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<!DOCTYPE html>
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<dl class='L'><dt>Start Here</dt>
<dd><a href='/getting_started.html'>Getting Started: Part 1</a></dd>
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<h2>Data Source - Connecting with a Data Soure</h2>
<p>This guide covers how to write a DataSource using the API's in SproutCore 1.0–1.10. After reading this guide, you will be able to:</p>
<ul>
<li>Understand what a DataSource is, and where it fits into the SproutCore Data Stream</li>
<li>Create your own DataSource and link it to your App</li>
</ul>
</div>
<div class='note'><p> If you are looking for other methods of talking to the server,
[look here](connect_server.html).
</p></div>
<div class='warning'><p> This is a Draft Copy, and although the information in here is correct,
it may be incomplete in places.
</p></div>
<h3 id='-What-is-a-DataSource--'>1 - What is a DataSource?
</h3>
<p>A DataSource is the layer that sits between your SproutCore application's
<a href="records.html#models-records-and-the-store">store</a> and your backend. To start
out, your app will probably be setup to use <a href="fixtures.html">fixtures</a>. This
will populate your app with data without having to hit your server in
development. When you are ready to interact with your backend, you can create
your own DataSource that will send and receive data to and from your backend.</p>
<div class='note'><p> A DataSource is different from the Store. The Store is the in-memory
storage for your records, while the DataSource is the communication layer
linking the store to your backend.
</p></div>
<p>TODO: A diagram will be nice, showing the layers of a SproutCore application,
with the datasource highlighted to show where it fits in.</p>
<h3 id='-When-should-I-make-my-own-DataSource--'>2 - When should I make my own DataSource?
</h3>
<p>If you want to be able to persist the data that your users enter, over
sessions, then you'll want to save it, either to a server or to local storage.
The beauty of SproutCore's data layers is that you can write your app and
seamlessly move from one data source to another and nothing but your DataSource
will need to be changed.</p>
<h3 id='-A-look-at-the-API-'>3 - A look at the API
</h3>
<p>Here we will look at an example API from the server. Creating the server side
code is a "digging deeper topic". For now you can have a look at the numerous
examples in the
<a href="http://wiki.sproutcore.com/w/page/12413020/Todos%2006-Building%20the%20Backend">todo app tutorial</a>.</p>
<p>For the purpose of this guide, we are going to assume that we have a server
that will provide us with a basic
<a href="http://en.wikipedia.org/wiki/Representational_State_Transfer#RESTful_web_services">RESTful API</a>.
If we wanted to get a list of all ToDo items, we would send a GET request to:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs bash">GET: /todos/</code></div></pre>
<p>Which will return a <a href="http://en.wikipedia.org/wiki/Json">JSON</a> array like:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">[
{
<span class="hljs-string">"id"</span>: <span class="hljs-number">1</span>,
<span class="hljs-string">"title"</span>: <span class="hljs-string">"Learn to use SproutCore"</span>,
<span class="hljs-string">"done"</span>: <span class="hljs-literal">false</span>
},
{
<span class="hljs-string">"id"</span>: <span class="hljs-number">2</span>,
<span class="hljs-string">"title"</span>: <span class="hljs-string">"Something"</span>,
<span class="hljs-string">"done"</span>: <span class="hljs-literal">false</span>
}
]</code></div></pre>
<p>To create a new ToDo item, we can POST to this URL with JSON in the body.</p>
<pre class="highlighted"><div class="code_container"><code class="hljs bash">POST: /todos/
{
<span class="hljs-string">"title"</span>: <span class="hljs-string">"Profit!"</span>,
<span class="hljs-string">"done"</span>: <span class="hljs-literal">false</span>
}</code></div></pre>
<p>The server will return the new ID for us.</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">{
<span class="hljs-string">"id"</span>: <span class="hljs-number">3</span>
}</code></div></pre>
<p>If we specify an ID in the url:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs bash">GET: /todos/3</code></div></pre>
<p>You'll see just one object returned:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">{
<span class="hljs-string">"id"</span>: <span class="hljs-number">3</span>,
<span class="hljs-string">"title"</span>: <span class="hljs-string">"Profit!"</span>,
<span class="hljs-string">"done"</span>: <span class="hljs-literal">false</span>
}</code></div></pre>
<p>The API also allows us to send a PUT to update an existing ToDo item and DELETE
to remove it.</p>
<p>A PUT or DELETE response will not have a body, we will know that everything is
ok if the HTTP status code is 200 (ok).</p>
<p>With this basic understanding of how the server works, we can get started
writing our DataSource.</p>
<h3 id='-Setup-'>4 - Setup
</h3>
<h4 id='-Creating-a-DataSource-'>4.1 - Creating a DataSource
</h4>
<p>To generate a DataSource, use the command:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs bash">sc-gen data-source MyApp.RESTDataSource</code></div></pre>
<div class='note'><p> Anywhere you see MyApp, replace this with the name of the application
that you're building.
