protocol
Register a custom protocol and intercept existing protocol requests.
Process: Main
An example of implementing a protocol that has the same effect as the
file:// protocol:
const {app, protocol} = require('electron')
const path = require('path')
app.on('ready', () => {
protocol.registerFileProtocol('atom', (request, callback) => {
const url = request.url.substr(7)
callback({path: path.normalize(`${__dirname}/${url}`)})
}, (error) => {
if (error) console.error('Failed to register protocol')
})
})
Note: All methods unless specified can only be used after the ready event
of the app module gets emitted.
Methods
The protocol module has the following methods:
protocol.registerStandardSchemes(schemes[, options])
schemesString[] - Custom schemes to be registered as standard schemes.optionsObject (optional)secureBoolean (optional) -trueto register the scheme as secure. Defaultfalse.
A standard scheme adheres to what RFC 3986 calls generic URI
syntax. For example http and
https are standard schemes, while file is not.
Registering a scheme as standard, will allow relative and absolute resources to
be resolved correctly when served. Otherwise the scheme will behave like the
file protocol, but without the ability to resolve relative URLs.
For example when you load following page with custom protocol without registering it as standard scheme, the image will not be loaded because non-standard schemes can not recognize relative URLs:
<body>
<img src='test.png'>
</body>
Registering a scheme as standard will allow access to files through the FileSystem API. Otherwise the renderer will throw a security error for the scheme.
By default web storage apis (localStorage, sessionStorage, webSQL, indexedDB, cookies)
are disabled for non standard schemes. So in general if you want to register a
custom protocol to replace the http protocol, you have to register it as a standard scheme:
const {app, protocol} = require('electron')
protocol.registerStandardSchemes(['atom'])
app.on('ready', () => {
protocol.registerHttpProtocol('atom', '...')
})
Note: This method can only be used before the ready event of the app
module gets emitted.
protocol.registerServiceWorkerSchemes(schemes)
schemesString[] - Custom schemes to be registered to handle service workers.
protocol.registerFileProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctionfilePathString (optional)
completionFunction (optional)errorError
Registers a protocol of scheme that will send the file as a response. The
handler will be called with handler(request, callback) when a request is
going to be created with scheme. completion will be called with
completion(null) when scheme is successfully registered or
completion(error) when failed.
To handle the request, the callback should be called with either the file's
path or an object that has a path property, e.g. callback(filePath) or
callback({path: filePath}).
When callback is called with nothing, a number, or an object that has an
error property, the request will fail with the error number you
specified. For the available error numbers you can use, please see the
net error list.
By default the scheme is treated like http:, which is parsed differently
than protocols that follow the "generic URI syntax" like file:, so you
probably want to call protocol.registerStandardSchemes to have your scheme
treated as a standard scheme.
protocol.registerBufferProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctionbuffer(Buffer | MimeTypedBuffer) (optional)
completionFunction (optional)errorError
Registers a protocol of scheme that will send a Buffer as a response.
The usage is the same with registerFileProtocol, except that the callback
should be called with either a Buffer object or an object that has the data,
mimeType, and charset properties.
Example:
const {protocol} = require('electron')
protocol.registerBufferProtocol('atom', (request, callback) => {
callback({mimeType: 'text/html', data: new Buffer('<h5>Response</h5>')})
}, (error) => {
if (error) console.error('Failed to register protocol')
})
protocol.registerStringProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctiondataString (optional)
completionFunction (optional)errorError
Registers a protocol of scheme that will send a String as a response.
The usage is the same with registerFileProtocol, except that the callback
should be called with either a String or an object that has the data,
mimeType, and charset properties.
protocol.registerHttpProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctionredirectRequestObjecturlStringmethodStringsessionObject (optional)uploadDataObject (optional)contentTypeString - MIME type of the content.dataString - Content to be sent.
completionFunction (optional)errorError
Registers a protocol of scheme that will send an HTTP request as a response.
The usage is the same with registerFileProtocol, except that the callback
should be called with a redirectRequest object that has the url, method,
referrer, uploadData and session properties.
By default the HTTP request will reuse the current session. If you want the
request to have a different session you should set session to null.
For POST requests the uploadData object must be provided.
protocol.unregisterProtocol(scheme[, completion])
schemeStringcompletionFunction (optional)errorError
Unregisters the custom protocol of scheme.
protocol.isProtocolHandled(scheme, callback)
schemeStringcallbackFunctionerrorError
The callback will be called with a boolean that indicates whether there is
already a handler for scheme.
protocol.interceptFileProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctionfilePathString
completionFunction (optional)errorError
Intercepts scheme protocol and uses handler as the protocol's new handler
which sends a file as a response.
protocol.interceptStringProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctiondataString (optional)
completionFunction (optional)errorError
Intercepts scheme protocol and uses handler as the protocol's new handler
which sends a String as a response.
protocol.interceptBufferProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctionbufferBuffer (optional)
completionFunction (optional)errorError
Intercepts scheme protocol and uses handler as the protocol's new handler
which sends a Buffer as a response.
protocol.interceptHttpProtocol(scheme, handler[, completion])
schemeStringhandlerFunctionrequestObjecturlStringreferrerStringmethodStringuploadDataUploadData[]
callbackFunctionredirectRequestObjecturlStringmethodStringsessionObject (optional)uploadDataObject (optional)contentTypeString - MIME type of the content.dataString - Content to be sent.
completionFunction (optional)errorError
Intercepts scheme protocol and uses handler as the protocol's new handler
which sends a new HTTP request as a response.
protocol.uninterceptProtocol(scheme[, completion])
schemeStringcompletionFunction (optional)errorError
Remove the interceptor installed for scheme and restore its original handler.