QNetworkRequest Class
The QNetworkRequest class holds a request to be sent with QNetworkAccessManager. More...
| Header: | #include <QNetworkRequest> |
| qmake: | QT += network |
| Since: | Qt 4.4 |
This class was introduced in Qt 4.4.
Public Types
| enum | Attribute { HttpStatusCodeAttribute, HttpReasonPhraseAttribute, RedirectionTargetAttribute, ConnectionEncryptedAttribute, CacheLoadControlAttribute, …, UserMax } |
| enum | CacheLoadControl { AlwaysNetwork, PreferNetwork, PreferCache, AlwaysCache } |
| enum | KnownHeaders { ContentDispositionHeader, ContentTypeHeader, ContentLengthHeader, LocationHeader, LastModifiedHeader, …, ServerHeader } |
| enum | LoadControl { Automatic, Manual } |
| enum | Priority { HighPriority, NormalPriority, LowPriority } |
| enum | RedirectPolicy { ManualRedirectPolicy, NoLessSafeRedirectPolicy, SameOriginRedirectPolicy, UserVerifiedRedirectPolicy } |
| enum | TransferTimeoutConstant { DefaultTransferTimeoutConstant } |
Detailed Description
QNetworkRequest is part of the Network Access API and is the class holding the information necessary to send a request over the network. It contains a URL and some ancillary information that can be used to modify the request.
See also QNetworkReply and QNetworkAccessManager.
Member Type Documentation
enum QNetworkRequest::Attribute
Attribute codes for the QNetworkRequest and QNetworkReply.
Attributes are extra meta-data that are used to control the behavior of the request and to pass further information from the reply back to the application. Attributes are also extensible, allowing custom implementations to pass custom values.
The following table explains what the default attribute codes are, the QVariant types associated, the default value if said attribute is missing and whether it's used in requests or replies.
| Constant | Value | Description |
|---|---|---|
QNetworkRequest::HttpStatusCodeAttribute | 0 | Replies only, type: QMetaType::Int (no default) Indicates the HTTP status code received from the HTTP server (like 200, 304, 404, 401, etc.). If the connection was not HTTP-based, this attribute will not be present. |
QNetworkRequest::HttpReasonPhraseAttribute | 1 | Replies only, type: QMetaType::QByteArray (no default) Indicates the HTTP reason phrase as received from the HTTP server (like "Ok", "Found", "Not Found", "Access Denied", etc.) This is the human-readable representation of the status code (see above). If the connection was not HTTP-based, this attribute will not be present. |
QNetworkRequest::RedirectionTargetAttribute | 2 | Replies only, type: QMetaType::QUrl (no default) If present, it indicates that the server is redirecting the request to a different URL. The Network Access API does not by default follow redirections: the application can determine if the requested redirection should be allowed, according to its security policies, or it can set QNetworkRequest::FollowRedirectsAttribute to true (in which case the redirection will be followed and this attribute will not be present in the reply). The returned URL might be relative. Use QUrl::resolved() to create an absolute URL out of it. |
QNetworkRequest::ConnectionEncryptedAttribute | 3 | Replies only, type: QMetaType::Bool (default: false) Indicates whether the data was obtained through an encrypted (secure) connection. |
QNetworkRequest::CacheLoadControlAttribute | 4 | Requests only, type: QMetaType::Int (default: QNetworkRequest::PreferNetwork) Controls how the cache should be accessed. The possible values are those of QNetworkRequest::CacheLoadControl. Note that the default QNetworkAccessManager implementation does not support caching. However, this attribute may be used by certain backends to modify their requests (for example, for caching proxies). |
QNetworkRequest::CacheSaveControlAttribute | 5 | Requests only, type: QMetaType::Bool (default: true) Controls if the data obtained should be saved to cache for future uses. If the value is false, the data obtained will not be automatically cached. If true, data may be cached, provided it is cacheable (what is cacheable depends on the protocol being used). |
