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The QNetworkProxy class provides a network layer proxy. More...
The QNetworkProxy class provides a network layer proxy.
QNetworkProxy provides the method for configuring network layer proxy support to the Qt network classes. The currently supported classes are QAbstractSocket, QTcpSocket, QUdpSocket, QTcpServer, QNetworkAccessManager and QFtp. The proxy support is designed to be as transparent as possible. This means that existing network-enabled applications that you have written should automatically support network proxy using the following code.
QNetworkProxy proxy; proxy.setType(QNetworkProxy.Socks5Proxy); proxy.setHostName("proxy.example.com"); proxy.setPort(1080); proxy.setUser("username"); proxy.setPassword("password"); QNetworkProxy.setApplicationProxy(proxy);
An alternative to setting an application wide proxy is to specify the proxy for individual sockets using QAbstractSocket.setProxy() and QTcpServer.setProxy(). In this way, it is possible to disable the use of a proxy for specific sockets using the following code:
serverSocket->setProxy(QNetworkProxy.NoProxy);
Network proxy is not used if the address used in connectToHost(), bind() or listen() is equivalent to QHostAddress.LocalHost or QHostAddress.LocalHostIPv6.
Each type of proxy support has certain restrictions associated with it. You should read the ProxyType documentation carefully before selecting a proxy type to use.
Note: Changes made to currently connected sockets do not take effect. If you need to change a connected socket, you should reconnect it.
The SOCKS5 support in Qt 4 is based on RFC 1928 and RFC 1929. The supported authentication methods are no authentication and username/password authentication. Both IPv4 and IPv6 are supported. Domain names are resolved through the SOCKS5 server if the QNetworkProxy.HostNameLookupCapability is enabled, otherwise they are resolved locally and the IP address is sent to the server. There are several things to remember when using SOCKS5 with QUdpSocket and QTcpServer:
With QUdpSocket, a call to bind() may fail with a timeout error. If a port number other than 0 is passed to bind(), it is not guaranteed that it is the specified port that will be used. Use localPort() and localAddress() to get the actual address and port number in use. Because proxied UDP goes through two UDP connections, it is more likely that packets will be dropped.
With QTcpServer a call to listen() may fail with a timeout error. If a port number other than 0 is passed to listen(), then it is not guaranteed that it is the specified port that will be used. Use serverPort() and serverAddress() to get the actual address and port used to listen for connections. SOCKS5 only supports one accepted connection per call to listen(), and each call is likely to result in a different serverPort() being used.
These flags indicate the capabilities that a given proxy server supports.
QNetworkProxy sets different capabilities by default when the object is created (see QNetworkProxy.ProxyType for a list of the defaults). However, it is possible to change the capabitilies after the object has been created with setCapabilities().
The capabilities that QNetworkProxy supports are:
| Constant | Value | Description |
|---|---|---|
| QNetworkProxy.TunnelingCapability | 0x0001 | Ability to open transparent, tunneled TCP connections to a remote host. The proxy server relays the transmission verbatim from one side to the other and does no caching. |
| QNetworkProxy.ListeningCapability | 0x0002 | Ability to create a listening socket and wait for an incoming TCP connection from a remote host. |
| QNetworkProxy.UdpTunnelingCapability | 0x0004 | Ability to relay UDP datagrams via the proxy server to and from a remote host. |
| QNetworkProxy.CachingCapability | 0x0008 | Ability to cache the contents of the transfer. This capability is specific to each protocol and proxy type. For example, HTTP proxies can cache the contents of web data transferred with "GET" commands. |
| QNetworkProxy.HostNameLookupCapability | 0x0010 | Ability to connect to perform the lookup on a remote host name and connect to it, as opposed to requiring the application to perform the name lookup and request connection to IP addresses only. |
This enum was introduced or modified in Qt 4.5.
The Capabilities type is a typedef for QFlags<Capability>. It stores an OR combination of Capability values.
This enum describes the types of network proxying provided in Qt.
