chrome/common/extensions/docs/templates/intros/contentSettings.html

   1 <h2 id="manifest">Manifest</h2>
   2 <p>You must declare the "contentSettings" permission
   3 in your extension's manifest to use the API.
   4 For example:</p>
   5 <pre data-filename="manifest.json">
   6 {
   7   "name": "My extension",
   8   ...
   9   <b>"permissions": [
  10     "contentSettings"
  11   ]</b>,
  12   ...
  13 }
  14 </pre>
  15
  16
  17 <h2 id="patterns">Content setting patterns</h2>
  18 <p>
  19 You can use patterns to specify the websites that each content setting affects.
  20 For example, <code>http://*.youtube.com/*</code> specifies youtube.com and all
  21 of its subdomains. The syntax for content setting patterns is the same as for
  22 <a href="match_patterns">match patterns</a>, with a few differences:
  23 <ul><li>For <code>http</code>,
  24 <code>https</code>, and <code>ftp</code> URLs, the path must be a wildcard
  25 (<code>/*</code>). For <code>file</code> URLs, the path must be completely
  26 specified and <strong>must not</strong> contain wildcards.</li>
  27 <li>In contrast to match patterns, content setting patterns can specify a port
  28 number. If a port number is specified, the pattern only matches websites with
  29 that port. If no port number is specified, the pattern matches all ports.
  30 </li>
  31 </ul>
  32 </p>
  33
  34 <h3 id="pattern-precedence">Pattern precedence</h3>
  35 <p>
  36 When more than one content setting rule applies for a given site, the rule with
  37 the more specific pattern takes precedence.
  38 </p>
  39 <p>For example, the following patterns are ordered by precedence:</p>
  40 <ol>
  41 <li><code>http://www.example.com/*</code></li>
  42 <li><code>http://*.example.com/*</code> (matching
  43 example.com and all subdomains)</li>
  44 <li><code>&lt;all_urls&gt;</code> (matching every URL)</li>
  45 </ol>
  46 <p>
  47 Three kinds of wildcards affect how specific a pattern is:
  48 </p>
  49 <ul>
  50 <li>Wildcards in the port (for example
  51 <code>http://www.example.com:*/*</code>)</li>
  52 <li>Wildcards in the scheme (for example
  53 <code>*://www.example.com:123/*</code>)</li>
  54 <li>Wildcards in the hostname (for example
  55 <code>http://*.example.com:123/*</code>)</li>
  56 </ul>
  57 <p>
  58 If a pattern is more specific than another pattern in one part but less specific
  59 in another part, the different parts are checked in the following order:
  60 hostname, scheme, port. For example, the following patterns are ordered by
  61 precedence:</p>
  62 <ol>
  63 <li><code>http://www.example.com:*/*</code><br>
  64 Specifies the hostname and scheme.</li>
  65 <li><code>*:/www.example.com:123/*</code><br>
  66 Not as high, because although it specifies the hostname, it doesn't specify
  67 the scheme.</li>
  68 <li><code>http://*.example.com:123/*</code><br>
  69 Lower because although it specifies the port and scheme, it has a wildcard
  70 in the hostname.</li>
  71 </ol>
  72
  73 <h2 id="primary-secondary">Primary and secondary patterns</h2>
  74 <p>
  75 The URL taken into account when deciding which content setting to apply depends
  76 on the content type. For example, for
  77 $(ref:contentSettings.notifications) settings are
  78 based on the URL shown in the omnibox. This URL is called the "primary" URL.</p>
  79 <p>
  80 Some content types can take additional URLs into account. For example,
  81 whether a site is allowed to set a
  82 $(ref:contentSettings.cookies) is decided based on the URL
  83 of the HTTP request (which is the primary URL in this case) as well as the URL
  84 shown in the omnibox (which is called the "secondary" URL).
  85 </p>
  86 <p>
  87 If multiple rules have primary and secondary patterns, the rule with the more
  88 specific primary pattern takes precedence. If there multiple rules have the same
  89 primary pattern, the rule with the more specific secondary pattern takes
  90 precedence. For example, the following list of primary/secondary pattern pairs
  91 is ordered by precedence:</p>
  92 <table>
  93 <tr><th>Precedence</th><th>Primary pattern</th><th>Secondary pattern</th>
  94 <tr>
  95   <td>1</td>
  96   <td><code>http://www.moose.com/*</code>, </td>
  97   <td><code>http://www.wombat.com/*</code></td>
  98 </tr><tr>
  99   <td>2</td>
 100   <td><code>http://www.moose.com/*</code>, </td>
 101   <td><code>&lt;all_urls&gt;</code></td>
 102 </tr><tr>
 103   <td>3</td>
 104   <td><code>&lt;all_urls&gt;</code>, </td>
 105   <td><code>http://www.wombat.com/*</code></td>
 106 </tr><tr>
 107   <td>4</td>
 108   <td><code>&lt;all_urls&gt;</code>, </td>
 109   <td><code>&lt;all_urls&gt;</code></td>
 110 </tr>
 111 </table>
 112
 113 <h2 id="resource-identifiers">Resource identifiers</h2>
 114 <p>
 115 Resource identifiers allow you to specify content settings for specific
 116 subtypes of a content type. Currently, the only content type that supports
 117 resource identifiers is $(ref:contentSettings.plugins),
 118 where a resource identifier identifies a specific plugin. When applying content
 119 settings, first the settings for the specific plugin are checked. If there are
 120 no settings found for the specific plugin, the general content settings for
 121 plugins are checked.
 122 </p>
 123 <p>
 124 For example, if a content setting rule has the resource identifier
 125 <code>adobe-flash-player</code> and the pattern <code>&lt;all_urls&gt;</code>,
 126 it takes precedence over a rule without a resource identifier and the pattern
 127 <code>http://www.example.com/*</code>, even if that pattern is more specific.
 128 </p>
 129 <p>
 130 You can get a list of resource identifiers for a content type by calling the
 131 $(ref:contentSettings.ContentSetting.getResourceIdentifiers) method. The returned list
 132 can change with the set of installed plugins on the user's machine, but Chrome
 133 tries to keep the identifiers stable across plugin updates.
 134 </p>
 135
 136 <h2 id="examples">Examples</h2>
 137
 138 <p>
 139 You can find samples of this API on the
 140 <a href="samples#search:contentSettings">sample page</a>.
 141 </p>