Load a preview of Sketch 43 files

Sketch 43 files are technically a zip file, so the JavaScript opens the
zip file & locates a preview.png which is just a quick preview of the
last sketch page edited. After that is loaded it simply places the image
into the DOM

app/assets/javascripts/blob/sketch/index.js

+import JSZip from 'jszip';
+import JSZipUtils from 'jszip-utils';
+
+export default class SketchLoader {
+  constructor(container) {
+    this.container = container;
+    this.loadingIcon = this.container.querySelector('.js-loading-icon');
+
+    this.load();
+  }
+
+  load() {
+    return this.getZipFile()
+      .then(data => JSZip.loadAsync(data))
+      .then(asyncResult => asyncResult.files['previews/preview.png'].async('uint8array'))
+      .then((content) => {
+        const url = window.URL || window.webkitURL;
+        const blob = new Blob([new Uint8Array(content)], {
+          type: 'image/png',
+        });
+        const previewUrl = url.createObjectURL(blob);
+
+        this.render(previewUrl);
+      })
+      .catch(this.error.bind(this));
+  }
+
+  getZipFile() {
+    return new JSZip.external.Promise((resolve, reject) => {
+      JSZipUtils.getBinaryContent(this.container.dataset.endpoint, (err, data) => {
+        if (err) {
+          reject(err);
+        } else {
+          resolve(data);
+        }
+      });
+    });
+  }
+
+  render(previewUrl) {
+    const previewLink = document.createElement('a');
+    const previewImage = document.createElement('img');
+
+    previewLink.href = previewUrl;
+    previewLink.target = '_blank';
+    previewImage.src = previewUrl;
+    previewImage.className = 'img-responsive';
+
+    previewLink.appendChild(previewImage);
+    this.container.appendChild(previewLink);
+
+    this.removeLoadingIcon();
+  }
+
+  error() {
+    const errorMsg = document.createElement('p');
+
+    errorMsg.className = 'prepend-top-default append-bottom-default text-center';
+    errorMsg.textContent = `
+      Cannot show preview. For previews on sketch files, they must have the file format
+      introduced by Sketch version 43 and above.
+    `;
+    this.container.appendChild(errorMsg);
+
+    this.removeLoadingIcon();
+  }
+
+  removeLoadingIcon() {
+    if (this.loadingIcon) {
+      this.loadingIcon.remove();
+    }
+  }
+}

app/assets/javascripts/blob/sketch_viewer.js

+/* eslint-disable no-new */
+import SketchLoader from './sketch';
+
+document.addEventListener('DOMContentLoaded', () => {
+  const el = document.getElementById('js-sketch-viewer');
+
+  new SketchLoader(el);
+});

app/models/blob.rb

@@ -50,6 +50,10 @@ class Blob < SimpleDelegator
     text? && language&.name == 'Jupyter Notebook'
   end
+  def sketch?
+    binary? && extname.downcase.delete('.') == 'sketch'
+  end
+
   def size_within_svg_limits?
     size <= MAXIMUM_SVG_SIZE
   end
@@ -69,6 +73,8 @@ class Blob < SimpleDelegator
       'image'
     elsif ipython_notebook?
       'notebook'
+    elsif sketch?
+      'sketch'
     elsif text?
       'text'
     else

app/views/projects/blob/_sketch.html.haml

+- content_for :page_specific_javascripts do
+  = page_specific_javascript_bundle_tag('common_vue')
+  = page_specific_javascript_bundle_tag('sketch_viewer')
+
+.file-content#js-sketch-viewer{ data: { endpoint: namespace_project_raw_path(@project.namespace, @project, @id) } }
+  .js-loading-icon.text-center.prepend-top-default.append-bottom-default.js-loading-icon{ 'aria-label' => 'Loading Sketch preview' }
+    = icon('spinner spin 2x', 'aria-hidden' => 'true');

config/dependency_decisions.yml

@@ -326,3 +326,21 @@
     :why: https://github.com/domenic/opener/blob/1.4.3/LICENSE.txt
     :versions: []
     :when: 2017-02-21 22:33:41.729629000 Z
+- - :approve
+  - jszip
+  - :who: Phil Hughes
+    :why: https://github.com/Stuk/jszip/blob/master/LICENSE.markdown
+    :versions: []
+    :when: 2017-04-05 10:38:46.275721000 Z
+- - :approve
+  - jszip-utils
+  - :who: Phil Hughes
+    :why: https://github.com/Stuk/jszip-utils/blob/master/LICENSE.markdown
+    :versions: []
+    :when: 2017-04-05 10:39:32.676232000 Z
+- - :approve
+  - pako
+  - :who: Phil Hughes
+    :why: https://github.com/nodeca/pako/blob/master/LICENSE
+    :versions: []
+    :when: 2017-04-05 10:43:45.897720000 Z

config/webpack.config.js

@@ -37,6 +37,7 @@ var config = {
     monitoring:           './monitoring/monitoring_bundle.js',
     network:              './network/network_bundle.js',
     notebook_viewer:      './blob/notebook_viewer.js',
+    sketch_viewer:        './blob/sketch_viewer.js',
     profile:              './profile/profile_bundle.js',
     protected_branches:   './protected_branches/protected_branches_bundle.js',
     snippet:              './snippet/snippet_bundle.js',

