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/thread.h>
  25 #include <event2/buffer.h>
  26 #include <event2/util.h>
  27 #include <event2/keyvalq_struct.h>
  28
  29 #include "support/events.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()() override
  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     for (const std::string& strAllow : gArgs.GetArgs("-rpcallowip")) {
 200         CSubNet subnet;
 201         LookupSubNet(strAllow.c_str(), subnet);
 202         if (!subnet.IsValid()) {
 203             uiInterface.ThreadSafeMessageBox(
 204                 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),
 205                 "", CClientUIInterface::MSG_ERROR);
 206             return false;
 207         }
 208         rpc_allow_subnets.push_back(subnet);
 209     }
 210     std::string strAllowed;
 211     for (const CSubNet& subnet : rpc_allow_subnets)
 212         strAllowed += subnet.ToString() + " ";
 213     LogPrint(BCLog::HTTP, "Allowing HTTP connections from: %s\n", strAllowed);
 214     return true;
 215 }
 216
 217 /** HTTP request method as string - use for logging only */
 218 static std::string RequestMethodString(HTTPRequest::RequestMethod m)
 219 {
 220     switch (m) {
 221     case HTTPRequest::GET:
 222         return "GET";
 223         break;
 224     case HTTPRequest::POST:
 225         return "POST";
 226         break;
 227     case HTTPRequest::HEAD:
 228         return "HEAD";
 229         break;
 230     case HTTPRequest::PUT:
 231         return "PUT";
 232         break;
 233     default:
 234         return "unknown";
 235     }
 236 }
 237
 238 /** HTTP request callback */
 239 static void http_request_cb(struct evhttp_request* req, void* arg)
 240 {
 241     std::unique_ptr<HTTPRequest> hreq(new HTTPRequest(req));
 242
 243     LogPrint(BCLog::HTTP, "Received a %s request for %s from %s\n",
 244              RequestMethodString(hreq->GetRequestMethod()), hreq->GetURI(), hreq->GetPeer().ToString());
 245
 246     // Early address-based allow check
 247     if (!ClientAllowed(hreq->GetPeer())) {
 248         hreq->WriteReply(HTTP_FORBIDDEN);
 249         return;
 250     }
 251
 252     // Early reject unknown HTTP methods
 253     if (hreq->GetRequestMethod() == HTTPRequest::UNKNOWN) {
 254         hreq->WriteReply(HTTP_BADMETHOD);
 255         return;
 256     }
 257
 258     // Find registered handler for prefix
 259     std::string strURI = hreq->GetURI();
 260     std::string path;
 261     std::vector<HTTPPathHandler>::const_iterator i = pathHandlers.begin();
 262     std::vector<HTTPPathHandler>::const_iterator iend = pathHandlers.end();
 263     for (; i != iend; ++i) {
 264         bool match = false;
 265         if (i->exactMatch)
 266             match = (strURI == i->prefix);
 267         else
 268             match = (strURI.substr(0, i->prefix.size()) == i->prefix);
 269         if (match) {
 270             path = strURI.substr(i->prefix.size());
 271             break;
 272         }
 273     }
 274
 275     // Dispatch to worker thread
 276     if (i != iend) {
 277         std::unique_ptr<HTTPWorkItem> item(new HTTPWorkItem(std::move(hreq), path, i->handler));
 278         assert(workQueue);
 279         if (workQueue->Enqueue(item.get()))
 280             item.release(); /* if true, queue took ownership */
 281         else {
 282             LogPrintf("WARNING: request rejected because http work queue depth exceeded, it can be increased with the -rpcworkqueue= setting\n");
 283             item->req->WriteReply(HTTP_INTERNAL, "Work queue depth exceeded");
 284         }
 285     } else {
 286         hreq->WriteReply(HTTP_NOTFOUND);
 287     }
 288 }
 289
 290 /** Callback to reject HTTP requests after shutdown. */
 291 static void http_reject_request_cb(struct evhttp_request* req, void*)
 292 {
 293     LogPrint(BCLog::HTTP, "Rejecting request while shutting down\n");
