class QNetworkAccessManager#

The QNetworkAccessManager class allows the application to send network requests and receive replies. More

Inheritance diagram of PySide6.QtNetwork.QNetworkAccessManager

Synopsis#

Methods#

Virtual methods#

Slots#

Signals#

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description#

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

The Network Access API is constructed around one QNetworkAccessManager object, which holds the common configuration and settings for the requests it sends. It contains the proxy and cache configuration, as well as the signals related to such issues, and reply signals that can be used to monitor the progress of a network operation. One QNetworkAccessManager instance should be enough for the whole Qt application. Since QNetworkAccessManager is based on QObject, it can only be used from the thread it belongs to.

Once a QNetworkAccessManager object has been created, the application can use it to send requests over the network. A group of standard functions are supplied that take a request and optional data, and each return a QNetworkReply object. The returned object is used to obtain any data returned in response to the corresponding request.

A simple download off the network could be accomplished with:

manager = QNetworkAccessManager(self)
manager.finished.connect(
        self.replyFinished)
manager.get(QNetworkRequest(QUrl("http://qt-project.org")))

QNetworkAccessManager has an asynchronous API. When the replyFinished slot above is called, the parameter it takes is the QNetworkReply object containing the downloaded data as well as meta-data (headers, etc.).

Note

After the request has finished, it is the responsibility of the user to delete the QNetworkReply object at an appropriate time. Do not directly delete it inside the slot connected to finished() . You can use the deleteLater() function.

Note

QNetworkAccessManager queues the requests it receives. The number of requests executed in parallel is dependent on the protocol. Currently, for the HTTP protocol on desktop platforms, 6 requests are executed in parallel for one host/port combination.

A more involved example, assuming the manager is already existent, can be:

request = QNetworkRequest()
request.setUrl(QUrl("http://qt-project.org"))
request.setRawHeader("User-Agent", "MyOwnBrowser 1.0")
reply = manager.get(request)
reply.readyRead.connect(self.slotReadyRead)
reply.errorOccurred.connect(
        self.slotError)
reply.sslErrors.connect(
        self.slotSslErrors)
class Operation#

Indicates the operation this reply is processing.

Constant

Description

QNetworkAccessManager.HeadOperation

retrieve headers operation (created with head() )

QNetworkAccessManager.GetOperation

retrieve headers and download contents (created with get() )

QNetworkAccessManager.PutOperation

upload contents operation (created with put() )

QNetworkAccessManager.PostOperation

send the contents of an HTML form for processing via HTTP POST (created with post() )

QNetworkAccessManager.DeleteOperation

delete contents operation (created with deleteResource() )

QNetworkAccessManager.CustomOperation

custom operation (created with sendCustomRequest() )

See also

operation()

__init__([parent=None])#
Parameters:

parentQObject

Constructs a QNetworkAccessManager object that is the center of the Network Access API and sets parent as the parent object.

addStrictTransportSecurityHosts(knownHosts)#
Parameters:

knownHosts – .list of QHstsPolicy

Adds HTTP Strict Transport Security policies into HSTS cache. knownHosts contains the known hosts that have QHstsPolicy information.

Note

An expired policy will remove a known host from the cache, if previously present.

Note

While processing HTTP responses, QNetworkAccessManager can also update the HSTS cache, removing or updating exitsting policies or introducing new knownHosts. The current implementation thus is server-driven, client code can provide QNetworkAccessManager with previously known or discovered policies, but this information can be overridden by “Strict-Transport-Security” response headers.

authenticationRequired(reply, authenticator)#
Parameters:

This signal is emitted whenever a final server requests authentication before it delivers the requested contents. The slot connected to this signal should fill the credentials for the contents (which can be determined by inspecting the reply object) in the authenticator object.

QNetworkAccessManager will cache the credentials internally and will send the same values if the server requires authentication again, without emitting the authenticationRequired() signal. If it rejects the credentials, this signal will be emitted again.

Note

To have the request not send credentials you must not call setUser() or setPassword() on the authenticator object. This will result in the finished() signal being emitted with a QNetworkReply with error AuthenticationRequiredError .