</p></div>
<p>This will make a file in <tt>apps/my_app/data_sources/rest.js</tt>. This file will be
stubbed with the default functions that will get called by the store.</p>
<h4 id='-Linking-to-the-Store-'>4.2 - Linking to the Store
</h4>
<p>The next step is linking the new DataSource to the store. By default, the store
will be using <a href="fixtures.html">Fixtures</a>. In <tt>core.js</tt> you'll see:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript"> store: SC.Store.create().from(SC.Record.fixtures)</code></div></pre>
<p>Replace this with the newly created DataSource:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript"> store: SC.Store.create().from(<span class="hljs-string">'MyApp.RESTDataSource'</span>)</code></div></pre>
<p>This will tell the store to use the new DataSource when trying to find data.</p>
<div class='note'><p> As you can see we are replacing a JavaScript Object: <tt>SC.Record.fixtures</tt>
with a string <tt>'MyApp.RESTDataSource'</tt>. This is because our DataSource won't
have been initialised. The first time the store tries to access the DataSource
it will convert the string to an object and save it for future reference. See
[Core Concepts](core_concepts.html#property-paths) for more information.
</p></div>
<h3 id='-Writing-The-DataSource-'>5 - Writing The DataSource
</h3>
<h4 id='-Our-First-Fetch-'>5.1 - Our First Fetch
</h4>
<p>The first thing that your app will likely do is to fetch a bunch of data. This
is usually done via a <a href="records.html#using-queries">query</a>. The query for
finding all ToDo's will look like:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript"> MyApp.QUERY_ALL_TODOS = SC.Query.local(MyApp.Todo)</code></div></pre>
<div class='note'><p> Our DataSource will be written assuming that
[local queries](records.html#local-vs-remote-queries) are being used. Local
queries are what you will be using most of the time. Remote queries will be
covered in a separate guide.
