1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
/*
* Copyright (C) 2019-2020 Alex Yatskov <alex@foosoft.net>
* Author: Alex Yatskov <alex@foosoft.net>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
class FrontendApiSender {
constructor() {
this.senderId = FrontendApiSender.generateId(16);
this.ackTimeout = 3000; // 3 seconds
this.responseTimeout = 10000; // 10 seconds
this.callbacks = new Map();
this.disconnected = false;
this.nextId = 0;
this.port = null;
}
invoke(action, params, target) {
if (this.disconnected) {
return Promise.reject(new Error('Disconnected'));
}
if (this.port === null) {
this.createPort();
}
const id = `${this.nextId}`;
++this.nextId;
return new Promise((resolve, reject) => {
const info = {id, resolve, reject, ack: false, timer: null};
this.callbacks.set(id, info);
info.timer = setTimeout(() => this.onError(id, 'Timeout (ack)'), this.ackTimeout);
this.port.postMessage({id, action, params, target, senderId: this.senderId});
});
}
createPort() {
this.port = chrome.runtime.connect(null, {name: 'backend-api-forwarder'});
this.port.onDisconnect.addListener(this.onDisconnect.bind(this));
this.port.onMessage.addListener(this.onMessage.bind(this));
}
onMessage({type, id, data, senderId}) {
if (senderId !== this.senderId) { return; }
switch (type) {
case 'ack':
this.onAck(id);
break;
case 'result':
this.onResult(id, data);
break;
}
}
onDisconnect() {
this.disconnected = true;
for (const id of this.callbacks.keys()) {
this.onError(id, 'Disconnected');
}
}
onAck(id) {
const info = this.callbacks.get(id);
if (typeof info === 'undefined') {
console.warn(`ID ${id} not found for ack`);
return;
}
if (info.ack) {
console.warn(`Request ${id} already ack'd`);
return;
}
info.ack = true;
clearTimeout(info.timer);
info.timer = setTimeout(() => this.onError(id, 'Timeout (response)'), this.responseTimeout);
}
onResult(id, data) {
const info = this.callbacks.get(id);
if (typeof info === 'undefined') {
console.warn(`ID ${id} not found`);
return;
}
if (!info.ack) {
console.warn(`Request ${id} not ack'd`);
return;
}
this.callbacks.delete(id);
clearTimeout(info.timer);
info.timer = null;
if (typeof data.error !== 'undefined') {
info.reject(jsonToError(data.error));
} else {
info.resolve(data.result);
}
}
onError(id, reason) {
const info = this.callbacks.get(id);
if (typeof info === 'undefined') { return; }
this.callbacks.delete(id);
info.timer = null;
info.reject(new Error(reason));
}
static generateId(length) {
let id = '';
for (let i = 0; i < length; ++i) {
id += Math.floor(Math.random() * 256).toString(16).padStart(2, '0');
}
return id;
}
}
|