Add a sample for streaming callables (#1185)

Node/quickstarts/callable-functions-streaming/.gitignore

@@ -0,0 +1,66 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+firebase-debug.log*
+firebase-debug.*.log*
+
+# Firebase cache
+.firebase/
+
+# Firebase config
+
+# Uncomment this if you'd like others to create their own Firebase project.
+# For a team working on the same Firebase project(s), it is recommended to leave
+# it commented so all members can deploy to the same project(s) in .firebaserc.
+# .firebaserc
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variables file
+.env

Node/quickstarts/callable-functions-streaming/README.md

@@ -0,0 +1,19 @@
+Firebase HTTPS Callable functions streaming quickstart
+================================================
+
+This quickstart demonstrates how to send requests to a server-side function and _stream_ a response to a client SDK.
+
+[Read more about Cloud Functions for Firebase](https://firebase.google.com/docs/functions/)
+
+
+Getting Started
+---------------
+
+1. Install dependencies with `npm install`
+1. Start the hosting and functions emulators with `firebase emulators:start --only functions,hosting`
+1. Visit the url of the emulated Hosting site, and click "Get forecasts"
+
+License
+-------
+
+© Google, 2025. Licensed under an [Apache-2](../../../LICENSE) license.

Node/quickstarts/callable-functions-streaming/firebase.json

@@ -0,0 +1,11 @@
+{
+  "functions": {
+    "codebase": "callable-functions",
+    "predeploy": [
+      "npm --prefix \"$RESOURCE_DIR\" run lint"
+    ]
+  },
+  "hosting": {
+    "public": "website"
+  }
+}

Node/quickstarts/callable-functions-streaming/functions/.eslintrc.js

@@ -0,0 +1,30 @@
+/**
+ * Copyright 2023 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+module.exports = {
+  root: true,
+  env: {
+    es2020: true,
+    node: true,
+  },
+  extends: [
+    "eslint:recommended",
+    "google",
+  ],
+  rules: {
+    quotes: ["error", "double"],
+  },
+};

Node/quickstarts/callable-functions-streaming/functions/.gitignore

@@ -0,0 +1 @@
+node_modules/

Node/quickstarts/callable-functions-streaming/functions/index.js

@@ -0,0 +1,74 @@
+/**
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// [START full-sample]
+// Dependencies for callable functions.
+const {onCall, HttpsError} = require("firebase-functions/v2/https");
+
+/**
+ * Gets the weather from the national weather service
+ * https://www.weather.gov/documentation/services-web-api
+ *
+ * @param {number} lat
+ * @param {number} lng
+ */
+async function weatherForecastApi(lat, lng) {
+  const resp = await fetch(`https://api.weather.gov/points/${lat},${lng}`);
+
+  if (!resp.ok) {
+    return `error: ${resp.status}`;
+  }
+
+  const forecastUrl = (await resp.json()).properties.forecast;
+  const forecastResp = await fetch(forecastUrl);
+
+  if (!forecastResp.ok) {
+    return `error: ${forecastResp.status}`;
+  }
+
+  // add an artificial wait to emphasize stream-iness
+  await new Promise((resolve) => setTimeout(resolve, Math.random() * 1500));
+
+  return forecastResp.json();
+}
+
+// [START streaming-callable]
+exports.getForecast = onCall(async (request, response) => {
+  if (request.data?.locations?.length < 1) {
+    throw new HttpsError("invalid-argument", "Missing locations to forecast");
+  }
+
+  // fetch forecast data for all requested locations
+  const allRequests = request.data.locations.map(
+      async ({latitude, longitude}) => {
+        const forecast = await weatherForecastApi(latitude, longitude);
+        const result = {latitude, longitude, forecast};
+
+        // clients that support streaming will have each
+        // forecast streamed to them as they complete
+        if (request.acceptsStreaming) {
+          response.sendChunk(result);
+        }
+
+        return result;
+      },
+  );
+
+  // Return the full set of data to all clients
+  return Promise.all(allRequests);
+});
+// [END streaming-callable]
+// [END full-sample]

Node/quickstarts/callable-functions-streaming/functions/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "callable-functions-streaming",
+  "description": "Cloud Functions for Firebase",
+  "scripts": {
+    "lint": "eslint .",
+    "lintfix": "eslint . --fix",
+    "serve": "firebase emulators:start --only functions",
+    "shell": "firebase functions:shell",
+    "start": "npm run shell",
+    "deploy": "firebase deploy --only functions",
+    "logs": "firebase functions:log",
+    "compile": "cp ../../../../tsconfig.template.json ./tsconfig-compile.json && tsc --project tsconfig-compile.json"
+  },
+  "engines": {
+    "node": "22"
+  },
+  "main": "index.js",
+  "dependencies": {
+    "firebase-admin": "^13.0.2",
+    "firebase-functions": "^6.3.1"
+  },
+  "devDependencies": {
+    "eslint": "^8.57.1",
+    "eslint-config-google": "^0.14.0",
+    "firebase-functions-test": "^3.4.0"
+  },
+  "private": true
+}