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<title>The MongoGridFS class</title>
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<h1 class="title">The MongoGridFS class</h1>
<div class="partintro"><p class="verinfo">(PECL mongo >=0.9.0)</p>
<div class="section" id="mongogridfs.intro">
<h2 class="title">Introduction</h2>
<p class="para">
Utilities for storing and retrieving files from the database.
</p>
<p class="para">
GridFS is a storage specification all supported drivers implement.
Basically, it defines two collections: <em>files</em>, for file
metadata, and <em>chunks</em>, for file content. If the file is
large, it will automatically be split into smaller chunks and each chunk
will be saved as a document in the chunks collection.
</p>
<p class="para">
Each document in the files collection contains the filename, upload date,
and md5 hash. It also contains a unique <em>_id</em> field, which
can be used to query the chunks collection for the file's content. Each
document in the chunks collection contains a chunk of binary data, a
<em>files_id</em> field that matches its file's
<em>_id</em>, and the position of this chunk in the overall file.
</p>
<p class="para">
For example, the files document is something like:
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">array(</span><span style="color: #DD0000">"_id" </span><span style="color: #007700">=> </span><span style="color: #0000BB">123456789</span><span style="color: #007700">, </span><span style="color: #DD0000">"filename" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"foo.txt"</span><span style="color: #007700">, </span><span style="color: #DD0000">"chunkSize" </span><span style="color: #007700">=> </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #DD0000">"length" </span><span style="color: #007700">=> </span><span style="color: #0000BB">12</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
and the chunks documents look like:
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">array(</span><span style="color: #DD0000">"files_id" </span><span style="color: #007700">=> </span><span style="color: #0000BB">123456789</span><span style="color: #007700">, </span><span style="color: #DD0000">"n" </span><span style="color: #007700">=> </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #DD0000">"data" </span><span style="color: #007700">=> new </span><span style="color: #0000BB">MongoBinData</span><span style="color: #007700">(</span><span style="color: #DD0000">"abc"</span><span style="color: #007700">));<br />array(</span><span style="color: #DD0000">"files_id" </span><span style="color: #007700">=> </span><span style="color: #0000BB">123456789</span><span style="color: #007700">, </span><span style="color: #DD0000">"n" </span><span style="color: #007700">=> </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">"data" </span><span style="color: #007700">=> new </span><span style="color: #0000BB">MongoBinData</span><span style="color: #007700">(</span><span style="color: #DD0000">"def"</span><span style="color: #007700">));<br />array(</span><span style="color: #DD0000">"files_id" </span><span style="color: #007700">=> </span><span style="color: #0000BB">123456789</span><span style="color: #007700">, </span><span style="color: #DD0000">"n" </span><span style="color: #007700">=> </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #DD0000">"data" </span><span style="color: #007700">=> new </span><span style="color: #0000BB">MongoBinData</span><span style="color: #007700">(</span><span style="color: #DD0000">"ghi"</span><span style="color: #007700">));<br />array(</span><span style="color: #DD0000">"files_id" </span><span style="color: #007700">=> </span><span style="color: #0000BB">123456789</span><span style="color: #007700">, </span><span style="color: #DD0000">"n" </span><span style="color: #007700">=> </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #DD0000">"data" </span><span style="color: #007700">=> new </span><span style="color: #0000BB">MongoBinData</span><span style="color: #007700">(</span><span style="color: #DD0000">"jkl"</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
Of course, the default chunk size is thousands of bytes, but that makes an unwieldy example.
