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| /**
* Copyright 2017 Google Inc.
*
* 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.
*/
import {
ErrorCode,
EventType,
WebChannel,
XhrIoPool,
createWebChannelTransport
} from '@firebase/webchannel-wrapper';
import { Token } from '../api/credentials';
import { DatabaseId, DatabaseInfo } from '../core/database_info';
import { SDK_VERSION } from '../core/version';
import { Connection, Stream } from '../remote/connection';
import {
mapCodeFromHttpStatus,
mapCodeFromRpcStatus
} from '../remote/rpc_error';
import { StreamBridge } from '../remote/stream_bridge';
import { assert, fail } from '../util/assert';
import { Code, FirestoreError } from '../util/error';
import * as log from '../util/log';
import { Rejecter, Resolver } from '../util/promise';
import { StringMap } from '../util/types';
const LOG_TAG = 'Connection';
const RPC_STREAM_SERVICE = 'google.firestore.v1beta1.Firestore';
const RPC_URL_VERSION = 'v1beta1';
/** Maps RPC names to the corresponding REST endpoint name. */
const RPC_NAME_REST_MAPPING = {
BatchGetDocuments: 'batchGet',
Commit: 'commit'
};
// TODO(b/38203344): The SDK_VERSION is set independently from Firebase because
// we are doing out-of-band releases. Once we release as part of Firebase, we
// should use the Firebase version instead.
const X_GOOG_API_CLIENT_VALUE = 'gl-js/ fire/' + SDK_VERSION;
const XHR_TIMEOUT_SECS = 15;
export class WebChannelConnection implements Connection {
private readonly databaseId: DatabaseId;
private readonly baseUrl: string;
private readonly pool: XhrIoPool;
constructor(info: DatabaseInfo) {
this.databaseId = info.databaseId;
this.pool = new XhrIoPool();
const proto = info.ssl ? 'https' : 'http';
this.baseUrl = proto + '://' + info.host;
}
/**
* Modifies the headers for a request, adding any authorization token if
* present and any additional headers for the request.
*/
private modifyHeadersForRequest(headers: StringMap, token: Token | null) {
Iif (token) {
for (const header in token.authHeaders) {
if (token.authHeaders.hasOwnProperty(header)) {
headers[header] = token.authHeaders[header];
}
}
}
headers['X-Goog-Api-Client'] = X_GOOG_API_CLIENT_VALUE;
// This header is used to improve routing and project isolation by the
// backend.
headers['google-cloud-resource-prefix'] =
`projects/${this.databaseId.projectId}/` +
`databases/${this.databaseId.database}`;
}
invokeRPC<Req, Resp>(
rpcName: string,
request: Req,
token: Token | null
): Promise<Resp> {
const url = this.makeUrl(rpcName);
return new Promise((resolve: Resolver<Resp>, reject: Rejecter) => {
// tslint:disable-next-line:no-any XhrIoPool doesn't have TS typings.
this.pool.getObject((xhr: any) => {
xhr.listenOnce(EventType.COMPLETE, () => {
try {
switch (xhr.getLastErrorCode()) {
case ErrorCode.NO_ERROR:
const json = xhr.getResponseJson() as Resp;
log.debug(LOG_TAG, 'XHR received:', JSON.stringify(json));
resolve(json);
break;
case ErrorCode.TIMEOUT:
log.debug(LOG_TAG, 'RPC "' + rpcName + '" timed out');
reject(
new FirestoreError(Code.DEADLINE_EXCEEDED, 'Request time out')
);
break;
case ErrorCode.HTTP_ERROR:
const status = xhr.getStatus();
log.debug(
LOG_TAG,
'RPC "' + rpcName + '" failed with status:',
status,
'response text:',
xhr.getResponseText()
);
Eif (status > 0) {
reject(
new FirestoreError(
mapCodeFromHttpStatus(status),
'Server responded with status ' + xhr.getStatusText()
)
);
} else {
// If we received an HTTP_ERROR but there's no status code,
// it's most probably a connection issue
log.debug(LOG_TAG, 'RPC "' + rpcName + '" failed');
reject(
new FirestoreError(Code.UNAVAILABLE, 'Connection failed.')
);
}
break;
default:
fail(
'RPC "' +
rpcName +
'" failed with unanticipated ' +
'webchannel error ' +
xhr.getLastErrorCode() +
': ' +
xhr.getLastError() +
', giving up.'
);
}
} finally {
log.debug(LOG_TAG, 'RPC "' + rpcName + '" completed.');
this.pool.releaseObject(xhr);
}
});
const requestString = JSON.stringify(request);
log.debug(LOG_TAG, 'XHR sending: ', url + ' ' + requestString);
// Content-Type: text/plain will avoid preflight requests which might
// mess with CORS and redirects by proxies. If we add custom headers
// we will need to change this code to potentially use the
// $httpOverwrite parameter supported by ESF to avoid
// triggering preflight requests.
const headers: StringMap = { 'Content-Type': 'text/plain' };
this.modifyHeadersForRequest(headers, token);
xhr.send(url, 'POST', requestString, headers, XHR_TIMEOUT_SECS);
});
});
}
invokeStreamingRPC<Req, Resp>(
rpcName: string,
request: Req,
token: Token | null
): Promise<Resp[]> {
// The REST API automatically aggregates all of the streamed results, so we
// can just use the normal invoke() method.
return this.invokeRPC<Req, Resp[]>(rpcName, request, token);
}
openStream<Req, Resp>(
rpcName: string,
token: Token | null
): Stream<Req, Resp> {
const urlParts = [
this.baseUrl,
'/',
RPC_STREAM_SERVICE,
'/',
rpcName,
'/channel'
];
const webchannelTransport = createWebChannelTransport();
const request = {
// Background channel test avoids the initial two test calls and decreases
// initial cold start time.
