1 // This may look like C code, but it's really -*- C++ -*- 2 /* 3 * Copyright (C) 2009 Emweb bv, Herent, Belgium. 4 * 5 * See the LICENSE file for terms of use. 6 */ 7 #ifndef HTTP_RESPONSE_H_ 8 #define HTTP_RESPONSE_H_ 9 10 #include <string> 11 #include <Wt/WGlobal.h> 12 #include <Wt/Http/ResponseContinuation.h> 13 #include <ostream> 14 15 namespace Wt { 16 17 class WResource; 18 class WebSession; 19 20 namespace Http { 21 22 /*! \class Response Wt/Http/Response.h Wt/Http/Response.h 23 * \brief A resource response. 24 * 25 * This class defines the HTTP response for a WResource request. 26 * 27 * More specifically you can: 28 * - set the content mime type using setMimeType() 29 * - add HTTP headers using addHeader() 30 * - stream content into out() 31 * 32 * You may chose to provide only a partial response. In that case, use 33 * createContinuation() to create a continuation object to which you 34 * can annotate information for the next request to process the 35 * response further. 36 * 37 * \sa WResource::handleRequest(), Request 38 * 39 * \ingroup http 40 */ 41 class WT_API Response 42 { 43 public: 44 /*! \brief Sets the response status. 45 * 46 * Unless a overriden, 200 OK will be assumed. 47 */ 48 void setStatus(int status); 49 50 /*! \brief Sets the content length 51 * 52 * If content length is known, use this method to set it. File downloads 53 * will see progress bars. If not set, Wt will use chunked transfers. 54 * 55 * Always use this method instead of setting the Content-Length header 56 * with addHeader(). 57 * 58 * Headers may be added only before setting the content mime-type 59 * (setMimeType()), and before streaming any data to the out() 60 * stream. 61 */ 62 void setContentLength(::uint64_t length); 63 64 /*! \brief Set the content mime type. 65 * 66 * The content mimetype is used by the browser to correctly interpret 67 * the resource. 68 */ 69 void setMimeType(const std::string& mimeType); 70 71 /*! \brief Add an HTTP header. 72 * 73 * Headers may be added only before setting the content mime-type 74 * (setMimeType()), and before streaming any data to the out() 75 * stream. 76 */ 77 void addHeader(const std::string& name, const std::string& value); 78 79 /*! \brief Create a continuation object for this response. 80 * 81 * A continuation is used to resume sending more data later for this 82 * response. There are two possible reasons for this: 83 * - the entire response is quite big and you may want to read and send 84 * it in smaller chunks to avoid memory consumption problems since the 85 * I/O layer buffers the response first in memory to send it then out 86 * to a possibly slow client using async I/O. 87 * - you may not have any more data available, currently, but expect more 88 * data later. In that case you can call 89 * ResponseContinuation::waitForMoreData() and later call 90 * WResource::haveMoreData() when more data is available. 91 * 92 * A new call to handleRequest() will be made to retrieve more 93 * data. 94 * 95 * \sa continuation() 96 */ 97 ResponseContinuation *createContinuation(); 98 99 /*! \brief Return the continuation, if one was created for this response. 100 * 101 * Returns the continuation that was previously created using 102 * createContinuation(), or \c nullptr if no continuation was created yet. 103 * 104 * \sa createContinuation() 105 */ 106 ResponseContinuation *continuation() const; 107 108 /*! \brief Returns the stream for getting the response output. 109 */ 110 std::ostream& out(); 111 bout()112 WT_BOSTREAM& bout() { return out(); } 113 114 private: 115 WResource *resource_; 116 WebResponse *response_; 117 ResponseContinuationPtr continuation_; 118 WT_BOSTREAM *out_; 119 bool headersCommitted_; 120 121 Response(WResource *resource, WebResponse *response, 122 ResponseContinuationPtr continuation); 123 Response(WResource *resource, WT_BOSTREAM& out); 124 125 friend class Wt::WResource; 126 friend class Wt::WebSession; 127 }; 128 129 } 130 } 131 132 #endif // HTTP_RESPONSE_H_ 133