client-side checksum -not finished yet

partially copied from tus#347

Author: 1token

lib/browser/extensions/checksum.js

@@ -0,0 +1,40 @@
+class Checksum {
+  static supportedAlgorithms = ['SHA-1', 'SHA-256', 'SHA-384', 'SHA-512'];
+
+  constructor (algo = 'SHA-256') {
+    this.algo = this._resolveAlgo(algo)
+  }
+
+  /**
+   * Resolves algorithm to one of the inbuilt types
+   * @param {String} algo contains user provided checksumAlgo option
+   */
+  _resolveAlgo = (algo) => {
+    const resolvedAlgo = Checksum.supportedAlgorithms.find(supportedAlgo => supportedAlgo === algo.toUpperCase())
+    if (!resolvedAlgo) {
+      throw new Error(
+        `tus: unsupported checksumAlgo provided. Supported values are : ${Checksum.supportedAlgorithms.join(',')}`,
+      )
+    }
+    return resolvedAlgo
+  }
+
+  /**
+   * Gets hexadecimal digest using the algorithm set in this.algo
+   * @param {ArrayBuffer} data contains the chunk of data to be hashed
+   */
+  getHexDigest = async (data) => {
+    try {
+      const hashBuffer = await crypto.subtle.digest(this.algo, data)
+      const hashArray = Array.from(new Uint8Array(hashBuffer)) // convert buffer to byte array
+      const hashHex = hashArray
+        .map((b) => b.toString(16).padStart(2, '0'))
+        .join('') // convert bytes to hex string
+      return hashHex
+    } catch (err) {
+      throw new Error('tus: could not compute checksum for integrity check')
+    }
+  };
+}
+
+export default Checksum

lib/index.d.ts

@@ -42,6 +42,7 @@ interface UploadOptions {
 
   chunkSize?: number;
   retryDelays?: number[];
+  enableChecksum?: boolean | null;
   parallelUploads?: number;
   parallelUploadBoundaries?: { start: number; end: number }[] | null;
   storeFingerprintForResuming?: boolean;  removeFingerprintOnSuccess?: boolean;

lib/upload.js

@@ -3,6 +3,7 @@ import URL from 'url-parse'
 import DetailedError from './error.js'
 import { log } from './logger.js'
 import uuid from './uuid.js'
+import Checksum from './browser/extensions/checksum.js'
 
 const defaultOptions = {
   endpoint: null,
@@ -100,6 +101,9 @@ class BaseUpload {
     // An array of upload URLs which are used for uploading the different
     // parts, if the parallelUploads option is used.
     this._parallelUploadUrls = null
+
+    // A platform dependent checksum generator, this is instantiated if options.enableChecksum is provided
+    this._checksum = null
   }
 
   /**
@@ -531,6 +535,11 @@ class BaseUpload {
       return
     }
 
+    // eslint-disable-next-line no-undef
+    if (this.options.enableChecksum && window) {
+      this._checksum = new Checksum()
+    }
+
     const req = this._openRequest('POST', this.options.endpoint)
 
     if (this.options.uploadLengthDeferred) {
@@ -749,6 +758,17 @@ class BaseUpload {
           req.setHeader('Upload-Length', this._size)
         }
 
+        if (this.options.enableChecksum && this._checksum) {
+          value.arrayBuffer().then((chunkBuffer) => {
+            this._checksum
+              .getHexDigest(chunkBuffer)
+              .then((hash) => {
+                console.log('Upload-Checksum', `${this._checksum.algo} ${hash}`)
+              })
+              .catch((err) => log(err))
+          })
+        }
+
         if (value === null) {
           return this._sendRequest(req)
         }