class Writer(QObject):
def __init__(self, filename):
QObject.__init__(self, None)
self._filename = filename
self._file = None
self._dstream = None
def __enter__(self):
self.open()
return self
def __exit__(self, exc_type, exc_value, traceback):
self.close
def open(self):
self._file = QFile(self._filename)
if not self._file.open(QIODevice.WriteOnly):
raise ValueError("Cannot open " + self._filename)
self._dstream = QDataStream(self._file)
self._dstream.setVersion(QDataStream.Qt_4_5)
for c in b"QGis.MemoryLayerData":
self._dstream.writeUInt8(c)
# Version of MLD format
self._dstream.writeUInt32(2)
def close(self):
try:
self._dstream.setDevice(None)
self._file.close()
except: # noqa: E722
pass
self._dstream = None
self._file = None
def writeLayers(self, layers):
for layer in layers:
self.writeLayer(layer)
def writeLayer(self, layer):
if not self._dstream:
raise ValueError("Layer stream not open for reading")
ds = self._dstream
dp = layer.dataProvider()
ss = layer.subsetString()
attr = dp.attributeIndexes()
ds.writeQString(layer.id())
ds.writeQString(ss)
ds.writeInt16(len(attr))
flds = dp.fields() # noqa: F841
fldnames = []
for i in attr:
fld = dp.fields()[i]
fldnames.append(fld.name())
ds.writeQString(fld.name())
ds.writeInt16(int(fld.type()))
ds.writeQString(fld.typeName())
ds.writeInt16(fld.length())
ds.writeInt16(fld.precision())
ds.writeQString(fld.comment())
layer.setSubsetString("")
feats = layer.getFeatures()
for feat in feats:
ds.writeBool(True)
if attr:
for field in fldnames:
try:
ds.writeQVariant(feat[field])
except KeyError:
ds.writeQVariant(None)
geom = feat.geometry()
if not geom:
ds.writeUInt32(0)
else:
wkb = geom.asWkb()
ds.writeUInt32(len(wkb))
ds.writeRawData(wkb)
ds.writeBool(False)
layer.setSubsetString(ss)
class Reader(QObject):
def __init__(self, filename):
self._filename = filename
self._file = None
self._dstream = None
self._version = None
def __enter__(self):
self.open()
return self
def __exit__(self, exc_type, exc_value, traceback):
self.close
def open(self):
self._file = QFile(self._filename)
if not self._file.open(QIODevice.ReadOnly):
raise ValueError("Cannot open " + self._filename)
self._dstream = QDataStream(self._file)
self._dstream.setVersion(QDataStream.Qt_4_5)
for c in b"QGis.MemoryLayerData":
ct = self._dstream.readUInt8()
if ct != c:
raise ValueError(self._filename +
" is not a valid memory layer data file")
version = self._dstream.readInt32()
if version not in (1, 2):
raise ValueError(
self._filename +
" is not compatible with this version of the MemoryLayerSaver plugin"
)
self._version = version
def close(self):
try:
self._dstream.setDevice(None)
self._file.close()
except: # noqa: E722
pass
self._dstream = None
self._file = None
def readLayers(self, layers):
if not self._dstream:
raise ValueError("Layer stream not open for reading")
ds = self._dstream
while True:
if ds.atEnd():
return
id = ds.readQString()
layer = None
for l in layers: # noqa: E741
if l.id() == id:
layer = l
break
if layer is None:
self.skipLayer()
else:
self.readLayer(layer)
def readLayer(self, layer):
ds = self._dstream
dp = layer.dataProvider()
if dp.featureCount() > 0:
raise ValueError("Memory layer " + id + " is already loaded")
attr = dp.attributeIndexes()
dp.deleteAttributes(attr)
ss = ""
if self._version > 1:
ss = ds.readQString()
nattr = ds.readInt16()
attr = list(range(nattr))
for i in attr:
name = ds.readQString()
qtype = ds.readInt16()
typename = ds.readQString()
length = ds.readInt16()
precision = ds.readInt16()
comment = ds.readQString()
fld = QgsField(name, qtype, typename, length, precision, comment)
dp.addAttributes([fld])
nullgeom = QgsGeometry()
fields = dp.fields()
while ds.readBool():
feat = QgsFeature(fields)
for i in attr:
value = ds.readQVariant()
if value is not None:
feat[i] = value
wkbSize = ds.readUInt32()
if wkbSize == 0:
feat.setGeometry(nullgeom)
else:
geom = QgsGeometry()
geom.fromWkb(ds.readRawData(wkbSize))
feat.setGeometry(geom)
dp.addFeatures([feat])
layer.setSubsetString(ss)
layer.updateFields()
layer.updateExtents()
def skipLayer(self):
ds = self._dstream
nattr = ds.readInt16()
attr = list(range(nattr))
for i in attr:
name = ds.readQString() # noqa: F841
qtype = ds.readInt16() # noqa: F841
typename = ds.readQString() # noqa: F841
length = ds.readInt16() # noqa: F841
precision = ds.readInt16() # noqa: F841
comment = ds.readQString() # noqa: F841
while ds.readBool():
for i in attr:
ds.readQVariant()
wkbSize = ds.readUInt32()
if wkbSize > 0:
ds.readRawData(wkbSize)
class Client(QDialog):
def __init__(self, parent: QWidget = None):
super().__init__(parent)
self._in = QDataStream()
self.blockSize = 0
self.currentFortune = ""
self.hostLineEdit = QLineEdit("fortune")
self.getFortuneButton = QPushButton(self.tr("Get Fortune"))
self.statusLabel = QLabel(
self.
