1 {{+bindTo:partials.standard_nacl_article}} 2 3 <section id="distributing-your-application"> 4 <span id="distributing"></span><h1 id="distributing-your-application"><span id="distributing"></span>Distributing Your Application</h1> 5 <div class="contents local" id="contents" style="display: none"> 6 <ul class="small-gap"> 7 <li><a class="reference internal" href="#portable-native-client" id="id1">Portable Native Client</a></li> 8 <li><p class="first"><a class="reference internal" href="#non-portable-native-client" id="id2">Non-portable Native Client</a></p> 9 <ul class="small-gap"> 10 <li><a class="reference internal" href="#packaged-application" id="id3">Packaged application</a></li> 11 <li><a class="reference internal" href="#extension" id="id4">Extension</a></li> 12 <li><a class="reference internal" href="#hosted-application" id="id5">Hosted application</a></li> 13 <li><a class="reference internal" href="#registering-native-client-modules-to-handle-mime-types" id="id6">Registering Native Client modules to handle MIME types</a></li> 14 </ul> 15 </li> 16 </ul> 17 18 </div><p>This document describes how to distribute Portable Native Client applications 19 on the web, and Native Client applications through the 20 <a class="reference external" href="/webstore">Chrome Web Store</a> (CWS).</p> 21 <h2 id="portable-native-client">Portable Native Client</h2> 22 <p>Portable Native Client is enabled by default for web pages, so no separate 23 distribution step is requred. Making PNaCl a part of your web application is as 24 simple as embedding a manifest file that points to a <strong>pexe</strong>. See the 25 <a class="reference internal" href="/native-client/overview.html"><em>technical overview</em></a> for more details.</p> 26 <img alt="/native-client/images/nacl-in-a-web-app.png" src="/native-client/images/nacl-in-a-web-app.png" /> 27 <p>The only constraint for distributing PNaCl modules with a web application is 28 abiding by the <a class="reference external" href="http://en.wikipedia.org/wiki/Same_origin_policy">Same-origin policy</a>. The PNaCl manifest and 29 <strong>pexe</strong> must either be served from the same domain with the HTML, or the <a class="reference external" href="http://en.wikipedia.org/wiki/Cross-origin_resource_sharing">CORS 30 mechanism</a> should 31 be used to safely host them on a different domain.</p> 32 <h2 id="non-portable-native-client">Non-portable Native Client</h2> 33 <p>NaCl modules are only allowed for applications distributed through the <a class="reference external" href="https://chrome.google.com/webstore/category/apps">Chrome 34 Web Store (CWS)</a> 35 The CWS requirement is in place to prevent the proliferation of Native Client 36 executables (<strong>nexe</strong>s) compiled for specific architecures (e.g., x86-32, 37 x86-64, or ARM).</p> 38 <p>In general, the considerations and guidelines for distributing applications 39 through the Chrome Web Store apply to applications that contain NaCl modules as 40 well. Here are a few pointers to relevant documentation:</p> 41 <ul class="small-gap"> 42 <li><a class="reference external" href="/webstore">CWS Overview</a></li> 43 <li><a class="reference external" href="/webstore/choosing">Choosing an App Type</a></li> 44 <li><a class="reference external" href="/apps/about_apps">Getting started with packaged apps</a></li> 45 <li><a class="reference external" href="https://developers.google.com/chrome/apps/docs/developers_guide">Hosted apps</a></li> 46 <li><a class="reference external" href="/extensions">Chrome extensions</a></li> 47 </ul> 48 <p>In this document, we’ll focus only on distribution issues specific to 49 applications that contain NaCl modules.</p> 50 <h3 id="packaged-application"><span id="distributing-packaged"></span>Packaged application</h3> 51 <p>A packaged application is a special zip file (with a .crx extension) hosted in 52 the Chrome Web Store. This file contains all of the application parts: A Chrome 53 Web Store manifest file (manifest.json), an icon, and all of the regular Native 54 Client application files. Refer to 55 <a class="reference external" href="/apps/about_apps">Packaged Apps</a> 56 for more information about creating a packaged application.