 294     evhttp_send_error(req, HTTP_SERVUNAVAIL, NULL);
 295 }
 296
 297 /** Event dispatcher thread */
 298 static bool ThreadHTTP(struct event_base* base, struct evhttp* http)
 299 {
 300     RenameThread("bitcoin-http");
 301     LogPrint(BCLog::HTTP, "Entering http event loop\n");
 302     event_base_dispatch(base);
 303     // Event loop will be interrupted by InterruptHTTPServer()
 304     LogPrint(BCLog::HTTP, "Exited http event loop\n");
 305     return event_base_got_break(base) == 0;
 306 }
 307
 308 /** Bind HTTP server to specified addresses */
 309 static bool HTTPBindAddresses(struct evhttp* http)
 310 {
 311     int defaultPort = GetArg("-rpcport", BaseParams().RPCPort());
 312     std::vector<std::pair<std::string, uint16_t> > endpoints;
 313
 314     // Determine what addresses to bind to
 315     if (!IsArgSet("-rpcallowip")) { // Default to loopback if not allowing external IPs
 316         endpoints.push_back(std::make_pair("::1", defaultPort));
 317         endpoints.push_back(std::make_pair("127.0.0.1", defaultPort));
 318         if (IsArgSet("-rpcbind")) {
 319             LogPrintf("WARNING: option -rpcbind was ignored because -rpcallowip was not specified, refusing to allow everyone to connect\n");
 320         }
 321     } else if (gArgs.IsArgSet("-rpcbind")) { // Specific bind address
 322         for (const std::string& strRPCBind : gArgs.GetArgs("-rpcbind")) {
 323             int port = defaultPort;
 324             std::string host;
 325             SplitHostPort(strRPCBind, port, host);
 326             endpoints.push_back(std::make_pair(host, port));
 327         }
 328     } else { // No specific bind address specified, bind to any
 329         endpoints.push_back(std::make_pair("::", defaultPort));
 330         endpoints.push_back(std::make_pair("0.0.0.0", defaultPort));
 331     }
 332
 333     // Bind addresses
 334     for (std::vector<std::pair<std::string, uint16_t> >::iterator i = endpoints.begin(); i != endpoints.end(); ++i) {
 335         LogPrint(BCLog::HTTP, "Binding RPC on address %s port %i\n", i->first, i->second);
 336         evhttp_bound_socket *bind_handle = evhttp_bind_socket_with_handle(http, i->first.empty() ? NULL : i->first.c_str(), i->second);
 337         if (bind_handle) {
 338             boundSockets.push_back(bind_handle);
 339         } else {
 340             LogPrintf("Binding RPC on address %s port %i failed.\n", i->first, i->second);
 341         }
 342     }
 343     return !boundSockets.empty();
 344 }
 345
 346 /** Simple wrapper to set thread name and run work queue */
 347 static void HTTPWorkQueueRun(WorkQueue<HTTPClosure>* queue)
 348 {
 349     RenameThread("bitcoin-httpworker");
 350     queue->Run();
 351 }
 352
 353 /** libevent event log callback */
 354 static void libevent_log_cb(int severity, const char *msg)
 355 {
 356 #ifndef EVENT_LOG_WARN
 357 // EVENT_LOG_WARN was added in 2.0.19; but before then _EVENT_LOG_WARN existed.
 358 # define EVENT_LOG_WARN _EVENT_LOG_WARN
 359 #endif
 360     if (severity >= EVENT_LOG_WARN) // Log warn messages and higher without debug category
 361         LogPrintf("libevent: %s\n", msg);
 362     else
 363         LogPrint(BCLog::LIBEVENT, "libevent: %s\n", msg);
 364 }
 365
 366 bool InitHTTPServer()
 367 {
 368     if (!InitHTTPAllowList())
 369         return false;
 370
 371     if (GetBoolArg("-rpcssl", false)) {
 372         uiInterface.ThreadSafeMessageBox(
 373             "SSL mode for RPC (-rpcssl) is no longer supported.",
 374             "", CClientUIInterface::MSG_ERROR);
 375         return false;
 376     }
 377
 378     // Redirect libevent's logging to our own log
 379     event_set_log_callback(&libevent_log_cb);
 380     // Update libevent's log handling. Returns false if our version of
 381     // libevent doesn't support debug logging, in which case we should
 382     // clear the BCLog::LIBEVENT flag.