Note

It is not possible to use a QueuedConnection to connect to this signal, as the connection will fail if the authenticator has not been filled in with new information when the signal returns.

autoDeleteReplies()#
Return type:

bool

Returns the true if QNetworkAccessManager is currently configured to automatically delete QNetworkReplies, false otherwise.

cache()#
Return type:

QAbstractNetworkCache

Returns the cache that is used to store data obtained from the network.

See also

setCache()

clearAccessCache()#

Flushes the internal cache of authentication data and network connections.

This function is useful for doing auto tests.

clearConnectionCache()#

Flushes the internal cache of network connections. In contrast to clearAccessCache() the authentication data is preserved.

connectToHost(hostName[, port=80])#
Parameters:
  • hostName – str

  • port – int

Initiates a connection to the host given by hostName at port port. This function is useful to complete the TCP handshake to a host before the HTTP request is made, resulting in a lower network latency.

Note

This function has no possibility to report errors.

connectToHostEncrypted(hostName[, port=443[, sslConfiguration=QSslConfiguration.defaultConfiguration()]])#
Parameters:

Initiates a connection to the host given by hostName at port port, using sslConfiguration. This function is useful to complete the TCP and SSL handshake to a host before the HTTPS request is made, resulting in a lower network latency.

Note

Preconnecting a HTTP/2 connection can be done by calling setAllowedNextProtocols() on sslConfiguration with QSslConfiguration::ALPNProtocolHTTP2 contained in the list of allowed protocols. When using HTTP/2, one single connection per host is enough, i.e. calling this method multiple times per host will not result in faster network transactions.

Note

This function has no possibility to report errors.

connectToHostEncrypted(hostName, port, sslConfiguration, peerName)
Parameters:
  • hostName – str

  • port – int

  • sslConfigurationQSslConfiguration

  • peerName – str

This is an overloaded function.

Initiates a connection to the host given by hostName at port port, using sslConfiguration with peerName set to be the hostName used for certificate validation. This function is useful to complete the TCP and SSL handshake to a host before the HTTPS request is made, resulting in a lower network latency.

Note

Preconnecting a HTTP/2 connection can be done by calling setAllowedNextProtocols() on sslConfiguration with QSslConfiguration::ALPNProtocolHTTP2 contained in the list of allowed protocols. When using HTTP/2, one single connection per host is enough, i.e. calling this method multiple times per host will not result in faster network transactions.

Note

This function has no possibility to report errors.

cookieJar()#
Return type:

QNetworkCookieJar

Returns the QNetworkCookieJar that is used to store cookies obtained from the network as well as cookies that are about to be sent.

See also

setCookieJar()

createRequest(op, request[, outgoingData=None])#
Parameters:
Return type:

QNetworkReply

Returns a new QNetworkReply object to handle the operation op and request originalReq. The device outgoingData is always 0 for Get and Head requests, but is the value passed to post() and put() in those operations (the QByteArray variants will pass a QBuffer object).

The default implementation calls cookiesForUrl() on the cookie jar set with setCookieJar() to obtain the cookies to be sent to the remote server.

The returned object must be in an open state.

deleteResource(request)#
Parameters:

requestQNetworkRequest

Return type:

QNetworkReply

Sends a request to delete the resource identified by the URL of request.

Note

This feature is currently available for HTTP only, performing an HTTP DELETE request.

enableStrictTransportSecurityStore(enabled[, storeDir=""])#
Parameters:
  • enabled – bool

  • storeDir – str

If enabled is true, the internal HSTS cache will use a persistent store to read and write HSTS policies. storeDir defines where this store will be located. The default location is defined by QStandardPaths::CacheLocation. If there is no writable QStandartPaths::CacheLocation and storeDir is an empty string, the store will be located in the program’s working directory.

Note

If HSTS cache already contains HSTS policies by the time persistent store is enabled, these policies will be preserved in the store. In case both cache and store contain the same known hosts, policies from cache are considered to be more up-to-date (and thus will overwrite the previous values in the store). If this behavior is undesired, enable HSTS store before enabling Strict Transport Security. By default, the persistent store of HSTS policies is disabled.

encrypted(reply)#
Parameters:

replyQNetworkReply

This signal is emitted when an SSL/TLS session has successfully completed the initial handshake. At this point, no user data has been transmitted. The signal can be used to perform additional checks on the certificate chain, for example to notify users when the certificate for a website has changed. The reply parameter specifies which network reply is responsible. If the reply does not match the expected criteria then it should be aborted by calling abort() by a slot connected to this signal. The SSL configuration in use can be inspected using the sslConfiguration() method.

