Detailed Description
The QNetworkProtocol class provides a common API for network protocols.
This is a base class which should be used for network protocols
implementations that can then be used in Qt (e.g. in the file
dialog) together with the QUrlOperator.
The easiest way to implement a new network protocol is to
reimplement the operation*() methods, e.g. operationGet(), etc.
Only the supported operations should be reimplemented. To specify
which operations are supported, also reimplement
supportedOperations() and return an int that is OR'd together
using the supported operations from the QNetworkProtocol::Operation enum.
When you implement a network protocol this way, it is important to
emit the correct signals. Also, always emit the finished() signal
when an operation is done (on success and on failure). Qt
relies on correctly emitted finished() signals.
For a detailed description of the Qt Network Architecture and how
to implement and use network protocols in Qt, see the Qt Network Documentation.
See also Input/Output and Networking.
Member Type Documentation
QNetworkProtocol::ConnectionState
When the connection state of a network protocol changes it emits
the signal connectionStateChanged(). The first argument is one of
the following values:
- QNetworkProtocol::ConHostFound - Host has been found.
- QNetworkProtocol::ConConnected - Connection to the host has been established.
- QNetworkProtocol::ConClosed - Connection has been closed.
QNetworkProtocol::Error
When an operation fails (finishes unsuccessfully), the
QNetworkOperation of the operation returns an error code which has
one of the following values:
- QNetworkProtocol::NoError - No error occurred.
- QNetworkProtocol::ErrValid - The URL you are operating on is not valid.
- QNetworkProtocol::ErrUnknownProtocol - There is no protocol implementation
available for the protocol of the URL you are operating on (e.g.
if the protocol is http and no http implementation has been
registered).
- QNetworkProtocol::ErrUnsupported - The operation is not supported by the
protocol.
- QNetworkProtocol::ErrParse - The URL could not be parsed correctly.
- QNetworkProtocol::ErrLoginIncorrect - You needed to login but the username
or password is wrong.
- QNetworkProtocol::ErrHostNotFound - The specified host (in the URL) couldn't
be found.
- QNetworkProtocol::ErrListChildren - An error occurred while listing the
children (files).
- QNetworkProtocol::ErrMkDir - An error occurred when creating a directory.
- QNetworkProtocol::ErrRemove - An error occurred when removing a child (file).
- QNetworkProtocol::ErrRename - An error occurred when renaming a child (file).
- QNetworkProtocol::ErrGet - An error occurred while getting (retrieving) data.
- QNetworkProtocol::ErrPut - An error occurred while putting (uploading) data.
- QNetworkProtocol::ErrFileNotExisting - A file which is needed by the operation
doesn't exist.
- QNetworkProtocol::ErrPermissionDenied - Permission for doing the operation has
been denied.
You should also use these error codes when implementing custom
network protocols. If this is not possible, you can define your own
error codes by using integer values that don't conflict with any
of these values.
QNetworkProtocol::Operation
This enum lists the possible operations that a network protocol
can support. supportedOperations() returns an int of these that is
OR'd together. Also, the type() of a QNetworkOperation is always
one of these values.
- QNetworkProtocol::OpListChildren - List the children of a URL, e.g. of a directory.
- QNetworkProtocol::OpMkDir - Create a directory.
- QNetworkProtocol::OpRemove - Remove a child (e.g. a file).
- QNetworkProtocol::OpRename - Rename a child (e.g. a file).
- QNetworkProtocol::OpGet - Get data from a location.
- QNetworkProtocol::OpPut - Put data to a location.
QNetworkProtocol::State
This enum contains the state that a QNetworkOperation can have.
- QNetworkProtocol::StWaiting - The operation is in the QNetworkProtocol's queue
waiting to be prcessed.
- QNetworkProtocol::StInProgress - The operation is being processed.
- QNetworkProtocol::StDone - The operation has been processed succesfully.
- QNetworkProtocol::StFailed - The operation has been processed but an error occurred.
- QNetworkProtocol::StStopped - The operation has been processed but has been
stopped before it finished, and is waiting to be processed.