 383     if (!UpdateHTTPServerLogging(logCategories & BCLog::LIBEVENT)) {
 384         logCategories &= ~BCLog::LIBEVENT;
 385     }
 386
 387 #ifdef WIN32
 388     evthread_use_windows_threads();
 389 #else
 390     evthread_use_pthreads();
 391 #endif
 392
 393     raii_event_base base_ctr = obtain_event_base();
 394
 395     /* Create a new evhttp object to handle requests. */
 396     raii_evhttp http_ctr = obtain_evhttp(base_ctr.get());
 397     struct evhttp* http = http_ctr.get();
 398     if (!http) {
 399         LogPrintf("couldn't create evhttp. Exiting.\n");
 400         return false;
 401     }
 402
 403     evhttp_set_timeout(http, GetArg("-rpcservertimeout", DEFAULT_HTTP_SERVER_TIMEOUT));
 404     evhttp_set_max_headers_size(http, MAX_HEADERS_SIZE);
 405     evhttp_set_max_body_size(http, MAX_SIZE);
 406     evhttp_set_gencb(http, http_request_cb, NULL);
 407
 408     if (!HTTPBindAddresses(http)) {
 409         LogPrintf("Unable to bind any endpoint for RPC server\n");
 410         return false;
 411     }
 412
 413     LogPrint(BCLog::HTTP, "Initialized HTTP server\n");
 414     int workQueueDepth = std::max((long)GetArg("-rpcworkqueue", DEFAULT_HTTP_WORKQUEUE), 1L);
 415     LogPrintf("HTTP: creating work queue of depth %d\n", workQueueDepth);
 416
 417     workQueue = new WorkQueue<HTTPClosure>(workQueueDepth);
 418     // transfer ownership to eventBase/HTTP via .release()
 419     eventBase = base_ctr.release();
 420     eventHTTP = http_ctr.release();
 421     return true;
 422 }
 423
 424 bool UpdateHTTPServerLogging(bool enable) {
 425 #if LIBEVENT_VERSION_NUMBER >= 0x02010100
 426     if (enable) {
 427         event_enable_debug_logging(EVENT_DBG_ALL);
 428     } else {
 429         event_enable_debug_logging(EVENT_DBG_NONE);
 430     }
 431     return true;
 432 #else
 433     // Can't update libevent logging if version < 02010100
 434     return false;
 435 #endif
 436 }
 437
 438 std::thread threadHTTP;
 439 std::future<bool> threadResult;
 440
 441 bool StartHTTPServer()
 442 {
 443     LogPrint(BCLog::HTTP, "Starting HTTP server\n");
 444     int rpcThreads = std::max((long)GetArg("-rpcthreads", DEFAULT_HTTP_THREADS), 1L);
 445     LogPrintf("HTTP: starting %d worker threads\n", rpcThreads);
 446     std::packaged_task<bool(event_base*, evhttp*)> task(ThreadHTTP);
 447     threadResult = task.get_future();
 448     threadHTTP = std::thread(std::move(task), eventBase, eventHTTP);
 449
 450     for (int i = 0; i < rpcThreads; i++) {
 451         std::thread rpc_worker(HTTPWorkQueueRun, workQueue);
 452         rpc_worker.detach();
 453     }
 454     return true;
 455 }
 456
 457 void InterruptHTTPServer()
 458 {
 459     LogPrint(BCLog::HTTP, "Interrupting HTTP server\n");
 460     if (eventHTTP) {
 461         // Unlisten sockets
 462         for (evhttp_bound_socket *socket : boundSockets) {
 463             evhttp_del_accept_socket(eventHTTP, socket);
 464         }
 465         // Reject requests on current connections
 466         evhttp_set_gencb(eventHTTP, http_reject_request_cb, NULL);
 467     }
 468     if (workQueue)
 469         workQueue->Interrupt();
 470 }
 471
 472 void StopHTTPServer()
 473 {
 474     LogPrint(BCLog::HTTP, "Stopping HTTP server\n");
 475     if (workQueue) {
 476         LogPrint(BCLog::HTTP, "Waiting for HTTP worker threads to exit\n");
 477         workQueue->WaitExit();
 478         delete workQueue;
 479         workQueue = nullptr;
 480     }
 481     if (eventBase) {
 482         LogPrint(BCLog::HTTP, "Waiting for HTTP event thread to exit\n");
 483         // Give event loop a few seconds to exit (to send back last RPC responses), then break it
 484         // Before this was solved with event_base_loopexit, but that didn't work as expected in
 485         // at least libevent 2.0.21 and always introduced a delay. In libevent
 486         // master that appears to be solved, so in the future that solution
 487         // could be used again (if desirable).
 488         // (see discussion in https://github.com/bitcoin/bitcoin/pull/6990)
 489         if (threadResult.valid() && threadResult.wait_for(std::chrono::milliseconds(2000)) == std::future_status::timeout) {
 490             LogPrintf("HTTP event loop did not exit within allotted time, sending loopbreak\n");
 491             event_base_loopbreak(eventBase);
 492         }
 493         threadHTTP.join();
 494     }
 495     if (eventHTTP) {
 496         evhttp_free(eventHTTP);
 497         eventHTTP = 0;
 498     }
 499     if (eventBase) {
 500         event_base_free(eventBase);
 501         eventBase = 0;
 502     }
 503     LogPrint(BCLog::HTTP, "Stopped HTTP server\n");
 504 }
 505
 506 struct event_base* EventBase()
 507 {
 508     return eventBase;
 509 }
 510
 511 static void httpevent_callback_fn(evutil_socket_t, short, void* data)
 512 {
 513     // Static handler: simply call inner handler
 514     HTTPEvent *self = ((HTTPEvent*)data);
 515     self->handler();
 516     if (self->deleteWhenTriggered)
 517         delete self;
 518 }
 519
 520 HTTPEvent::HTTPEvent(struct event_base* base, bool _deleteWhenTriggered, const std::function<void(void)>& _handler):
 521     deleteWhenTriggered(_deleteWhenTriggered), handler(_handler)
 522 {
 523     ev = event_new(base, -1, 0, httpevent_callback_fn, this);
 524     assert(ev);
 525 }
 526 HTTPEvent::~HTTPEvent()
 527 {
 528     event_free(ev);
 529 }
 530 void HTTPEvent::trigger(struct timeval* tv)
 531 {
 532     if (tv == NULL)
 533         event_active(ev, 0, 0); // immediately trigger event in main thread
 534     else
 535         evtimer_add(ev, tv); // trigger after timeval passed
 536 }
 537 HTTPRequest::HTTPRequest(struct evhttp_request* _req) : req(_req),
 538                                                        replySent(false)
 539 {
 540 }
 541 HTTPRequest::~HTTPRequest()
 542 {
 543     if (!replySent) {
 544         // Keep track of whether reply was sent to avoid request leaks
 545         LogPrintf("%s: Unhandled request\n", __func__);
 546         WriteReply(HTTP_INTERNAL, "Unhandled request");
 547     }
 548     // evhttpd cleans up the request, as long as a reply was sent.
 549 }
 550
 551 std::pair<bool, std::string> HTTPRequest::GetHeader(const std::string& hdr)
 552 {
 553     const struct evkeyvalq* headers = evhttp_request_get_input_headers(req);
 554     assert(headers);
 555     const char* val = evhttp_find_header(headers, hdr.c_str());
 556     if (val)
 557         return std::make_pair(true, val);
 558     else
 559         return std::make_pair(false, "");
 560 }
 561
 562 std::string HTTPRequest::ReadBody()
 563 {
 564     struct evbuffer* buf = evhttp_request_get_input_buffer(req);
 565     if (!buf)
 566         return "";
 567     size_t size = evbuffer_get_length(buf);
 568     /** Trivial implementation: if this is ever a performance bottleneck,
 569      * internal copying can be avoided in multi-segment buffers by using
 570      * evbuffer_peek and an awkward loop. Though in that case, it'd be even
 571      * better to not copy into an intermediate string but use a stream
 572      * abstraction to consume the evbuffer on the fly in the parsing algorithm.
 573      */
 574     const char* data = (const char*)evbuffer_pullup(buf, size);
 575     if (!data) // returns NULL in case of empty buffer
 576         return "";
 577     std::string rv(data, size);
 578     evbuffer_drain(buf, size);
 579     return rv;
 580 }
 581
 582 void HTTPRequest::WriteHeader(const std::string& hdr, const std::string& value)
 583 {
 584     struct evkeyvalq* headers = evhttp_request_get_output_headers(req);
 585     assert(headers);
 586     evhttp_add_header(headers, hdr.c_str(), value.c_str());
 587 }
 588
 589 /** Closure sent to main thread to request a reply to be sent to
 590  * a HTTP request.
 591  * Replies must be sent in the main loop in the main http thread,
 592  * this cannot be done from worker threads.
 593  */
 594 void HTTPRequest::WriteReply(int nStatus, const std::string& strReply)
 595 {
 596     assert(!replySent && req);
 597     // Send event to main http thread to send reply message
 598     struct evbuffer* evb = evhttp_request_get_output_buffer(req);
 599     assert(evb);
 600     evbuffer_add(evb, strReply.data(), strReply.size());
 601     HTTPEvent* ev = new HTTPEvent(eventBase, true,
 602         std::bind(evhttp_send_reply, req, nStatus, (const char*)NULL, (struct evbuffer *)NULL));
 603     ev->trigger(0);
 604     replySent = true;
 605     req = 0; // transferred back to main thread
 606 }
 607
 608 CService HTTPRequest::GetPeer()
 609 {
 610     evhttp_connection* con = evhttp_request_get_connection(req);
 611     CService peer;
 612     if (con) {
 613         // evhttp retains ownership over returned address string
 614         const char* address = "";
 615         uint16_t port = 0;
 616         evhttp_connection_get_peer(con, (char**)&address, &port);
 617         peer = LookupNumeric(address, port);
 618     }
 619     return peer;
 620 }
 621
 622 std::string HTTPRequest::GetURI()
 623 {
 624     return evhttp_request_get_uri(req);
 625 }
 626
 627 HTTPRequest::RequestMethod HTTPRequest::GetRequestMethod()
 628 {
 629     switch (evhttp_request_get_command(req)) {
 630     case EVHTTP_REQ_GET:
 631         return GET;
 632         break;
 633     case EVHTTP_REQ_POST:
 634         return POST;
 635         break;
 636     case EVHTTP_REQ_HEAD:
 637         return HEAD;
 638         break;
 639     case EVHTTP_REQ_PUT:
 640         return PUT;
 641         break;
 642     default:
 643         return UNKNOWN;
 644         break;
 645     }
 646 }
 647
 648 void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler)
 649 {
 650     LogPrint(BCLog::HTTP, "Registering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
 651     pathHandlers.push_back(HTTPPathHandler(prefix, exactMatch, handler));
 652 }
 653
 654 void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch)
 655 {
 656     std::vector<HTTPPathHandler>::iterator i = pathHandlers.begin();
 657     std::vector<HTTPPathHandler>::iterator iend = pathHandlers.end();
 658     for (; i != iend; ++i)
 659         if (i->prefix == prefix && i->exactMatch == exactMatch)
 660             break;
 661     if (i != iend)
 662     {
 663         LogPrint(BCLog::HTTP, "Unregistering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
 664         pathHandlers.erase(i);
 665     }
 666 }
 667