QNetworkRequest::SourceIsFromCacheAttribute | 6 | Replies only, type: QMetaType::Bool (default: false) Indicates whether the data was obtained from cache or not. |
QNetworkRequest::DoNotBufferUploadDataAttribute | 7 | Requests only, type: QMetaType::Bool (default: false) Indicates whether the QNetworkAccessManager code is allowed to buffer the upload data, e.g. when doing a HTTP POST. When using this flag with sequential upload data, the ContentLengthHeader header must be set. |
QNetworkRequest::HttpPipeliningAllowedAttribute | 8 | Requests only, type: QMetaType::Bool (default: false) Indicates whether the QNetworkAccessManager code is allowed to use HTTP pipelining with this request. |
QNetworkRequest::HttpPipeliningWasUsedAttribute | 9 | Replies only, type: QMetaType::Bool Indicates whether the HTTP pipelining was used for receiving this reply. |
QNetworkRequest::CustomVerbAttribute | 10 | Requests only, type: QMetaType::QByteArray Holds the value for the custom HTTP verb to send (destined for usage of other verbs than GET, POST, PUT and DELETE). This verb is set when calling QNetworkAccessManager::sendCustomRequest(). |
QNetworkRequest::CookieLoadControlAttribute | 11 | Requests only, type: QMetaType::Int (default: QNetworkRequest::Automatic) Indicates whether to send 'Cookie' headers in the request. This attribute is set to false by Qt WebKit when creating a cross-origin XMLHttpRequest where withCredentials has not been set explicitly to true by the Javascript that created the request. See here for more information. (This value was introduced in 4.7.) |
QNetworkRequest::CookieSaveControlAttribute | 13 | Requests only, type: QMetaType::Int (default: QNetworkRequest::Automatic) Indicates whether to save 'Cookie' headers received from the server in reply to the request. This attribute is set to false by Qt WebKit when creating a cross-origin XMLHttpRequest where withCredentials has not been set explicitly to true by the Javascript that created the request. See here for more information. (This value was introduced in 4.7.) |
QNetworkRequest::AuthenticationReuseAttribute | 12 | Requests only, type: QMetaType::Int (default: QNetworkRequest::Automatic) Indicates whether to use cached authorization credentials in the request, if available. If this is set to QNetworkRequest::Manual and the authentication mechanism is 'Basic' or 'Digest', Qt will not send an an 'Authorization' HTTP header with any cached credentials it may have for the request's URL. This attribute is set to QNetworkRequest::Manual by Qt WebKit when creating a cross-origin XMLHttpRequest where withCredentials has not been set explicitly to true by the Javascript that created the request. See here for more information. (This value was introduced in 4.7.) |
QNetworkRequest::BackgroundRequestAttribute | 17 | Type: QMetaType::Bool (default: false) Indicates that this is a background transfer, rather than a user initiated transfer. Depending on the platform, background transfers may be subject to different policies. The QNetworkSession ConnectInBackground property will be set according to this attribute. |
QNetworkRequest::SpdyAllowedAttribute | 18 | Requests only, type: QMetaType::Bool (default: false) Indicates whether the QNetworkAccessManager code is allowed to use SPDY with this request. This applies only to SSL requests, and depends on the server supporting SPDY. Obsolete, use Http2 instead of Spdy. |
QNetworkRequest::SpdyWasUsedAttribute | 19 | Replies only, type: QMetaType::Bool Indicates whether SPDY was used for receiving this reply. Obsolete, use Http2 instead of Spdy. |
QNetworkRequest::Http2AllowedAttribute | 22 | Requests only, type: QMetaType::Bool (default: false) Indicates whether the QNetworkAccessManager code is allowed to use HTTP/2 with this request. This applies to SSL requests or 'cleartext' HTTP/2. |
