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java.lang.Objectcom.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.core.QObject
com.trolltech.qt.network.QHttp
public class QHttp
The QHttp class provides an implementation of the HTTP protocol.
This class provides a direct interface to HTTP that allows you to have more control over the requests and that allows you to access the response header fields.
The class works asynchronously, so there are no blocking functions. If an operation cannot be executed immediately, the function will still return straight away and the operation will be scheduled for later execution. The results of scheduled operations are reported via signals. This approach depends on the event loop being in operation.
The operations that can be scheduled (they are called "requests" in the rest of the documentation) are the following: setHost(), get, post, head and request.
All of these requests return a unique identifier that allows you to keep track of the request that is currently executed. When the execution of a request starts, the requestStarted signal with the identifier is emitted and when the request is finished, the requestFinished signal is emitted with the identifier and a bool that indicates if the request finished with an error.
To make an HTTP request you must set up suitable HTTP headers. The following example demonstrates, how to request the main HTML page from the Trolltech home page (i.e. the URL http://www.trolltech.com/index.html):
QHttpRequestHeader header("GET", "/index.html"); header.setValue("Host", "www.trolltech.com"); http->setHost("www.trolltech.com"); http->request(header);
For the common HTTP requests GET, POST and HEAD, QHttp provides the convenience functions get, post and head. They already use a reasonable header and if you don't have to set special header fields, they are easier to use. The above example can also be written as:
http->setHost("www.trolltech.com"); // id == 1 http->get("/index.html"); // id == 2
For this example the following sequence of signals is emitted (with small variations, depending on network traffic, etc.):
requestStarted(1) requestFinished(1, false) requestStarted(2) stateChanged(Connecting) stateChanged(Sending) dataSendProgress(77, 77) stateChanged(Reading) responseHeaderReceived(responseheader) dataReadProgress(5388, 0) readyRead(responseheader) dataReadProgress(18300, 0) readyRead(responseheader) stateChanged(Connected) requestFinished(2, false) done(false) stateChanged(Closing) stateChanged(Unconnected)
The dataSendProgress and dataReadProgress signals in the above example are useful if you want to show a progress bar to inform the user about the progress of the download. The second argument is the total size of data. In certain cases it is not possible to know the total amount in advance, in which case the second argument is 0. (If you connect to a QProgressBar a total of 0 results in a busy indicator.)
When the response header is read, it is reported with the responseHeaderReceived signal.
The readyRead signal tells you that there is data ready to be read. The amount of data can then be queried with the bytesAvailable function and it can be read with the read() or readAll functions.
If an error occurs during the execution of one of the commands in a sequence of commands, all the pending commands (i.e. scheduled, but not yet executed commands) are cleared and no signals are emitted for them.
For example, if you have the following sequence of requests
http->setHost("www.foo.bar"); // id == 1 http->get("/index.html"); // id == 2 http->post("register.html", data); // id == 3
and the get request fails because the host lookup fails, then the post request is never executed and the signals would look like this:
requestStarted(1) requestFinished(1, false) requestStarted(2) stateChanged(HostLookup) requestFinished(2, true) done(true) stateChanged(Unconnected)
You can then get details about the error with the error and errorString functions. Note that only unexpected behavior, like network failure is considered as an error. If the server response contains an error status, like a 404 response, this is reported as a normal response case. So you should always check the status code of the response header.
The functions currentId and currentRequest provide more information about the currently executing request.
The functions hasPendingRequests and clearPendingRequests allow you to query and clear the list of pending requests.