There are two types of proxies that Qt understands: transparent proxies and caching proxies. The first group consists of proxies that can handle any arbitrary data transfer, while the second can only handle specific requests. The caching proxies only make sense for the specific classes where they can be used.
| Constant | Value | Description |
|---|---|---|
| QNetworkProxy.NoProxy | 2 | No proxying is used |
| QNetworkProxy.DefaultProxy | 0 | Proxy is determined based on the application proxy set using setApplicationProxy() |
| QNetworkProxy.Socks5Proxy | 1 | Socks5 proxying is used |
| QNetworkProxy.HttpProxy | 3 | HTTP transparent proxying is used (This value was introduced in 4.3.) |
| QNetworkProxy.HttpCachingProxy | 4 | Proxying for HTTP requests only (This value was introduced in 4.4.) |
| QNetworkProxy.FtpCachingProxy | 5 | Proxying for FTP requests only (This value was introduced in 4.4.) |
The table below lists different proxy types and their capabilities. Since each proxy type has different capabilities, it is important to understand them before choosing a proxy type.
| Proxy type | Description | Default capabilities |
|---|---|---|
| SOCKS 5 | Generic proxy for any kind of connection. Supports TCP, UDP, binding to a port (incoming connections) and authentication. | TunnelingCapability, ListeningCapability, UdpTunnelingCapability, HostNameLookupCapability |
| HTTP | Implemented using the "CONNECT" command, supports only outgoing TCP connections; supports authentication. | TunnelingCapability, CachingCapability, HostNameLookupCapability |
| Caching-only HTTP | Implemented using normal HTTP commands, it is useful only in the context of HTTP requests (see QNetworkAccessManager) | CachingCapability, HostNameLookupCapability |
| Caching FTP | Implemented using an FTP proxy, it is useful only in the context of FTP requests (see QFtp, QNetworkAccessManager) | CachingCapability, HostNameLookupCapability |
Also note that you shouldn't set the application default proxy (setApplicationProxy()) to a proxy that doesn't have the TunnelingCapability capability. If you do, QTcpSocket will not know how to open connections.
See also setType(), type(), capabilities(), and setCapabilities().
Constructs a QNetworkProxy with DefaultProxy type; the proxy type is determined by applicationProxy(), which defaults to NoProxy.
See also setType() and setApplicationProxy().
Constructs a QNetworkProxy with type, hostName, port, user and password.
The default capabilities for proxy type type are set automatically.
See also capabilities().
Constructs a copy of other.
Returns the application level network proxying.
If a QAbstractSocket or QTcpSocket has the QNetworkProxy.DefaultProxy type, then the QNetworkProxy returned by this function is used.
See also QNetworkProxyFactory, setApplicationProxy(), QAbstractSocket.proxy(), and QTcpServer.proxy().
Returns the capabilities of this proxy server.
This function was introduced in Qt 4.5.
See also setCapabilities() and type().
Returns the host name of the proxy host.
See also setHostName(), setPort(), and port().
Returns true if this proxy supports the QNetworkProxy.CachingCapability capability.
In Qt 4.4, the capability was tied to the proxy type, but since Qt 4.5 it is possible to remove the capability of caching from a proxy by calling setCapabilities().
This function was introduced in Qt 4.4.
See also capabilities(), type(), and isTransparentProxy().
Returns true if this proxy supports transparent tunneling of TCP connections. This matches the QNetworkProxy.TunnelingCapability capability.
In Qt 4.4, the capability was tied to the proxy type, but since Qt 4.5 it is possible to remove the capability of caching from a proxy by calling setCapabilities().
This function was introduced in Qt 4.4.
See also capabilities(), type(), and isCachingProxy().
Returns the password used for authentication.
See also user(), setPassword(), and setUser().
Returns the port of the proxy host.
See also setHostName(), setPort(), and hostName().
Sets the application level network proxying to be networkProxy.
If a QAbstractSocket or QTcpSocket has the QNetworkProxy.DefaultProxy type, then the QNetworkProxy set with this function is used. If you want more flexibility in determining which the proxy, use the QNetworkProxyFactory class.
Setting a default proxy value with this function will override the application proxy factory set with QNetworkProxyFactory.setApplicationProxyFactory.
See also QNetworkProxyFactory, applicationProxy(), QAbstractSocket.setProxy(), and QTcpServer.setProxy().
Sets the capabilities of this proxy to capabilities.
This function was introduced in Qt 4.5.
See also setType() and capabilities().
Sets the host name of the proxy host to be hostName.
See also hostName(), setPort(), and port().
Sets the password for proxy authentication to be password.
See also user(), setUser(), and password().
Sets the port of the proxy host to be port.
See also hostName(), setHostName(), and port().
Sets the proxy type for this instance to be type.
Note that changing the type of a proxy does not change the set of capabilities this QNetworkProxy object holds if any capabilities have been set with setCapabilities().
See also type() and setCapabilities().
Sets the user name for proxy authentication to be user.
See also user(), setPassword(), and password().
Returns the proxy type for this instance.
See also setType().
Returns the user name used for authentication.
See also setUser(), setPassword(), and password().
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