</p> 57 <h4 id="reducing-the-size-of-the-user-download-package">Reducing the size of the user download package</h4> 58 <aside class="note"> 59 <strong>Tip:</strong> 60 Packaging an app in a multi-platform zip file can significantly reduce the 61 download and storage requirements for the app. 62 </aside> 63 <p>As described above, to upload a packaged app to the CWS you have to create a zip 64 file with all the resources that your app needs, including .nexe files for 65 multiple architectures (x86-64, x86-32, and ARM). Prior to Chrome 28, when users 66 installed your app they had to download a .crx file from the CWS with all the 67 included .nexe files.</p> 68 <p>Starting with Chrome 28, the Chrome Web Store includes a feature called 69 <strong>multi-platform zip files.</strong> This feature lets you structure your application 70 directory and zip file in a way that reduces the size of the user download 71 package. Here’s how this feature works:</p> 72 <ul class="small-gap"> 73 <li>You still include all the .nexe files in the zip file that you upload to 74 the CWS, but you designate specific .nexe files (and other files if 75 appropriate) for specific architectures.</li> 76 <li>The Chrome Web Store re-packages your app, so that users only download 77 the files that they need for their specific architecture.</li> 78 </ul> 79 <p>Here is how to use this feature:</p> 80 <ol class="arabic"> 81 <li><p class="first">Create a directory called <code>_platform_specific</code>. 82 Put this directory at the same level where your CWS manifest file, 83 <code>manifest.json</code>, is located.</p> 84 </li> 85 <li><p class="first">Create a subdirectory for each specific architecture that you support, 86 and add the files for each architecture in the relevant subdirectory.</p> 87 <p>Here is a sample app directory structure:</p> 88 <pre> 89 |-- my_app_directory/ 90 | |-- manifest.json 91 | |-- my_app.html 92 | |-- my_module.nmf 93 | +-- css/ 94 | +-- images/ 95 | +-- scripts/ 96 | |-- _platform_specific/ 97 | | |-- x86-64/ 98 | | | |-- my_module_x86_64.nexe 99 | | |-- x86-32/ 100 | | | |-- my_module_x86_32.nexe 101 | | |-- arm/ 102 | | | |-- my_module_arm.nexe 103 | | |-- all/ 104 | | | |-- my_module_x86_64.nexe 105 | | | |-- my_module_x86_64.nexe 106 | | | |-- my_module_x86_32.nexe 107 </pre> 108 <p>Please note a few important points about the app directory structure:</p> 109 <ul class="small-gap"> 110 <li><p class="first">The architecture-specific subdirectories:</p> 111 <ul class="small-gap"> 112 <li><p class="first">can have arbitrary names;</p> 113 </li> 114 <li><p class="first">must be directly under the <code>_platform_specific</code> directory; and</p> 115 </li> 116 <li><p class="first">must be listed in the CWS manifest file (see step 3 below).</p> 117 </li> 118 </ul> 119 </li> 120 <li><p class="first">You can include a fallback subdirectory that provides a download package 121 with all the architecture-specific files. (In the example above this 122 is the <code>all/</code> subdirectory.) This folder is used if the user has an 123 earlier version of Chrome (prior to Chrome 28) that does not support 124 multi-platform zip files.</p> 125 </li> 126 <li><p class="first">You cannot include any files directly in the folder 127 <code>_platform_specific</code>. All architecture-specific files 128 must be under one of the architecture-specific subdirectories.</p> 129 </li> 130 <li><p class="first">Files that are not under the <code>_platform_specific</code> directory are 131 included in all download packages. (In the example above, that 132 includes <code>my_app.html</code>, <code>my_module.nmf</code>, 133 and the <code>css/</code>, <code>images/</code>, and <code>scripts/</code> directories.)