Support streaming streaming responses for callable functions. (#8609)

The new .stream() API allows the client to consume streaming responses from the WIP streaming callable functions in Firebase Functions Node.js SDK.

When client makes a request to the callable function w/ header Accept: text/event-stream, the callable function responds with response chunks in Server-Sent Event format.

The sdk changes here abstracts over the wire-protocol by parsing the response chunks and returning an instance of a AsyncIterable to consume to data:

import { getFunctions, httpsCallable } from "firebase/functions";

const functions = getFunctions();
const generateText = httpsCallable(functions, 'generateText');
const resp = await generateText.stream(
  { text: 'What is your favorite Firebase service and why?' },
  { signal: AbortSignal.timeout(60_000) },
);
try {
  for await (const message of resp.stream) {
     console.log(message); // prints "foo", "bar"
  }
  console.log(await resp.data) // prints "foo bar"
} catch (e) {
  // FirebaseError(code='cancelled', message='Request was cancelled.');
  console.error(e)
}

.changeset/bright-scissors-care.md

@@ -0,0 +1,6 @@
+---
+'@firebase/functions': minor
+'firebase': minor
+---
+
+Add `.stream()` api for callable functions for consuming streaming responses.

common/api-review/functions.api.md

@@ -35,13 +35,18 @@ export type FunctionsErrorCodeCore = 'ok' | 'cancelled' | 'unknown' | 'invalid-a
 export function getFunctions(app?: FirebaseApp, regionOrCustomDomain?: string): Functions;
 
 // @public
-export type HttpsCallable<RequestData = unknown, ResponseData = unknown> = (data?: RequestData | null) => Promise<HttpsCallableResult<ResponseData>>;
+export interface HttpsCallable<RequestData = unknown, ResponseData = unknown, StreamData = unknown> {
+    // (undocumented)
+    (data?: RequestData | null): Promise<HttpsCallableResult<ResponseData>>;
+    // (undocumented)
+    stream: (data?: RequestData | null, options?: HttpsCallableStreamOptions) => Promise<HttpsCallableStreamResult<ResponseData, StreamData>>;
+}
 
 // @public
-export function httpsCallable<RequestData = unknown, ResponseData = unknown>(functionsInstance: Functions, name: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData>;
+export function httpsCallable<RequestData = unknown, ResponseData = unknown, StreamData = unknown>(functionsInstance: Functions, name: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData, StreamData>;
 
 // @public
-export function httpsCallableFromURL<RequestData = unknown, ResponseData = unknown>(functionsInstance: Functions, url: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData>;
+export function httpsCallableFromURL<RequestData = unknown, ResponseData = unknown, StreamData = unknown>(functionsInstance: Functions, url: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData, StreamData>;
 
 // @public
 export interface HttpsCallableOptions {
@@ -54,5 +59,19 @@ export interface HttpsCallableResult<ResponseData = unknown> {
     readonly data: ResponseData;
 }
 