// TODO(dimond): wenboz@ mentioned this might affect use with proxies and
// we should monitor closely for any reports.
backgroundChannelTest: true,
// Required for backend stickiness, routing behavior is based on this
// parameter.
httpSessionIdParam: 'gsessionid',
initMessageHeaders: {},
// Send our custom headers as a '$httpHeaders=' url param to avoid CORS
// preflight round-trip. This is formally defined here:
// https://github.com/google/closure-library/blob/b0e1815b13fb92a46d7c9b3c30de5d6a396a3245/closure/goog/net/rpc/httpcors.js#L40
httpHeadersOverwriteParam: '$httpHeaders',
sendRawJson: true,
supportsCrossDomainXhr: true
};
this.modifyHeadersForRequest(request.initMessageHeaders, token);
const url = urlParts.join('');
log.debug(LOG_TAG, 'Creating WebChannel: ' + url + ' ' + request);
// tslint:disable-next-line:no-any Because listen isn't defined on it.
const channel = webchannelTransport.createWebChannel(url, request) as any;
// WebChannel supports sending the first message with the handshake - saving
// a network round trip. However, it will have to call send in the same
// JS event loop as open. In order to enforce this, we delay actually
// opening the WebChannel until send is called. Whether we have called
// open is tracked with this variable.
let opened = false;
// A flag to determine whether the stream was closed (by us or through an
// error/close event) to avoid delivering multiple close events or sending
// on a closed stream
let closed = false;
const streamBridge = new StreamBridge<Req, Resp>({
sendFn: (msg: Req) => {
Eif (!closed) {
if (!opened) {
log.debug(LOG_TAG, 'Opening WebChannel transport.');
channel.open();
opened = true;
}
log.debug(LOG_TAG, 'WebChannel sending:', msg);
channel.send(msg);
} else {
log.debug(LOG_TAG, 'Not sending because WebChannel is closed:', msg);
}
},
closeFn: () => channel.close()
});
// Closure events are guarded and exceptions are swallowed, so catch any
// exception and rethrow using a setTimeout so they become visible again.
// Note that eventually this function could go away if we are confident
// enough the code is exception free.
const unguardedEventListen = <T>(
type: WebChannel.EventType,
fn: (param?: T) => void
) => {
// TODO(dimond): closure typing seems broken because WebChannel does
// not implement goog.events.Listenable
channel.listen(type, (param?: T) => {
try {
fn(param);
} catch (e) {
setTimeout(() => {
throw e;
}, 0);
}
});
};
unguardedEventListen(WebChannel.EventType.OPEN, () => {
Eif (!closed) {
log.debug(LOG_TAG, 'WebChannel transport opened.');
}
});
unguardedEventListen(WebChannel.EventType.CLOSE, () => {
if (!closed) {
closed = true;
log.debug(LOG_TAG, 'WebChannel transport closed');
streamBridge.callOnClose();
}
});
unguardedEventListen<Error>(WebChannel.EventType.ERROR, err => {
if (!closed) {
closed = true;
log.debug(LOG_TAG, 'WebChannel transport errored:', err);
streamBridge.callOnClose(
new FirestoreError(
Code.UNAVAILABLE,
'The operation could not be completed'
)
);
}
});
// WebChannel delivers message events as array. If batching is not enabled
// (it's off by default) each message will be delivered alone, resulting in
// a single element array.
type WebChannelResponse = { data: Resp[] };
unguardedEventListen<WebChannelResponse>(
WebChannel.EventType.MESSAGE,
msg => {
Eif (!closed) {
const msgData = msg.data[0];
assert(!!msgData, 'Got a webchannel message without data.');
// TODO(b/35143891): There is a bug in One Platform that caused errors
// (and only errors) to be wrapped in an extra array. To be forward
// compatible with the bug we need to check either condition. The latter
// can be removed once the fix has been rolled out.
const error =
// tslint:disable-next-line:no-any msgData.error is not typed.
(msgData as any).error || (msgData[0] && msgData[0].error);
if (error) {
log.debug(LOG_TAG, 'WebChannel received error:', error);
// error.status will be a string like 'OK' or 'NOT_FOUND'.
const status: string = error.status;
let code = mapCodeFromRpcStatus(status);
let message = error.message;
Iif (code === undefined) {
code = Code.INTERNAL;
message =
'Unknown error status: ' +
status +
' with message ' +
error.message;
}
// Mark closed so no further events are propagated
closed = true;
streamBridge.callOnClose(new FirestoreError(code, message));
channel.close();
} else {
log.debug(LOG_TAG, 'WebChannel received:', msgData);
streamBridge.callOnMessage(msgData);
}
}
}
);
setTimeout(() => {
// Technically we could/should wait for the WebChannel opened event,
// but because we want to send the first message with the WebChannel
// handshake we pretend the channel opened here (asynchronously), and
// then delay the actual open until the first message is sent.
streamBridge.callOnOpen();
}, 0);
return streamBridge;
}
// visible for testing
makeUrl(rpcName: string): string {
const urlRpcName = RPC_NAME_REST_MAPPING[rpcName];
assert(urlRpcName !== undefined, 'Unknown REST mapping for: ' + rpcName);
const url = [this.baseUrl, '/', RPC_URL_VERSION];
url.push('/projects/');
url.push(this.databaseId.projectId);
url.push('/databases/');
url.push(this.databaseId.database);
url.push('/documents');
url.push(':');
url.push(urlRpcName);
return url.join('');
}
}
|