Serving resource to QWebView of PyQT5
Question: How can serve resource (files like html, css, js, fonts) for a desktop app to
QWebView (in PyQT5)?

What I want is:

  1. If possible handling requested resource by Webkit engine of PyQT5 with a custom scheme like say `custom://app/jquery.js` and returning the file.
  2. If possible handling standard http verbs (GET, POST, ...) for that custom scheme.

If these 2 are not possible (at least not possible in a pure Pythonic way):

  * How can I intercept requests coming from the embedded Webkit and provide resource (html, css, js) based on a pattern in url (like say some regex `(?<controller>[^/])/(?<action>[^/])`)?


Answer: You need to create your own subclass of QNetworkAccessManager, which returns a
custom QNetworkReply for the desired protocol, and then set this as network
access manager for you QWebView's page.

[This article](http://doc.qt.digia.com/qq/32/qq32-webkit-protocols.html) shows
a good example how this can be done - applied to PyQt5, this is how it could
look:

    
    
    from PyQt5.QtCore import QUrl, QTimer, QIODevice
    from PyQt5.QtWidgets import QApplication
    from PyQt5.QtNetwork import (QNetworkAccessManager,
                                 QNetworkReply,
                                 QNetworkRequest)
    from PyQt5.QtWebKitWidgets import QWebView
    
    import sys
    
    class ExampleNetworkAccessManager(QNetworkAccessManager):
    
        def __init__(self, parent=None):
            super().__init__(parent=parent)
    
        def createRequest(self, operation, request, device):
            if request.url().scheme() == 'example':
                return ExampleReply(self, operation, request, device)
            return super().createRequest(operation, request, device)
    
    
    class ExampleReply(QNetworkReply):
    
        def __init__(self, parent, operation, request, device):
            super().__init__(parent=parent)
            self.setRequest(request)
            self.setOperation(operation)
            self.setUrl(request.url())
            self.bytes_read = 0
            self.content = b''
    
            # give webkit time to connect to the finished and readyRead signals
            QTimer.singleShot(200, self.load_content)
    
        def load_content(self):
            if self.operation() == QNetworkAccessManager.PostOperation:
                # handle operations ...
                pass
            # some dummy content for this example
            self.content = b'''<html>
                <h1>hello world!</h1>
                <p>...</p>
                </html>'''
            self.open(QIODevice.ReadOnly | QIODevice.Unbuffered)
            self.setHeader(QNetworkRequest.ContentLengthHeader, len(self.content))
            self.setHeader(QNetworkRequest.ContentTypeHeader, "text/html")
            self.readyRead.emit()
            self.finished.emit()
    
        def abort(self):
            pass
    
        def isSequential(self):
            return True
    
        def bytesAvailable(self):
            ba = len(self.content) - self.bytes_read + super().bytesAvailable()
            return ba
    
        def readData(self, size):
            if self.bytes_read >= len(self.content):
                return None
            data = self.content[self.bytes_read:self.bytes_read + size]
            self.bytes_read += len(data)
            return data
    
        def manager(self):
            return self.parent()
    
    if __name__ == '__main__':
        app = QApplication(sys.argv)
        wv = QWebView()
        enam = ExampleNetworkAccessManager()
        wv.page().setNetworkAccessManager(enam)
        wv.show()
        wv.setUrl(QUrl("example://test.html"))
        app.exec()
    