+// @public
+export interface HttpsCallableStreamOptions {
+    limitedUseAppCheckTokens?: boolean;
+    signal?: AbortSignal;
+}
+
+// @public
+export interface HttpsCallableStreamResult<ResponseData = unknown, StreamData = unknown> {
+    // (undocumented)
+    readonly data: Promise<ResponseData>;
+    // (undocumented)
+    readonly stream: AsyncIterable<StreamData>;
+}
+
 
 ```

config/.gitignore

@@ -0,0 +1 @@
+# Uncomment this if you'd like others to create their own Firebase project.

docs-devsite/_toc.yaml

@@ -375,10 +375,16 @@ toc:
         path: /docs/reference/js/functions.functions.md
       - title: FunctionsError
         path: /docs/reference/js/functions.functionserror.md
+      - title: HttpsCallable
+        path: /docs/reference/js/functions.httpscallable.md
       - title: HttpsCallableOptions
         path: /docs/reference/js/functions.httpscallableoptions.md
       - title: HttpsCallableResult
         path: /docs/reference/js/functions.httpscallableresult.md
+      - title: HttpsCallableStreamOptions
+        path: /docs/reference/js/functions.httpscallablestreamoptions.md
+      - title: HttpsCallableStreamResult
+        path: /docs/reference/js/functions.httpscallablestreamresult.md
   - title: installations
     path: /docs/reference/js/installations.md
     section:

docs-devsite/functions.httpscallable.md

@@ -0,0 +1,33 @@
+Project: /docs/reference/js/_project.yaml
+Book: /docs/reference/_book.yaml
+page_type: reference
+
+{% comment %}
+DO NOT EDIT THIS FILE!
+This is generated by the JS SDK team, and any local changes will be
+overwritten. Changes should be made in the source code at
+https://github.com/firebase/firebase-js-sdk
+{% endcomment %}
+
+# HttpsCallable interface
+A reference to a "callable" HTTP trigger in Cloud Functions.
+
+<b>Signature:</b>
+
+```typescript
+export interface HttpsCallable<RequestData = unknown, ResponseData = unknown, StreamData = unknown> 
+```
+
+## Properties
+
+|  Property | Type | Description |
+|  --- | --- | --- |
+|  [stream](./functions.httpscallable.md#httpscallablestream) | (data?: RequestData \| null, options?: [HttpsCallableStreamOptions](./functions.httpscallablestreamoptions.md#httpscallablestreamoptions_interface)<!-- -->) =&gt; Promise&lt;[HttpsCallableStreamResult](./functions.httpscallablestreamresult.md#httpscallablestreamresult_interface)<!-- -->&lt;ResponseData, StreamData&gt;&gt; |  |
+
+## HttpsCallable.stream
+
+<b>Signature:</b>
+
+```typescript
+stream: (data?: RequestData | null, options?: HttpsCallableStreamOptions) => Promise<HttpsCallableStreamResult<ResponseData, StreamData>>;
+```

docs-devsite/functions.httpscallableoptions.md

@@ -22,12 +22,12 @@ export interface HttpsCallableOptions
 
 |  Property | Type | Description |
 |  --- | --- | --- |
-|  [limitedUseAppCheckTokens](./functions.httpscallableoptions.md#httpscallableoptionslimiteduseappchecktokens) | boolean | If set to true, uses limited-use App Check token for callable function requests from this instance of [Functions](./functions.functions.md#functions_interface)<!-- -->. You must use limited-use tokens to call functions with replay protection enabled. By default, this is false. |
+|  [limitedUseAppCheckTokens](./functions.httpscallableoptions.md#httpscallableoptionslimiteduseappchecktokens) | boolean | If set to true, uses a limited-use App Check token for callable function requests from this instance of [Functions](./functions.functions.md#functions_interface)<!-- -->. You must use limited-use tokens to call functions with replay protection enabled. By default, this is false. |
 |  [timeout](./functions.httpscallableoptions.md#httpscallableoptionstimeout) | number | Time in milliseconds after which to cancel if there is no response. Default is 70000. |
 