Example
Nested Class Summary | |
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static class |
QHttp.ConnectionMode
This enum is used to specify the mode of connection to use. |
static class |
QHttp.Error
This enum identifies the error that occurred. |
static class |
QHttp.State
This enum is used to specify the state the client is in. |
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
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QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I> |
Field Summary | |
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QSignalEmitter.Signal3<java.lang.String,java.lang.Integer,QAuthenticator> |
authenticationRequired
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QSignalEmitter.Signal2<java.lang.Integer,java.lang.Integer> |
dataReadProgress
This signal is emitted when this object reads data from a HTTP server to indicate the current progress of the download. |
QSignalEmitter.Signal2<java.lang.Integer,java.lang.Integer> |
dataSendProgress
This signal is emitted when this object sends data to a HTTP server to inform it about the progress of the upload. |
QSignalEmitter.Signal1<java.lang.Boolean> |
done
This signal is emitted when the last pending request has finished; (it is emitted after the last request's requestFinished signal). |
QSignalEmitter.Signal2<QNetworkProxy,QAuthenticator> |
proxyAuthenticationRequired
|
QSignalEmitter.Signal1<QHttpResponseHeader> |
readyRead
This signal is emitted when there is new response data to read. |
QSignalEmitter.Signal2<java.lang.Integer,java.lang.Boolean> |
requestFinished
This signal is emitted when processing the request identified by arg__1 has finished. |
QSignalEmitter.Signal1<java.lang.Integer> |
requestStarted
This signal is emitted when processing the request identified by arg__1 starts. |
QSignalEmitter.Signal1<QHttpResponseHeader> |
responseHeaderReceived
This signal is emitted when the HTTP header of a server response is available. |
QSignalEmitter.Signal1<java.lang.Integer> |
stateChanged
This signal is emitted when the state of the QHttp object changes. |
Constructor Summary | |
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QHttp()
Equivalent to QHttp(0). |
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QHttp(QObject parent)
Constructs a QHttp object. |
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QHttp(java.lang.String hostname,
int port)
This is an overloaded constructor provided for convenince. |
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QHttp(java.lang.String hostname,
int port,
QObject parent)
This is an overloaded constructor provided for convenince. |
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QHttp(java.lang.String hostname,
QHttp.ConnectionMode mode,
int port)
This is an overloaded constructor provided for convenince. |
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QHttp(java.lang.String hostname,
QHttp.ConnectionMode mode,
int port,
QObject parent)
Constructs a QHttp object. |
Method Summary | |
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void |
abort()
Aborts the current request and deletes all scheduled requests. |
long |
bytesAvailable()
Returns the number of bytes that can be read from the response content at the moment. |
void |
clearPendingRequests()
Deletes all pending requests from the list of scheduled requests. |
int |
close()
Closes the connection; this is useful if you have a keep-alive connection and want to close it. |
QIODevice |
currentDestinationDevice()
Returns the QIODevice pointer that is used as to store the data of the HTTP request being executed. |
int |
currentId()
Returns the identifier of the HTTP request being executed or 0 if there is no request being executed (i.e. they've all finished). |
QHttpRequestHeader |
currentRequest()
Returns the request header of the HTTP request being executed. |
QIODevice |
currentSourceDevice()
Returns the QIODevice pointer that is used as the data source of the HTTP request being executed. |
QHttp.Error |
error()
Returns the last error that occurred. |
java.lang.String |
errorString()
Returns a human-readable description of the last error that occurred. |
static QHttp |
fromNativePointer(QNativePointer nativePointer)
This function returns the QHttp instance pointed to by nativePointer |
int |
get(java.lang.String path)
Equivalent to get(path, 0). |
int |
get(java.lang.String path,
QIODevice to)
Sends a get request for path to the server set by setHost() or as specified in the constructor. |
boolean |
hasPendingRequests()
Returns true if there are any requests scheduled that have not yet been executed; otherwise returns false. |
int |
head(java.lang.String path)
Sends a header request for path to the server set by setHost() or as specified in the constructor. |
void |
ignoreSslErrors()
Tells the QSslSocket used for the Http connection to ignore the errors reported in the sslErrors() signal. |
QHttpResponseHeader |
lastResponse()
Returns the received response header of the most recently finished HTTP request. |
int |
post(java.lang.String path,
QByteArray data)
Equivalent to post(path, data, 0). |
int |
post(java.lang.String path,
QByteArray data,
QIODevice to)
data is used as the content data of the HTTP request. |
int |
post(java.lang.String path,
QIODevice data)
Equivalent to post(path, data, 0). |
int |
post(java.lang.String path,
QIODevice data,
QIODevice to)
Sends a post request for path to the server set by setHost() or as specified in the constructor. |
int |
read(byte[] data)
Reads from the response content into data and returns the number of bytes read. |
QByteArray |
readAll()
Reads all the bytes from the response content and returns them. |
int |
request(QHttpRequestHeader header)
Equivalent to request(header, 0, 0). |
int |
request(QHttpRequestHeader header,
QByteArray data)
Equivalent to request(header, data, 0). |
int |
request(QHttpRequestHeader header,
QByteArray data,
QIODevice to)
data is used as the content data of the HTTP request. |
int |
request(QHttpRequestHeader header,
QIODevice device)
Equivalent to request(header, device, 0). |
int |
request(QHttpRequestHeader header,
QIODevice device,
