-
-
Notifications
You must be signed in to change notification settings - Fork 1.8k
/
subscriber-filterid.ts
180 lines (142 loc) · 5.34 KB
/
subscriber-filterid.ts
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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
import { isError } from "../utils/index.js";
import { PollingEventSubscriber } from "./subscriber-polling.js";
import type { AbstractProvider, Subscriber } from "./abstract-provider.js";
import type { Network } from "./network.js";
import type { EventFilter } from "./provider.js";
import type { JsonRpcApiProvider } from "./provider-jsonrpc.js";
function copy(obj: any): any {
return JSON.parse(JSON.stringify(obj));
}
/**
* Some backends support subscribing to events using a Filter ID.
*
* When subscribing with this technique, the node issues a unique
* //Filter ID//. At this point the node dedicates resources to
* the filter, so that periodic calls to follow up on the //Filter ID//
* will receive any events since the last call.
*
* @_docloc: api/providers/abstract-provider
*/
export class FilterIdSubscriber implements Subscriber {
#provider: JsonRpcApiProvider;
#filterIdPromise: null | Promise<string>;
#poller: (b: number) => Promise<void>;
#running: boolean;
#network: null | Network;
#hault: boolean;
constructor(provider: JsonRpcApiProvider) {
this.#provider = provider;
this.#filterIdPromise = null;
this.#poller = this.#poll.bind(this);
this.#running = false;
this.#network = null;
this.#hault = false;
}
_subscribe(provider: JsonRpcApiProvider): Promise<string> {
throw new Error("subclasses must override this");
}
_emitResults(provider: AbstractProvider, result: Array<any>): Promise<void> {
throw new Error("subclasses must override this");
}
_recover(provider: AbstractProvider): Subscriber {
throw new Error("subclasses must override this");
}
async #poll(blockNumber: number): Promise<void> {
try {
// Subscribe if necessary
if (this.#filterIdPromise == null) {
this.#filterIdPromise = this._subscribe(this.#provider);
}
// Get the Filter ID
let filterId: null | string = null;
try {
filterId = await this.#filterIdPromise;
} catch (error) {
if (!isError(error, "UNSUPPORTED_OPERATION") || error.operation !== "eth_newFilter") {
throw error;
}
}
// The backend does not support Filter ID; downgrade to
// polling
if (filterId == null) {
this.#filterIdPromise = null;
this.#provider._recoverSubscriber(this, this._recover(this.#provider));
return;
}
const network = await this.#provider.getNetwork();
if (!this.#network) { this.#network = network; }
if ((this.#network as Network).chainId !== network.chainId) {
throw new Error("chaid changed");
}
if (this.#hault) { return; }
const result = await this.#provider.send("eth_getFilterChanges", [ filterId ]);
await this._emitResults(this.#provider, result);
} catch (error) { console.log("@TODO", error); }
this.#provider.once("block", this.#poller);
}
#teardown(): void {
const filterIdPromise = this.#filterIdPromise;
if (filterIdPromise) {
this.#filterIdPromise = null;
filterIdPromise.then((filterId) => {
this.#provider.send("eth_uninstallFilter", [ filterId ]);
});
}
}
start(): void {
if (this.#running) { return; }
this.#running = true;
this.#poll(-2);
}
stop(): void {
if (!this.#running) { return; }
this.#running = false;
this.#hault = true;
this.#teardown();
this.#provider.off("block", this.#poller);
}
pause(dropWhilePaused?: boolean): void {
if (dropWhilePaused){ this.#teardown(); }
this.#provider.off("block", this.#poller);
}
resume(): void { this.start(); }
}
/**
* A **FilterIdSubscriber** for receiving contract events.
*
* @_docloc: api/providers/abstract-provider
*/
export class FilterIdEventSubscriber extends FilterIdSubscriber {
#event: EventFilter;
constructor(provider: JsonRpcApiProvider, filter: EventFilter) {
super(provider);
this.#event = copy(filter);
}
_recover(provider: AbstractProvider): Subscriber {
return new PollingEventSubscriber(provider, this.#event);
}
async _subscribe(provider: JsonRpcApiProvider): Promise<string> {
const filterId = await provider.send("eth_newFilter", [ this.#event ]);
return filterId;
}
async _emitResults(provider: JsonRpcApiProvider, results: Array<any>): Promise<void> {
for (const result of results) {
provider.emit(this.#event, provider._wrapLog(result, provider._network));
}
}
}
/**
* A **FilterIdSubscriber** for receiving pending transactions events.
*
* @_docloc: api/providers/abstract-provider
*/
export class FilterIdPendingSubscriber extends FilterIdSubscriber {
async _subscribe(provider: JsonRpcApiProvider): Promise<string> {
return await provider.send("eth_newPendingTransactionFilter", [ ]);
}
async _emitResults(provider: JsonRpcApiProvider, results: Array<any>): Promise<void> {
for (const result of results) {
provider.emit("pending", result);
}
}
}