 ## HttpsCallableOptions.limitedUseAppCheckTokens
 
-If set to true, uses limited-use App Check token for callable function requests from this instance of [Functions](./functions.functions.md#functions_interface)<!-- -->. You must use limited-use tokens to call functions with replay protection enabled. By default, this is false.
+If set to true, uses a limited-use App Check token for callable function requests from this instance of [Functions](./functions.functions.md#functions_interface)<!-- -->. You must use limited-use tokens to call functions with replay protection enabled. By default, this is false.
 
 <b>Signature:</b>
 

docs-devsite/functions.httpscallablestreamoptions.md

@@ -0,0 +1,46 @@
+Project: /docs/reference/js/_project.yaml
+Book: /docs/reference/_book.yaml
+page_type: reference
+
+{% comment %}
+DO NOT EDIT THIS FILE!
+This is generated by the JS SDK team, and any local changes will be
+overwritten. Changes should be made in the source code at
+https://github.com/firebase/firebase-js-sdk
+{% endcomment %}
+
+# HttpsCallableStreamOptions interface
+An interface for metadata about how a stream call should be executed.
+
+<b>Signature:</b>
+
+```typescript
+export interface HttpsCallableStreamOptions 
+```
+
+## Properties
+
+|  Property | Type | Description |
+|  --- | --- | --- |
+|  [limitedUseAppCheckTokens](./functions.httpscallablestreamoptions.md#httpscallablestreamoptionslimiteduseappchecktokens) | boolean | If set to true, uses a limited-use App Check token for callable function requests from this instance of [Functions](./functions.functions.md#functions_interface)<!-- -->. You must use limited-use tokens to call functions with replay protection enabled. By default, this is false. |
+|  [signal](./functions.httpscallablestreamoptions.md#httpscallablestreamoptionssignal) | AbortSignal | An <code>AbortSignal</code> that can be used to cancel the streaming response. When the signal is aborted, the underlying HTTP connection will be terminated. |
+
+## HttpsCallableStreamOptions.limitedUseAppCheckTokens
+
+If set to true, uses a limited-use App Check token for callable function requests from this instance of [Functions](./functions.functions.md#functions_interface)<!-- -->. You must use limited-use tokens to call functions with replay protection enabled. By default, this is false.
+
+<b>Signature:</b>
+
+```typescript
+limitedUseAppCheckTokens?: boolean;
+```
+
+## HttpsCallableStreamOptions.signal
+
+An `AbortSignal` that can be used to cancel the streaming response. When the signal is aborted, the underlying HTTP connection will be terminated.
+
+<b>Signature:</b>
+
+```typescript
+signal?: AbortSignal;
+```

docs-devsite/functions.httpscallablestreamresult.md

@@ -0,0 +1,42 @@
+Project: /docs/reference/js/_project.yaml
+Book: /docs/reference/_book.yaml
+page_type: reference
+
+{% comment %}
+DO NOT EDIT THIS FILE!
+This is generated by the JS SDK team, and any local changes will be
+overwritten. Changes should be made in the source code at
+https://github.com/firebase/firebase-js-sdk
+{% endcomment %}
+
+# HttpsCallableStreamResult interface
+An `HttpsCallableStreamResult` wraps a single streaming result from a function call.
+
+<b>Signature:</b>
+
+```typescript
+export interface HttpsCallableStreamResult<ResponseData = unknown, StreamData = unknown> 
+```
+
+## Properties
+
+|  Property | Type | Description |
+|  --- | --- | --- |
+|  [data](./functions.httpscallablestreamresult.md#httpscallablestreamresultdata) | Promise&lt;ResponseData&gt; |  |
+|  [stream](./functions.httpscallablestreamresult.md#httpscallablestreamresultstream) | AsyncIterable&lt;StreamData&gt; |  |
+
+## HttpsCallableStreamResult.data
+
+<b>Signature:</b>
+
+```typescript
+readonly data: Promise<ResponseData>;
+```
+
+## HttpsCallableStreamResult.stream
+
+<b>Signature:</b>
+
+```typescript