Member Function Documentation
QNetworkProtocol::QNetworkProtocol ()
Constructor of the network protocol base class. Does some
initialization and connecting of signals and slots.
QNetworkProtocol::~QNetworkProtocol () [virtual]
Destructor.
void QNetworkProtocol::addOperation ( QNetworkOperation * op ) [virtual]
Adds the operation op to the operation queue. The operation
will be processed as soon as possible. This method returns
immediately.
bool QNetworkProtocol::autoDelete () const
Returns TRUE if auto-deleting is enabled; otherwise returns FALSE.
See also QNetworkProtocol::setAutoDelete().
bool QNetworkProtocol::checkConnection ( QNetworkOperation * op ) [virtual protected]
For processing operations the network protocol base class calls
this method quite often. This should be reimplemented by new
network protocols. It should return TRUE if the connection is OK
(open); otherwise it should return FALSE. If the connection is not
open the protocol should open it.
If the connection can't be opened (e.g. because you already tried
but the host couldn't be found), set the state of op to
QNetworkProtocol::StFailed and emit the finished() signal with
this QNetworkOperation as argument.
op is the operation that needs an open connection.
Example: network/networkprotocol/nntp.cpp.
void QNetworkProtocol::clearOperationQueue () [virtual]
Clears the operation queue.
void QNetworkProtocol::connectionStateChanged ( int state, const QString & data ) [signal]
This signal is emitted whenever the state of the connection of the
network protocol is changed. state describes the new state,
which is one of, ConHostFound, ConConnected or ConClosed.
data is a message text.
void QNetworkProtocol::createdDirectory ( const QUrlInfo & i, QNetworkOperation * op ) [signal]
This signal is emitted when mkdir() has been succesful and the
directory has been created. i holds the information about the
new directory. op is the pointer to the operation object which
contains all the information about the operation, including the
state, etc. Using op->arg( 0 ), you can get the file name of the
new directory.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator, which is used by the network
protocol, emit its corresponding signal.
void QNetworkProtocol::data ( const QByteArray & data, QNetworkOperation * op ) [signal]
This signal is emitted when new data has been received after
calling get() or put(). op holds the name of the file from
which data is retrieved or uploaded in its first argument, and the
(raw) data in its second argument. You can get them with
op->arg( 0 ) and op->rawArg( 1 ). op is the pointer to the
operation object, which contains all the information about the
operation, including the state, etc.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator (which is used by the network
protocol) emit its corresponding signal.
void QNetworkProtocol::dataTransferProgress ( int bytesDone, int bytesTotal, QNetworkOperation * op ) [signal]
This signal is emitted during the transfer of data (using put() or
get()). bytesDone is how many bytes of bytesTotal have been
transferred. bytesTotal may be -1, which means that the total
number of bytes is not known. op is the pointer to the
operation object which contains all the information about the
operation, including the state, etc.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator, which is used by the network
protocol, emit its corresponding signal.
void QNetworkProtocol::finished ( QNetworkOperation * op ) [signal]
This signal is emitted when an operation finishes. This signal is
always emitted, for both success and failure. op is the pointer
to the operation object which contains all the information about
the operation, including the state, etc. Check the state and error
code of the operation object to determine whether or not the
operation was successful.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator, which is used by the network
protocol, emit its corresponding signal.
QNetworkProtocol * QNetworkProtocol::getNetworkProtocol ( const QString & protocol ) [static]
Static method to get a new instance of the network protocol protocol. For example, if you need to do some FTP operations, do
the following:
QFtp *ftp = QNetworkProtocol::getNetworkProtocol( "ftp" );
This returns a pointer to a new instance of an ftp implementation
or null if no protocol for ftp was registered. The ownership of
the pointer is transferred to you, so you must delete it if you
don't need it anymore.
Normally you should not work directly with network protocols, so
you will not need to call this method yourself. Instead, use
QUrlOperator, which makes working with network protocols much more
convenient.