</p></div>
<p>When you call <tt>MyApp.store.find(MyApp.QUERY_ALL_TODOS)</tt>, the store will return a
<a href="http://docs.sproutcore.com/symbols/SC.RecordArray.html">RecordArray</a>
containing matching records (or an empty recordArray, if nothing matches). This
RecordArray is linked to the query so that it will automatically update any
time the query conditions match a new record. After it has returned, the store
will call 'fetch' on its attached DataSource. </p>
<p>This is when we get to take action. The generated DataSource will already
contain the following code:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript"> fetch: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, query</span>) </span>{
<span class="hljs-comment">// <span class="hljs-doctag">TODO:</span> Add handlers to fetch data for specific queries. </span>
<span class="hljs-comment">// call store.dataSourceDidFetchQuery(query) when done.</span>
<span class="hljs-keyword">return</span> NO ; <span class="hljs-comment">// return YES if you handled the query</span>
},</code></div></pre>
<p>Currently, this DataSource will not do anything except return NO. This tells
the store that we are not going to handle this query.</p>
<p>We are also given a hint of what we need to do next. When the server responds,
we will call <tt>store.dataSourceDidFetchQuery(query)</tt> to let the store know that
this query has been updated.</p>
<p>Now we want to fetch all the Todo's</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">fetch: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, query</span>) </span>{
SC.Request.getUrl(<span class="hljs-string">'/todos/'</span>).json()
.notify(<span class="hljs-keyword">this</span>, <span class="hljs-string">'fetchDidComplete'</span>, store, query)
.send()
<span class="hljs-keyword">return</span> YES;
},
<span class="hljs-attr">fetchDidComplete</span>: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">response, store, query</span>) </span>{
<span class="hljs-keyword">if</span>(SC.ok(response)) {
<span class="hljs-keyword">var</span> recordType = query.get(<span class="hljs-string">'recordType'</span>),
records = response.get(<span class="hljs-string">'body'</span>);
store.loadRecords(recordType, records);
store.dataSourceDidFetchQuery(query);
} <span class="hljs-keyword">else</span> {
<span class="hljs-comment">// Tell the store that your server returned an error</span>
store.dataSourceDidErrorQuery(query, response);
}
}</code></div></pre>
<p>Our <tt>Fetch</tt> function is pretty simple. For now, we are constructing
a <tt>Request</tt> to send to the server.</p>
<p><a href="http://docs.sproutcore.com/symbols/SC.Request.html">SC.Request</a> is
SproutCore's simple wrapper around an Ajax call.</p>
<div class='note'><p> You are not restricted to using an SC.Request inside of a DataSource, but
it is advised that you don't go making calls to your server from just anywhere
in your app.
</p></div>
<p><a href="http://docs.sproutcore.com/symbols/SC.Request.html#.getUrl">.getUrl</a> tells our
request that we want to use the GET method to contact the given url. You can
also use the following:</p>
<ul>
<li><a href="http://docs.sproutcore.com/symbols/SC.Request.html#.putUrl">putUrl</a></li>
<li><a href="http://docs.sproutcore.com/symbols/SC.Request.html#.postUrl">postUrl</a></li>
<li><a href="http://docs.sproutcore.com/symbols/SC.Request.html#.deleteUrl">deleteUrl</a></li>
</ul>
<p><a href="http://docs.sproutcore.com/symbols/SC.Request.html#json">.json</a> lets the
request know that we are expecting the server to send back JSON, so it will
automatically parse it for us. Without this, the return value would be a
string. We could also have called <tt>.xml()</tt> if your server speaks XML.</p>
<p><a href="http://docs.sproutcore.com/symbols/SC.Request.html#notify">.notify</a> sets the
callback method. By default SC.Requests are asynchronous, so the app can keep
running while waiting for the server. The parameters used here are:</p>
<ol>
<li><tt>this</tt> {Object} The target object that the action will run on</li>
<li><tt>'fetchDidComplete'</tt> {String} The name of the function that is located on
<code>target</code> that will get called</li>
<li><tt>store, query</tt> {Any Objects} All following parameters will get passed into
the call back</li>
</ol>
<p><a href="http://docs.sproutcore.com/symbols/SC.Request.html#send">.send</a> will now
actually send the built up request and return immediately (as we have kept the
default async behaviour), without waiting for the server. </p>
<div class='note'><p> <tt>.send()</tt> also takes a <tt>String</tt> parameter for the <tt>POST</tt> and <tt>PUT</tt>
methods to send as the body of the request.