+readonly stream: AsyncIterable<StreamData>;
+```

docs-devsite/functions.md

@@ -34,16 +34,18 @@ Cloud Functions for Firebase
 |  Interface | Description |
 |  --- | --- |
 |  [Functions](./functions.functions.md#functions_interface) | A <code>Functions</code> instance. |
+|  [HttpsCallable](./functions.httpscallable.md#httpscallable_interface) | A reference to a "callable" HTTP trigger in Cloud Functions. |
 |  [HttpsCallableOptions](./functions.httpscallableoptions.md#httpscallableoptions_interface) | An interface for metadata about how calls should be executed. |
 |  [HttpsCallableResult](./functions.httpscallableresult.md#httpscallableresult_interface) | An <code>HttpsCallableResult</code> wraps a single result from a function call. |
+|  [HttpsCallableStreamOptions](./functions.httpscallablestreamoptions.md#httpscallablestreamoptions_interface) | An interface for metadata about how a stream call should be executed. |
+|  [HttpsCallableStreamResult](./functions.httpscallablestreamresult.md#httpscallablestreamresult_interface) | An <code>HttpsCallableStreamResult</code> wraps a single streaming result from a function call. |
 
 ## Type Aliases
 
 |  Type Alias | Description |
 |  --- | --- |
 |  [FunctionsErrorCode](./functions.md#functionserrorcode) | The set of Firebase Functions status codes. The codes are the same at the ones exposed by gRPC here: https://github.com/grpc/grpc/blob/master/doc/statuscodes.md<!-- -->Possible values: - 'cancelled': The operation was cancelled (typically by the caller). - 'unknown': Unknown error or an error from a different error domain. - 'invalid-argument': Client specified an invalid argument. Note that this differs from 'failed-precondition'. 'invalid-argument' indicates arguments that are problematic regardless of the state of the system (e.g. an invalid field name). - 'deadline-exceeded': Deadline expired before operation could complete. For operations that change the state of the system, this error may be returned even if the operation has completed successfully. For example, a successful response from a server could have been delayed long enough for the deadline to expire. - 'not-found': Some requested document was not found. - 'already-exists': Some document that we attempted to create already exists. - 'permission-denied': The caller does not have permission to execute the specified operation. - 'resource-exhausted': Some resource has been exhausted, perhaps a per-user quota, or perhaps the entire file system is out of space. - 'failed-precondition': Operation was rejected because the system is not in a state required for the operation's execution. - 'aborted': The operation was aborted, typically due to a concurrency issue like transaction aborts, etc. - 'out-of-range': Operation was attempted past the valid range. - 'unimplemented': Operation is not implemented or not supported/enabled. - 'internal': Internal errors. Means some invariants expected by underlying system has been broken. If you see one of these errors, something is very broken. - 'unavailable': The service is currently unavailable. This is most likely a transient condition and may be corrected by retrying with a backoff. - 'data-loss': Unrecoverable data loss or corruption. - 'unauthenticated': The request does not have valid authentication credentials for the operation. |
 |  [FunctionsErrorCodeCore](./functions.md#functionserrorcodecore) | Functions error code string appended after "functions/" product prefix. See [FunctionsErrorCode](./functions.md#functionserrorcode) for full documentation of codes. |
-|  [HttpsCallable](./functions.md#httpscallable) | A reference to a "callable" HTTP trigger in Google Cloud Functions. |
 
 ## function(app, ...)
 
@@ -101,7 +103,7 @@ Returns a reference to the callable HTTPS trigger with the given name.
 <b>Signature:</b>
 