See also QUrlOperator.
bool QNetworkProtocol::hasOnlyLocalFileSystem () [static]
Returns TRUE if the only protocol registered is for working on the
local filesystem; returns FALSE if other network protocols are
also registered.
void QNetworkProtocol::itemChanged ( QNetworkOperation * op ) [signal]
This signal is emitted whenever a file which is a child of this
URL has been changed, e.g. by successfully calling rename(). op
holds the original and the new file names in the first and second
arguments, accessible with op->arg( 0 ) and op->arg( 1 )
respectively. op is the pointer to the operation object which
contains all the information about the operation, including the
state, etc.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator, which is used by the network
protocol, emit its corresponding signal.
void QNetworkProtocol::newChild ( const QUrlInfo & i, QNetworkOperation * op ) [signal]
This signal is emitted if a new child (file) has been read.
QNetworkProtocol automatically connects it to a slot which creates
a list of QUrlInfo objects (with just one QUrlInfo i) and emits
the newChildren() signal with this list. op is the pointer to
the operation object which contains all the information about the
operation that has finished, including the state, etc.
This is just a convenience signal useful for implementing your own
network protocol. In all other cases connect to the newChildren()
signal with its list of QUrlInfo objects.
void QNetworkProtocol::newChildren ( const QValueList<QUrlInfo> & i, QNetworkOperation * op ) [signal]
This signal is emitted after listChildren() was called and new
children (files) have been read from the list of files. i holds
the information about the new children. op is the pointer to
the operation object which contains all the information about the
operation, including the state, etc.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator, which is used by the network
protocol, emit its corresponding signal.
When implementing your own network protocol and reading children,
you usually don't read one child at once, but rather a list of
them. That's why this signal takes a list of QUrlInfo objects. If
you prefer to read just one child at a time you can use the
convenience signal newChild(), which takes a single QUrlInfo
object.
void QNetworkProtocol::operationGet ( QNetworkOperation * op ) [virtual protected]
When implementing a new network protocol, this method should be
reimplemented if the protocol supports getting data; this method
should then process the QNetworkOperation.
When you reimplement this method it's very important that you emit
the correct signals at the correct time (especially the finished()
signal after processing an operation). Take a look at the Qt Network Documentation which describes in
detail how to reimplement this method. You may also want to look
at the example implementation in
examples/network/networkprotocol/nntp.cpp.
op is the pointer to the operation object which contains all
the information on the operation that has finished, including the
state, etc.
Example: network/networkprotocol/nntp.cpp.
QNetworkOperation * QNetworkProtocol::operationInProgress () const
Returns the operation, which is being processed, or 0 of no
operation is being processed at the moment.
void QNetworkProtocol::operationListChildren ( QNetworkOperation * op ) [virtual protected]
When implementing a new network protocol, this method should be
reimplemented if the protocol supports listing children (files);
this method should then process this QNetworkOperation.
When you reimplement this method it's very important that you emit
the correct signals at the correct time (especially the finished()
signal after processing an operation). Take a look at the Qt Network Documentation which describes in
detail how to reimplement this method. You may also want to look
at the example implementation in
examples/network/networkprotocol/nntp.cpp.
op is the pointer to the operation object which contains all
the information on the operation that has finished, including the
state, etc.
Example: network/networkprotocol/nntp.cpp.
void QNetworkProtocol::operationMkDir ( QNetworkOperation * op ) [virtual protected]
When implementing a new network protocol, this method should be
reimplemented if the protocol supports making directories; this
method should then process this QNetworkOperation.
When you reimplement this method it's very important that you emit
the correct signals at the correct time (especially the finished()
signal after processing an operation). Take a look at the Qt Network Documentation which describes in
detail how to reimplement this method. You may also want to look
at the example implementation in
examples/network/networkprotocol/nntp.cpp.
op is the pointer to the operation object which contains all
the information on the operation that has finished, including the
state, etc.
void QNetworkProtocol::operationPut ( QNetworkOperation * op ) [virtual protected]
When implementing a new network protocol, this method should be
reimplemented if the protocol supports putting (uploading) data;
this method should then process the QNetworkOperation.
