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

   1 <h2 id="usage">Usage</h2>
   2
   3 <p>The mediaGalleries API lets you prompt the user for permission to access
   4 media galleries on the user's computer. The permission dialog contains common
   5 media locations for the platform and allows the user to specify additional
   6 locations. From those locations, only media files will be present in the file
   7 system objects.</p>
   8
   9 <h2 id="manifest">Manifest</h2>
  10
  11 <p>The media galleries API has two axes of permission parameters:</p>
  12
  13 <ul>
  14   <li>the locations that can be accessed</li>
  15   <li>the type of access</li>
  16 </ul>
  17
  18 <p>These two axes and the permission parameters on each axis are described
  19 in the table below:</p>
  20
  21 <table>
  22     <tr>
  23       <th>Axis</th>
  24       <th>Parameter</th>
  25       <th>Effect</th>
  26     </tr>
  27     <tr>
  28       <td rowspan="2">Locations</td>
  29       <td>none</td>
  30       <td>
  31         If you do not specify a location permission parameter, your app will
  32         not be able to access any media galleries until the user grants
  33         permission to access specific media galleries at runtime using the
  34         media gallery permission dialog.
  35       </td>
  36     </tr>
  37     <tr>
  38       <td>"allAutoDetected"</td>
  39       <td>
  40         Grants your app access to all auto-detected media galleries on the
  41         user's computer. This permission causes an install-time prompt to be
  42         displayed indicating that the app will have access to the user's media
  43         files.
  44       </td>
  45     </tr>
  46     <tr>
  47       <td rowspan="3">Access&nbsp;type</td>
  48       <td>"read"</td>
  49       <td>Grants your app the right to read files in media galleries.</td>
  50     </tr>
  51     <tr>
  52       <td>"delete"</td>
  53       <td>
  54         Grants your app the right to delete files from media galleries.
  55         "read" permission is a prerequisite for "delete". Specify both "read"
  56         and "delete" to obtain both types of permissions to media galleries.
  57       </td>
  58     </tr>
  59     <tr>
  60       <td>"copyTo"</td>
  61       <td>
  62         Grants your app the right to copy files into media galleries.
  63         Only valid media files that Chrome is capable of playing or displaying
  64         are permitted; files that Chrome is not able to validate will result
  65         in a security error. "read" and "delete" permissions are prerequisites
  66         for "copyTo". Specify "read", "delete" and "copyTo" to obtain all three
  67         types of permissions to media galleries.
  68       </td>
  69     </tr>
  70 </table>
  71
  72 <p>Notes:</p>
  73 <ul>
  74   <li>The media gallery permission dialog can be triggered programmatically.
  75   The user may have alternate media locations, so even if you specify
  76   "allAutoDetected" permsission, it is still important to provide a mechanism
  77   to open the permission dialog in your app.</li>
  78
  79   <li>There is no write access to media galleries due to the
  80   file validation requirement. However, you can write files to
  81   a different file system like the temporary file system, and then copy
  82   the files into the desired media gallery.</li>
  83
  84   <li>Access type permissions do not trigger an install-time prompt
  85   by themselves. However, the type of access will be reflected in the
  86   media gallery permission dialog, as well as the install-time prompt if
  87   "allAutoDetected" permission is requested.</li>
  88 </ul>
  89
  90 <p>Below is an example of a manifest file with mediaGalleries permissions:</p>
  91
  92 <pre data-filename="manifest.json">
  93 {
  94   "name": "My app",
  95   ...
  96   "permissions": [
  97     <b>{ "mediaGalleries": ["read", "allAutoDetected"] }</b>
  98   ],
  99   ...
 100 }
 101 </pre>
 102
 103 <p>This example manifest file will trigger an install-time permission prompt,
 104 and let the app read from all auto-detected media galleries on the
 105 user's computer. The user may add or remove galleries using the
 106 media gallery permission dialog, after which the app will be able
 107 to read all the media files from galleries that the user selected.</p>
 108
 109 <h2 id="iTunes">iTunes</h2>
 110
 111 <p>If present, the user's iTunes library can be accessed as a media gallery.
 112 In addition to the media files in the library, the "iTunes Music Library.xml"
 113 file is also presented.</p>
 114 <p>Regardless of where the music files are actually on the disk (and where
 115 the xml file says they are), they are mapped into an Artist/Album/Track
 116 hierarchy like iTunes does by default.  This mapping doesn't always work
 117 perfectly, so there are two things to note for Apps trying to match the
 118 xml file with files in the gallery.</p>
 119 <p>If the filenames for tracks within an album are not unique, they will be
 120 uniquified by adding the track id in parentheses before the extension, and
 121 if there is a colon or a slash in the artist, album, or track name, they are
 122 turned into underscore characters.</p>
 123
 124 <h2 id="Picasa">Picasa</h2>
 125
 126 <p>If present, the user's Picasa library can also be accessed as a media
 127 gallery. Directories on the filesystem scanned by Picasa are presented under
 128 folders/. Picasa Albums are presented under albums/.</p>
 129 <p>Albums and Folders that have duplicate names and dates will be uniquified
 130 using an incrementing integer in parenthesis before the extension.</p>
 131 <p>Duplicate filenames within the same Album will also be uniquified using an
 132 incrementing integer in parenthesis before the extension.</p>
 133
 134 <h2 id="iPhoto">iPhoto</h2>
 135
 136 <p>If present, the user's iPhoto library can be accessed as a media gallery.
 137 The files are structured within a subdirectory called "Albums/". Within that
 138 subdirectory, each album in the user's iPhoto library will appear as a
 139 subdirectory by name, and contain file entries for the photos in that album.
 140 </p>
 141 <p>Duplicate album names or image filenames within albums will get a
 142 disambiguating suffix like "(NN)" where NN is a unique number.</p>
 143 <p>Any items appearing in multiple albums in iPhoto will appear in all those
 144 albums in the gallery.</p>
 145 <p>If the user has modified any images within an album, there will be an
 146 additional subdirectory called "originals/" within the album directory.
 147 It will contain the original image with the same filename as in the parent
 148 album subdirectory. The file as it appears in the parrent album directory
 149 will be the one the user has invested time cropping, rotating, or
 150 otherwise editing.</p>
 151