package.json

@@ -27,6 +27,8 @@
     "jquery": "^2.2.1",
     "jquery-ujs": "^1.2.1",
     "js-cookie": "^2.1.3",
+    "jszip": "^3.1.3",
+    "jszip-utils": "^0.0.2",
     "mousetrap": "^1.4.6",
     "pikaday": "^1.5.1",
     "raphael": "^2.2.7",

spec/javascripts/blob/sketch/index_spec.js

+/* eslint-disable no-new */
+import JSZip from 'jszip';
+import SketchLoader from '~/blob/sketch';
+
+describe('Sketch viewer', () => {
+  const generateZipFileArrayBuffer = (zipFile, resolve, done) => {
+    zipFile
+      .generateAsync({ type: 'arrayBuffer' })
+      .then((content) => {
+        resolve(content);
+
+        setTimeout(() => {
+          done();
+        }, 100);
+      });
+  };
+
+  preloadFixtures('static/sketch_viewer.html.raw');
+
+  beforeEach(() => {
+    loadFixtures('static/sketch_viewer.html.raw');
+  });
+
+  describe('with error message', () => {
+    beforeEach((done) => {
+      spyOn(SketchLoader.prototype, 'getZipFile').and.callFake(() => new Promise((resolve, reject) => {
+        reject();
+
+        setTimeout(() => {
+          done();
+        });
+      }));
+
+      new SketchLoader(document.getElementById('js-sketch-viewer'));
+    });
+
+    it('renders error message', () => {
+      expect(
+        document.querySelector('#js-sketch-viewer p'),
+      ).not.toBeNull();
+
+      expect(
+        document.querySelector('#js-sketch-viewer p').textContent.trim(),
+      ).toContain('Cannot show preview.');
+    });
+
+    it('removes render the loading icon', () => {
+      expect(
+        document.querySelector('.js-loading-icon'),
+      ).toBeNull();
+    });
+  });
+
+  describe('success', () => {
+    beforeEach((done) => {
+      spyOn(SketchLoader.prototype, 'getZipFile').and.callFake(() => new Promise((resolve) => {
+        const zipFile = new JSZip();
+        zipFile.folder('previews')
+          .file('preview.png', 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAMAAAAoyzS7AAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAA1JREFUeNoBAgD9/wAAAAIAAVMrnDAAAAAASUVORK5CYII=', {
+            base64: true,
+          });
+
+        generateZipFileArrayBuffer(zipFile, resolve, done);
+      }));
+
+      new SketchLoader(document.getElementById('js-sketch-viewer'));
+    });
+
+    it('does not render error message', () => {
+      expect(
+        document.querySelector('#js-sketch-viewer p'),
+      ).toBeNull();
+    });
+
+    it('removes render the loading icon', () => {
+      expect(
+        document.querySelector('.js-loading-icon'),
+      ).toBeNull();
+    });
+
+    it('renders preview img', () => {
+      const img = document.querySelector('#js-sketch-viewer img');
+
+      expect(img).not.toBeNull();
+      expect(img.classList.contains('img-responsive')).toBeTruthy();
+    });
+
+    it('renders link to image', () => {
+      const img = document.querySelector('#js-sketch-viewer img');
+      const link = document.querySelector('#js-sketch-viewer a');
+
+      expect(link.href).toBe(img.src);
+      expect(link.target).toBe('_blank');
+    });
+  });
+
+  describe('incorrect file', () => {
+    beforeEach((done) => {
+      spyOn(SketchLoader.prototype, 'getZipFile').and.callFake(() => new Promise((resolve) => {
+        const zipFile = new JSZip();
+
+        generateZipFileArrayBuffer(zipFile, resolve, done);
+      }));
+
+      new SketchLoader(document.getElementById('js-sketch-viewer'));
+    });
+
+    it('renders error message', () => {
+      expect(
+        document.querySelector('#js-sketch-viewer p'),
+      ).not.toBeNull();
+
+      expect(
+        document.querySelector('#js-sketch-viewer p').textContent.trim(),
+      ).toContain('Cannot show preview.');
+    });
+  });
+});

spec/javascripts/fixtures/sketch_viewer.html.haml

+.file-content#js-sketch-viewer{ data: { endpoint: '/test_sketch_file.sketch' } }
+  .js-loading-icon

spec/models/blob_spec.rb

@@ -67,6 +67,20 @@ describe Blob do
     end
   end
+  describe '#sketch?' do
+    it 'is falsey with image extension' do
+      git_blob = Gitlab::Git::Blob.new(name: "design.png")
+
+      expect(described_class.decorate(git_blob)).not_to be_sketch
+    end
+
+    it 'is truthy with sketch extension' do
+      git_blob = Gitlab::Git::Blob.new(name: "design.sketch")
+
+      expect(described_class.decorate(git_blob)).to be_sketch
+    end
+  end
+
   describe '#video?' do
     it 'is falsey with image extension' do
       git_blob = Gitlab::Git::Blob.new(name: 'image.png')
@@ -92,7 +106,8 @@ describe Blob do
         language: nil,
         lfs_pointer?: false,
         svg?: false,
-        text?: false
+        text?: false,
+        binary?: false
       )
       described_class.decorate(double).tap do |blob|
@@ -135,6 +150,11 @@ describe Blob do
       blob = stubbed_blob(text?: true, ipython_notebook?: true)
       expect(blob.to_partial_path(project)).to eq 'notebook'
     end
+
+    it 'handles Sketch files' do
+      blob = stubbed_blob(text?: true, sketch?: true, binary?: true)
+      expect(blob.to_partial_path(project)).to eq 'sketch'
+    end
   end
   describe '#size_within_svg_limits?' do