QIODevice to)
Sends a request to the server set by setHost() or as specified in the constructor. |
int |
setHost(java.lang.String hostname,
int port)
Sets the HTTP server that is used for requests to hostname on port port. |
int |
setHost(java.lang.String hostname,
QHttp.ConnectionMode mode,
int port)
Sets the HTTP server that is used for requests to hostname on port port using the connection mode mode. |
int |
setProxy(QNetworkProxy proxy)
Enables HTTP proxy support using the proxy settings from proxy. |
int |
setProxy(java.lang.String host,
int port)
Equivalent to setProxy(host, port, QString(), QString()). |
int |
setProxy(java.lang.String host,
int port,
java.lang.String username)
Equivalent to setProxy(host, port, username, QString()). |
int |
setProxy(java.lang.String host,
int port,
java.lang.String username,
java.lang.String password)
Enables HTTP proxy support, using the proxy server host on port port. |
int |
setSocket(QTcpSocket socket)
Replaces the internal QTcpSocket that QHttp uses with socket. |
int |
setUser(java.lang.String username)
Equivalent to setUser(username, QString()). |
int |
setUser(java.lang.String username,
java.lang.String password)
This function sets the user name username and password password for web pages that require authentication. |
QHttp.State |
state()
Returns the current state of the object. |
Methods inherited from class com.trolltech.qt.core.QObject |
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blockSignals, childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, property, removeEventFilter, setObjectName, setParent, setProperty, signalsBlocked, startTimer, thread, timerEvent |
Methods inherited from class com.trolltech.qt.QtJambiObject |
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dispose, disposed, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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disconnect, disconnect, signalSender |
Methods inherited from class java.lang.Object |
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clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
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disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Field Detail |
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public final QSignalEmitter.Signal2<java.lang.Integer,java.lang.Integer> dataReadProgress
This signal is emitted when this object reads data from a HTTP server to indicate the current progress of the download.
arg__1 is the amount of data that has already arrived and arg__2 is the total amount of data. It is possible that the total amount of data that should be transferred cannot be determined, in which case arg__2 is 0.(If you connect to a QProgressBar, the progress bar shows a busy indicator if the total is 0).
Warning: arg__1 and arg__2 are not necessarily the size in bytes, since for large files these values might need to be "scaled" to avoid overflow.
public final QSignalEmitter.Signal2<java.lang.Integer,java.lang.Integer> dataSendProgress
This signal is emitted when this object sends data to a HTTP server to inform it about the progress of the upload.
arg__1 is the amount of data that has already arrived and arg__2 is the total amount of data. It is possible that the total amount of data that should be transferred cannot be determined, in which case arg__2 is 0.(If you connect to a QProgressBar, the progress bar shows a busy indicator if the total is 0).
Warning: arg__1 and arg__2 are not necessarily the size in bytes, since for large files these values might need to be "scaled" to avoid overflow.
public final QSignalEmitter.Signal1<java.lang.Boolean> done
This signal is emitted when the last pending request has finished; (it is emitted after the last request's requestFinished signal). arg__1 is true if an error occurred during the processing; otherwise arg__1 is false.
public final QSignalEmitter.Signal1<QHttpResponseHeader> readyRead
This signal is emitted when there is new response data to read.
If you specified a device in the request where the data should be written to, then this signal is not emitted; instead the data is written directly to the device.
The response header is passed in resp.
You can read the data with the readAll or read() functions
This signal is useful if you want to process the data in chunks as soon as it becomes available. If you are only interested in the complete data, just connect to the requestFinished signal and read the data then instead.
public final QSignalEmitter.Signal2<java.lang.Integer,java.lang.Boolean> requestFinished
This signal is emitted when processing the request identified by arg__1 has finished. arg__2 is true if an error occurred during the processing; otherwise arg__2 is false.
public final QSignalEmitter.Signal1<java.lang.Integer> requestStarted
This signal is emitted when processing the request identified by arg__1 starts.
public final QSignalEmitter.Signal1<QHttpResponseHeader> responseHeaderReceived
This signal is emitted when the HTTP header of a server response is available. The header is passed in resp.
public final QSignalEmitter.Signal1<java.lang.Integer> stateChanged
This signal is emitted when the state of the QHttp object changes. The argument arg__1 is the new state of the connection; it is one of the State values.
This usually happens when a request is started, but it can also happen when the server closes the connection or when a call to close succeeded.
public QSignalEmitter.Signal2<QNetworkProxy,QAuthenticator> proxyAuthenticationRequired
public QSignalEmitter.Signal3<java.lang.String,java.lang.Integer,QAuthenticator> authenticationRequired
Constructor Detail |
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public QHttp()
Equivalent to QHttp(0).
public QHttp(QObject parent)
public QHttp(java.lang.String hostname, int port)
public QHttp(java.lang.String hostname, int port, QObject parent)
public QHttp(java.lang.String hostname, QHttp.ConnectionMode mode, int port)
public QHttp(java.lang.String hostname, QHttp.ConnectionMode mode, int port, QObject parent)
If port is 0, it will use the default port for the mode used (80 for Http and 443 for Https).