</p>
</div>
<div class="section">
<h2 class="title">Inter-Language Compatibility</h2>
<p class="para">
You should be able to use any files created by MongoGridFS with any other
drivers, and vice versa. However, some drivers expect that all metadata
associated with a file be in a "metadata" field. If you're going to be
using other languages, it's a good idea to wrap info you might want them to
see in a "metadata" field. For example, instead of:
</p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">storeFile</span><span style="color: #007700">(</span><span style="color: #DD0000">"somefile.txt"</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"date" </span><span style="color: #007700">=> new </span><span style="color: #0000BB">MongoDate</span><span style="color: #007700">()));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">
use something like:
</p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">storeFile</span><span style="color: #007700">(</span><span style="color: #DD0000">"somefile.txt"</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"metadata" </span><span style="color: #007700">=> array(</span><span style="color: #DD0000">"date" </span><span style="color: #007700">=> new </span><span style="color: #0000BB">MongoDate</span><span style="color: #007700">())));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="section">
<h2 class="title">The <strong class="classname">MongoGridFS</strong> Family</h2>
<p class="para">
<strong class="classname">MongoGridFS</strong> represents the files and chunks
collections. <strong class="classname">MongoGridFS</strong> extends MongoCollection,
and an instance of <strong class="classname">MongoGridFS</strong> has access to all of
<a href="class.mongocollection.html" class="classname">MongoCollection</a> methods, which act on the files
collection:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$grid </span><span style="color: #007700">= </span><span style="color: #0000BB">$db</span><span style="color: #007700">-></span><span style="color: #0000BB">getGridFS</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">update</span><span style="color: #007700">(array(</span><span style="color: #DD0000">"filename" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"foo"</span><span style="color: #007700">), </span><span style="color: #0000BB">$newObj</span><span style="color: #007700">); </span><span style="color: #FF8000">// update on the files collection<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
Another example of manipulating metadata:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #FF8000">// save a file<br /></span><span style="color: #0000BB">$id </span><span style="color: #007700">= </span><span style="color: #0000BB">$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">storeFile</span><span style="color: #007700">(</span><span style="color: #DD0000">"game.tgz"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$game </span><span style="color: #007700">= </span><span style="color: #0000BB">$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">findOne</span><span style="color: #007700">();<br /><br /></span><span style="color: #FF8000">// add a downloads counter<br /></span><span style="color: #0000BB">$game</span><span style="color: #007700">-></span><span style="color: #0000BB">file</span><span style="color: #007700">[</span><span style="color: #DD0000">'downloads'</span><span style="color: #007700">] = </span><span style="color: #0000BB">0</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">save</span><span style="color: #007700">(</span><span style="color: #0000BB">$game</span><span style="color: #007700">-></span><span style="color: #0000BB">file</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// increment the counter<br /></span><span style="color: #0000BB">$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">update</span><span style="color: #007700">(array(</span><span style="color: #DD0000">"_id" </span><span style="color: #007700">=> </span><span style="color: #0000BB">$id</span><span style="color: #007700">), array(</span><span style="color: #DD0000">'$inc' </span><span style="color: #007700">=> array(</span><span style="color: #DD0000">"downloads" </span><span style="color: #007700">=> </span><span style="color: #0000BB">1</span><span style="color: #007700">)));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
You can also access the chunks collection from an instance of
<strong class="classname">MongoGridFS</strong>:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /> $chunks </span><span style="color: #007700">= </span><span style="color: #0000BB">$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">chunks</span><span style="color: #007700">; </span><span style="color: #FF8000">// $chunks is a normal MongoCollection<br /></span><span style="color: #0000BB">$chunks</span><span style="color: #007700">-></span><span style="color: #0000BB">insert</span><span style="color: #007700">(array(</span><span style="color: #DD0000">"x" </span><span style="color: #007700">=> </span><span style="color: #0000BB">4</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
There are some methods for <strong class="classname">MongoGridFS</strong> with the same
name as <a href="class.mongocollection.html" class="classname">MongoCollection</a> methods, that behave
slightly differently. For example, <span class="function"><a href="mongogridfs.remove.html" class="function">MongoGridFS::remove()</a></span>
will remove any objects that match the criteria from the files collection
and their content from the chunks collection.
</p>
<p class="para">
To store something new in GridFS, there are a couple options. If you have
a filename, you can say:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">storeFile</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"whatever" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"metadata"</span><span style="color: #007700">, </span><span style="color: #DD0000">"you" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"want"</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
If you have a string of bytes that isn't a file, you can also store that
using <span class="function"><a href="mongogridfs.storebytes.html" class="function">MongoGridFS::storeBytes()</a></span>:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$grid</span><span style="color: #007700">-></span><span style="color: #0000BB">storeBytes</span><span style="color: #007700">(</span><span style="color: #0000BB">$bytes</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"whatever" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"metadata"</span><span style="color: #007700">, </span><span style="color: #DD0000">"you" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"want"</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
Querying a <strong class="classname">MongoGridFS</strong> collection returns a
<a href="class.mongogridfscursor.html" class="classname">MongoGridFSCursor</a>, which behaves like a normal
<a href="class.mongocursor.html" class="classname">MongoCursor</a> except that it returns
<strong class="classname">MongoGridFSFiles</strong> instead of associative arrays.
</p>
<p class="para">
<strong class="classname">MongoGridFSFiles</strong> can be written back to disc using
<span class="function"><a href="mongogridfsfile.write.html" class="function">MongoGridFSFile::write()</a></span> or retrieved in memory using
<span class="function"><a href="mongogridfsfile.getbytes.html" class="function">MongoGridFSFile::getBytes()</a></span>. There is currently no
method that automatically streams chunks, but it would be fairly easy to
write by querying the <em>$grid->chunks</em> collection.
</p>
<p class="para">
<a href="class.mongogridfsfile.html" class="classname">MongoGridFSFile</a> objects contain a field file which
contains any file metadata.
