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# This file is part of the Frescobaldi project, http://www.frescobaldi.org/
#
# Copyright (c) 2008 - 2014 by Wilbert Berendsen
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
# See http://www.gnu.org/licenses/ for more information.
"""
A QNetworkAccessManager subclass with easy registration of custom url schemes.
"""
from PyQt5.QtCore import QThread, QTimer, QUrl
from PyQt5.QtNetwork import QNetworkAccessManager, QNetworkReply, QNetworkRequest
class NetworkAccessManager(QNetworkAccessManager):
"""A QNetworkAccessManager subclass with easy registration of custom url schemes.
Use the registerHandler() method to add custom scheme handlers.
The registerHtmlHandler() method is used to add a simple callable as handler that
gets a QUrl and should return the HTML as a normal string.
The headers instance attribute is a dictionary (empty by default) containing
extra headers (as key, value) that are added to outgoing requests.
"""
def __init__(self, parent=None):
QNetworkAccessManager.__init__(self, parent)
self._dispatcher = {}
self.headers = {}
def createRequest(self, operation, request, data):
try:
requestFunc = self._dispatcher[request.url().scheme()]
except KeyError:
self.addHeadersToRequest(request)
return QNetworkAccessManager.createRequest(self, operation, request, data)
return requestFunc(self, operation, request, data)
def addHeadersToRequest(self, request):
"""Called on outgoing requests and should add raw headers to the request.
The default implementation of this method simply adds all the headers in the
headers instance attribute.
"""
for name, value in self.headers.items():
request.setRawHeader(bytearray(name, "latin_1"), bytearray(value, "latin_1"))
def registerHandler(self, scheme, handler):
"""Registers a handler for the given scheme.
The handler is called with four arguments (manager, operation, request,
data), just like the QNetworkAccessManager.createRequest method, and
should return a QNetworkReply instance.
"""
self._dispatcher[scheme] = handler
def registerHtmlHandler(self, scheme, handler, threaded=False, encoding="UTF-8"):
"""Registers a simple callable as the handler for the given scheme.
The handler only gets a GET URL (QUrl) and should return a HTML string.
If threaded is True, the handler is called in a background thread.
The encoding defaults to UTF-8 and is used for encoding the HTML returned
by then handler and also set in the Content-Type header.
"""
cls = ThreadedHtmlReply if threaded else HtmlReply
def createRequest(mgr, operation, request, data):
return cls(mgr, request.url(), handler, encoding)
self._dispatcher[scheme] = createRequest
def unregisterHandler(self, scheme):
"""Removes the special handling for the given scheme."""
try:
del self._dispatcher[scheme]
except KeyError:
pass
class HtmlReplyBase(QNetworkReply):
"""Abstract base class for a QNetworkReply that represents a generated HTML string."""
def __init__(self, manager, url, handler, encoding="UTF-8"):
QNetworkReply.__init__(self, manager)
self.setUrl(url)
self._handler = handler
self._encoding = encoding
def callHandler(self):
self._content = self._handler(self.url()).encode(self._encoding)
def outputReady(self):
self._offset = 0
self.setHeader(QNetworkRequest.ContentTypeHeader, "text/html; charset={0}".format(self._encoding))
self.setHeader(QNetworkRequest.ContentLengthHeader, len(self._content))
self.open(QNetworkReply.ReadOnly | QNetworkReply.Unbuffered)
def emitSignals(self):
self.readyRead.emit()
self.finished.emit()
def abort(self):
pass
def bytesAvailable(self):
return len(self._content) - self._offset
def isSequential(self):
return True
def readData(self, maxSize):
if self._offset < len(self._content):
end = min(self._offset + maxSize, len(self._content))
data = self._content[self._offset:end]
self._offset = end
return data
class HtmlReply(HtmlReplyBase):
"""QNetworkReply that generates a HTML string by calling handler(url).encode(encoding)."""
def __init__(self, manager, url, handler, encoding="UTF-8"):
HtmlReplyBase.__init__(self, manager, url, handler, encoding)
self.callHandler()
self.outputReady()
QTimer.singleShot(0, self.emitSignals)
class ThreadedHtmlReply(HtmlReplyBase):
"""HtmlReply that calls handler(url) in a background thread."""
def __init__(self, manager, url, handler, encoding="UTF-8"):
HtmlReplyBase.__init__(self, manager, url, handler, encoding)
self._thread = Thread(self.callHandler)
self._thread.finished.connect(self.threadFinished)
self._thread.start()
def threadFinished(self):
self.outputReady()
self.emitSignals()
class Thread(QThread):
"""QThread that runs a single callable."""
def __init__(self, func):
QThread.__init__(self)
self._func = func
def run(self):
self._func()
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