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refactor: move to flatten protocol (#3827)
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DevTools protocol is dropping nested targets and switching to
flatten protocol. This patch adopts the new scheme.

Once this change lands, tip-of-tree Puppeteer will be incompatible
with Chromium below 72.0.3606.0. Chromium 72 goes stable on [Jan, 29](https://www.chromestatus.com/features/schedule) - the same time we release the
next version of Puppeteer, so this change won't hurt those clients who try using
tip-of-tree Puppeteer with stable chrome. 

For the record: the previous attempt to land this was #3524.
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@aslushnikov
aslushnikov committed Jan 22, 2019
1 parent 678b8e8 commit 89a5c39
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Showing 2 changed files with 48 additions and 71 deletions.
113 changes: 45 additions & 68 deletions lib/Connection.js
View file
Expand Up @@ -16,7 +16,6 @@
const {helper, assert} = require('./helper');
const {Events} = require('./Events');
const debugProtocol = require('debug')('puppeteer:protocol');
const debugSession = require('debug')('puppeteer:session');
const EventEmitter = require('events');

class Connection extends EventEmitter {
Expand Down Expand Up @@ -46,11 +45,15 @@ class Connection extends EventEmitter {
* @return {!Connection}
*/
static fromSession(session) {
let connection = session._connection;
// TODO(lushnikov): move to flatten protocol to avoid this.
while (connection instanceof CDPSession)
connection = connection._connection;
return connection;
return session._connection;
}

/**
* @param {string} sessionId
* @return {?CDPSession}
*/
session(sessionId) {
return this._sessions.get(sessionId) || null;
}

/**
Expand All @@ -66,15 +69,24 @@ class Connection extends EventEmitter {
* @return {!Promise<?Object>}
*/
send(method, params = {}) {
const id = ++this._lastId;
const message = JSON.stringify({id, method, params});
debugProtocol('SEND ► ' + message);
this._transport.send(message);
const id = this._rawSend({method, params});
return new Promise((resolve, reject) => {
this._callbacks.set(id, {resolve, reject, error: new Error(), method});
});
}

/**
* @param {*} message
* @return {number}
*/
_rawSend(message) {
const id = ++this._lastId;
message = JSON.stringify(Object.assign({}, message, {id}));
debugProtocol('SEND ► ' + message);
this._transport.send(message);
return id;
}

/**
* @param {string} message
*/
Expand All @@ -83,7 +95,22 @@ class Connection extends EventEmitter {
await new Promise(f => setTimeout(f, this._delay));
debugProtocol('◀ RECV ' + message);
const object = JSON.parse(message);
if (object.id) {
if (object.method === 'Target.attachedToTarget') {
const sessionId = object.params.sessionId;
const session = new CDPSession(this, object.params.targetInfo.type, sessionId);
this._sessions.set(sessionId, session);
} else if (object.method === 'Target.detachedFromTarget') {
const session = this._sessions.get(object.params.sessionId);
if (session) {
session._onClosed();
this._sessions.delete(object.params.sessionId);
}
}
if (object.sessionId) {
const session = this._sessions.get(object.sessionId);
if (session)
session._onMessage(object);
} else if (object.id) {
const callback = this._callbacks.get(object.id);
// Callbacks could be all rejected if someone has called `.dispose()`.
if (callback) {
Expand All @@ -94,18 +121,7 @@ class Connection extends EventEmitter {
callback.resolve(object.result);
}
} else {
if (object.method === 'Target.receivedMessageFromTarget') {
const session = this._sessions.get(object.params.sessionId);
if (session)
session._onMessage(object.params.message);
} else if (object.method === 'Target.detachedFromTarget') {
const session = this._sessions.get(object.params.sessionId);
if (session)
session._onClosed();
this._sessions.delete(object.params.sessionId);
} else {
this.emit(object.method, object.params);
}
this.emit(object.method, object.params);
}
}

Expand Down Expand Up @@ -134,30 +150,24 @@ class Connection extends EventEmitter {
* @return {!Promise<!CDPSession>}
*/
async createSession(targetInfo) {
const {sessionId} = await this.send('Target.attachToTarget', {targetId: targetInfo.targetId});
const session = new CDPSession(this, targetInfo.type, sessionId);
this._sessions.set(sessionId, session);
return session;
const {sessionId} = await this.send('Target.attachToTarget', {targetId: targetInfo.targetId, flatten: true});
return this._sessions.get(sessionId);
}
}

class CDPSession extends EventEmitter {
/**
* @param {!Connection|!CDPSession} connection
* @param {!Connection} connection
* @param {string} targetType
* @param {string} sessionId
*/
constructor(connection, targetType, sessionId) {
super();
this._lastId = 0;
/** @type {!Map<number, {resolve: function, reject: function, error: !Error, method: string}>}*/
this._callbacks = new Map();
/** @type {null|Connection|CDPSession} */
this._connection = connection;
this._targetType = targetType;
this._sessionId = sessionId;
/** @type {!Map<string, !CDPSession>}*/
this._sessions = new Map();
}

