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Document new node-style callbacks and send() method
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lsegal committed Dec 7, 2012
1 parent bfc473c commit 6a76a51
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6 changes: 3 additions & 3 deletions doc-src/guide/Examples.md
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ The following example lists all buckets associated with your AWS account:

```js
var s3 = new AWS.S3();
s3.client.listBuckets().done(function(resp) {
s3.client.listBuckets(function(err, data) {
for (var index in resp.data.Buckets) {
var bucket = resp.data.Buckets[index];
console.log("Bucket: ", bucket.Name, ' : ', bucket.CreationDate);
Expand All @@ -35,7 +35,7 @@ object 'myKey' of bucket 'myBucket':

```js
var s3 = new AWS.S3();
s3.client.createBucket({Bucket: 'myBucket'}).done(function(resp) {
s3.client.createBucket({Bucket: 'myBucket'}, function(err, data) {
var data = {Bucket: 'myBucket', Key: 'myKey', Body: 'Hello!'};
s3.client.putObject(data).done(function(resp) {
console.log("Successfully uploaded data to myBucket/myKey");
Expand All @@ -51,7 +51,7 @@ The following example will list all tables in a DynamoDB instance:

```js
var db = new AWS.DynamoDB();
db.client.listTables().done(function(resp) {
db.client.listTables(function(err, data) {
console.log(resp.data.TableNames);
});
```
115 changes: 97 additions & 18 deletions doc-src/guide/MakingRequests.md
Original file line number Diff line number Diff line change
Expand Up @@ -2,24 +2,45 @@

# Making Requests

## Asynchronous Promise Objects (`AWS.AWSRequest`)
## Asynchronous Callbacks

All requests made through the SDK are asynchronous and use an
event-based promise callback interface. Each service method
that kicks off a request returns an `AWS.AWSRequest` promise
object that you can use to register callbacks.
All requests made through the SDK are asynchronous and use a
callback interface. Each service method that kicks off a request
can accept a callback as the last parameter with the signature
`function(error, data) { ... }`. This callback will be called when
the response or error data is available.

For example, the following service method returns the request
object as "request", which can be used to register callbacks:
For example, the following service method can be called with
a standard callback to retrieve the response data or error:

```js
// request is an AWS.AWSRequest object
var request = ec2.client.describeInstances();
new AWS.EC2().client.describeInstances(function(error, data) {
if (error) {
console.log(error); // an error occurred
} else {
console.log(data); // request succeeded
}
});
```

The `error` and `data` parameters are described in the "Response Object"
section below.

Note that if you do not specify a callback, the operation will
return an `AWS.AWSRequest` object that must be manually sent using
the `send()` method:

// register callbacks on request to retrieve response data
request.done(function(response) {
console.log(resp.data);
```js
// create the AWS.AWSRequest object
var request = new AWS.EC2().client.describeInstances();

// register a callback to report on the data
request.done(function(resp) {
console.log(resp.data); // log the successful data response
});

// send the request
request.send();
```

### The Response Object (`AWS.AWSResponse`)
Expand All @@ -28,6 +49,10 @@ The response object is passed into each callback function so
that you can access response data. The `AWS.AWSResponse` object that
is passed in contains two important properties to get at this data:

When using the standard callback mechanism, the two properties will
be made available as parameters on the callback method in the form:
`function(error, data) { ... }`

#### The `data` property

The `response.data` property contains the serialized object data
Expand Down Expand Up @@ -62,9 +87,62 @@ before attempting to access the `response.data` property.
### Supported Callbacks

Currently, you can register callbacks for various events by
using the following methods:
either using the simplified callback syntax, or by using the callback
methods on the returned `AWS.AWSRequest` object.

#### Simplified Callback Method

#### `done(function(response) { ... })`
Each operation supports a simplified callback that can be passed as the last
parameter to any low-level client operation. The callback function should
accept an `error` parameter, followed by the `data` from the response.

For example:

```js
s3.client.listBuckets(function(error, data) {
if (err) {
console.log(error); // error is AWSResponse.error
} else {
console.log(data); // data is AWSResponse.data
}
});
```

Prints (assuming the request succeeded):

```js
{ Owner: { ID: '...', DisplayName: '...' },
Buckets:
[ { Name: 'someBucketName', CreationDate: someCreationDate },
{ Name: 'otherBucketName', CreationDate: otherCreationDate } ],
RequestId: '...' }
```

The error and data parameters accepted are equivalent to the `error` and
`data` properties discussed in the `AWS.AWSResponse` response object section
above.

If you are passing parameters to the operation, the callback should be placed
after the parameters:

```
s3.client.getObject({Bucket: 'bucket', Key: 'key'}, function(err, data) {
// ...
});
```

#### AWS.AWSRequest Callbacks

You can alternatively register callbacks on events provided by the
`AWS.AWSRequest` object returned by each low-level client operation method.
This request object exposes the `done`, `fail`, `data`, and `always`
events, each taking a callback that accepts the response object.

Note that if you omit the simplified callback parameter on the operation
method, you must call `send()` on the returned request object in order to
kick off the request to the remote server.

##### `done(function(response) { ... })`

This event registers a callback to be called when a successful response
from the server is returned. The response contains a `.data` field
Expand All @@ -75,7 +153,7 @@ For example:
```js
s3.client.listBuckets().done(function(response) {
console.log(response.data);
});
}).send();
```

Prints:
Expand All @@ -99,7 +177,7 @@ the error data:
s3.config.credentials.accessKeyId = 'invalid';
s3.client.listBuckets().fail(function(response) {
console.log(response.error);
});
}).send();
```

Prints:
Expand Down Expand Up @@ -137,7 +215,7 @@ request.always(function(response) {
} else {
// we can use response.data here
}
});
}).send();
```

## Binding Custom Context Data on a Callback
Expand All @@ -161,7 +239,8 @@ request.
}).
always(function(response) {
console.log("Always!");
});
}).
send();
```

The above example will print either "Success! Always!", or "Error! Always!",
Expand Down

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