Internally, QNetworkAccessManager may open multiple connections to a server, in order to allow it process requests in parallel. These connections may be reused, which means that the encrypted() signal would not be emitted. This means that you are only guaranteed to receive this signal for the first connection to a site in the lifespan of the QNetworkAccessManager .

finished(reply)#
Parameters:

replyQNetworkReply

This signal is emitted whenever a pending network reply is finished. The reply parameter will contain a pointer to the reply that has just finished. This signal is emitted in tandem with the finished() signal.

See finished() for information on the status that the object will be in.

Note

Do not delete the reply object in the slot connected to this signal. Use deleteLater().

See also

finished() error()

get(request)#
Parameters:

requestQNetworkRequest

Return type:

QNetworkReply

Posts a request to obtain the contents of the target request and returns a new QNetworkReply object opened for reading which emits the readyRead() signal whenever new data arrives.

The contents as well as associated headers will be downloaded.

head(request)#
Parameters:

requestQNetworkRequest

Return type:

QNetworkReply

Posts a request to obtain the network headers for request and returns a new QNetworkReply object which will contain such headers.

The function is named after the HTTP request associated (HEAD).

isStrictTransportSecurityEnabled()#
Return type:

bool

Returns true if HTTP Strict Transport Security (HSTS) was enabled. By default HSTS is disabled.

isStrictTransportSecurityStoreEnabled()#
Return type:

bool

Returns true if HSTS cache uses a permanent store to load and store HSTS policies.

post(request, multiPart)#
Parameters:
Return type:

QNetworkReply

This is an overloaded function.

Sends the contents of the multiPart message to the destination specified by request.

This can be used for sending MIME multipart messages over HTTP.

post(request, data)
Parameters:
Return type:

QNetworkReply

Sends an HTTP POST request to the destination specified by request and returns a new QNetworkReply object opened for reading that will contain the reply sent by the server. The contents of the data device will be uploaded to the server.

data must be open for reading and must remain valid until the finished() signal is emitted for this reply.

Note

Sending a POST request on protocols other than HTTP and HTTPS is undefined and will probably fail.

post(request, data)
Parameters:
Return type:

QNetworkReply

This is an overloaded function.

Sends the contents of the data byte array to the destination specified by request.

preSharedKeyAuthenticationRequired(reply, authenticator)#
Parameters:

This signal is emitted if the SSL/TLS handshake negotiates a PSK ciphersuite, and therefore a PSK authentication is then required. The reply object is the QNetworkReply that is negotiating such ciphersuites.

When using PSK, the client must send to the server a valid identity and a valid pre shared key, in order for the SSL handshake to continue. Applications can provide this information in a slot connected to this signal, by filling in the passed authenticator object according to their needs.

Note

Ignoring this signal, or failing to provide the required credentials, will cause the handshake to fail, and therefore the connection to be aborted.

Note

The authenticator object is owned by the reply and must not be deleted by the application.

proxy()#
Return type:

QNetworkProxy

Returns the QNetworkProxy that the requests sent using this QNetworkAccessManager object will use. The default value for the proxy is DefaultProxy .

proxyAuthenticationRequired(proxy, authenticator)#
Parameters:

This signal is emitted whenever a proxy requests authentication and QNetworkAccessManager cannot find a valid, cached credential. The slot connected to this signal should fill in the credentials for the proxy proxy in the authenticator object.

QNetworkAccessManager will cache the credentials internally. The next time the proxy requests authentication, QNetworkAccessManager will automatically send the same credential without emitting the proxyAuthenticationRequired signal again.

If the proxy rejects the credentials, QNetworkAccessManager will emit the signal again.

proxyFactory()#
Return type:

QNetworkProxyFactory

Returns the proxy factory that this QNetworkAccessManager object is using to determine the proxies to be used for requests.

Note that the pointer returned by this function is managed by QNetworkAccessManager and could be deleted at any time.

put(request, multiPart)#
Parameters:
Return type:

QNetworkReply

This is an overloaded function.