QNetworkRequest::Http2WasUsedAttribute | 23 | Replies only, type: QMetaType::Bool (default: false) Indicates whether HTTP/2 was used for receiving this reply. (This value was introduced in 5.9.) |
QNetworkRequest::HTTP2AllowedAttribute | Http2AllowedAttribute | Obsolete alias for Http2AllowedAttribute. |
QNetworkRequest::HTTP2WasUsedAttribute | 23 | Obsolete alias for Http2WasUsedAttribute. |
QNetworkRequest::EmitAllUploadProgressSignalsAttribute | BackgroundRequestAttribute + 3 | Requests only, type: QMetaType::Bool (default: false) Indicates whether all upload signals should be emitted. By default, the uploadProgress signal is emitted only in 100 millisecond intervals. (This value was introduced in 5.5.) |
QNetworkRequest::FollowRedirectsAttribute | 21 | Requests only, type: QMetaType::Bool (default: false) Indicates whether the Network Access API should automatically follow a HTTP redirect response or not. Currently redirects that are insecure, that is redirecting from "https" to "http" protocol, are not allowed. (This value was introduced in 5.6.) |
QNetworkRequest::OriginalContentLengthAttribute | 24 | Replies only, type QMetaType::Int Holds the original content-length attribute before being invalidated and removed from the header when the data is compressed and the request was marked to be decompressed automatically. (This value was introduced in 5.9.) |
QNetworkRequest::RedirectPolicyAttribute | 25 | Requests only, type: QMetaType::Int, should be one of the QNetworkRequest::RedirectPolicy values (default: ManualRedirectPolicy). This attribute obsoletes FollowRedirectsAttribute. (This value was introduced in 5.9.) |
QNetworkRequest::Http2DirectAttribute | 26 | Requests only, type: QMetaType::Bool (default: false) If set, this attribute will force QNetworkAccessManager to use HTTP/2 protocol without initial HTTP/2 protocol negotiation. Use of this attribute implies prior knowledge that a particular server supports HTTP/2. The attribute works with SSL or 'cleartext' HTTP/2. If a server turns out to not support HTTP/2, when HTTP/2 direct was specified, QNetworkAccessManager gives up, without attempting to fall back to HTTP/1.1. If both Http2AllowedAttribute and Http2DirectAttribute are set, Http2DirectAttribute takes priority. (This value was introduced in 5.11.) |
QNetworkRequest::AutoDeleteReplyOnFinishAttribute | 28 | Requests only, type: QMetaType::Bool (default: false) If set, this attribute will make QNetworkAccessManager delete the QNetworkReply after having emitted "finished". (This value was introduced in 5.14.) |
QNetworkRequest::User | 1000 | Special type. Additional information can be passed in QVariants with types ranging from User to UserMax. The default implementation of Network Access will ignore any request attributes in this range and it will not produce any attributes in this range in replies. The range is reserved for extensions of QNetworkAccessManager. |
QNetworkRequest::UserMax | 32767 | Special type. See User. |
This enum was introduced or modified in Qt 4.7.
enum QNetworkRequest::CacheLoadControl
Controls the caching mechanism of QNetworkAccessManager.
| Constant | Value | Description |
|---|---|---|
QNetworkRequest::AlwaysNetwork | 0 | always load from network and do not check if the cache has a valid entry (similar to the "Reload" feature in browsers); in addition, force intermediate caches to re-validate. |
QNetworkRequest::PreferNetwork | 1 | default value; load from the network if the cached entry is older than the network entry. This will never return stale data from the cache, but revalidate resources that have become stale. |
QNetworkRequest::PreferCache | 2 | load from cache if available, otherwise load from network. Note that this can return possibly stale (but not expired) items from cache. |
QNetworkRequest::AlwaysCache | 3 | only load from cache, indicating error if the item was not cached (i.e., off-line mode) |
enum QNetworkRequest::KnownHeaders
List of known header types that QNetworkRequest parses. Each known header is also represented in raw form with its full HTTP name.