The parent parameter is passed on to the QObject constructor.
Method Detail |
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public final void abort()
Aborts the current request and deletes all scheduled requests.
For the current request, the requestFinished signal with the error argument true is emitted. For all other requests that are affected by the abort, no signals are emitted.
Since this slot also deletes the scheduled requests, there are no requests left and the done signal is emitted (with the error argument true).
public final long bytesAvailable()
Returns the number of bytes that can be read from the response content at the moment.
public final void clearPendingRequests()
Deletes all pending requests from the list of scheduled requests. This does not affect the request that is being executed. If you want to stop this this as well, use abort.
public final int close()
Closes the connection; this is useful if you have a keep-alive connection and want to close it.
For the requests issued with get, post and head, QHttp sets the connection to be keep-alive. You can also do this using the header you pass to the request function. QHttp only closes the connection to the HTTP server if the response header requires it to do so.
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted and requestFinished.
When the request is started the requestStarted signal is emitted. When it is finished the requestFinished signal is emitted.
If you want to close the connection immediately, you have to use abort instead.
public final QIODevice currentDestinationDevice()
Returns the QIODevice pointer that is used as to store the data of the HTTP request being executed. If there is no current request or if the request does not store the data to an IO device, this function returns 0.
This function can be used to delete the QIODevice in the slot connected to the requestFinished signal.
public final int currentId()
Returns the identifier of the HTTP request being executed or 0 if there is no request being executed (i.e. they've all finished).
public final QHttpRequestHeader currentRequest()
Returns the request header of the HTTP request being executed. If the request is one issued by setHost() or close, it returns an invalid request header, i.e. QHttpRequestHeader::isValid() returns false.
public final QIODevice currentSourceDevice()
Returns the QIODevice pointer that is used as the data source of the HTTP request being executed. If there is no current request or if the request does not use an IO device as the data source, this function returns 0.
This function can be used to delete the QIODevice in the slot connected to the requestFinished signal.
public final QHttp.Error error()
Returns the last error that occurred. This is useful to find out what happened when receiving a requestFinished or a done signal with the error argument true.
If you start a new request, the error status is reset to NoError.
public final java.lang.String errorString()
Returns a human-readable description of the last error that occurred. This is useful to present a error message to the user when receiving a requestFinished or a done signal with the error argument true.
public final int get(java.lang.String path)
Equivalent to get(path, 0).
public final int get(java.lang.String path, QIODevice to)
Sends a get request for path to the server set by setHost() or as specified in the constructor.
path must be an absolute path like /index.html or an absolute URI like http://www.trolltech.com/index.html.
If the IO device to is 0 the readyRead signal is emitted every time new content data is available to read.
If the IO device to is not 0, the content data of the response is written directly to the device. Make sure that the to pointer is valid for the duration of the operation (it is safe to delete it when the requestFinished signal is emitted).
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted and requestFinished.
When the request is started the requestStarted signal is emitted. When it is finished the requestFinished signal is emitted.
public final boolean hasPendingRequests()
Returns true if there are any requests scheduled that have not yet been executed; otherwise returns false.
The request that is being executed is not considered as a scheduled request.
public final int head(java.lang.String path)
Sends a header request for path to the server set by setHost() or as specified in the constructor.
path must be an absolute path like /index.html or an absolute URI like http://www.trolltech.com/index.html.
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted and requestFinished.
When the request is started the requestStarted signal is emitted. When it is finished the requestFinished signal is emitted.
public final void ignoreSslErrors()
Tells the QSslSocket used for the Http connection to ignore the errors reported in the sslErrors() signal.
Note that this function must be called from within a slot connected to the sslErrors() signal to have any effect.
public final QHttpResponseHeader lastResponse()
Returns the received response header of the most recently finished HTTP request. If no response has yet been received QHttpResponseHeader::isValid() will return false.
public final int post(java.lang.String path, QIODevice data)
Equivalent to post(path, data, 0).
public final int post(java.lang.String path, QIODevice data, QIODevice to)
Sends a post request for path to the server set by setHost() or as specified in the constructor.
path must be an absolute path like /index.html or an absolute URI like http://www.trolltech.com/index.html.
