src/httpserver.h

   1 // Copyright (c) 2015-2016 The Bitcoin Core developers
   2 // Distributed under the MIT software license, see the accompanying
   3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   4
   5 #ifndef BITCOIN_HTTPSERVER_H
   6 #define BITCOIN_HTTPSERVER_H
   7
   8 #include <string>
   9 #include <stdint.h>
  10 #include <functional>
  11
  12 static const int DEFAULT_HTTP_THREADS=4;
  13 static const int DEFAULT_HTTP_WORKQUEUE=16;
  14 static const int DEFAULT_HTTP_SERVER_TIMEOUT=30;
  15
  16 struct evhttp_request;
  17 struct event_base;
  18 class CService;
  19 class HTTPRequest;
  20
  21 /** Initialize HTTP server.
  22  * Call this before RegisterHTTPHandler or EventBase().
  23  */
  24 bool InitHTTPServer();
  25 /** Start HTTP server.
  26  * This is separate from InitHTTPServer to give users race-condition-free time
  27  * to register their handlers between InitHTTPServer and StartHTTPServer.
  28  */
  29 bool StartHTTPServer();
  30 /** Interrupt HTTP server threads */
  31 void InterruptHTTPServer();
  32 /** Stop HTTP server */
  33 void StopHTTPServer();
  34
  35 /** Handler for requests to a certain HTTP path */
  36 typedef std::function<bool(HTTPRequest* req, const std::string &)> HTTPRequestHandler;
  37 /** Register handler for prefix.
  38  * If multiple handlers match a prefix, the first-registered one will
  39  * be invoked.
  40  */
  41 void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler);
  42 /** Unregister handler for prefix */
  43 void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch);
  44
  45 /** Return evhttp event base. This can be used by submodules to
  46  * queue timers or custom events.
  47  */
  48 struct event_base* EventBase();
  49
  50 /** In-flight HTTP request.
  51  * Thin C++ wrapper around evhttp_request.
  52  */
  53 class HTTPRequest
  54 {
  55 private:
  56     struct evhttp_request* req;
  57     bool replySent;
  58
  59 public:
  60     HTTPRequest(struct evhttp_request* req);
  61     ~HTTPRequest();
  62
  63     enum RequestMethod {
  64         UNKNOWN,
  65         GET,
  66         POST,
  67         HEAD,
  68         PUT
  69     };
  70
  71     /** Get requested URI.
  72      */
  73     std::string GetURI();
  74
  75     /** Get CService (address:ip) for the origin of the http request.
  76      */
  77     CService GetPeer();
  78
  79     /** Get request method.
  80      */
  81     RequestMethod GetRequestMethod();
  82
  83     /**
  84      * Get the request header specified by hdr, or an empty string.
  85      * Return an pair (isPresent,string).
  86      */
  87     std::pair<bool, std::string> GetHeader(const std::string& hdr);
  88
  89     /**
  90      * Read request body.
  91      *
  92      * @note As this consumes the underlying buffer, call this only once.
  93      * Repeated calls will return an empty string.
  94      */
  95     std::string ReadBody();
  96
  97     /**
  98      * Write output header.
  99      *
 100      * @note call this before calling WriteErrorReply or Reply.
 101      */
 102     void WriteHeader(const std::string& hdr, const std::string& value);
 103
 104     /**
 105      * Write HTTP reply.
 106      * nStatus is the HTTP status code to send.
 107      * strReply is the body of the reply. Keep it empty to send a standard message.
 108      *
 109      * @note Can be called only once. As this will give the request back to the
 110      * main thread, do not call any other HTTPRequest methods after calling this.
 111      */
 112     void WriteReply(int nStatus, const std::string& strReply = "");
 113 };
 114
 115 /** Event handler closure.
 116  */
 117 class HTTPClosure
 118 {
 119 public:
 120     virtual void operator()() = 0;
 121     virtual ~HTTPClosure() {}
 122 };
 123
 124 /** Event class. This can be used either as an cross-thread trigger or as a timer.
 125  */
 126 class HTTPEvent
 127 {
 128 public:
 129     /** Create a new event.
 130      * deleteWhenTriggered deletes this event object after the event is triggered (and the handler called)
 131      * handler is the handler to call when the event is triggered.
 132      */
 133     HTTPEvent(struct event_base* base, bool deleteWhenTriggered, const std::function<void(void)>& handler);
 134     ~HTTPEvent();
 135
 136     /** Trigger the event. If tv is 0, trigger it immediately. Otherwise trigger it after
 137      * the given time has elapsed.
 138      */
 139     void trigger(struct timeval* tv);
 140
 141     bool deleteWhenTriggered;
 142     std::function<void(void)> handler;
 143 private:
 144     struct event* ev;
 145 };
 146
 147 #endif // BITCOIN_HTTPSERVER_H