Sends the contents of the multiPart message to the destination specified by request.

This can be used for sending MIME multipart messages over HTTP.

put(request, data)
Parameters:
Return type:

QNetworkReply

Uploads the contents of data to the destination request and returns a new QNetworkReply object that will be open for reply.

data must be opened for reading when this function is called and must remain valid until the finished() signal is emitted for this reply.

Whether anything will be available for reading from the returned object is protocol dependent. For HTTP, the server may send a small HTML page indicating the upload was successful (or not). Other protocols will probably have content in their replies.

Note

For HTTP, this request will send a PUT request, which most servers do not allow. Form upload mechanisms, including that of uploading files through HTML forms, use the POST mechanism.

put(request, data)
Parameters:
Return type:

QNetworkReply

This is an overloaded function.

Sends the contents of the data byte array to the destination specified by request.

redirectPolicy()#
Return type:

RedirectPolicy

Returns the redirect policy that is used when creating new requests.

sendCustomRequest(request, verb, multiPart)#
Parameters:
Return type:

QNetworkReply

This is an overloaded function.

Sends a custom request to the server identified by the URL of request.

Sends the contents of the multiPart message to the destination specified by request.

This can be used for sending MIME multipart messages for custom verbs.

sendCustomRequest(request, verb[, data=None])
Parameters:
Return type:

QNetworkReply

Sends a custom request to the server identified by the URL of request.

It is the user’s responsibility to send a verb to the server that is valid according to the HTTP specification.

This method provides means to send verbs other than the common ones provided via get() or post() etc., for instance sending an HTTP OPTIONS command.

If data is not empty, the contents of the data device will be uploaded to the server; in that case, data must be open for reading and must remain valid until the finished() signal is emitted for this reply.

Note

This feature is currently available for HTTP(S) only.

sendCustomRequest(request, verb, data)
Parameters:
Return type:

QNetworkReply

This is an overloaded function.

Sends the contents of the data byte array to the destination specified by request.

setAutoDeleteReplies(autoDelete)#
Parameters:

autoDelete – bool

Enables or disables automatic deletion of QNetworkReplies .

Setting shouldAutoDelete to true is the same as setting the AutoDeleteReplyOnFinishAttribute attribute to true on all future QNetworkRequests passed to this instance of QNetworkAccessManager unless the attribute was already explicitly set on the QNetworkRequest .

setCache(cache)#
Parameters:

cacheQAbstractNetworkCache

Sets the manager’s network cache to be the cache specified. The cache is used for all requests dispatched by the manager.

Use this function to set the network cache object to a class that implements additional features, like saving the cookies to permanent storage.

Note

QNetworkAccessManager takes ownership of the cache object.

QNetworkAccessManager by default does not have a set cache. Qt provides a simple disk cache, QNetworkDiskCache , which can be used.

setCookieJar(cookieJar)#
Parameters:

cookieJarQNetworkCookieJar

Sets the manager’s cookie jar to be the cookieJar specified. The cookie jar is used by all requests dispatched by the manager.

Use this function to set the cookie jar object to a class that implements additional features, like saving the cookies to permanent storage.

Note

QNetworkAccessManager takes ownership of the cookieJar object.

If cookieJar is in the same thread as this QNetworkAccessManager , it will set the parent of the cookieJar so that the cookie jar is deleted when this object is deleted as well. If you want to share cookie jars between different QNetworkAccessManager objects, you may want to set the cookie jar’s parent to 0 after calling this function.

QNetworkAccessManager by default does not implement any cookie policy of its own: it accepts all cookies sent by the server, as long as they are well formed and meet the minimum security requirements (cookie domain matches the request’s and cookie path matches the request’s). In order to implement your own security policy, override the cookiesForUrl() and setCookiesFromUrl() virtual functions. Those functions are called by QNetworkAccessManager when it detects a new cookie.

setProxy(proxy)#
Parameters:

proxyQNetworkProxy

Sets the proxy to be used in future requests to be proxy. This does not affect requests that have already been sent. The proxyAuthenticationRequired() signal will be emitted if the proxy requests authentication.

