0、說明
QNetworkReply對象包含了Manager發送的請求頭和返回的數據。
它繼承自QIODevice，所以可以用各種read獲取其中返回的數據：
QByteArray data = reply->readAll();
QNetworkReply是順序訪問的QIODevice，這意味着一旦數據從中讀取出來之后，它就不再為Device保存了。因此保存數據的工作必須要由應用程序自己來實現。每當有新的數據從網絡中傳來時，readyRead()信號就會被發送。
此外，數據接收時downloadProgress()信號也會被發送，只是其中包含的bytes數並不代表實際接收的bytes，因為可能存在着數據轉換（如解壓縮和撤銷協議）。
它也會發送uploadProgress()信號，指示上傳這些內容的進度。
注意
不要在信號errorOccurred()和finished()的槽中刪除Object，而應該使用deleteLater()。
1、模塊和加載項
| Header: | #include <QNetworkReply> |
| qmake: | QT += network |
| Since: | Qt 4.4 |
| Inherits: | QIODevice |
2、構造
無
3、靜態字段
類型 |
字段 |
說明 |
| enum | NetworkError | 標識在處理Request期間可能發生的所有錯誤。 常見的是QNetworkReply::NoError，標識沒有錯誤。 |
| typedef | RawHeaderPair | 一個QPair < QByteArray , QByteArray >，第一個QByteArray是header name，第二個QByteArray是header |
NetworkError
| Constant | Value | Description |
|---|---|---|
QNetworkReply::ConnectionRefusedError |
1 |
the remote server refused the connection (the server is not accepting requests) |
QNetworkReply::RemoteHostClosedError |
2 |
the remote server closed the connection prematurely, before the entire reply was received and processed |
QNetworkReply::HostNotFoundError |
3 |
the remote host name was not found (invalid hostname) |
QNetworkReply::TimeoutError |
4 |
the connection to the remote server timed out |
QNetworkReply::OperationCanceledError |
5 |
the operation was canceled via calls to abort() or close() before it was finished. |
QNetworkReply::SslHandshakeFailedError |
6 |
the SSL/TLS handshake failed and the encrypted channel could not be established. The sslErrors() signal should have been emitted. |
QNetworkReply::TemporaryNetworkFailureError |
7 |
the connection was broken due to disconnection from the network, however the system has initiated roaming to another access point. The request should be resubmitted and will be processed as soon as the connection is re-established. |
QNetworkReply::NetworkSessionFailedError |
8 |
the connection was broken due to disconnection from the network or failure to start the network. |
QNetworkReply::BackgroundRequestNotAllowedError |
9 |
the background request is not currently allowed due to platform policy. |
QNetworkReply::TooManyRedirectsError |
10 |
while following redirects, the maximum limit was reached. The limit is by default set to 50 or as set by QNetworkRequest::setMaxRedirectsAllowed(). (This value was introduced in 5.6.) |
QNetworkReply::InsecureRedirectError |
11 |
while following redirects, the network access API detected a redirect from a encrypted protocol (https) to an unencrypted one (http). (This value was introduced in 5.6.) |
QNetworkReply::ProxyConnectionRefusedError |
101 |
the connection to the proxy server was refused (the proxy server is not accepting requests) |
QNetworkReply::ProxyConnectionClosedError |
102 |
the proxy server closed the connection prematurely, before the entire reply was received and processed |
QNetworkReply::ProxyNotFoundError |
103 |
the proxy host name was not found (invalid proxy hostname) |
QNetworkReply::ProxyTimeoutError |
104 |
the connection to the proxy timed out or the proxy did not reply in time to the request sent |
QNetworkReply::ProxyAuthenticationRequiredError |
105 |
the proxy requires authentication in order to honour the request but did not accept any credentials offered (if any) |
QNetworkReply::ContentAccessDenied |
201 |
the access to the remote content was denied (similar to HTTP error 403) |
QNetworkReply::ContentOperationNotPermittedError |
202 |
the operation requested on the remote content is not permitted |
QNetworkReply::ContentNotFoundError |
203 |
the remote content was not found at the server (similar to HTTP error 404) |
QNetworkReply::AuthenticationRequiredError |
204 |
the remote server requires authentication to serve the content but the credentials provided were not accepted (if any) |
QNetworkReply::ContentReSendError |
205 |
the request needed to be sent again, but this failed for example because the upload data could not be read a second time. |
QNetworkReply::ContentConflictError |
206 |
the request could not be completed due to a conflict with the current state of the resource. |
QNetworkReply::ContentGoneError |
207 |
the requested resource is no longer available at the server. |
QNetworkReply::InternalServerError |
401 |
the server encountered an unexpected condition which prevented it from fulfilling the request. |
QNetworkReply::OperationNotImplementedError |
402 |
the server does not support the functionality required to fulfill the request. |
QNetworkReply::ServiceUnavailableError |
403 |
the server is unable to handle the request at this time. |
QNetworkReply::ProtocolUnknownError |
301 |
the Network Access API cannot honor the request because the protocol is not known |
QNetworkReply::ProtocolInvalidOperationError |
302 |
the requested operation is invalid for this protocol |
QNetworkReply::UnknownNetworkError |
99 |
an unknown network-related error was detected |
QNetworkReply::UnknownProxyError |
199 |
an unknown proxy-related error was detected |
QNetworkReply::UnknownContentError |
299 |
an unknown error related to the remote content was detected |
QNetworkReply::ProtocolFailure |
399 |
a breakdown in protocol was detected (parsing error, invalid or unexpected responses, etc.) |
QNetworkReply::UnknownServerError |
499 |
an unknown error related to the server response was detected |
4、實例方法
返回值類型 |
方法 |
說明 |
| QVariant | attribute(QNetworkRequest::Attribute code) | |
| QNetworkReply::NetworkError | error() | |
| bool | hasRawHeader(QByteArray headerName) | |
| QVariant | header(QNetworkRequest::KnownHeaders header) | |
| void | ignoreSslErrors(QList<QSslError> errors) | |
| bool | isFinished() | |
| bool | isRunning() | |
| QNetworkAccessManager * | manager() | |
| QNetworkAccessManager::Operation | operation() | |
| QByteArray | rawHeader(QByteArray headerName) | |
| QList<QByteArray> | rawHeaderList() | |
| QList<QNetworkReply::RawHeaderPair> | rawHeaderPairs() | |
| qint64 | readBufferSize() | |
| QNetworkRequest | request() | |
| virtual void | setReadBufferSize(qint64 size) | |
| void | setSslConfiguration(QSslConfiguration config) | |
| QSslConfiguration | sslConfiguration() | |
| QUrl | url() |
5、信號
信號 |
說明 |
| downloadProgress(qint64 bytesReceived, qint64 bytesTotal) | |
| encrypted() | |
| errorOccurred(QNetworkReply::NetworkError code) | |
| finished() | |
| metaDataChanged() | |
| preSharedKeyAuthenticationRequired(QSslPreSharedKeyAuthenticator *authenticator) | |
| redirectAllowed() | |
| redirected(QUrl url) | |
| sslErrors(QList<QSslError> errors) | |
| uploadProgress(qint64 bytesSent, qint64 bytesTotal) |