</p></div>
<p>When the server responds to the request, our callback method <tt>fetchDidComplete</tt>
will get called. The first parameter is the SC.Response related to the Request
we just sent. Any following parameters are the ones we passed
into <tt>.notify()</tt>: <tt>store</tt> and <tt>query</tt>.</p>
<p>First thing we do when the response comes back is check to see if there was an
error or not.</p>
<p><a href="http://docs.sproutcore.com/symbols/SC.html#.ok">SC.ok</a> will do this for us.</p>
<p>If all is good, we can now load the records into the store. First we need to
get the RecordType that is stored in the query so we can inform the store. For
us, it will be <tt>MyApp.Todo</tt>.</p>
<p>Next, we get our records with <tt>response.get('body')</tt>. This is where the JSON
string is converted into JS objects for us. If we did not call <tt>.json()</tt> on
the <tt>Request</tt>, it would return a string.</p>
<p>This works because our server responds with an array at the top level of the
JSON. If your server returned something like:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">{
<span class="hljs-attr">length</span>: <span class="hljs-number">1</span>,
<span class="hljs-attr">records</span>: [
{
<span class="hljs-string">"id"</span>: <span class="hljs-number">1</span>,
<span class="hljs-string">"title"</span>: <span class="hljs-string">"Learn to use SproutCore"</span>,
<span class="hljs-string">"done"</span>: <span class="hljs-literal">false</span>
}
]
}</code></div></pre>
<p>Then we would use this instead:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript"><span class="hljs-keyword">var</span> body = response.get(<span class="hljs-string">'body'</span>)
records = body.records;</code></div></pre>
<div class='note'><p> Note how we didn't use <tt>.get('records')</tt>, this is because the JSON is
converted into plain Javascript objects, not <tt>SC.Object</tt>'s.
</p></div>
<p>Now we call
<a href="http://docs.sproutcore.com/symbols/SC.Store.html#loadRecords">loadRecords</a> on
the store to actually put our data into the store. The first parameter is the
Record Type of the objects you are going to load. The second is an array of
plain JS object hashes containing your records data.</p>
<div class='warning'><p> You need to make sure that your data hashes have their
[primary key](records.html#record-ids) properties, in this case '<tt>id</tt>'.
</p></div>
<div class='note'><p> This is the usual way of calling <tt>loadRecords</tt>, but it can be called with
a few different signatures. This allows for quite complex behaviour, such as
loading multiple record types at once. These will be covered by other guides.
</p></div>
<p>Finally, we call
<a href="http://docs.sproutcore.com/symbols/SC.Store.html#dataSourceDidFetchQuery">.dataSourceDidFetchQuery</a>
to let the store know that we have finished loading records, and it is now time
to update the passed in query. The query that we passed in is the one that was
given to us by <tt>fetch</tt>; it was passed as a parameter in the callback.</p>
<p>If the server returned an error, such as <tt>404</tt> Not Found, or the <tt>500</tt> series
of server errors, then we'll let the store know with
<a href="http://docs.sproutcore.com/symbols/SC.Store.html#dataSourceDidErrorQuery">.dataSourceDidErrorQuery</a>.
This sets the query into an error state, for which you can later check and deal
with.</p>
<h4 id='-Gaining-Flexibility-'>5.2 - Gaining Flexibility
</h4>
<p>This design is simple, but as you can see, not very flexible, it only allows
for one url. That won't get us very far. But given that all of our records are
going to have a very similar URL, it should be simple to dynamically generate
this URL.</p>
<p>We can have each of our models know what their URL will be:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">MyApp.Todo = SC.Record.extend(
<span class="hljs-comment">/** @scope MyApp.Todo.prototype */</span> {
<span class="hljs-comment">// <span class="hljs-doctag">TODO:</span> Add your own code here.</span>
}) ;
MyApp.Todo.mixin({
<span class="hljs-attr">resourcePath</span>: <span class="hljs-string">'todo'</span>,
<span class="hljs-attr">pluralResourcePath</span>: <span class="hljs-string">'todos'</span>
}) ;</code></div></pre>
<p>We use a mixin here to set these as class properties. it allows us to get the
path without an instance. For example: <tt>MyApp.Todo.resourcePath</tt>.</p>
<p>This will allow our DataSource to find the path needed. We'll change the fetch
method to:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">fetch: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, query</span>) </span>{
SC.Request.getUrl(<span class="hljs-string">'/%@/'</span>.fmt(query.recordType.pluralResourcePath))
.notify(<span class="hljs-keyword">this</span>, <span class="hljs-string">'fetchDidComplete'</span>, store, query)
.json().send()
<span class="hljs-keyword">return</span> YES;
},</code></div></pre>
<p>The fetch method will now use a dynamic URL for each record type. </p>
<div class='note'><p> The [fmt](http://docs.sproutcore.com/symbols/String.html#String#fmt)
function outputs a formatted string.
