refactor(image-stream): get rid of read-chunk (#1243)

We also took the opportunity to make `utils.getArchiveMimeType()`
asynchronous.

Signed-off-by: Juan Cruz Viotti <jviotti@openmailbox.org>

lib/image-stream/index.js

@@ -67,9 +67,7 @@ const errors = require('../shared/errors');
  * });
  */
 exports.getFromFilePath = (file) => {
-  return Bluebird.try(() => {
+  return utils.getArchiveMimeType(file).then((type) => {
-    const type = utils.getArchiveMimeType(file);
-
     if (!_.has(handlers, type)) {
       throw errors.createUserError('Invalid image', `The ${type} format is not supported`);
     }

lib/image-stream/utils.js

@@ -17,7 +17,8 @@
 'use strict';
 
 const _ = require('lodash');
-const readChunk = require('read-chunk');
+const Bluebird = require('bluebird');
+const fs = Bluebird.promisifyAll(require('fs'));
 const archiveType = require('archive-type');
 
 /**
@@ -26,18 +27,34 @@ const archiveType = require('archive-type');
  * @public
  *
  * @param {String} file - file path
- * @returns {String} mime type
+ * @fulfil {String} - mime type
+ * @returns {Promise}
  *
  * @example
- * utils.getArchiveMimeType('path/to/raspberrypi.img.gz');
+ * utils.getArchiveMimeType('path/to/raspberrypi.img.gz').then((mimeType) => {
+ *   console.log(mimeType);
+ * });
  */
 exports.getArchiveMimeType = (file) => {
 
   // `archive-type` only needs the first 261 bytes
   // See https://github.com/kevva/archive-type
-  const MAGIC_NUMBER_BUFFER_START = 0;
+  const ARCHIVE_TYPE_IDENTIFICATION_BYTES_LENGTH = 261;
-  const MAGIC_NUMBER_BUFFER_END = 261;
-  const chunk = readChunk.sync(file, MAGIC_NUMBER_BUFFER_START, MAGIC_NUMBER_BUFFER_END);
 
-  return _.get(archiveType(chunk), [ 'mime' ], 'application/octet-stream');
+  return Bluebird.using(fs.openAsync(file, 'r').disposer((fileDescriptor) => {
+    return fs.closeAsync(fileDescriptor);
+  }), (fileDescriptor) => {
+    const BUFFER_START = 0;
+    const chunk = new Buffer(ARCHIVE_TYPE_IDENTIFICATION_BYTES_LENGTH);
+
+    return fs.readAsync(
+      fileDescriptor,
+      chunk,
+      BUFFER_START,
+      ARCHIVE_TYPE_IDENTIFICATION_BYTES_LENGTH,
+      null
+    ).then(() => {
+      return _.get(archiveType(chunk), [ 'mime' ], 'application/octet-stream');
+    });
+  });
 };

npm-shrinkwrap.json

@@ -5521,11 +5521,6 @@
       "resolved": "https://registry.npmjs.org/read/-/read-1.0.7.tgz",
       "dev": true
     },
-    "read-chunk": {
-      "version": "2.0.0",
-      "from": "read-chunk@>=2.0.0 <3.0.0",
-      "resolved": "https://registry.npmjs.org/read-chunk/-/read-chunk-2.0.0.tgz"
-    },
     "read-only-stream": {
       "version": "2.0.0",
       "from": "read-only-stream@>=2.0.0 <3.0.0",

package.json

@@ -90,7 +90,6 @@
     "node-ipc": "^8.9.2",
     "node-stream-zip": "^1.3.4",
     "path-is-inside": "^1.0.2",
-    "read-chunk": "^2.0.0",
     "redux": "^3.5.2",
     "redux-localstorage": "^0.4.1",
     "resin-cli-form": "^1.4.1",

tests/image-stream/utils.spec.js

@@ -25,29 +25,44 @@ describe('ImageStream: Utils', function() {
 
   describe('.getArchiveMimeType()', function() {
 
-    it('should return application/x-bzip2 for a bz2 archive', function() {
+    it('should resolve application/x-bzip2 for a bz2 archive', function(done) {
       const file = path.join(DATA_PATH, 'bz2', 'raspberrypi.img.bz2');
-      m.chai.expect(utils.getArchiveMimeType(file)).to.equal('application/x-bzip2');
+      utils.getArchiveMimeType(file).then((type) => {
+        m.chai.expect(type).to.equal('application/x-bzip2');
+        done();
+      }).catch(done);
     });
 
-    it('should return application/x-xz for a xz archive', function() {
+    it('should resolve application/x-xz for a xz archive', function(done) {
       const file = path.join(DATA_PATH, 'xz', 'raspberrypi.img.xz');
-      m.chai.expect(utils.getArchiveMimeType(file)).to.equal('application/x-xz');
+      utils.getArchiveMimeType(file).then((type) => {
+        m.chai.expect(type).to.equal('application/x-xz');
+        done();
+      }).catch(done);
     });
 
-    it('should return application/gzip for a gz archive', function() {
+    it('should resolve application/gzip for a gz archive', function(done) {
       const file = path.join(DATA_PATH, 'gz', 'raspberrypi.img.gz');
-      m.chai.expect(utils.getArchiveMimeType(file)).to.equal('application/gzip');
+      utils.getArchiveMimeType(file).then((type) => {
+        m.chai.expect(type).to.equal('application/gzip');
+        done();
+      }).catch(done);
     });
 
-    it('should return application/zip for a zip archive', function() {
+    it('should resolve application/zip for a zip archive', function(done) {
       const file = path.join(DATA_PATH, 'zip', 'zip-directory-rpi-only.zip');
-      m.chai.expect(utils.getArchiveMimeType(file)).to.equal('application/zip');
+      utils.getArchiveMimeType(file).then((type) => {
+        m.chai.expect(type).to.equal('application/zip');
+        done();
+      }).catch(done);
     });
 
-    it('should return application/octet-stream for an uncompress image', function() {
+    it('should resolve application/octet-stream for an uncompress image', function(done) {
       const file = path.join(DATA_PATH, 'images', 'raspberrypi.img');
-      m.chai.expect(utils.getArchiveMimeType(file)).to.equal('application/octet-stream');
+      utils.getArchiveMimeType(file).then((type) => {
+        m.chai.expect(type).to.equal('application/octet-stream');
+        done();
+      }).catch(done);
     });
 
   });