| Constant | Value | Description |
|---|---|---|
QNetworkRequest::ContentDispositionHeader | 6 | Corresponds to the HTTP Content-Disposition header and contains a string containing the disposition type (for instance, attachment) and a parameter (for instance, filename). |
QNetworkRequest::ContentTypeHeader | 0 | Corresponds to the HTTP Content-Type header and contains a string containing the media (MIME) type and any auxiliary data (for instance, charset). |
QNetworkRequest::ContentLengthHeader | 1 | Corresponds to the HTTP Content-Length header and contains the length in bytes of the data transmitted. |
QNetworkRequest::LocationHeader | 2 | Corresponds to the HTTP Location header and contains a URL representing the actual location of the data, including the destination URL in case of redirections. |
QNetworkRequest::LastModifiedHeader | 3 | Corresponds to the HTTP Last-Modified header and contains a QDateTime representing the last modification date of the contents. |
QNetworkRequest::IfModifiedSinceHeader | 9 | Corresponds to the HTTP If-Modified-Since header and contains a QDateTime. It is usually added to a QNetworkRequest. The server shall send a 304 (Not Modified) response if the resource has not changed since this time. |
QNetworkRequest::ETagHeader | 10 | Corresponds to the HTTP ETag header and contains a QString representing the last modification state of the contents. |
QNetworkRequest::IfMatchHeader | 11 | Corresponds to the HTTP If-Match header and contains a QStringList. It is usually added to a QNetworkRequest. The server shall send a 412 (Precondition Failed) response if the resource does not match. |
QNetworkRequest::IfNoneMatchHeader | 12 | Corresponds to the HTTP If-None-Match header and contains a QStringList. It is usually added to a QNetworkRequest. The server shall send a 304 (Not Modified) response if the resource does match. |
QNetworkRequest::CookieHeader | 4 | Corresponds to the HTTP Cookie header and contains a QList<QNetworkCookie> representing the cookies to be sent back to the server. |
QNetworkRequest::SetCookieHeader | 5 | Corresponds to the HTTP Set-Cookie header and contains a QList<QNetworkCookie> representing the cookies sent by the server to be stored locally. |
QNetworkRequest::UserAgentHeader | 7 | The User-Agent header sent by HTTP clients. |
QNetworkRequest::ServerHeader | 8 | The Server header received by HTTP clients. |
See also header(), setHeader(), rawHeader(), and setRawHeader().
enum QNetworkRequest::LoadControl
Indicates if an aspect of the request's loading mechanism has been manually overridden, e.g. by Qt WebKit.
| Constant | Value | Description |
|---|---|---|
QNetworkRequest::Automatic | 0 | default value: indicates default behaviour. |
QNetworkRequest::Manual | 1 | indicates behaviour has been manually overridden. |
This enum was introduced or modified in Qt 4.7.
enum QNetworkRequest::Priority
This enum lists the possible network request priorities.
| Constant | Value | Description |
|---|---|---|
QNetworkRequest::HighPriority | 1 | High priority |
QNetworkRequest::NormalPriority | 3 | Normal priority |
QNetworkRequest::LowPriority | 5 | Low priority |
This enum was introduced or modified in Qt 4.7.
enum QNetworkRequest::RedirectPolicy
Indicates whether the Network Access API should automatically follow a HTTP redirect response or not.
| Constant | Value | Description |
|---|---|---|
QNetworkRequest::ManualRedirectPolicy | 0 | Default value: not following any redirects. |
QNetworkRequest::NoLessSafeRedirectPolicy | 1 | Only "http"->"http", "http" -> "https" or "https" -> "https" redirects are allowed. Equivalent to setting the old FollowRedirectsAttribute to true |
QNetworkRequest::SameOriginRedirectPolicy | 2 | Require the same protocol, host and port. Note, http://example.com and http://example.com:80 will fail with this policy (implicit/explicit ports are considered to be a mismatch). |
QNetworkRequest::UserVerifiedRedirectPolicy | 3 | Client decides whether to follow each redirect by handling the redirected() signal, emitting redirectAllowed() on the QNetworkReply object to allow the redirect or aborting/finishing it to reject the redirect. This can be used, for example, to ask the user whether to accept the redirect, or to decide based on some app-specific configuration. |
Note: When Qt handles redirects it will, for legacy and compatibility reasons, issue the redirected request using GET when the server returns a 301 or 302 response, regardless of the original method used, unless it was HEAD.
This enum was introduced or modified in Qt 5.9.
enum QNetworkRequest::TransferTimeoutConstant
A constant that can be used for enabling transfer timeouts with a preset value.
| Constant | Value | Description |
|---|---|---|
QNetworkRequest::DefaultTransferTimeoutConstant | 30000 | The transfer timeout in milliseconds. Used if setTimeout() is called without an argument. |
This enum was introduced or modified in Qt 5.15.