docs/_includes/api/get_attachment.html

{% include anchor.html edit="true" title="Get an attachment" hash="get_attachment" %} 

{% highlight js %}
db.getAttachment(docId, attachmentId, [options], [callback])
{% endhighlight %}

Get attachment data.

### Options

* `options.rev`: as with [get()](#fetch_document), you can pass a `rev` in and get back an attachment for the document at that particular revision.

#### Example Usage:

Get an attachment with filename `'att.txt'` from document with ID `'doc'`:

{% include code/start.html id="get_att1" type="callback" %}
{% highlight js %}
db.getAttachment('doc', 'att.txt', function(err, blobOrBuffer) {
  if (err) { return console.log(err); }
  // handle result
});
{% endhighlight %}
{% include code/end.html %}

{% include code/start.html id="get_att1" type="async" %}
{% highlight js %}
try {
  var blobOrBuffer = await db.getAttachment('doc', 'att.txt');
} catch (err) {
  console.log(err);
}
{% endhighlight %}
{% include code/end.html %}

{% include code/start.html id="get_att1" type="promise" %}
{% highlight js %}
db.getAttachment('doc', 'att.txt').then(function (blobOrBuffer) {
  // handle result
}).catch(function (err) {
  console.log(err);
});
{% endhighlight %}
{% include code/end.html %}

Get an attachment with filename `'att.txt'` from document with ID `'doc'`, at
the revision `'1-abcd'`:

{% include code/start.html id="get_att2" type="callback" %}
{% highlight js %}
db.getAttachment('doc', 'att.txt', {rev: '1-abcd'}, function(err, blobOrBuffer) {
  if (err) { return console.log(err); }
  // handle result
});
{% endhighlight %}
{% include code/end.html %}

{% include code/start.html id="get_att2" type="async" %}
{% highlight js %}
try {
  var blobOrBuffer = await db.getAttachment('doc', 'att.txt', {rev: '1-abcd'});
} catch (err) {
  console.log(err);
}
{% endhighlight %}
{% include code/end.html %}

{% include code/start.html id="get_att2" type="promise" %}
{% highlight js %}
db.getAttachment('doc', 'att.txt', {rev: '1-abcd'}).then(function (blobOrBuffer) {
  // handle result
}).catch(function (err) {
  console.log(err);
});
{% endhighlight %}
{% include code/end.html %}

#### Response type:

The response will be a `Blob` object in the browser, and a `Buffer` object in Node.js. See [blob-util](https://github.com/nolanlawson/blob-util) for utilities to transform `Blob`s to other formats, such as base64-encoded strings, data URLs, array buffers, etc.

#### Inline base64 attachments

You can specify `{attachments: true}` to most "read" operations, such as `get()`, `allDocs()`, `changes()`, and `query()`. The attachment data will then be included inlined in the resulting doc(s). However, it will always be supplied as base64. For example:

{% highlight js %}
{
  "_attachments": {
    "att.txt": {
      "content_type": "text/plain",
      "digest": "d5ccfd24a8748bed4e2c9a279a2b6089",
      "data": "SXMgdGhlcmUgbGlmZSBvbiBNYXJzPw=="
    }
  },
  "_id": "mydoc",
  "_rev": "1-e147d9ec9c85139dfe7e93bc17148d1a"
}
{% endhighlight %}

For such APIs, when you don't specify `{attachments: true}`, you will instead get metadata about the attachments. For example:

{% highlight js %}
{
  "_attachments": {
    "att.txt": {
      "content_type": "text/plain",
      "digest": "d5ccfd24a8748bed4e2c9a279a2b6089",
      "stub": true
    }
  },
  "_id": "mydoc",
  "_rev": "1-e147d9ec9c85139dfe7e93bc17148d1a"
}
{% endhighlight %}

This "summary" operation may be faster in some cases, because the attachment itself does not need to be read from disk.