/**
Expand All @@ -168,28 +178,16 @@ class CDPSession extends EventEmitter {
send(method, params = {}) {
if (!this._connection)
return Promise.reject(new Error(`Protocol error (${method}): Session closed. Most likely the ${this._targetType} has been closed.`));
const id = ++this._lastId;
const message = JSON.stringify({id, method, params});
debugSession('SEND ► ' + message);
this._connection.send('Target.sendMessageToTarget', {sessionId: this._sessionId, message}).catch(e => {
// The response from target might have been already dispatched.
if (!this._callbacks.has(id))
return;
const callback = this._callbacks.get(id);
this._callbacks.delete(id);
callback.reject(rewriteError(callback.error, e && e.message));
});
const id = this._connection._rawSend({sessionId: this._sessionId, method, params});
return new Promise((resolve, reject) => {
this._callbacks.set(id, {resolve, reject, error: new Error(), method});
});
}

/**
* @param {string} message
* @param {{id?: number, method: string, params: Object, error: {message: string, data: any}, result?: *}} object
*/
_onMessage(message) {
debugSession('◀ RECV ' + message);
const object = JSON.parse(message);
_onMessage(object) {
if (object.id && this._callbacks.has(object.id)) {
const callback = this._callbacks.get(object.id);
this._callbacks.delete(object.id);
Expand All @@ -198,17 +196,6 @@ class CDPSession extends EventEmitter {
else
callback.resolve(object.result);
} else {
if (object.method === 'Target.receivedMessageFromTarget') {
const session = this._sessions.get(object.params.sessionId);
if (session)
session._onMessage(object.params.message);
} else if (object.method === 'Target.detachedFromTarget') {
const session = this._sessions.get(object.params.sessionId);
if (session) {
session._onClosed();
this._sessions.delete(object.params.sessionId);
}
}
assert(!object.id);
this.emit(object.method, object.params);
}
Expand All @@ -227,16 +214,6 @@ class CDPSession extends EventEmitter {
this._connection = null;
this.emit(Events.CDPSession.Disconnected);
}

/**
* @param {string} targetType
* @param {string} sessionId
*/
_createSession(targetType, sessionId) {
const session = new CDPSession(this, targetType, sessionId);
this._sessions.set(sessionId, session);
return session;
}
}

helper.tracePublicAPI(CDPSession);
Expand Down
6 changes: 3 additions & 3 deletions lib/Page.js
View file
Expand Up @@ -18,6 +18,7 @@ const fs = require('fs');
const EventEmitter = require('events');
const mime = require('mime');
const {Events} = require('./Events');
const {Connection} = require('./Connection');
const {NetworkManager} = require('./NetworkManager');
const {Dialog} = require('./Dialog');
const {EmulationManager} = require('./EmulationManager');
Expand Down Expand Up @@ -47,7 +48,7 @@ class Page extends EventEmitter {
const page = new Page(client, target, frameTree, ignoreHTTPSErrors, screenshotTaskQueue);

await Promise.all([
client.send('Target.setAutoAttach', {autoAttach: true, waitForDebuggerOnStart: false}),
client.send('Target.setAutoAttach', {autoAttach: true, waitForDebuggerOnStart: false, flatten: true}),
client.send('Page.setLifecycleEventsEnabled', { enabled: true }),
client.send('Network.enable', {}),
client.send('Runtime.enable', {}).then(() => page._frameManager.ensureSecondaryDOMWorld()),
Expand Down Expand Up @@ -106,11 +107,10 @@ class Page extends EventEmitter {
}).catch(debugError);
return;
}
const session = client._createSession(event.targetInfo.type, event.sessionId);
const session = Connection.fromSession(client).session(event.sessionId);
const worker = new Worker(session, event.targetInfo.url, this._addConsoleMessage.bind(this), this._handleException.bind(this));
this._workers.set(event.sessionId, worker);
this.emit(Events.Page.WorkerCreated, worker);

});
client.on('Target.detachedFromTarget', event => {
const worker = this._workers.get(event.sessionId);
Expand Down

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