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https://github.com/binded/webcap

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# Webcap

Webcap (for **web** screen **cap**ture) is a fork of [node-webshot](https://github.com/brenden/node-webshot) which
appears to be dead unfortunately. This forks adds:

- Streams now emits errors instead of ending silently

Webcap provides a simple API for taking webpage screenshots. The module is a
light wrapper around PhantomJS, which utilizes WebKit to perform the page
rendering.

## Examples

A simple url example:

```javascript
var webcap = require('webcap');

webcap('google.com', 'google.png', function(err) {
// screenshot now saved to google.png
});
```

An html example:

```javascript
var webcap = require('webcap');

webcap('Hello World', 'hello_world.png', {siteType:'html'}, function(err) {
// screenshot now saved to hello_world.png
});
```

Alternately, the screenshot can be streamed back to the caller:

```javascript
var webcap = require('webcap');
var fs = require('fs');

var renderStream = webcap('google.com');
var file = fs.createWriteStream('google.png', {encoding: 'binary'});

renderStream.on('data', function(data) {
file.write(data.toString('binary'), 'binary');
});
```

An example showing how to take a screenshot of a site's mobile version:

```javascript
var webcap = require('webcap');

var options = {
screenSize: {
width: 320
, height: 480
}
, shotSize: {
width: 320
, height: 'all'
}
, userAgent: 'Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_2 like Mac OS X; en-us)'
+ ' AppleWebKit/531.21.20 (KHTML, like Gecko) Mobile/7B298g'
};

webcap('flickr.com', 'flickr.jpeg', options, function(err) {
// screenshot now saved to flickr.jpeg
});
```

## Options
An optional `options` object can be passed as the parameter directly preceding
the callback in a call to webcap.



Option
Default Value
Description




windowSize

{ width: 1024

, height: 768 }


The dimensions of the browser window. screenSize is an alias
for this property.


shotSize

{ width: 'window'

, height: 'window' }


The area of the page document, starting at the upper left corner, to
render. Possible values are 'screen', 'all', and a number defining a
pixel length.



'window' causes the length to be set to the length of
the window (i.e. the shot displays what is initially visible within the
browser window).



'all' causes the length to be set to the length of the
document along the given dimension.


shotOffset
{ left: 0

, right: 0
, top: 0
, bottom: 0 }

The left and top offsets define the upper left corner of the
screenshot rectangle. The right and bottom offsets allow pixels to be
removed from the shotSize dimensions (e.g. a shotSize height of 'all' with
a bottom offset of 30 would cause all but the last 30 rows of pixels on
the site to be rendered).


phantomPath
'phantomjs'
The location of phantomjs. Webcap tries to use the binary provided by
the phantomjs NPM module, and falls back to 'phantomjs' if the module
isn't available.


phantomConfig
{}
Object with key value pairs corresponding to phantomjs command
line options
. Don't include `--`. For example:
`phantomConfig: {'ignore-ssl-errors': 'true'}`


cookies
[]
List of cookie objects to use, or null to disable cookies.


customHeaders
null
Any additional headers to be sent in the HTTP request.


defaultWhiteBackground
false
When taking the screenshot, adds a white background if not defined
elsewhere.


customCSS
''
When taking the screenshot, adds custom CSS rules if defined.


quality
75
JPEG compression quality. A higher number will look better, but creates
a larger file. Quality setting has no effect when streaming.


streamType
'png'
If streaming is used, this designates the file format of the streamed
rendering. Possible values are 'png', 'jpg', and 'jpeg'.


siteType
'url'
siteType indicates whether the content needs to be requested ('url'),
loaded locally ('file'), or is being provided directly as a string
('html').


renderDelay
0
Number of milliseconds to wait after a page loads before taking the
screenshot.


timeout
0
Number of milliseconds to wait before killing the phantomjs process
and assuming web shotting has failed. (0 is no timeout.)


takeShotOnCallback
false
Wait for the web page to signal to webcap when to take the photo
using window.callPhantom('takeShot');


errorIfStatusIsNot200
false
If the loaded page has a non-200 status code, don't take a screenshot, cause an error instead.


errorIfJSException
false
If a script on the page throws an exception, don't take a screenshot, cause an error instead.


captureSelector
false
Captures the page area containing the provided selector and saves it to file.

### PhantomJS version

By default this package installs PhantomJS 1.9.x. Several issues exist
in this version that are fixed in v2, but v2 is not yet stable across
all platforms. The `phantomPath` option can be used to get around this
if you want to try a more recent PhantomJS version. See this issue:
https://github.com/brenden/node-webshot/issues/100

### Phantom page properties
In addition to these options, the following options can be specified and will be
passed to the [Phantom page
object](https://github.com/ariya/phantomjs/wiki/API-Reference-WebPage):
`paperSize`, `zoomFactor`, `cookies`, `customHeaders`, and `settings`.

### Phantom callbacks
Arbitrary scripts can be run on the page before it gets rendered by using any of
Phantom's [page callbacks](https://github.com/ariya/phantomjs/wiki/API-Reference-WebPage#callbacks-list),
such as `onLoadFinished` or `onResourceRequested`. For example, the script below
changes the text of every link on the page:

```javascript
var options = {
onLoadFinished: function() {
var links = document.getElementsByTagName('a');

for (var i=0; i