 ```typescript
-export declare function httpsCallable<RequestData = unknown, ResponseData = unknown>(functionsInstance: Functions, name: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData>;
+export declare function httpsCallable<RequestData = unknown, ResponseData = unknown, StreamData = unknown>(functionsInstance: Functions, name: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData, StreamData>;
 ```
 
 #### Parameters
@@ -114,7 +116,7 @@ export declare function httpsCallable<RequestData = unknown, ResponseData = unkn
 
 <b>Returns:</b>
 
-[HttpsCallable](./functions.md#httpscallable)<!-- -->&lt;RequestData, ResponseData&gt;
+[HttpsCallable](./functions.httpscallable.md#httpscallable_interface)<!-- -->&lt;RequestData, ResponseData, StreamData&gt;
 
 ### httpsCallableFromURL(functionsInstance, url, options) {:#httpscallablefromurl_7af6987}
 
@@ -123,7 +125,7 @@ Returns a reference to the callable HTTPS trigger with the specified url.
 <b>Signature:</b>
 
 ```typescript
-export declare function httpsCallableFromURL<RequestData = unknown, ResponseData = unknown>(functionsInstance: Functions, url: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData>;
+export declare function httpsCallableFromURL<RequestData = unknown, ResponseData = unknown, StreamData = unknown>(functionsInstance: Functions, url: string, options?: HttpsCallableOptions): HttpsCallable<RequestData, ResponseData, StreamData>;
 ```
 
 #### Parameters
@@ -136,7 +138,7 @@ export declare function httpsCallableFromURL<RequestData = unknown, ResponseData
 
 <b>Returns:</b>
 
-[HttpsCallable](./functions.md#httpscallable)<!-- -->&lt;RequestData, ResponseData&gt;
+[HttpsCallable](./functions.httpscallable.md#httpscallable_interface)<!-- -->&lt;RequestData, ResponseData, StreamData&gt;
 
 ## FunctionsErrorCode
 
@@ -159,13 +161,3 @@ Functions error code string appended after "functions/" product prefix. See [Fun
 ```typescript
 export type FunctionsErrorCodeCore = 'ok' | 'cancelled' | 'unknown' | 'invalid-argument' | 'deadline-exceeded' | 'not-found' | 'already-exists' | 'permission-denied' | 'resource-exhausted' | 'failed-precondition' | 'aborted' | 'out-of-range' | 'unimplemented' | 'internal' | 'unavailable' | 'data-loss' | 'unauthenticated';
 ```
-
-## HttpsCallable
-
-A reference to a "callable" HTTP trigger in Google Cloud Functions.
-
-<b>Signature:</b>
-
-```typescript
-export type HttpsCallable<RequestData = unknown, ResponseData = unknown> = (data?: RequestData | null) => Promise<HttpsCallableResult<ResponseData>>;
-```

packages/functions/package.json

@@ -37,7 +37,7 @@
     "test:browser": "karma start",
     "test:browser:debug": "karma start --browsers=Chrome --auto-watch",
     "test:node": "TS_NODE_COMPILER_OPTIONS='{\"module\":\"commonjs\"}' nyc --reporter lcovonly -- mocha 'src/{,!(browser)/**/}*.test.ts' --file src/index.ts --config ../../config/mocharc.node.js",
-    "test:emulator": "env FIREBASE_FUNCTIONS_EMULATOR_ORIGIN=http://localhost:5005 run-p --npm-path npm test:node",
+    "test:emulator": "env FIREBASE_FUNCTIONS_EMULATOR_ORIGIN=http://127.0.0.1:5005 run-p --npm-path npm test:node",
     "trusted-type-check": "tsec -p tsconfig.json --noEmit",
     "api-report": "api-extractor run --local --verbose",
     "doc": "api-documenter markdown --input temp --output docs",

packages/functions/src/api.ts

@@ -88,12 +88,16 @@ export function connectFunctionsEmulator(
  * @param name - The name of the trigger.
  * @public
  */
-export function httpsCallable<RequestData = unknown, ResponseData = unknown>(
+export function httpsCallable<
+  RequestData = unknown,
+  ResponseData = unknown,
+  StreamData = unknown
+>(
   functionsInstance: Functions,
   name: string,
   options?: HttpsCallableOptions
-): HttpsCallable<RequestData, ResponseData> {
-  return _httpsCallable<RequestData, ResponseData>(
+): HttpsCallable<RequestData, ResponseData, StreamData> {
+  return _httpsCallable<RequestData, ResponseData, StreamData>(
     getModularInstance<FunctionsService>(functionsInstance as FunctionsService),
     name,
     options
@@ -107,13 +111,14 @@ export function httpsCallable<RequestData = unknown, ResponseData = unknown>(
  */
 export function httpsCallableFromURL<
   RequestData = unknown,
-  ResponseData = unknown
+  ResponseData = unknown,
+  StreamData = unknown
 >(
   functionsInstance: Functions,
   url: string,
   options?: HttpsCallableOptions
-): HttpsCallable<RequestData, ResponseData> {
-  return _httpsCallableFromURL<RequestData, ResponseData>(
+): HttpsCallable<RequestData, ResponseData, StreamData> {
+  return _httpsCallableFromURL<RequestData, ResponseData, StreamData>(
     getModularInstance<FunctionsService>(functionsInstance as FunctionsService),
     url,
     options