</p></div>
<p>Alternatively, you could dynamically generate the path using built-in methods
such as <a href="http://docs.sproutcore.com/#doc=String&method=decamelize&src=false">decamalize</a>
and <a href="http://docs.sproutcore.com/#doc=SC.String&method=.pluralize&src=false">pluralize</a>
as in the code below:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">fetch: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, query</span>) </span>{
<span class="hljs-keyword">var</span> path = query.recordType.decamalize().pluralize();
SC.Request.getUrl(<span class="hljs-string">'/%@/'</span>.fmt(path))
.notify(<span class="hljs-keyword">this</span>, <span class="hljs-string">'fetchDidComplete'</span>, store, query)
.json().send()
<span class="hljs-keyword">return</span> YES;
},</code></div></pre>
<p>However, this may not work for more complex scenarios, so specifically defining
the resource path on the model is a much more robust approach.</p>
<h4 id='-Change-of-Mind-'>5.3 - Change of Mind
</h4>
<p>Fetching records is fun but it will only get us so far. Eventually we are going
to want to make some changes to these records.</p>
<p>Each time our store wants to commit changes to the server, the <tt>updateRecord</tt>
method will be called for each of the changed records.</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">updateRecord: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, storeKey</span>) </span>{
<span class="hljs-keyword">var</span> recordType = store.recordTypeFor(storeKey),
id = store.idFor(storeKey),
data = store.readDataHash(storeKey);
SC.Request.putUrl(<span class="hljs-string">"/%@/%@"</span>.fmt(recordType.resourcePath, id))
.notify(<span class="hljs-keyword">this</span>, <span class="hljs-string">'updateRecordDidComplete'</span>, store, storeKey, id)
.json().send(data);
<span class="hljs-keyword">return</span> YES;
},
<span class="hljs-attr">updateRecordDidComplete</span>: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">response, store, storeKey, id</span>) </span>{
<span class="hljs-keyword">if</span>(SC.ok(response) && response.get(<span class="hljs-string">'status'</span>) === <span class="hljs-number">200</span>) {
<span class="hljs-comment">// Tell the store that we have successfully updated</span>
store.dataSourceDidComplete(storeKey);
} <span class="hljs-keyword">else</span> {
<span class="hljs-comment">// Tell the store that your server returned an error</span>
store.dataSourceDidError(storeKey, response);
}
}</code></div></pre>
<p>Our API uses the PUT method for making changes, so we use <tt>putUrl()</tt>, the
string that we are making for the url, will end up looking something
like: <tt>/todo/1</tt></p>
<p>This code should look familiar with only a few differences. This time we don't
have a query, but instead just a reference to a single record, via
it's <tt>storeKey</tt>. With this, we get the <tt>recordType</tt>, <tt>id</tt> and the <tt>data</tt> (the
actual properties of our record).</p>
<div class='note'><p> In this instance we call <tt>send()</tt> with an object. This is possible,
because we also called <tt>json()</tt>. Without this, <tt>send()</tt> would need to be called
with a string.