When you reimplement this method it's very important that you emit
the correct signals at the correct time (especially the finished()
signal after processing an operation). Take a look at the Qt Network Documentation which describes in
detail how to reimplement this method. You may also want to look
at the example implementation in
examples/network/networkprotocol/nntp.cpp.
op is the pointer to the operation object which contains all
the information on the operation that has finished, including the
state, etc.
void QNetworkProtocol::operationRemove ( QNetworkOperation * op ) [virtual protected]
When implementing a new network protocol, this method should be
reimplemented if the protocol supports removing children (files);
this method should then process this QNetworkOperation.
When you reimplement this method it's very important that you emit
the correct signals at the correct time (especially the finished()
signal after processing an operation). Take a look at the Qt Network Documentation which is describes
in detail how to reimplement this method. You may also want to
look at the example implementation in
examples/network/networkprotocol/nntp.cpp.
op is the pointer to the operation object which contains all
the information on the operation that has finished, including the
state, etc.
void QNetworkProtocol::operationRename ( QNetworkOperation * op ) [virtual protected]
When implementing a new newtork protocol, this method should be
reimplemented if the protocol supports renaming children (files);
this method should then process this QNetworkOperation.
When you reimplement this method it's very important that you emit
the correct signals at the correct time (especially the finished()
signal after processing an operation). Take a look at the Qt Network Documentation which describes in
detail how to reimplement this method. You may also want to look
at the example implementation in
examples/network/networkprotocol/nntp.cpp.
op is the pointer to the operation object which contains all
the information on the operation that has finished, including the
state, etc.
void QNetworkProtocol::registerNetworkProtocol ( const QString & protocol, QNetworkProtocolFactoryBase * protocolFactory ) [static]
Static method to register a network protocol for Qt. For example,
if you have an implementation of NNTP (called Nntp) which is
derived from QNetworkProtocol, call:
QNetworkProtocol::registerNetworkProtocol( "nntp", new QNetworkProtocolFactory<Nntp> );
after which your implementation is registered for future nntp
operations.
The name of the protocol is given in protocol and a pointer to
the protocol factory is given in protocolFactory.
void QNetworkProtocol::removed ( QNetworkOperation * op ) [signal]
This signal is emitted when remove() has been succesful and the
file has been removed. op holds the file name of the removed
file in the first argument, accessible with op->arg( 0 ). op is
the pointer to the operation object which contains all the
information about the operation, including the state, etc.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator, which is used by the network
protocol, emit its corresponding signal.
void QNetworkProtocol::setAutoDelete ( bool b, int i = 10000 ) [virtual]
Because it's sometimes hard to take care of removing network
protocol instances, QNetworkProtocol provides an auto-delete
mechanism. If you set b to TRUE, the network protocol instance
is removed after it has been inactive for i milliseconds (i.e.
i milliseconds after the last operation has been processed).
If you set b to FALSE the auto-delete mechanism is switched
off.
If you switch on auto-delete, the QNetworkProtocol also deletes
its QUrlOperator.
void QNetworkProtocol::setUrl ( QUrlOperator * u ) [virtual]
Sets the QUrlOperator, on which the protocol works, to u.
See also QUrlOperator.
void QNetworkProtocol::start ( QNetworkOperation * op ) [signal]
Some operations (such as listChildren()) emit this signal when
they start processing the operation. op is the pointer to the
operation object which contains all the information about the
operation, including the state, etc.
When a protocol emits this signal, QNetworkProtocol is smart
enough to let the QUrlOperator, which is used by the network
protocol, emit its corresponding signal.
void QNetworkProtocol::stop () [virtual]
Stops the current operation that is being processed and clears all
waiting operations.
int QNetworkProtocol::supportedOperations () const [virtual]
Returns an int that is OR'd together using the enum values of
QNetworkProtocol::Operation, which describes which operations
are supported by the network protocol. Should be reimplemented by
new network protocols.
Example: network/networkprotocol/nntp.cpp.
QUrlOperator * QNetworkProtocol::url () const
Returns the QUrlOperator on which the protocol works.
This file is part of the Qt toolkit.
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