</p>
</div>
<div class="section" id="mongogridfs.synopsis">
<h2 class="title">Class synopsis</h2>
<div class="classsynopsis">
<div class="ooclass"></div>
<div class="classsynopsisinfo">
<span class="ooclass">
<span class="modifier">extends</span>
<a href="class.mongocollection.html" class="classname">MongoCollection</a>
</span>
{</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Fields */</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<span class="type"><a href="class.mongocollection.html" class="type MongoCollection">MongoCollection</a></span>
<var class="varname">$<var class="varname">chunks</var></var>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
;</div>
<div class="fieldsynopsis">
<span class="modifier">protected</span>
<span class="type">string</span>
<var class="varname">$<var class="varname">filesName</var></var>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
;</div>
<div class="fieldsynopsis">
<span class="modifier">protected</span>
<span class="type">string</span>
<var class="varname">$<var class="varname">chunksName</var></var>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
;</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="methodname"><a href="mongogridfs.construct.html" class="methodname">__construct</a></span>
( <span class="methodparam"><span class="type"><a href="class.mongodb.html" class="type MongoDB">MongoDB</a></span> <code class="parameter">$db</code></span>
[, <span class="methodparam"><span class="type">string</span> <code class="parameter">$prefix</code><span class="initializer"> = "fs"</span></span>
[, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$chunks</code><span class="initializer"> = "fs"</span></span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="mongogridfs.delete.html" class="methodname">delete</a></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$id</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><a href="mongogridfs.drop.html" class="methodname">drop</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">MongoGridFSCursor</span> <span class="methodname"><a href="mongogridfs.find.html" class="methodname">find</a></span>
([ <span class="methodparam"><span class="type">array</span> <code class="parameter">$query</code><span class="initializer"> = array()</span></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$fields</code><span class="initializer"> = array()</span></span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">MongoGridFSFile</span> <span class="methodname"><a href="mongogridfs.findone.html" class="methodname">findOne</a></span>
([ <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$query</code><span class="initializer"> = array()</span></span>
[, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$fields</code><span class="initializer"> = array()</span></span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">MongoGridFSFile</span> <span class="methodname"><a href="mongogridfs.get.html" class="methodname">get</a></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$id</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">mixed</span> <span class="methodname"><a href="mongogridfs.put.html" class="methodname">put</a></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$filename</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$metadata</code><span class="initializer"> = array()</span></span>
] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="mongogridfs.remove.html" class="methodname">remove</a></span>
([ <span class="methodparam"><span class="type">array</span> <code class="parameter">$criteria</code><span class="initializer"> = array()</span></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$options</code><span class="initializer"> = array()</span></span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">mixed</span> <span class="methodname"><a href="mongogridfs.storebytes.html" class="methodname">storeBytes</a></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$bytes</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$metadata</code><span class="initializer"> = array()</span></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$options</code><span class="initializer"> = array()</span></span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">mixed</span> <span class="methodname"><a href="mongogridfs.storefile.html" class="methodname">storeFile</a></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$filename</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$metadata</code><span class="initializer"> = array()</span></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$options</code><span class="initializer"> = array()</span></span>
]] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">mixed</span> <span class="methodname"><a href="mongogridfs.storeupload.html" class="methodname">storeUpload</a></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$name</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$metadata</code></span>
] )</div>
}</div>
</div>
<div class="section">
<h2 class="title">See Also</h2>
<ul class="simplelist">
<li class="member">MongoDB core docs on <a href="http://docs.mongodb.org/manual/core/gridfs/" class="link external">» GridFS</a></li>
<li class="member">LightCube Solutions blog post on <a href="http://www.lightcubesolutions.com/blog/?p=209" class="link external">» saving user uploads</a></li>
<li class="member">LightCube Solutions blog post on <a href="http://www.lightcubesolutions.com/blog/?p=228" class="link external">» adding metadata to files</a></li>
</ul>
</div>
</div>
<h2>Table of Contents</h2><ul class="chunklist chunklist_reference"><li><a href="mongogridfs.construct.html">MongoGridFS::__construct</a> — Creates new file collections</li><li><a href="mongogridfs.delete.html">MongoGridFS::delete</a> — Delete a file from the database</li><li><a href="mongogridfs.drop.html">MongoGridFS::drop</a> — Drops the files and chunks collections</li><li><a href="mongogridfs.find.html">MongoGridFS::find</a> — Queries for files</li><li><a href="mongogridfs.findone.html">MongoGridFS::findOne</a> — Returns a single file matching the criteria</li><li><a href="mongogridfs.get.html">MongoGridFS::get</a> — Retrieve a file from the database</li><li><a href="mongogridfs.put.html">MongoGridFS::put</a> — Stores a file in the database</li><li><a href="mongogridfs.remove.html">MongoGridFS::remove</a> — Removes files from the collections</li><li><a href="mongogridfs.storebytes.html">MongoGridFS::storeBytes</a> — Stores a string of bytes in the database</li><li><a href="mongogridfs.storefile.html">MongoGridFS::storeFile</a> — Stores a file in the database</li><li><a href="mongogridfs.storeupload.html">MongoGridFS::storeUpload</a> — Stores an uploaded file in the database</li></ul>
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