</p></div>
<p>Our API will return empty response with status 200 from our PUT command.</p>
<p>So we test for it:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">response.get(<span class="hljs-string">'status'</span>) === <span class="hljs-number">200</span></code></div></pre>
<p>If all is good, then we call <tt>dataSourceDidComplete</tt> to tell the store we are
done.</p>
<h5 id='-Server-Processing-'>5.3.1 - Server Processing
</h5>
<p>If your server needs to process the data, it might need to send back different
data than what you send up. Your server might send back something like:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">{
<span class="hljs-string">"record"</span>: {
<span class="hljs-string">"id"</span>: <span class="hljs-number">3</span>,
<span class="hljs-string">"title"</span>: <span class="hljs-string">"Profit!"</span>,
<span class="hljs-string">"done"</span>: <span class="hljs-literal">false</span>,
<span class="hljs-string">"updatedAt"</span>: <span class="hljs-string">"2011-02-20 11:36Z"</span>
}
}</code></div></pre>
<p>You'll then need to update your callback to tell the store about it:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">store.dataSourceDidComplete(storeKey, response.get(<span class="hljs-string">'body'</span>).record);</code></div></pre>
<p>This will update the properties on your record with any changes that the server
makes.</p>
<h4 id='-Going-for-Creation-'>5.4 - Going for Creation
</h4>
<p>Creating records is much like updating them, but when you first create a record
in the store, it does not have an <tt>id</tt>. So when the server responds, with
the <tt>id</tt>:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">{
<span class="hljs-string">"id"</span>: <span class="hljs-number">3</span>
}</code></div></pre>
<p>We tell the store about it:</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">createRecord: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, storeKey</span>) </span>{
<span class="hljs-keyword">var</span> recordType = store.recordTypeFor(storeKey),
data = store.readDataHash(storeKey);
SC.Request.postUrl(<span class="hljs-string">"/%@"</span>.fmt(recordType.pluralResourcePath))
.notify(<span class="hljs-keyword">this</span>, <span class="hljs-string">'createRecordDidComplete'</span>, store, storeKey)
.json().send(data);
<span class="hljs-keyword">return</span> YES;
},
<span class="hljs-attr">createRecordDidComplete</span>: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">response, store, storeKey</span>) </span>{
<span class="hljs-keyword">var</span> body = response.get(<span class="hljs-string">'body'</span>);
<span class="hljs-keyword">if</span>(SC.ok(response) && response.get(<span class="hljs-string">'status'</span>) === <span class="hljs-number">200</span>) {
<span class="hljs-comment">// Tell the store that we have successfully updated</span>
store.dataSourceDidComplete(storeKey, <span class="hljs-literal">null</span>, body.id);
} <span class="hljs-keyword">else</span> {
<span class="hljs-comment">// Tell the store that your server returned an error</span>
store.dataSourceDidError(storeKey, response);
}
}</code></div></pre>
<h5 id='-Server-Processing-'>5.4.1 - Server Processing
</h5>
<p>The same deal with server side processing applies here as with updates.</p>
<h4 id='-Feeling-Destructive-'>5.5 - Feeling Destructive
</h4>
<p>Things should start feeling pretty familiar now, you can probably guess what's
going to come next.</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">destroyRecord: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, storeKey</span>) </span>{
<span class="hljs-keyword">var</span> recordType = store.recordTypeFor(storeKey),
id = store.idFor(storeKey);
