///////////////////////////////////////////////////////////////////////////// // Name: webrequest.h // Created: 2018-10-14 // Copyright: (c) 2018 wxWidgets development team // Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// /** @class wxWebRequest This class allows for simple HTTP requests using the operating systems components as implementation. The latest features of the operating system will be used if available (e.g. HTTP/2, TLS 1.3). System-wide configuration like proxy and SSL certificates will be used when possible. Instances of wxWebRequest are created by using wxWebSession::CreateRequest(). The requests are handled asynchronously and event handlers are used to communicate the request status. The response data may be stored in memory, to a file or processed directly, see SetStorage() for details. Example usage: @code // Create the request object wxObjectDataPtr request( wxWebSession::GetDefault().CreateRequest("https://www.wxwidgets.org/downloads/logos/blocks.png")); // Bind state event request->Bind(wxEVT_WEBREQUEST_STATE, [](wxWebRequestEvent& evt) { switch (evt.GetState()) { // Request completed case wxWebRequest::State_Completed: { wxImage logoImage(*evt->GetResponse()->GetStream()); if (logoImage.IsOK()) wxLogInfo("Image loaded"); break; } // Request failed case wxWebRequest::State_Failed: wxLogError("Could not load logo: %s", evt.GetErrorDescription()); break; } }); // Start the request request->Start(); @endcode @section descriptions Implementation Descriptions The following APIs are used per platform, additional documentation about supported features may be found in their documentation Available features by implementation and minimum version:
Operating SystemAPIHTTPSHTTP/2
Windows WinHTTP Yes Windows 10 1607
macOS NSURLSession macOS 10.9 macOS 10.11
iOS NSURLSession iOS 7.0 iOS 9.0
Linux libcurl Yes 7.47.0
@beginEventEmissionTable{wxWebRequestEvent} @event{wxEVT_WEBREQUEST_STATE(id, func)} The request state changed. @event{wxEVT_WEBREQUEST_DATA(id, func)} A new block of data has been downloaded. @endEventTable @since 3.1.2 @library{wxnet} @category{net} @see wxWebResponse, wxWebSession */ class wxWebRequest: public wxEvtHandler, public wxRefCounter { public: /** Possible request states returned by GetState(). */ enum State { /// The request has just been created and Start() has not been called State_Idle, /// The request has been started and is transferring data State_Active, /** The request is currently unauthorized. Calling GetAuthChallenge() returns a challenge object with further details. */ State_Unauthorized, /// The request completed successfully and all data has been received. State_Completed, /// The request failed State_Failed, /// The request has been cancelled before completion by calling Cancel() State_Cancelled }; /** Possible storage types. Set by SetStorage(). */ enum Storage { /// All data is collected in memory until the request is complete Storage_Memory, /// The data is written to a file on disk Storage_File, /** The data is not stored by the request and is only available via events. */ Storage_None }; /** Send the request to the server asynchronously. Events will be triggered on success or failure. @see Cancel() */ void Start(); /** Cancel an active request. */ void Cancel(); /** Returns a response object after a successful request. Before sending a request or after a failed request this will return @c NULL. */ wxWebResponse* GetResponse(); /** Returns the current authentication challenge object while the request is in @c State_Unauthorized. */ wxWebAuthChallenge* GetAuthChallenge(); /** Returns the id specified while creating this request. */ int GetId() const; /** @name Request options Methods that set options before starting the request */ ///@{ /** Sets a request header which will be sent to the server by this request. The header will be added if it hasn't been set before or replaced otherwise. @param name Name of the header @param value String value of the header. An empty string will remove the header. */ void SetHeader(const wxString& name, const wxString& value); /** Set common or expanded HTTP method. The default method is GET unless request data is provided in which case POST is the default. @param method HTTP method name, e.g. "GET". */ void SetMethod(const wxString& method); /** Set the text to be posted to the server. After a successful call to this method, the request will use HTTP @c POST instead of the default @c GET when it's executed. @param text The text data to post. @param contentType The value of HTTP "Content-Type" header, e.g. "text/html; charset=UTF-8". @param conv Conversion used when sending the text to the server */ void SetData(const wxString& text, const wxString& contentType, const wxMBConv& conv = wxConvUTF8); /** Set the binary data to be posted to the server. The next request will be a HTTP @c POST instead of the default HTTP @c GET and the given @a dataStream will be posted as the body of this request. @param dataStream The data in this stream will be posted as the request body @param contentType The value of HTTP "Content-Type" header, e.g. "application/octet-stream". @param dataSize Amount of data which is sent to the server. If set to @c wxInvalidOffset all stream data is sent. */ void SetData(wxSharedPtr dataStream, const wxString& contentType, wxFileOffset dataSize = wxInvalidOffset); /** Instructs the request to ignore server error status codes. Per default, server side errors (status code 400-599) will enter the State_Failed state just like network errors, but if the response is still required in such cases (e.g. to get more details from the response body), set this option to ignore all errors. If ignored, wxWebResponse::GetStatus() has to be checked from the State_Completed event handler. */ void SetIgnoreServerErrorStatus(bool ignore); /** Sets how response data will be stored. The default storage method @c Storage_Memory collects all response data in memory until the request is completed. This is fine for most usage scenarios like API calls, loading images, etc. For larger downloads or if the response data will be used permanently @c Storage_File instructs the request to write the response to a temporary file. This temporary file may then be read or moved after the request is complete. The file will be downloaded to the system temp directory as returned by wxStandardPaths::GetTempDir(). To specify a different directory use wxWebSession::SetTempDir(). Sometimes response data needs to be processed while its downloaded from the server. For example if the response is in a format that can be parsed piece by piece like XML, JSON or an archive format like ZIP. In these cases storing the data in memory or a file before being able to process it might not be ideal and @c Storage_None should be set. With this storage method the data is only available during the @c wxEVT_WEBREQUEST_DATA event calls as soon as it's received from the server. */ void SetStorage(Storage storage); ///@} /** @name Progress methods Methods that describe the requests progress */ ///@{ /** Returns the current state of the request. */ State GetState() const { return m_state; } /// Returns the number of bytes sent to the server. wxFileOffset GetBytesSent() const; /// Returns the number of bytes expected to be send to the server. wxFileOffset GetBytesExpectedToSend() const; /// Returns the number of bytes received from the server. wxFileOffset GetBytesReceived() const; /** Returns the number of bytes expected to be received from the server. This value is based on the @c Content-Length header, if none is found it will return -1. */ wxFileOffset GetBytesExpectedToReceive() const; ///@} }; /** Authentication challenge information available via wxWebRequest::GetAuthChallenge(). Use SetCredentials() to provide user credentials. */ class wxWebAuthChallenge { public: enum Source { /// The server requested authentication Source_Server, /// A proxy requested authentication Source_Proxy }; /** Returns which source requested credentials with this challenge. */ Source GetSource() const { return m_source; } /** Used to provide user credentials to the authentication challenge. @param user User name. @param password The users password. */ void SetCredentials(const wxString& user, const wxString& password); }; /** A wxWebResponse allows access to the response sent by the server. @since 3.1.2 @library{wxnet} @category{net} @see wxWebRequest */ class wxWebResponse { public: /** Returns the final URL. This URL might be different than the request URL when a redirection occurred. */ wxString GetURL() const; /** Returns a header from the response or an empty string if the header could not be found. @param name Name of the header field */ wxString GetHeader(const wxString& name) const; /** Returns the MIME type of the response (if available). */ wxString GetMimeType() const; /** Returns the status code returned by the server. */ int GetStatus() const; /** Returns the status text of the response. */ wxString GetStatusText() const; /** Returns a stream which represents the response data sent by the server. */ wxInputStream* GetStream(); /** Returns