tornado-packages/ethers.js
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Added Retry-After support and adjustable slot interval to fetchJson.

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Richard Moore 2020-07-14 22:50:05 -04:00
parent 6fa853b309
commit 7d43545303
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GPG Key ID: 665176BE8E9DC651
1 changed files with 16 additions and 4 deletions
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20
packages/web/src.ts/index.ts
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@ -27,6 +27,7 @@ export type ConnectionInfo = {
allowInsecureAuthentication?: boolean,
throttleLimit?: number,
throttleSlotInterval?: number;
throttleCallback?: (attempt: number, url: string) => Promise<boolean>,
timeout?: number,
@ -66,6 +67,9 @@ export function fetchJson(connection: string | ConnectionInfo, json?: string, pr
"invalid connection throttle limit", "connection.throttleLimit", attemptLimit);
const throttleCallback = ((typeof(connection) === "object") ? connection.throttleCallback: null);
const throttleSlotInterval = ((typeof(connection) === "object" && typeof(connection.throttleSlotInterval) === "number") ? connection.throttleSlotInterval: 100);
logger.assertArgument((throttleSlotInterval > 0 && (throttleSlotInterval % 1) === 0),
"invalid connection throttle slot interval", "connection.throttleSlotInterval", throttleSlotInterval);
const headers: { [key: string]: Header } = { };
@ -168,7 +172,7 @@ export function fetchJson(connection: string | ConnectionInfo, json?: string, pr
try {
response = await getUrl(url, options);
// Exponential back-off throttling (interval = 100ms)
// Exponential back-off throttling
if (response.statusCode === 429 && attempt < attemptLimit) {
let tryAgain = true;
if (throttleCallback) {
@ -176,8 +180,16 @@ export function fetchJson(connection: string | ConnectionInfo, json?: string, pr
}
if (tryAgain) {
const timeout = 100 * parseInt(String(Math.random() * Math.pow(2, attempt)));
await staller(timeout);
let stall = 0;
const retryAfter = response.headers["retry-after"];
if (typeof(retryAfter) === "string" && retryAfter.match(/^[1-9][0-9]*$/)) {
stall = parseInt(retryAfter) * 1000;
} else {
stall = throttleSlotInterval * parseInt(String(Math.random() * Math.pow(2, attempt)));
}
await staller(stall);
continue;
}
}
@ -241,7 +253,7 @@ export function fetchJson(connection: string | ConnectionInfo, json?: string, pr
}
if (tryAgain) {
const timeout = 100 * parseInt(String(Math.random() * Math.pow(2, attempt)));
const timeout = throttleSlotInterval * parseInt(String(Math.random() * Math.pow(2, attempt)));
await staller(timeout);
continue;
}