SC.Request.deleteUrl(<span class="hljs-string">"/%@/%@"</span>.fmt(recordType.resourcePath, id))
.notify(<span class="hljs-keyword">this</span>, <span class="hljs-string">'destroyRecordDidComplete'</span>, store, storeKey)
.json().send();
<span class="hljs-keyword">return</span> YES;
},
<span class="hljs-attr">destroyRecordDidComplete</span>: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">response, store, storeKey</span>) </span>{
<span class="hljs-keyword">var</span> body = response.get(<span class="hljs-string">'body'</span>);
<span class="hljs-keyword">if</span>(SC.ok(response) && response.get(<span class="hljs-string">'status'</span>) === <span class="hljs-number">200</span>) {
<span class="hljs-comment">// Tell the store that we have successfully updated</span>
store.dataSourceDidDestroy(storeKey);
} <span class="hljs-keyword">else</span> {
<span class="hljs-comment">// Tell the store that your server returned an error</span>
store.dataSourceDidError(storeKey, response);
}
}</code></div></pre>
<p>You should have noticed the 2 differences,</p>
<ol>
<li>We're using <tt>deleteUrl</tt></li>
<li>We're calling <tt>dataSourceDidDestroy</tt> in the callback.</li>
</ol>
<h4 id='-Ahh--Refreshing-'>5.6 - Ahh, Refreshing
</h4>
<p>One that that is not always used, but some apps find helpful, is being able to
refresh a record, to get the latest from the server.</p>
<p>This is similar to a query, but for only a single record.</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">retrieveRecord: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">store, storeKey</span>) </span>{
<span class="hljs-keyword">var</span> recordType = store.recordTypeFor(storeKey),
id = store.idFor(storeKey),
data = store.readDataHash(storeKey);
SC.Request.getUrl(<span class="hljs-string">"/%@/%@"</span>.fmt(recordType.resourcePath, id))
.notify(<span class="hljs-keyword">this</span>, <span class="hljs-string">'retrieveRecordDidComplete'</span>, store, storeKey, id)
.json().send(data);
<span class="hljs-keyword">return</span> YES;
},
<span class="hljs-attr">retrieveRecordDidComplete</span>: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">response, store, storeKey, id</span>) </span>{
<span class="hljs-keyword">if</span>(SC.ok(response) && response.get(<span class="hljs-string">'status'</span>) === <span class="hljs-number">200</span>) {
<span class="hljs-comment">// Tell the store that we have successfully updated</span>
store.dataSourceDidComplete(storeKey, response.get(<span class="hljs-string">'body'</span>).record);
} <span class="hljs-keyword">else</span> {
<span class="hljs-comment">// Tell the store that your server returned an error</span>
store.dataSourceDidError(storeKey, response);
}
}</code></div></pre>
<p>This time, we'll always be passing the datahash into <tt>dataSourceDidComplete</tt>,
to make sure that the local record is the same as the server copy.</p>
<h3 id='-Things-to-Note-'>6 - Things to Note
</h3>
<p>TODO: Some important things to note will go here.</p>
<h4 id='-A-Record-s-PrimaryKey-'>6.1 - A Record's PrimaryKey
</h4>
<p>By default, SproutCore sets the primaryKey property of records to 'guid'. A
common convention of many server side APIs is to use just 'id'. To make your
records work with this, you can override the default in your Model files.</p>
<pre class="highlighted"><div class="code_container"><code class="hljs javascript">App.Todo = SC.Record.extend({
<span class="hljs-attr">primaryKey</span>:<span class="hljs-string">'id'</span>
})</code></div></pre>
<p>You may set this to anything that you want, if your server uses, for
example, <tt>TID</tt> for your todo's id, you must set <tt>primaryKey:'TID'</tt>. Like normal
JS properties, this is case sensitive.</p>
<h4 id='-Prepare-for-a-Change-'>6.2 - Prepare for a Change