The incoming data comes via the data IO device.
If the IO device to is 0 the readyRead signal is emitted every time new content data is available to read.
If the IO device to is not 0, the content data of the response is written directly to the device. Make sure that the to pointer is valid for the duration of the operation (it is safe to delete it when the requestFinished signal is emitted).
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted and requestFinished.
When the request is started the requestStarted signal is emitted. When it is finished the requestFinished signal is emitted.
public final int post(java.lang.String path, QByteArray data)
Equivalent to post(path, data, 0).
public final int post(java.lang.String path, QByteArray data, QIODevice to)
data is used as the content data of the HTTP request.
public final QByteArray readAll()
Reads all the bytes from the response content and returns them.
public final int request(QHttpRequestHeader header, QIODevice device)
Equivalent to request(header, device, 0).
public final int request(QHttpRequestHeader header)
Equivalent to request(header, 0, 0).
public final int request(QHttpRequestHeader header, QIODevice device, QIODevice to)
Sends a request to the server set by setHost() or as specified in the constructor. Uses the header as the HTTP request header. You are responsible for setting up a header that is appropriate for your request.
The incoming data comes via the device IO device.
If the IO device to is 0 the readyRead signal is emitted every time new content data is available to read.
If the IO device to is not 0, the content data of the response is written directly to the device. Make sure that the to pointer is valid for the duration of the operation (it is safe to delete it when the requestFinished signal is emitted).
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted and requestFinished.
When the request is started the requestStarted signal is emitted. When it is finished the requestFinished signal is emitted.
public final int request(QHttpRequestHeader header, QByteArray data)
Equivalent to request(header, data, 0).
public final int request(QHttpRequestHeader header, QByteArray data, QIODevice to)
data is used as the content data of the HTTP request.
public final int setProxy(QNetworkProxy proxy)
Enables HTTP proxy support using the proxy settings from proxy.
public final int setProxy(java.lang.String host, int port, java.lang.String username)
Equivalent to setProxy(host, port, username, QString()).
public final int setProxy(java.lang.String host, int port)
Equivalent to setProxy(host, port, QString(), QString()).
public final int setProxy(java.lang.String host, int port, java.lang.String username, java.lang.String password)
Enables HTTP proxy support, using the proxy server host on port port. username and password can be provided if the proxy server requires authentication.
Example:
void Ticker::getTicks() { http = new QHttp(this); connect(http, SIGNAL(done(bool)), this, SLOT(showPage())); http->setProxy("proxy.example.com", 3128); http->setHost("ticker.example.com"); http->get("/ticks.asp"); } void Ticker::showPage() { display(http->readAll()); }
QHttp supports non-transparent web proxy servers only, such as the Squid Web proxy cache server (from http://www.squid.org/). For transparent proxying, such as SOCKS5, use QNetworkProxy instead.
public final int setSocket(QTcpSocket socket)
Replaces the internal QTcpSocket that QHttp uses with socket. This is useful if you want to use your own custom QTcpSocket subclass instead of the plain QTcpSocket that QHttp uses by default. QHttp does not take ownership of the socket, and will not delete socket when destroyed.
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted and requestFinished.
When the request is started the requestStarted signal is emitted. When it is finished the requestFinished signal is emitted.
Note: If QHttp is used in a non-GUI thread that runs its own event loop, you must move socket to that thread before calling setSocket.
public final int setUser(java.lang.String username)
Equivalent to setUser(username, QString()).
public final int setUser(java.lang.String username, java.lang.String password)
This function sets the user name username and password password for web pages that require authentication.
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted and requestFinished.
When the request is started the requestStarted signal is emitted. When it is finished the requestFinished signal is emitted.
public final QHttp.State state()
Returns the current state of the object. When the state changes, the stateChanged signal is emitted.
public static QHttp fromNativePointer(QNativePointer nativePointer)
nativePointer
- the QNativePointer of which object should be returned.public final int read(byte[] data)
public final int setHost(java.lang.String hostname, QHttp.ConnectionMode mode, int port)
If port is 0, it will use the default port for the mode used (80 for Http and 443 fopr Https).
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted() and requestFinished().
When the request is started the requestStarted() signal is emitted. When it is finished the requestFinished() signal is emitted.
public final int setHost(java.lang.String hostname, int port)
The function does not block and returns immediately. The request is scheduled, and its execution is performed asynchronously. The function returns a unique identifier which is passed by requestStarted() and requestFinished().
When the request is started the requestStarted() signal is emitted. When it is finished the requestFinished() signal is emitted.
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