = value.split(",")[0].split("-")[0].trim();
+    return base || value;
+};
+
+const normalizeTranslations = (translations) => {
+    if (!translations || typeof translations !== "object" || Array.isArray(translations)) return {};
+    const normalized = {};
+    for (const [langKey, translatedText] of Object.entries(translations)) {
+        const lang = normalizeLang(langKey);
+        const text = typeof translatedText === "string" ? translatedText.trim() : "";
+        if (!lang || !text) continue;
+        normalized[lang] = text;
+    }
+    return normalized;
+};
+
+const getAvailableLanguages = () => {
+    const langs = new Set();
+    for (const caption of liveCaptionState.captions) {
+        if (caption?.sourceLang) langs.add(caption.sourceLang);
+        const translationMap = caption?.translations || {};
+        Object.keys(translationMap).forEach((lang) => langs.add(normalizeLang(lang)));
+    }
+    return Array.from(langs).filter(Boolean).sort();
+};
+
+router.get("/stream", sessionChecker, async (req, res) => {
+    try {
+        const sinceSequence = Number.parseInt(req.query?.sinceSequence, 10);
+        const requestedLimit = Number.parseInt(req.query?.limit, 10);
+        const initialLimit = Number.isFinite(requestedLimit)
+            ? Math.max(1, Math.min(requestedLimit, MAX_INITIAL_LIMIT))
+            : DEFAULT_INITIAL_LIMIT;
+
+        let captions = [];
+        if (Number.isFinite(sinceSequence) && sinceSequence >= 0) {
+            captions = liveCaptionState.captions.filter((item) => item.sequence > sinceSequence);
+        } else {
+            captions = liveCaptionState.captions.slice(-initialLimit);
+        }
+
+        return res.json({
+            status: "ok",
+            latestSequence: liveCaptionState.latestSequence,
+            startedAt: new Date(liveCaptionState.startedAt).toISOString(),
+            availableLanguages: getAvailableLanguages(),
+            captions,
+        });
+    } catch (error) {
+        console.error("Error getting live captions stream", error);
+        return res.status(500).json({
+            status: "Internal server error",
+            latestSequence: liveCaptionState.latestSequence,
+            captions: [],
+            availableLanguages: [],
+        });
+    }
+});
+
+router.post("/ingest", async (req, res) => {
+    try {
+        // TODO: Add basic auth/API key validation before production roll-out.
+        const original = typeof req.body?.original === "string" ? req.body.original.trim() : "";
+        const sourceLang = normalizeLang(req.body?.sourceLang || "original");
+        const translations = normalizeTranslations(req.body?.translations);
+
+        if (!original) {
+            return res.status(400).json({ status: "Original text is required" });
+        }
+
+        const sequence = liveCaptionState.latestSequence + 1;
+        const caption = {
+            sequence,
+            createdAt: new Date().toISOString(),
+            sourceLang,
+            original,
+            translations,
+        };
+
+        liveCaptionState.latestSequence = sequence;
+        liveCaptionState.captions.push(caption);
+        if (liveCaptionState.captions.length > MAX_BUFFER_SIZE) {
+            liveCaptionState.captions.splice(0, liveCaptionState.captions.length - MAX_BUFFER_SIZE);
+        }
+
+        return res.json({
+            status: "ok",
+            caption,
+            latestSequence: liveCaptionState.latestSequence,
+            availableLanguages: getAvailableLanguages(),
+        });
+    } catch (error) {
+        console.error("Error ingesting live captions", error);
+        return res.status(500).json({ status: "Internal server error" });
+    }
+});
+
+router.post("/reset", async (_, res) => {
+    try {
+        // TODO: Add admin authorization before exposing this endpoint.
+        liveCaptionState.startedAt = Date.now();
+        liveCaptionState.latestSequence = 0;
+        liveCaptionState.captions = [];
+        return res.json({ status: "ok" });
+    } catch (error) {
+        console.error("Error resetting live captions state", error);
+        return res.status(500).json({ status: "Internal server error" });
+    }
+});
+
+module.exports = router;