</h4>
<p>The dataSource as we have it now is handy, but as people have been using it, we
have discovered that there are many improvements that can be made. As a
courtesy we are just letting you know that a future (yet undecided) version of
SproutCore is going to have a vastly updated DataSource layer.</p>
<p>Don't hold back developing your awesome app now. Just know, and be excited,
that there are great improvements coming.</p>
<h3 id='-Advanced-topics-'>7 - Advanced topics
</h3>
<h4 id='-Managing-Many-Records-with-a-Bulk-API-'>7.1 - Managing Many Records with a Bulk API
</h4>
<h4 id='-Datasource-for-sparseArray-'>7.2 - Datasource for sparseArray
</h4>
<h4 id='-Cascading-Datasource-'>7.3 - Cascading Datasource
</h4>
<h4 id='-Fetching-a-Query-with-Multiple-Data-Types-'>7.4 - Fetching a Query with Multiple Data Types
</h4>
<h4 id='-Datasource-for-Remote-Query-'>7.5 - Datasource for Remote Query
</h4>
<h3 id='-Changelog-'>8 - Changelog
</h3>
<ul>
<li>March 2, 2011: initial version by <a href="credits.html#geoffreyd">Geoffrey Donaldson</a></li>
<li>March 2, 2011: minor fixes by <a href="credits.html#wagenet">Peter Wagenet</a></li>
<li>March 22, 2011: minor fixes/formatting by <a href="credits.html#topherfangio">Topher Fangio</a></li>
<li>April 18, 2011: corrections and fixes by <a href="credits.html#drogus">Piotr Sarnacki</a></li>
<li>August 14, 2013: converted to Markdown format for DocPad guides by <a href="credits.html#topherfangio">Topher Fangio</a></li>
<li>January 31, 2014: minor updates/additions by <a href="credits.html#topherfangio">Topher Fangio</a></li>
</ul>
</div>
<!-- TODO: re-add index_items //-->
<div id="subCol">
<h3 class="chapter"><img src="images/graphics/chapters.png" alt="">Chapters</h3>
<ol class='chapters'>
<li>
<a href='#-What-is-a-DataSource--'><p> What is a DataSource?
</p></a>
<ul>
</ul>
</li>
<li>
<a href='#-When-should-I-make-my-own-DataSource--'><p> When should I make my own DataSource?
</p></a>
<ul>
</ul>
</li>
<li>
<a href='#-A-look-at-the-API-'><p> A look at the API
</p></a>
<ul>
</ul>
</li>
<li>
<a href='#-Setup-'><p> Setup
</p></a>
<ul>
<li><a href='#-Creating-a-DataSource-'><p> Creating a DataSource
</p></a></li>
<li><a href='#-Linking-to-the-Store-'><p> Linking to the Store
</p></a></li>
</ul>
</li>
<li>
<a href='#-Writing-The-DataSource-'><p> Writing The DataSource
</p></a>
<ul>
<li><a href='#-Our-First-Fetch-'><p> Our First Fetch
</p></a></li>
<li><a href='#-Gaining-Flexibility-'><p> Gaining Flexibility
</p></a></li>
<li><a href='#-Change-of-Mind-'><p> Change of Mind
</p></a></li>
<li><a href='#-Going-for-Creation-'><p> Going for Creation
</p></a></li>
<li><a href='#-Feeling-Destructive-'><p> Feeling Destructive
</p></a></li>
<li><a href='#-Ahh--Refreshing-'><p> Ahh, Refreshing
</p></a></li>
</ul>
</li>
<li>
<a href='#-Things-to-Note-'><p> Things to Note
</p></a>
<ul>
<li><a href='#-A-Record-s-PrimaryKey-'><p> A Record's PrimaryKey
</p></a></li>
<li><a href='#-Prepare-for-a-Change-'><p> Prepare for a Change
</p></a></li>
</ul>
</li>
<li>
<a href='#-Advanced-topics-'><p> Advanced topics
</p></a>
<ul>
<li><a href='#-Managing-Many-Records-with-a-Bulk-API-'><p> Managing Many Records with a Bulk API
</p></a></li>
<li><a href='#-Datasource-for-sparseArray-'><p> Datasource for sparseArray
</p></a></li>
<li><a href='#-Cascading-Datasource-'><p> Cascading Datasource
</p></a></li>
<li><a href='#-Fetching-a-Query-with-Multiple-Data-Types-'><p> Fetching a Query with Multiple Data Types
</p></a></li>
<li><a href='#-Datasource-for-Remote-Query-'><p> Datasource for Remote Query
</p></a></li>
</ul>
</li>
<li>
<a href='#-Changelog-'><p> Changelog
</p></a>
<ul>
</ul>
</li>
</ol>
</div>
</div>
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