</p> 134 </li> 135 </ul> 136 </li> 137 <li><p class="first">Modify the CWS manifest file, <code>manifest.json</code>, so that it specifies which 138 subdirectory under <code>_platform_specific</code> corresponds to which architecture.</p> 139 <p>The CWS manifest file must include a new name/value pair, where the name 140 is <code>platforms</code> and the value is an array. The array has an object for 141 each Native Client architecture with two name/value pairs:</p> 142 <table border="1" class="docutils"> 143 <colgroup> 144 </colgroup> 145 <thead valign="bottom"> 146 <tr class="row-odd"><th class="head"><p class="first last">Name</p> 147 </th> 148 <th class="head"><p class="first last">Value</p> 149 </th> 150 </tr> 151 </thead> 152 <tbody valign="top"> 153 <tr class="row-even"><td><p class="first last"><code>nacl_arch</code></p> 154 </td> 155 <td><p class="first last"><code>x86-64</code>, <code>x86-32</code>, or <code>arm</code></p> 156 </td> 157 </tr> 158 <tr class="row-odd"><td><p class="first last"><code>sub_package_path</code></p> 159 </td> 160 <td><p class="first last">the path of the directory (starting 161 with <code>_platform_specific</code>) that 162 contains the files for the designated 163 NaCl architecture</p> 164 </td> 165 </tr> 166 </tbody> 167 </table> 168 <p>Here is a sample <code>manifest.json</code> file:</p> 169 <pre> 170 { 171 "name": "My Reminder App", 172 "description": "A reminder app that syncs across Chrome browsers.", 173 "manifest_version": 2, 174 "minimum_chrome_version": "28", 175 "offline_enabled": true, 176 "version": "0.3", 177 "permissions": [ 178 {"fileSystem": ["write"]}, 179 "alarms", 180 "storage" 181 ], 182 "app": { 183 "background": { 184 "scripts": ["scripts/background.js"] 185 } 186 }, 187 "icons": { 188 "16": "images/icon-16x16.png", 189 "128": "images/icon-128x128.png" 190 }, 191 "platforms": [ 192 { 193 "nacl_arch": "x86-64", 194 "sub_package_path": "_platform_specific/x86-64/" 195 }, 196 { 197 "nacl_arch": "x86-32", 198 "sub_package_path": "_platform_specific/x86-32/" 199 }, 200 { 201 "nacl_arch": "arm", 202 "sub_package_path": "_platform_specific/arm/" 203 }, 204 { 205 "sub_package_path": "_platform_specific/all/" 206 } 207 ] 208 } 209 </pre> 210 <p>Note the last entry in the CWS manifest file above, which specifies a 211 <code>sub_package_path</code> without a corresponding <code>nacl_arch</code>. This entry 212 identifies the fallback directory, which is included in the download 213 package if the user architecture does not match any of the listed NaCl 214 architectures, or if the user is using an older version of Chrome that 215 does not support multi-platform zip files.</p> 216 </li> 217 <li><p class="first">Modify your application as necessary so that it uses the files for the 218 correct user architecture.</p> 219 <p>To reference architecture-specific files, use the JavaScript API 220 <a class="reference external" href="/extensions/runtime.html#method-getPlatformInfo">chrome.runtime.getPlatformInfo()</a>. 221 As an example, if you have architecture-specific files in the directories 222 <code>x86-64</code>, <code>x86-32</code>, and <code>arm</code>, you can use the following JavaScript 223 code to create a path for the files:</p> 224 <pre class="prettyprint"> 225 function getPath(name) { 226 return '_platform_specific/' + 227 chrome.runtime.getPlatformInfo().nacl_arch + 228 '/' + name; 229 } 230 </pre> 231 </li> 232 <li><p class="first">Test your app, create a zip file, and upload the app to the CWS as before.</p> 233 </li> 234 </ol> 235 <h4 id="additional-considerations-for-a-packaged-application"><span id="additional-considerations-packaged"></span>Additional considerations for a packaged application</h4> 236 <ul class="small-gap"> 237 <li>In the description of your application in the CWS, make sure to mention that 238 your application is a Native Client application that only works with the 239 Chrome browser. Also make sure to identify the minimum version of Chrome 240 that your application requires.