diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/api.js | 61 | ||||
| -rw-r--r-- | src/app.js | 5 |
2 files changed, 55 insertions, 11 deletions
@@ -13,6 +13,17 @@ export class Api { constructor(net = 'mainnet') { this.net = net; this.offline = false; + + // Global request throttle. mempool.space rate-limits bursts; an unthrottled + // scan (~40 address lookups at once) gets a chunk of requests rejected, and + // a throttled response arrives WITHOUT CORS headers, so the browser reports + // it as a CORS error. We cap concurrency and space out request starts so we + // stay under the limit, with exponential backoff to absorb the rest. + this._maxConcurrent = 2; + this._minGapMs = 250; + this._active = 0; + this._nextStart = 0; + this._queue = []; } base() { @@ -24,20 +35,52 @@ export class Api { return `https://mempool.space/${path}/${txid}`; } + // Schedule a task respecting max concurrency + a minimum gap between starts. + #schedule(task) { + return new Promise((resolve, reject) => { + this._queue.push({ task, resolve, reject }); + this.#pump(); + }); + } + + #pump() { + while (this._active < this._maxConcurrent && this._queue.length) { + const { task, resolve, reject } = this._queue.shift(); + this._active++; + const now = Date.now(); + const startAt = Math.max(now, this._nextStart); + this._nextStart = startAt + this._minGapMs; + const delay = startAt - now; + setTimeout(() => { + Promise.resolve() + .then(task) + .then(resolve, reject) + .finally(() => { + this._active--; + this.#pump(); + }); + }, delay); + } + } + async #get(path, asText = false) { if (this.offline) throw new Error('offline'); - // Retry transient failures (mempool.space rate-limits bursts of requests - // during a scan, which can surface as network/CORS errors from file://). + const url = this.base() + path; + // Each attempt (including retries) goes back through the throttle so a burst + // of retries can't re-trip the rate limit. + const backoffs = [0, 700, 1500, 3000, 5000]; let lastErr; - for (let attempt = 0; attempt < 3; attempt++) { - if (attempt) await sleep(400 * attempt + 200); + for (const wait of backoffs) { + if (wait) await sleep(wait); try { - const res = await fetch(this.base() + path); - if (res.status === 429) throw new Error('rate limited'); - if (!res.ok) throw new Error(`${res.status} ${res.statusText}: ${path}`); - return asText ? res.text() : res.json(); + return await this.#schedule(async () => { + const res = await fetch(url); + if (res.status === 429) throw new Error('rate limited'); + if (!res.ok) throw new Error(`${res.status} ${res.statusText}: ${path}`); + return asText ? res.text() : res.json(); + }); } catch (e) { - lastErr = e; + lastErr = e; // network/CORS rejection (TypeError) or thrown above } } throw lastErr; @@ -277,9 +277,10 @@ function importPane() { h( 'label', { class: 'field' }, - h('span', { class: 'lab' }, 'Seed phrase (12 or 24 words)'), + h('span', { class: 'lab' }, 'Seed phrase'), h('textarea', { - placeholder: 'word1 word2 word3 …', + placeholder: + 'word1 word2 word3 word4 word5 word6 word7 word8 word9 word10 word11 word12', autocapitalize: 'none', autocomplete: 'off', spellcheck: 'false', |