tr("This examples requires that you run the Local Fortune Server example as well."
))
self.socket = QLocalSocket(self)
self.setWindowFlags(self.windowFlags()
& ~Qt.WindowContextHelpButtonHint)
hostLabel = QLabel(self.tr("&Server name:"))
hostLabel.setBuddy(self.hostLineEdit)
self.statusLabel.setWordWrap(True)
self.getFortuneButton.setDefault(True)
quitButton = QPushButton(self.tr("Quit"))
buttonBox = QDialogButtonBox()
buttonBox.addButton(self.getFortuneButton, QDialogButtonBox.ActionRole)
buttonBox.addButton(quitButton, QDialogButtonBox.RejectRole)
self._in.setDevice(self.socket)
self._in.setVersion(QDataStream.Qt_5_10)
self.hostLineEdit.textChanged.connect(self.enableGetFortuneButton)
self.getFortuneButton.clicked.connect(self.requestNewFortune)
quitButton.clicked.connect(self.close)
self.socket.readyRead.connect(self.readFortune)
self.socket.errorOccurred.connect(self.displayError)
mainLayout = QGridLayout(self)
mainLayout.addWidget(hostLabel, 0, 0)
mainLayout.addWidget(self.hostLineEdit, 0, 1)
mainLayout.addWidget(self.statusLabel, 2, 0, 1, 2)
mainLayout.addWidget(buttonBox, 3, 0, 1, 2)
self.setWindowTitle(QGuiApplication.applicationDisplayName())
self.hostLineEdit.setFocus()
@pyqtSlot()
def requestNewFortune(self):
self.getFortuneButton.setEnabled(False)
self.blockSize = 0
self.socket.abort()
self.socket.connectToServer(self.hostLineEdit.text())
@pyqtSlot()
def readFortune(self):
if self.blockSize == 0:
# Relies on the fact that QDataStream serializes a quint32 into
# sizeof(quint32) bytes
if self.socket.bytesAvailable() < 4: # (int)sizeof(quint32))
return
self.blockSize = self._in.readUInt32()
if self.socket.bytesAvailable() < self.blockSize or self._in.atEnd():
return
nextFortune = ""
nextFortune = self._in.readQString()
if nextFortune == self.currentFortune:
QTimer.singleShot(0, self.requestNewFortune)
return
currentFortune = nextFortune
self.statusLabel.setText(currentFortune)
self.getFortuneButton.setEnabled(True)
@pyqtSlot(QLocalSocket.LocalSocketError)
def displayError(self, socketError):
if socketError == QLocalSocket.ServerNotFoundError:
QMessageBox.information(
self,
self.tr("Local Fortune Client"),
self.tr("The host was not found. Please make sure "
"that the server is running and that the "
"server name is correct."),
)
elif socketError == QLocalSocket.ConnectionRefusedError:
QMessageBox.information(
self,
self.tr("Local Fortune Client"),
self.tr("The connection was refused by the peer. "
"Make sure the fortune server is running, "
"and check that the server name is correct."),
)
elif socketError == QLocalSocket.PeerClosedError:
return
else:
QMessageBox.information(
self,
self.tr("Local Fortune Client"),
self.tr("The following error occurred: %s." %
(self.socket.errorString())),
)
self.getFortuneButton.setEnabled(True)
@pyqtSlot()
def enableGetFortuneButton(self):
self.getFortuneButton.setEnabled(bool(self.hostLineEdit.ext()))