</li> 241 <li><p class="first">Hosted and packaged applications have a “launch” parameter in the CWS 242 manifest. This parameter is present only in apps (not extensions), and it 243 tells Google Chrome what to show when a user starts an installed app. For 244 example:</p> 245 <pre> 246 "launch": { 247 "web_url": "http://mail.google.com/mail/"; 248 } 249 </pre> 250 </li> 251 <li>If you want to write local data using the Pepper 252 <a class="reference external" href="/native-client/peppercpp/classpp_1_1_file_i_o">FileIO</a> 253 API, you must set the ‘unlimitedStorage’ permission in your Chrome Web 254 Store manifest file, just as you would for a JavaScript application that 255 uses the HTML5 File API.</li> 256 <li>For packaged applications, you can only use in-app purchases.</li> 257 <li>You can place your application in the Google Web Store with access only to 258 certain people for testing. See <a class="reference external" href="/webstore/publish">Publishing to test accounts</a> for more information.</li> 259 </ul> 260 <h3 id="extension">Extension</h3> 261 <p>The NaCl-specific notes for a <a class="reference internal" href="#distributing-packaged"><em>package application</em></a> 262 apply to extensions as well.</p> 263 <h3 id="hosted-application">Hosted application</h3> 264 <p>The .html file, .nmf file (Native Client manifest file), and .nexe files must 265 be served from the same domain, and the Chrome Web Store manifest file must 266 specify the correct, verified domain. Other files can be served from the same 267 or another domain.</p> 268 <p>In addition, see <a class="reference internal" href="#additional-considerations-packaged"><em>Additional considerations for a packaged application</em></a>.</p> 269 <h3 id="registering-native-client-modules-to-handle-mime-types">Registering Native Client modules to handle MIME types</h3> 270 <p>If you want Chrome to use a Native Client module to display a particular type 271 of content, you can associate the MIME type of that content with the Native 272 Client module. Use the <code>nacl_modules</code> attribute in the Chrome Web Store 273 manifest file to register a Native Client module as the handler for one or more 274 specific MIME types. For example, the bold code in the snippet below registers 275 a Native Client module as the content handler for the OpenOffice spreadsheet 276 MIME type:</p> 277 <pre> 278 { 279 "name": "My Native Client Spreadsheet Viewer", 280 "version": "0.1", 281 "description": "Open spreadsheets right in your browser.", 282 "nacl_modules": [{ 283 "path": "SpreadsheetViewer.nmf", 284 "mime_type": "application/vnd.oasis.opendocument.spreadsheet" 285 }] 286 } 287 </pre> 288 <p>The value of “path” is the location of a Native Client manifest file (.nmf) 289 within the application directory. For more information on Native Client 290 manifest files, see <a class="reference internal" href="/native-client/devguide/coding/application-structure.html#manifest-file"><em>Manifest Files</em></a>.</p> 291 <p>The value of “mime_type” is a specific MIME type that you want the Native 292 Client module to handle. Each MIME type can be associated with only one .nmf 293 file, but a single .nmf file might handle multiple MIME types. The following 294 example shows an extension with two .nmf files that handle three MIME types.</p> 295 <pre> 296 { 297 "name": "My Native Client Spreadsheet and Document Viewer", 298 "version": "0.1", 299 "description": "Open spreadsheets and documents right in your browser.", 300 "nacl_modules": [{ 301 "path": "SpreadsheetViewer.nmf", 302 "mime_type": "application/vnd.oasis.opendocument.spreadsheet" 303 }, 304 { 305 "path": "SpreadsheetViewer.nmf", 306 "mime_type": "application/vnd.oasis.opendocument.spreadsheet-template" 307 }, 308 { 309 "path": "DocumentViewer.nmf", 310 "mime_type": "application/vnd.oasis.opendocument.text" 311 }] 312 } 313 </pre> 314 <p>The <code>nacl_modules</code> attribute is optional—specify this attribute only if 315 you want Chrome to use a Native Client module to display a particular type of 316 content.</p> 317 </section> 318 319 {{/partials.standard_nacl_article}} 320
