Build exports (#20)

* chore: rename file

* feat: add new entrypoint with exports.

Switch Saturn to named export

* build: expose entire module instead of just the default export

* docs: update README

Author: guanzo

README.md

@@ -11,7 +11,7 @@ npm install @filecoin-saturn/js-client
 ## Usage
 
 ```js
-import Saturn from '@filecoin-saturn/js-client'
+import { Saturn } from '@filecoin-saturn/js-client'
 
 const client = new Saturn()
 

src/client.js

@@ -0,0 +1,297 @@
+import { CID } from 'multiformats'
+
+import { extractVerifiedContent } from './utils/car.js'
+import { asAsyncIterable, asyncIteratorToBuffer } from './utils/itr.js'
+import { randomUUID } from './utils/uuid.js'
+import { memoryStorage } from './storage/index.js'
+import { getJWT } from './utils/jwt.js'
+
+export class Saturn {
+  /**
+   *
+   * @param {object} [opts={}]
+   * @param {string} [opts.clientKey]
+   * @param {string} [opts.clientId=randomUUID()]
+   * @param {string} [opts.cdnURL=saturn.ms]
+   * @param {number} [opts.connectTimeout=5000]
+   * @param {number} [opts.downloadTimeout=0]
+   * @param {import('./storage/index.js').Storage} [opts.storage]
+   */
+  constructor (opts = {}) {
+    this.opts = Object.assign({}, {
+      clientId: randomUUID(),
+      cdnURL: 'saturn.ms',
+      logURL: 'https://twb3qukm2i654i3tnvx36char40aymqq.lambda-url.us-west-2.on.aws/',
+      authURL: 'https://fz3dyeyxmebszwhuiky7vggmsu0rlkoy.lambda-url.us-west-2.on.aws/',
+      connectTimeout: 5_000,
+      downloadTimeout: 0
+    }, opts)
+
+    if (!this.opts.clientKey) {
+      throw new Error('clientKey is required')
+    }
+
+    this.logs = []
+    this.storage = this.opts.storage || memoryStorage()
+    this.reportingLogs = process?.env?.NODE_ENV !== 'development'
+    this.hasPerformanceAPI = typeof window !== 'undefined' && window?.performance
+    this.isBrowser = typeof window !== 'undefined'
+    if (this.reportingLogs && this.hasPerformanceAPI) {
+      this._monitorPerformanceBuffer()
+    }
+  }
+
+  /**
+   *
+   * @param {string} cidPath
+   * @param {object} [opts={}]
+   * @param {('car'|'raw')} [opts.format]
+   * @param {number} [opts.connectTimeout=5000]
+   * @param {number} [opts.downloadTimeout=0]
+   * @returns {Promise<object>}
+   */
+  async fetchCID (cidPath, opts = {}) {
+    const [cid] = (cidPath ?? '').split('/')
+    CID.parse(cid)
+
+    const jwt = await getJWT(this.opts, this.storage)
+
+    const options = Object.assign({}, this.opts, { format: 'car', jwt }, opts)
+    const url = this.createRequestURL(cidPath, options)
+
+    const log = {
+      url,
+      startTime: new Date()
+    }
+
+    const controller = options.controller ?? new AbortController()
+    const connectTimeout = setTimeout(() => {
+      controller.abort()
+    }, options.connectTimeout)
+
+    if (!this.isBrowser) {
+      options.headers = {
+        ...(options.headers || {}),
+        Authorization: 'Bearer ' + options.jwt
+      }
+    }
+
+    let res
+    try {
+      res = await fetch(url, { signal: controller.signal, ...options })
+
+      clearTimeout(connectTimeout)
+
+      const { headers } = res
+      log.ttfbMs = new Date() - log.startTime
+      log.httpStatusCode = res.status
+      log.cacheHit = headers.get('saturn-cache-status') === 'HIT'
+      log.nodeId = headers.get('saturn-node-id')
+      log.requestId = headers.get('saturn-transfer-id')
+      log.httpProtocol = headers.get('quic-status')
+
+      if (!res.ok) {
+        throw new Error(
+          `Non OK response received: ${res.status} ${res.statusText}`
+        )
+      }
+    } catch (err) {
+      if (!res) {
+        log.error = err.message
+      }
+      // Report now if error, otherwise report after download is done.
+      this._finalizeLog(log)
+
+      throw err
+    }
+
+    return { res, controller, log }
+  }
+
+  /**
+   *
+   * @param {string} cidPath
+   * @param {object} [opts={}]
+   * @param {('car'|'raw')} [opts.format]
+   * @param {number} [opts.connectTimeout=5000]
+   * @param {number} [opts.downloadTimeout=0]
+   * @returns {Promise<AsyncIterable<Uint8Array>>}
+   */
+  async * fetchContent (cidPath, opts = {}) {
+    const { res, controller, log } = await this.fetchCID(cidPath, opts)
+
+    async function * metricsIterable (itr) {