yarn.lock

@@ -1245,6 +1245,10 @@ core-js@^2.2.0, core-js@^2.4.0, core-js@^2.4.1:
   version "2.4.1"
   resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.4.1.tgz#4de911e667b0eae9124e34254b53aea6fc618d3e"
+core-js@~2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.3.0.tgz#fab83fbb0b2d8dc85fa636c4b9d34c75420c6d65"
+
 core-util-is@~1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz#b5fd54220aa2bc5ab57aab7140c940754503c1a7"
@@ -1581,6 +1585,10 @@ es6-map@^0.1.3:
     es6-symbol "~3.1.0"
     event-emitter "~0.3.4"
+es6-promise@~3.0.2:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/es6-promise/-/es6-promise-3.0.2.tgz#010d5858423a5f118979665f46486a95c6ee2bb6"
+
 es6-promise@~4.0.3:
   version "4.0.5"
   resolved "https://registry.yarnpkg.com/es6-promise/-/es6-promise-4.0.5.tgz#7882f30adde5b240ccfa7f7d78c548330951ae42"
@@ -2335,6 +2343,10 @@ ignore@^3.2.0:
   version "3.2.2"
   resolved "https://registry.yarnpkg.com/ignore/-/ignore-3.2.2.tgz#1c51e1ef53bab6ddc15db4d9ac4ec139eceb3410"
+immediate@~3.0.5:
+  version "3.0.6"
+  resolved "https://registry.yarnpkg.com/immediate/-/immediate-3.0.6.tgz#9db1dbd0faf8de6fbe0f5dd5e56bb606280de69b"
+
 imurmurhash@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/imurmurhash/-/imurmurhash-0.1.4.tgz#9218b9b2b928a238b13dc4fb6b6d576f231453ea"
@@ -2764,6 +2776,20 @@ jsprim@^1.2.2:
     json-schema "0.2.3"
     verror "1.3.6"
+jszip-utils@^0.0.2:
+  version "0.0.2"
+  resolved "https://registry.yarnpkg.com/jszip-utils/-/jszip-utils-0.0.2.tgz#457d5cbca60a1c2e0706e9da2b544e8e7bc50bf8"
+
+jszip@^3.1.3:
+  version "3.1.3"
+  resolved "https://registry.yarnpkg.com/jszip/-/jszip-3.1.3.tgz#8a920403b2b1651c0fc126be90192d9080957c37"
+  dependencies:
+    core-js "~2.3.0"
+    es6-promise "~3.0.2"
+    lie "~3.1.0"
+    pako "~1.0.2"
+    readable-stream "~2.0.6"
+
 karma-coverage-istanbul-reporter@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/karma-coverage-istanbul-reporter/-/karma-coverage-istanbul-reporter-0.2.0.tgz#5766263338adeb0026f7e4ac7a89a5f056c5642c"
@@ -2868,6 +2894,12 @@ levn@^0.3.0, levn@~0.3.0:
     prelude-ls "~1.1.2"
     type-check "~0.3.2"
+lie@~3.1.0:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/lie/-/lie-3.1.1.tgz#9a436b2cc7746ca59de7a41fa469b3efb76bd87e"
+  dependencies:
+    immediate "~3.0.5"
+
 load-json-file@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/load-json-file/-/load-json-file-1.1.0.tgz#956905708d58b4bab4c2261b04f59f31c99374c0"
@@ -3349,6 +3381,10 @@ pako@~0.2.0:
   version "0.2.9"
   resolved "https://registry.yarnpkg.com/pako/-/pako-0.2.9.tgz#f3f7522f4ef782348da8161bad9ecfd51bf83a75"
+pako@~1.0.2:
+  version "1.0.5"
+  resolved "https://registry.yarnpkg.com/pako/-/pako-1.0.5.tgz#d2205dfe5b9da8af797e7c163db4d1f84e4600bc"
+
 parse-asn1@^5.0.0:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/parse-asn1/-/parse-asn1-5.0.0.tgz#35060f6d5015d37628c770f4e091a0b5a278bc23"
@@ -3661,7 +3697,7 @@ readable-stream@~1.0.2:
     isarray "0.0.1"
     string_decoder "~0.10.x"
-readable-stream@~2.0.0:
+readable-stream@~2.0.0, readable-stream@~2.0.6:
   version "2.0.6"
   resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-2.0.6.tgz#8f90341e68a53ccc928788dacfcd11b36eb9b78e"
   dependencies: