src/httpserver.cpp

   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 #include "httpserver.h"
   6
   7 #include "chainparamsbase.h"
   8 #include "compat.h"
   9 #include "util.h"
  10 #include "netbase.h"
  11 #include "rpc/protocol.h" // For HTTP status codes
  12 #include "sync.h"
  13 #include "ui_interface.h"
  14
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21 #include <signal.h>
  22 #include <future>
  23
  24 #include <event2/event.h>
  25 #include <event2/http.h>
  26 #include <event2/thread.h>
  27 #include <event2/buffer.h>
  28 #include <event2/util.h>
  29 #include <event2/keyvalq_struct.h>
  30
  31 #ifdef EVENT__HAVE_NETINET_IN_H
  32 #include <netinet/in.h>
  33 #ifdef _XOPEN_SOURCE_EXTENDED
  34 #include <arpa/inet.h>
  35 #endif
  36 #endif
  37
  38 /** Maximum size of http request (request line + headers) */
  39 static const size_t MAX_HEADERS_SIZE = 8192;
  40
  41 /** HTTP request work item */
  42 class HTTPWorkItem : public HTTPClosure
  43 {
  44 public:
  45     HTTPWorkItem(std::unique_ptr<HTTPRequest> _req, const std::string &_path, const HTTPRequestHandler& _func):
  46         req(std::move(_req)), path(_path), func(_func)
  47     {
  48     }
  49     void operator()()
  50     {
  51         func(req.get(), path);
  52     }
  53
  54     std::unique_ptr<HTTPRequest> req;
  55
  56 private:
  57     std::string path;
  58     HTTPRequestHandler func;
  59 };
  60
  61 /** Simple work queue for distributing work over multiple threads.
  62  * Work items are simply callable objects.
  63  */
  64 template <typename WorkItem>
  65 class WorkQueue
  66 {
  67 private:
  68     /** Mutex protects entire object */
  69     std::mutex cs;
  70     std::condition_variable cond;
  71     std::deque<std::unique_ptr<WorkItem>> queue;
  72     bool running;
  73     size_t maxDepth;
  74     int numThreads;
  75
  76     /** RAII object to keep track of number of running worker threads */
  77     class ThreadCounter
  78     {
  79     public:
  80         WorkQueue &wq;
  81         ThreadCounter(WorkQueue &w): wq(w)
  82         {
  83             std::lock_guard<std::mutex> lock(wq.cs);
  84             wq.numThreads += 1;
  85         }
  86         ~ThreadCounter()
  87         {
  88             std::lock_guard<std::mutex> lock(wq.cs);
  89             wq.numThreads -= 1;
  90             wq.cond.notify_all();
  91         }
  92     };
  93
  94 public:
  95     WorkQueue(size_t _maxDepth) : running(true),
  96                                  maxDepth(_maxDepth),
  97                                  numThreads(0)
  98     {
  99     }
 100     /** Precondition: worker threads have all stopped
 101      * (call WaitExit)
 102      */
 103     ~WorkQueue()
 104     {
 105     }
 106     /** Enqueue a work item */
 107     bool Enqueue(WorkItem* item)
 108     {
 109         std::unique_lock<std::mutex> lock(cs);
 110         if (queue.size() >= maxDepth) {
 111             return false;
 112         }
 113         queue.emplace_back(std::unique_ptr<WorkItem>(item));
 114         cond.notify_one();
 115         return true;
 116     }
 117     /** Thread function */
 118     void Run()
 119     {
 120         ThreadCounter count(*this);
 121         while (true) {
 122             std::unique_ptr<WorkItem> i;
 123             {
 124                 std::unique_lock<std::mutex> lock(cs);
 125                 while (running && queue.empty())
 126                     cond.wait(lock);
 127                 if (!running)
 128                     break;
 129                 i = std::move(queue.front());
 130                 queue.pop_front();
 131             }
 132             (*i)();
 133         }
 134     }
 135     /** Interrupt and exit loops */
 136     void Interrupt()
 137     {
 138         std::unique_lock<std::mutex> lock(cs);
 139         running = false;
 140         cond.notify_all();
 141     }
 142     /** Wait for worker threads to exit */
 143     void WaitExit()
 144     {
 145         std::unique_lock<std::mutex> lock(cs);
 146         while (numThreads > 0)
 147             cond.wait(lock);
 148     }
 149 };
 150
 151 struct HTTPPathHandler
 152 {
 153     HTTPPathHandler() {}
 154     HTTPPathHandler(std::string _prefix, bool _exactMatch, HTTPRequestHandler _handler):
 155         prefix(_prefix), exactMatch(_exactMatch), handler(_handler)
 156     {
 157     }
 158     std::string prefix;
 159     bool exactMatch;
 160     HTTPRequestHandler handler;
 161 };
 162
 163 /** HTTP module state */
 164
 165 //! libevent event loop
 166 static struct event_base* eventBase = 0;
 167 //! HTTP server
 168 struct evhttp* eventHTTP = 0;
 169 //! List of subnets to allow RPC connections from
 170 static std::vector<CSubNet> rpc_allow_subnets;
 171 //! Work queue for handling longer requests off the event loop thread
 172 static WorkQueue<HTTPClosure>* workQueue = 0;
 173 //! Handlers for (sub)paths
 174 std::vector<HTTPPathHandler> pathHandlers;
 175 //! Bound listening sockets
 176 std::vector<evhttp_bound_socket *> boundSockets;
 177
 178 /** Check if a network address is allowed to access the HTTP server */
 179 static bool ClientAllowed(const CNetAddr& netaddr)
 180 {
 181     if (!netaddr.IsValid())
 182         return false;
 183     for(const CSubNet& subnet : rpc_allow_subnets)
 184         if (subnet.Match(netaddr))
 185             return true;
 186     return false;
 187 }
 188
 189 /** Initialize ACL list for HTTP server */
 190 static bool InitHTTPAllowList()
 191 {
 192     rpc_allow_subnets.clear();
 193     CNetAddr localv4;
 194     CNetAddr localv6;
 195     LookupHost("127.0.0.1", localv4, false);
 196     LookupHost("::1", localv6, false);
 197     rpc_allow_subnets.push_back(CSubNet(localv4, 8));      // always allow IPv4 local subnet
 198     rpc_allow_subnets.push_back(CSubNet(localv6));         // always allow IPv6 localhost
 199     if (mapMultiArgs.count("-rpcallowip")) {
 200         const std::vector<std::string>& vAllow = mapMultiArgs.at("-rpcallowip");
 201         for (std::string strAllow : vAllow) {
 202             CSubNet subnet;
 203             LookupSubNet(strAllow.c_str(), subnet);
 204             if (!subnet.IsValid()) {
 205                 uiInterface.ThreadSafeMessageBox(
 206                     strprintf("Invalid -rpcallowip subnet specification: %s. Valid are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. 1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24).", strAllow),
 207                     "", CClientUIInterface::MSG_ERROR);
 208                 return false;
 209             }
 210             rpc_allow_subnets.push_back(subnet);
 211         }
 212     }
 213     std::string strAllowed;
 214     for (const CSubNet& subnet : rpc_allow_subnets)
 215         strAllowed += subnet.ToString() + " ";
 216     LogPrint("http", "Allowing HTTP connections from: %s\n", strAllowed);
 217     return true;
 218 }
 219
 220 /** HTTP request method as string - use for logging only */
 221 static std::string RequestMethodString(HTTPRequest::RequestMethod m)
 222 {
 223     switch (m) {
 224     case HTTPRequest::GET:
 225         return "GET";
 226         break;
 227     case HTTPRequest::POST:
 228         return "POST";
 229         break;
 230     case HTTPRequest::HEAD:
 231         return "HEAD";
 232         break;
 233     case HTTPRequest::PUT:
 234         return "PUT";
 235         break;
 236     default:
 237         return "unknown";
 238     }
 239 }
 240
 241 /** HTTP request callback */
 242 static void http_request_cb(struct evhttp_request* req, void* arg)
 243 {
 244     std::unique_ptr<HTTPRequest> hreq(new HTTPRequest(req));
 245
 246     LogPrint("http", "Received a %s request for %s from %s\n",
 247              RequestMethodString(hreq->GetRequestMethod()), hreq->GetURI(), hreq->GetPeer().ToString());
 248
 249     // Early address-based allow check
 250     if (!ClientAllowed(hreq->GetPeer())) {
 251         hreq->WriteReply(HTTP_FORBIDDEN);
 252         return;
 253     }
 254
 255     // Early reject unknown HTTP methods
 256     if (hreq->GetRequestMethod() == HTTPRequest::UNKNOWN) {
 257         hreq->WriteReply(HTTP_BADMETHOD);
 258         return;
 259     }
 260
 261     // Find registered handler for prefix
 262     std::string strURI = hreq->GetURI();
 263     std::string path;
 264     std::vector<HTTPPathHandler>::const_iterator i = pathHandlers.begin();
 265     std::vector<HTTPPathHandler>::const_iterator iend = pathHandlers.end();
 266     for (; i != iend; ++i) {
 267         bool match = false;
 268         if (i->exactMatch)
 269             match = (strURI == i->prefix);
 270         else
 271             match = (strURI.substr(0, i->prefix.size()) == i->prefix);
 272         if (match) {
 273             path = strURI.substr(i->prefix.size());
 274             break;
 275         }
 276     }
 277
 278     // Dispatch to worker thread
 279     if (i != iend) {
 280         std::unique_ptr<HTTPWorkItem> item(new HTTPWorkItem(std::move(hreq), path, i->handler));
 281         assert(workQueue);
 282         if (workQueue->Enqueue(item.get()))
 283             item.release(); /* if true, queue took ownership */
 284         else {
 285             LogPrintf("WARNING: request rejected because http work queue depth exceeded, it can be increased with the -rpcworkqueue= setting\n");
 286             item->req->WriteReply(HTTP_INTERNAL, "Work queue depth exceeded");
 287         }
 288     } else {
 289         hreq->WriteReply(HTTP_NOTFOUND);
 290     }
 291 }
 292
 293 /** Callback to reject HTTP requests after shutdown. */
 294 static void http_reject_request_cb(struct evhttp_request* req, void*)
 295 {
 296     LogPrint("http", "Rejecting request while shutting down\n");
 297     evhttp_send_error(req, HTTP_SERVUNAVAIL, NULL);
 298 }
 299
 300 /** Event dispatcher thread */
 301 static bool ThreadHTTP(struct event_base* base, struct evhttp* http)
 302 {
 303     RenameThread("bitcoin-http");
 304     LogPrint("http", "Entering http event loop\n");
 305     event_base_dispatch(base);
 306     // Event loop will be interrupted by InterruptHTTPServer()
 307     LogPrint("http", "Exited http event loop\n");
 308     return event_base_got_break(base) == 0;
 309 }
 310
 311 /** Bind HTTP server to specified addresses */
 312 static bool HTTPBindAddresses(struct evhttp* http)
 313 {
 314     int defaultPort = GetArg("-rpcport", BaseParams().RPCPort());
 315     std::vector<std::pair<std::string, uint16_t> > endpoints;
 316
 317     // Determine what addresses to bind to
 318     if (!IsArgSet("-rpcallowip")) { // Default to loopback if not allowing external IPs
 319         endpoints.push_back(std::make_pair("::1", defaultPort));
 320         endpoints.push_back(std::make_pair("127.0.0.1", defaultPort));
 321         if (IsArgSet("-rpcbind")) {
 322             LogPrintf("WARNING: option -rpcbind was ignored because -rpcallowip was not specified, refusing to allow everyone to connect\n");
 323         }
 324     } else if (mapMultiArgs.count("-rpcbind")) { // Specific bind address
 325         const std::vector<std::string>& vbind = mapMultiArgs.at("-rpcbind");
 326         for (std::vector<std::string>::const_iterator i = vbind.begin(); i != vbind.end(); ++i) {
 327             int port = defaultPort;
 328             std::string host;
 329             SplitHostPort(*i, port, host);
 330             endpoints.push_back(std::make_pair(host, port));
 331         }
 332     } else { // No specific bind address specified, bind to any
 333         endpoints.push_back(std::make_pair("::", defaultPort));
 334         endpoints.push_back(std::make_pair("0.0.0.0", defaultPort));
 335     }
 336
 337     // Bind addresses
 338     for (std::vector<std::pair<std::string, uint16_t> >::iterator i = endpoints.begin(); i != endpoints.end(); ++i) {
 339         LogPrint("http", "Binding RPC on address %s port %i\n", i->first, i->second);
 340         evhttp_bound_socket *bind_handle = evhttp_bind_socket_with_handle(http, i->first.empty() ? NULL : i->first.c_str(), i->second);
 341         if (bind_handle) {
 342             boundSockets.push_back(bind_handle);
 343         } else {
 344             LogPrintf("Binding RPC on address %s port %i failed.\n", i->first, i->second);
 345         }
 346     }
 347     return !boundSockets.empty();
 348 }
 349
 350 /** Simple wrapper to set thread name and run work queue */
 351 static void HTTPWorkQueueRun(WorkQueue<HTTPClosure>* queue)
 352 {
 353     RenameThread("bitcoin-httpworker");
 354     queue->Run();
 355 }
 356
 357 /** libevent event log callback */
 358 static void libevent_log_cb(int severity, const char *msg)
 359 {
 360 #ifndef EVENT_LOG_WARN
 361 // EVENT_LOG_WARN was added in 2.0.19; but before then _EVENT_LOG_WARN existed.
 362 # define EVENT_LOG_WARN _EVENT_LOG_WARN
 363 #endif
 364     if (severity >= EVENT_LOG_WARN) // Log warn messages and higher without debug category
 365         LogPrintf("libevent: %s\n", msg);
 366     else
 367         LogPrint("libevent", "libevent: %s\n", msg);
 368 }
 369
 370 bool InitHTTPServer()
 371 {
 372     struct evhttp* http = 0;
 373     struct event_base* base = 0;
 374
 375     if (!InitHTTPAllowList())
 376         return false;
 377
 378     if (GetBoolArg("-rpcssl", false)) {
 379         uiInterface.ThreadSafeMessageBox(
 380             "SSL mode for RPC (-rpcssl) is no longer supported.",
 381             "", CClientUIInterface::MSG_ERROR);
 382         return false;
 383     }
 384
 385     // Redirect libevent's logging to our own log
 386     event_set_log_callback(&libevent_log_cb);
 387 #if LIBEVENT_VERSION_NUMBER >= 0x02010100
 388     // If -debug=libevent, set full libevent debugging.
 389     // Otherwise, disable all libevent debugging.
 390     if (LogAcceptCategory("libevent"))
 391         event_enable_debug_logging(EVENT_DBG_ALL);
 392     else
 393         event_enable_debug_logging(EVENT_DBG_NONE);
 394 #endif
 395 #ifdef WIN32
 396     evthread_use_windows_threads();
 397 #else
 398     evthread_use_pthreads();
 399 #endif
 400
 401     base = event_base_new(); // XXX RAII
 402     if (!base) {
 403         LogPrintf("Couldn't create an event_base: exiting\n");
 404         return false;
 405     }
 406
 407     /* Create a new evhttp object to handle requests. */
 408     http = evhttp_new(base); // XXX RAII
 409     if (!http) {
 410         LogPrintf("couldn't create evhttp. Exiting.\n");
 411         event_base_free(base);
 412         return false;
 413     }
 414
 415     evhttp_set_timeout(http, GetArg("-rpcservertimeout", DEFAULT_HTTP_SERVER_TIMEOUT));
 416     evhttp_set_max_headers_size(http, MAX_HEADERS_SIZE);
 417     evhttp_set_max_body_size(http, MAX_SIZE);
 418     evhttp_set_gencb(http, http_request_cb, NULL);
 419
 420     if (!HTTPBindAddresses(http)) {
 421         LogPrintf("Unable to bind any endpoint for RPC server\n");
 422         evhttp_free(http);
 423         event_base_free(base);
 424         return false;
 425     }
 426
 427     LogPrint("http", "Initialized HTTP server\n");
 428     int workQueueDepth = std::max((long)GetArg("-rpcworkqueue", DEFAULT_HTTP_WORKQUEUE), 1L);
 429     LogPrintf("HTTP: creating work queue of depth %d\n", workQueueDepth);
 430
 431     workQueue = new WorkQueue<HTTPClosure>(workQueueDepth);
 432     eventBase = base;
 433     eventHTTP = http;
 434     return true;
 435 }
 436
 437 std::thread threadHTTP;
 438 std::future<bool> threadResult;
 439
 440 bool StartHTTPServer()
 441 {
 442     LogPrint("http", "Starting HTTP server\n");
 443     int rpcThreads = std::max((long)GetArg("-rpcthreads", DEFAULT_HTTP_THREADS), 1L);
 444     LogPrintf("HTTP: starting %d worker threads\n", rpcThreads);
 445     std::packaged_task<bool(event_base*, evhttp*)> task(ThreadHTTP);
 446     threadResult = task.get_future();
 447     threadHTTP = std::thread(std::move(task), eventBase, eventHTTP);
 448
 449     for (int i = 0; i < rpcThreads; i++) {
 450         std::thread rpc_worker(HTTPWorkQueueRun, workQueue);
 451         rpc_worker.detach();
 452     }
 453     return true;
 454 }
 455
 456 void InterruptHTTPServer()
 457 {
 458     LogPrint("http", "Interrupting HTTP server\n");
 459     if (eventHTTP) {
 460         // Unlisten sockets
 461         for (evhttp_bound_socket *socket : boundSockets) {
 462             evhttp_del_accept_socket(eventHTTP, socket);
 463         }
 464         // Reject requests on current connections
 465         evhttp_set_gencb(eventHTTP, http_reject_request_cb, NULL);
 466     }
 467     if (workQueue)
 468         workQueue->Interrupt();
 469 }
 470
 471 void StopHTTPServer()
 472 {
 473     LogPrint("http", "Stopping HTTP server\n");
 474     if (workQueue) {
 475         LogPrint("http", "Waiting for HTTP worker threads to exit\n");
 476         workQueue->WaitExit();
 477         delete workQueue;
 478     }
 479     if (eventBase) {
 480         LogPrint("http", "Waiting for HTTP event thread to exit\n");
 481         // Give event loop a few seconds to exit (to send back last RPC responses), then break it
 482         // Before this was solved with event_base_loopexit, but that didn't work as expected in
 483         // at least libevent 2.0.21 and always introduced a delay. In libevent
 484         // master that appears to be solved, so in the future that solution
 485         // could be used again (if desirable).
 486         // (see discussion in https://github.com/bitcoin/bitcoin/pull/6990)
 487         if (threadResult.valid() && threadResult.wait_for(std::chrono::milliseconds(2000)) == std::future_status::timeout) {
 488             LogPrintf("HTTP event loop did not exit within allotted time, sending loopbreak\n");
 489             event_base_loopbreak(eventBase);
 490         }
 491         threadHTTP.join();
 492     }
 493     if (eventHTTP) {
 494         evhttp_free(eventHTTP);
 495         eventHTTP = 0;
 496     }
 497     if (eventBase) {
 498         event_base_free(eventBase);
 499         eventBase = 0;
 500     }
 501     LogPrint("http", "Stopped HTTP server\n");
 502 }
 503
 504 struct event_base* EventBase()
 505 {
 506     return eventBase;
 507 }
 508
 509 static void httpevent_callback_fn(evutil_socket_t, short, void* data)
 510 {
 511     // Static handler: simply call inner handler
 512     HTTPEvent *self = ((HTTPEvent*)data);
 513     self->handler();
 514     if (self->deleteWhenTriggered)
 515         delete self;
 516 }
 517
 518 HTTPEvent::HTTPEvent(struct event_base* base, bool _deleteWhenTriggered, const std::function<void(void)>& _handler):
 519     deleteWhenTriggered(_deleteWhenTriggered), handler(_handler)
 520 {
 521     ev = event_new(base, -1, 0, httpevent_callback_fn, this);
 522     assert(ev);
 523 }
 524 HTTPEvent::~HTTPEvent()
 525 {
 526     event_free(ev);
 527 }
 528 void HTTPEvent::trigger(struct timeval* tv)
 529 {
 530     if (tv == NULL)
 531         event_active(ev, 0, 0); // immediately trigger event in main thread
 532     else
 533         evtimer_add(ev, tv); // trigger after timeval passed
 534 }
 535 HTTPRequest::HTTPRequest(struct evhttp_request* _req) : req(_req),
 536                                                        replySent(false)
 537 {
 538 }
 539 HTTPRequest::~HTTPRequest()
 540 {
 541     if (!replySent) {
 542         // Keep track of whether reply was sent to avoid request leaks
 543         LogPrintf("%s: Unhandled request\n", __func__);
 544         WriteReply(HTTP_INTERNAL, "Unhandled request");
 545     }
 546     // evhttpd cleans up the request, as long as a reply was sent.
 547 }
 548
 549 std::pair<bool, std::string> HTTPRequest::GetHeader(const std::string& hdr)
 550 {
 551     const struct evkeyvalq* headers = evhttp_request_get_input_headers(req);
 552     assert(headers);
 553     const char* val = evhttp_find_header(headers, hdr.c_str());
 554     if (val)
 555         return std::make_pair(true, val);
 556     else
 557         return std::make_pair(false, "");
 558 }
 559
 560 std::string HTTPRequest::ReadBody()
 561 {
 562     struct evbuffer* buf = evhttp_request_get_input_buffer(req);
 563     if (!buf)
 564         return "";
 565     size_t size = evbuffer_get_length(buf);
 566     /** Trivial implementation: if this is ever a performance bottleneck,
 567      * internal copying can be avoided in multi-segment buffers by using
 568      * evbuffer_peek and an awkward loop. Though in that case, it'd be even
 569      * better to not copy into an intermediate string but use a stream
 570      * abstraction to consume the evbuffer on the fly in the parsing algorithm.
 571      */
 572     const char* data = (const char*)evbuffer_pullup(buf, size);
 573     if (!data) // returns NULL in case of empty buffer
 574         return "";
 575     std::string rv(data, size);
 576     evbuffer_drain(buf, size);
 577     return rv;
 578 }
 579
 580 void HTTPRequest::WriteHeader(const std::string& hdr, const std::string& value)
 581 {
 582     struct evkeyvalq* headers = evhttp_request_get_output_headers(req);
 583     assert(headers);
 584     evhttp_add_header(headers, hdr.c_str(), value.c_str());
 585 }
 586
 587 /** Closure sent to main thread to request a reply to be sent to
 588  * a HTTP request.
 589  * Replies must be sent in the main loop in the main http thread,
 590  * this cannot be done from worker threads.
 591  */
 592 void HTTPRequest::WriteReply(int nStatus, const std::string& strReply)
 593 {
 594     assert(!replySent && req);
 595     // Send event to main http thread to send reply message
 596     struct evbuffer* evb = evhttp_request_get_output_buffer(req);
 597     assert(evb);
 598     evbuffer_add(evb, strReply.data(), strReply.size());
 599     HTTPEvent* ev = new HTTPEvent(eventBase, true,
 600         std::bind(evhttp_send_reply, req, nStatus, (const char*)NULL, (struct evbuffer *)NULL));
 601     ev->trigger(0);
 602     replySent = true;
 603     req = 0; // transferred back to main thread
 604 }
 605
 606 CService HTTPRequest::GetPeer()
 607 {
 608     evhttp_connection* con = evhttp_request_get_connection(req);
 609     CService peer;
 610     if (con) {
 611         // evhttp retains ownership over returned address string
 612         const char* address = "";
 613         uint16_t port = 0;
 614         evhttp_connection_get_peer(con, (char**)&address, &port);
 615         peer = LookupNumeric(address, port);
 616     }
 617     return peer;
 618 }
 619
 620 std::string HTTPRequest::GetURI()
 621 {
 622     return evhttp_request_get_uri(req);
 623 }
 624
 625 HTTPRequest::RequestMethod HTTPRequest::GetRequestMethod()
 626 {
 627     switch (evhttp_request_get_command(req)) {
 628     case EVHTTP_REQ_GET:
 629         return GET;
 630         break;
 631     case EVHTTP_REQ_POST:
 632         return POST;
 633         break;
 634     case EVHTTP_REQ_HEAD:
 635         return HEAD;
 636         break;
 637     case EVHTTP_REQ_PUT:
 638         return PUT;
 639         break;
 640     default:
 641         return UNKNOWN;
 642         break;
 643     }
 644 }
 645
 646 void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler)
 647 {
 648     LogPrint("http", "Registering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
 649     pathHandlers.push_back(HTTPPathHandler(prefix, exactMatch, handler));
 650 }
 651
 652 void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch)
 653 {
 654     std::vector<HTTPPathHandler>::iterator i = pathHandlers.begin();
 655     std::vector<HTTPPathHandler>::iterator iend = pathHandlers.end();
 656     for (; i != iend; ++i)
 657         if (i->prefix == prefix && i->exactMatch == exactMatch)
 658             break;
 659     if (i != iend)
 660     {
 661         LogPrint("http", "Unregistering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
 662         pathHandlers.erase(i);
 663     }
 664 }
 665