See WebRequest.CreateWebRequest().

You must keep a strong reference to the WebRequest object during the request, otherwise it gets destroyed and the WebRequestClient callbacks won't get called.

The methods of this class will be called on the same thread that created the request unless otherwise documented.

void OnUploadProgress(WebRequest webRequest, long current, long total)

Notifies the client of upload progress. |current| denotes the number of bytes sent so far and |total| is the total size of uploading data (or -1 if chunked upload is enabled). This method will only be called if the ReportUploadProgress flag is set on the request (see Request.GetFlags() and SetFlags())

void OnDownloadProgress(WebRequest webRequest, long current, long total)

Notifies the client of download progress. |current| denotes the number of bytes received up to the call and |total| is the expected total size of the response (or -1 if not determined).

void OnDownloadData(WebRequest webRequest, string data)

Called when some part of the response is read. |data| contains the current bytes received since the last call. This method will not be called if the NoDownloadData flag is set on the request (see Request.GetFlags() and SetFlags()).

void OnRequestComplete(WebRequest webRequest)

Notifies the client that the request has completed. Use the WebRequest.GetRequestStatus() method to determine if the request was successful or not.

bool GetAuthCredentials(bool isProxy, string host, int port, string realm, string scheme, Callback callback)

Called on the IO thread when the browser needs credentials from the user. |isProxy| indicates whether the host is a proxy server. |host| contains the hostname and |port| contains the port number. Return true to continue the request and call Callback.Continue() when the authentication information is available. Return false to cancel the request. This method will only be called for requests initiated from the browser process.

The methods of this class will always be called on the UI thread.

void OnStateChange(WebRequest webRequest, RequestState state)

Notifies the client that the request state has changed. State change notifications will always be sent before the below notification methods are called.

RequestState is one of:

cefpython.WebRequest.State["Unsent"]

cefpython.WebRequest.State["Started"]
cefpython.WebRequest.State["HeadersReceived"]
cefpython.WebRequest.State["Loading"]
cefpython.WebRequest.State["Done"]
cefpython.WebRequest.State["Error"]
cefpython.WebRequest.State["Abort"]

void OnRedirect(WebRequest webRequest, Request request, Response response)

Notifies the client that the request has been redirected and
provides a chance to change the request parameters.

void OnHeadersReceived(WebRequest webRequest, Response response)

Notifies the client of the response data.

void OnProgress(WebRequest webRequest, long bytesSent, long totalBytesToBeSent)

Notifies the client of the upload progress.

void OnData(WebRequest webRequest, str data)

Notifies the client that content has been received.

void OnError(WebRequest webRequest, NetworkError errorCode)

Notifies the client that the request ended with an error.