# protocol

The `protocol` module can register a new protocol or intercept an existing
protocol, so you can custom the response to the requests for various protocols.

An example of implementing a protocol that has the same effect with the
`file://` protocol:

```javascript
var app = require('app'),
    path = require('path');

app.on('will-finish-launching', function() {
    var protocol = require('protocol');
    protocol.registerProtocol('atom', function(request) {
      var url = request.url.substr(7)
      return new protocol.RequestFileJob(path.normalize(__dirname + '/' + url));
    });
});
```

**Note:** This module can only be used after the `will-finish-launching` event
was emitted.

## protocol.registerProtocol(scheme, handler)

* `scheme` String
* `handler` Function

Registers a custom protocol of `scheme`, the `handler` would be called with
`handler(request)` when the a request with registered `scheme` is made.

You need to return a request job in the `handler` to specify which type of
response you would like to send.

## protocol.unregisterProtocol(scheme)

* `scheme` String

Unregisters the custom protocol of `scheme`.

## protocol.isHandledProtocol(scheme)

* `scheme` String

Returns whether the `scheme` can be handled already.

## protocol.interceptProtocol(scheme, handler)

* `scheme` String
* `handler` Function

Intercepts an existing protocol with `scheme`, returning `null` or `undefined`
in `handler` would use the original protocol handler to handle the request.

## protocol.uninterceptProtocol(scheme)

* `scheme` String

Unintercepts a protocol.

## Class: protocol.RequestFileJob(path)

* `path` String

Create a request job which would query a file of `path` and set corresponding
mime types.

## Class: protocol.RequestStringJob(options)

* `options` Object
  * `mimeType` String - Default is `text/plain`
  * `charset` String - Default is `UTF-8`
  * `data` String

Create a request job which sends a string as response.