+      log.numBytesSent = 0
+
+      for await (const chunk of itr) {
+        log.numBytesSent += chunk.length
+        yield chunk
+      }
+    }
+
+    try {
+      const itr = metricsIterable(asAsyncIterable(res.body))
+      yield * extractVerifiedContent(cidPath, itr)
+    } catch (err) {
+      log.error = err.message
+      controller.abort()
+
+      throw err
+    } finally {
+      this._finalizeLog(log)
+    }
+  }
+
+  /**
+   *
+   * @param {string} cidPath
+   * @param {object} [opts={}]
+   * @param {('car'|'raw')} [opts.format]
+   * @param {number} [opts.connectTimeout=5000]
+   * @param {number} [opts.downloadTimeout=0]
+   * @returns {Promise<Uint8Array>}
+   */
+  async fetchContentBuffer (cidPath, opts = {}) {
+    return await asyncIteratorToBuffer(this.fetchContent(cidPath, opts))
+  }
+
+  /**
+   *
+   * @param {string} cidPath
+   * @param {object} [opts={}]
+   * @returns {URL}
+   */
+  createRequestURL (cidPath, opts) {
+    let origin = opts.cdnURL
+    if (!origin.startsWith('http')) {
+      origin = `https://${origin}`
+    }
+    const url = new URL(`${origin}/ipfs/${cidPath}`)
+
+    url.searchParams.set('format', opts.format)
+    if (opts.format === 'car') {
+      url.searchParams.set('dag-scope', 'entity')
+    }
+
+    if (this.isBrowser) {
+      url.searchParams.set('jwt', opts.jwt)
+    }
+
+    return url
+  }
+
+  /**
+   *
+   * @param {object} log
+   */
+  _finalizeLog (log) {
+    log.requestDurationSec = (new Date() - log.startTime) / 1000
+    this.reportLogs(log)
+  }
+
+  /**
+   *
+   * @param {object} log
+   */
+  reportLogs (log) {
+    if (!this.reportingLogs) return
+
+    this.logs.push(log)
+    this.reportLogsTimeout && clearTimeout(this.reportLogsTimeout)
+    this.reportLogsTimeout = setTimeout(this._reportLogs.bind(this), 3_000)
+  }
+
+  async _reportLogs () {
+    if (!this.logs.length) {
+      return
+    }
+
+    const bandwidthLogs = this.hasPerformanceAPI
+      ? this._matchLogsWithPerformanceMetrics(this.logs)
+      : this.logs
+
+    await fetch(
+      this.opts.logURL,
+      {
+        method: 'POST',
+        body: JSON.stringify({ bandwidthLogs, logSender: this.opts.logSender })
+      }
+    )
+
+    this.logs = []
+    this._clearPerformanceBuffer()
+  }
+
+  /**
+   *
+   * @param {Array<object>} logs
+   */
+  _matchLogsWithPerformanceMetrics (logs) {
+    return logs
+      .map(log => ({ ...log, ...this._getPerformanceMetricsForLog(log) }))
+      .filter(log => !log.isFromBrowserCache)
+      .map(log => {
+        const { isFromBrowserCache: _, ...cleanLog } = log
+        return cleanLog
+      })
+  }
+
+  /**
+   *
+   * @param {object} log
+   * @returns {object}
+   */
+  _getPerformanceMetricsForLog (log) {
+    const metrics = {}
+
+    // URL is the best differentiator available, though there can be multiple entries per URL.
+    // It's a good enough heuristic.
+    const entry = performance
+      .getEntriesByType('resource')
+      .find((r) => r.name === log.url.href)
+
+    if (entry) {
+      const dnsStart = entry.domainLookupStart
+      const dnsEnd = entry.domainLookupEnd
+      const hasDnsMetrics = dnsEnd > 0 && dnsStart > 0
+
+      if (hasDnsMetrics) {
+        metrics.dnsTimeMs = Math.round(dnsEnd - dnsStart)
+        metrics.ttfbAfterDnsMs = Math.round(
+          entry.responseStart - entry.requestStart
+        )
+      }
+
+      if (entry.nextHopProtocol) {
+        metrics.httpProtocol = entry.nextHopProtocol
+      }
+
+      metrics.isFromBrowserCache = (
+        entry.deliveryType === 'cache' ||
+        (log.httpStatusCode && entry.transferSize === 0)
+      )
+    }
+
+    return metrics
+  }
+
+  _monitorPerformanceBuffer () {
+    // Using static method prevents multiple unnecessary listeners.
+    performance.addEventListener('resourcetimingbufferfull', Saturn._setResourceBufferSize)
+  }
+
+  static _setResourceBufferSize () {
+    const increment = 250
+    const maxSize = 1000
+    const size = performance.getEntriesByType('resource').length
+    const newSize = Math.min(size + increment, maxSize)
+
+    performance.setResourceTimingBufferSize(newSize)
+  }
+
+  _clearPerformanceBuffer () {
+    if (this.hasPerformanceAPI) {
+      performance.clearResourceTimings()
+    }
+  }
+}