A proxy set with this function will be used for all requests issued by QNetworkAccessManager . In some cases, it might be necessary to select different proxies depending on the type of request being sent or the destination host. If that’s the case, you should consider using setProxyFactory() .

setProxyFactory(factory)#
Parameters:

factoryQNetworkProxyFactory

Sets the proxy factory for this class to be factory. A proxy factory is used to determine a more specific list of proxies to be used for a given request, instead of trying to use the same proxy value for all requests.

All queries sent by QNetworkAccessManager will have type UrlRequest .

For example, a proxy factory could apply the following rules:

  • if the target address is in the local network (for example, if the hostname contains no dots or if it’s an IP address in the organization’s range), return NoProxy

  • if the request is FTP, return an FTP proxy

  • if the request is HTTP or HTTPS, then return an HTTP proxy

  • otherwise, return a SOCKSv5 proxy server

The lifetime of the object factory will be managed by QNetworkAccessManager . It will delete the object when necessary.

Note

If a specific proxy is set with setProxy() , the factory will not be used.

setRedirectPolicy(policy)#
Parameters:

policyRedirectPolicy

Sets the manager’s redirect policy to be the policy specified. This policy will affect all subsequent requests created by the manager.

Use this function to enable or disable HTTP redirects on the manager’s level.

Note

When creating a request QNetworkRequest::RedirectAttributePolicy has the highest priority, next by priority the manager’s policy.

The default value is NoLessSafeRedirectPolicy . Clients relying on manual redirect handling are encouraged to set this policy explicitly in their code.

setStrictTransportSecurityEnabled(enabled)#
Parameters:

enabled – bool

If enabled is true, QNetworkAccessManager follows the HTTP Strict Transport Security policy (HSTS, RFC6797). When processing a request, QNetworkAccessManager automatically replaces the “http” scheme with “https” and uses a secure transport for HSTS hosts. If it’s set explicitly, port 80 is replaced by port 443.

When HSTS is enabled, for each HTTP response containing HSTS header and received over a secure transport, QNetworkAccessManager will update its HSTS cache, either remembering a host with a valid policy or removing a host with an expired or disabled HSTS policy.

setTransferTimeout([timeout=QNetworkRequest.DefaultTransferTimeoutConstant])#
Parameters:

timeout – int

Sets timeout as the transfer timeout in milliseconds.

Transfers are aborted if no bytes are transferred before the timeout expires. Zero means no timer is set. If no argument is provided, the timeout is DefaultTransferTimeoutConstant . If this function is not called, the timeout is disabled and has the value zero. The request-specific non-zero timeouts set for the requests that are executed override this value. This means that if QNetworkAccessManager has an enabled timeout, it needs to be disabled to execute a request without a timeout.

sslErrors(reply, errors)#
Parameters:

This signal is emitted if the SSL/TLS session encountered errors during the set up, including certificate verification errors. The errors parameter contains the list of errors and reply is the QNetworkReply that is encountering these errors.

To indicate that the errors are not fatal and that the connection should proceed, the ignoreSslErrors() function should be called from the slot connected to this signal. If it is not called, the SSL session will be torn down before any data is exchanged (including the URL).

This signal can be used to display an error message to the user indicating that security may be compromised and display the SSL settings (see sslConfiguration() to obtain it). If the user decides to proceed after analyzing the remote certificate, the slot should call ignoreSslErrors().

strictTransportSecurityHosts()#
Return type:

.list of QHstsPolicy

Returns the list of HTTP Strict Transport Security policies. This list can differ from what was initially set via addStrictTransportSecurityHosts() if HSTS cache was updated from a “Strict-Transport-Security” response header.

supportedSchemes()#
Return type:

list of strings

Lists all the URL schemes supported by the access manager.

Reimplement this method to provide your own supported schemes in a QNetworkAccessManager subclass. It is for instance necessary when your subclass provides support for new protocols.

supportedSchemesImplementation()#
Return type:

list of strings

Lists all the URL schemes supported by the access manager.

You should not call this function directly; use supportedSchemes() instead.

Because of binary compatibility constraints, the supportedSchemes() method (introduced in Qt 5.2) was not virtual in Qt 5, but now it is. Override the supportedSchemes method rather than this one.

transferTimeout()#
Return type:

int

Returns the timeout used for transfers, in milliseconds.

This timeout is zero if setTransferTimeout() hasn’t been called, which means that the timeout is not used.