a suggested filename for the response data. */ wxString GetSuggestedFileName() const; /** Returns all response data as a string. @param conv wxMBConv used to convert the response to a string. If @c NULL, the conversion will be determined by response headers. The default is UTF-8. */ wxString AsString(wxMBConv* conv = NULL) const; }; /** @class wxWebSession This class handles session-wide parameters and data used by wxWebRequest instances. Usually the default session available via wxWebSession::GetDefault() should be used. Additional instances might be useful if session separation is required. Instances must not be deleted before every active web request has finished. Every wxWebRequest sharing the same session object will use the same cookies. Additionally, an underlying network connection might be kept alive to achieve faster additional responses. @since 3.1.2 @library{wxnet} @category{net} @see wxWebRequest */ class wxWebSession { public: /** Constructor for the session All requests created by a call to CreateRequest() will use this session for communication and to store cookies. */ wxWebSession(); /** Create a new request for the specified URL @param url The URL of the HTTP resource for this request @param id Optional id sent with events */ wxWebRequest* CreateRequest(const wxString& url, int id = wxID_ANY); /** Sets a request header in every wxWebRequest created from this session after is has been set. A good example for a session-wide request header is the @c User-Agent header. @param name Name of the header @param value String value of the header */ void SetHeader(const wxString& name, const wxString& value); /** Override the default temporary directory that may be used by the session implemention, when required. */ void SetTempDir(const wxString& name); /** Returns the current temporary directory. @see SetTempDir() */ const wxString& GetTempDir() const; /** Returns the default session */ static wxWebSession& GetDefault(); /** Creates a new wxWebSession object. @param backend The backend web session implementation to use. @return The created wxWebSession */ static wxWebSession* New(const wxString& backend = wxWebSessionBackendDefault); /** Allows the registering of new backend for wxWebSession. backend can be used as an argument to New(). @param backend The name for the new backend to be registered under @param factory A shared pointer to the factory which creates the appropriate backend. */ static void RegisterFactory(const wxString& backend, wxSharedPtr factory); /** Allows to check if the specified backend is available at runtime. Usually the default backend should always be available, but e.g. macOS before 10.9 does not have the @c NSURLSession implementation available. */ static bool IsBackendAvailable(const wxString& backend); }; /** @class wxWebSessionFactory An abstract factory class for creation wxWebSession backends. Each implementation of wxWebSession should have its own factory. @since 3.1.2 @library{wxnet} @category{net} @see wxWebSession */ class wxWebSessionFactory { public: /** Creates a new web session object */ virtual wxWebSession* Create() = 0; }; /** @class wxWebRequestEvent A web request event sent during or after server communication. @since 3.1.2 @library{wxnet} @category{net} @see wxWebRequest */ class wxWebRequestEvent : public wxEvent { public: wxWebRequestEvent(); wxWebRequestEvent(wxEventType type, int id, wxWebRequest::State state, wxWebResponse* response = NULL, const wxString& errorDesc = ""); /** Return the current state of the request */ wxWebRequest::State GetState() const; /** The response with the state set to @c State_Complete or @c NULL for other events. */ wxWebResponse* GetResponse() const; /** A textual error description for a client side error in case of @c State_Failed */ const wxString& GetErrorDescription() const; /** Returns a file name to a temporary file containing the response data when the state is @c State_Completed and storage is @Storage_File. The file will be removed after the event handlers are called. You can move the file to location of your choice if you want to process the contents outside of the event handler. */ const wxString& GetResponseFileName() const; void SetResponseFileName(const wxString& filename); /** Only for @c wxEVT_WEBREQUEST_DATA events. The buffer is only valid in the event handler. */ ///@{ const void* GetDataBuffer() const; size_t GetDataSize() const; ///@} void SetDataBuffer(const void* buffer, size_t size); }; wxEventType wxEVT_WEBREQUEST_STATE; wxEventType wxEVT_WEBREQUEST_DATA;