src/httpserver.cpp

   1 // Copyright (c) 2015 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 (running) {
 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     /** Return current depth of queue */
 151     size_t Depth()
 152     {
 153         std::unique_lock<std::mutex> lock(cs);
 154         return queue.size();
 155     }
 156 };
 157
 158 struct HTTPPathHandler
 159 {
 160     HTTPPathHandler() {}
 161     HTTPPathHandler(std::string _prefix, bool _exactMatch, HTTPRequestHandler _handler):
 162         prefix(_prefix), exactMatch(_exactMatch), handler(_handler)
 163     {
 164     }
 165     std::string prefix;
 166     bool exactMatch;
 167     HTTPRequestHandler handler;
 168 };
 169
 170 /** HTTP module state */
 171
 172 //! libevent event loop
 173 static struct event_base* eventBase = 0;
 174 //! HTTP server
 175 struct evhttp* eventHTTP = 0;
 176 //! List of subnets to allow RPC connections from
 177 static std::vector<CSubNet> rpc_allow_subnets;
 178 //! Work queue for handling longer requests off the event loop thread
 179 static WorkQueue<HTTPClosure>* workQueue = 0;
 180 //! Handlers for (sub)paths
 181 std::vector<HTTPPathHandler> pathHandlers;
 182 //! Bound listening sockets
 183 std::vector<evhttp_bound_socket *> boundSockets;
 184
 185 /** Check if a network address is allowed to access the HTTP server */
 186 static bool ClientAllowed(const CNetAddr& netaddr)
 187 {
 188     if (!netaddr.IsValid())
 189         return false;
 190     for(const CSubNet& subnet : rpc_allow_subnets)
 191         if (subnet.Match(netaddr))
 192             return true;
 193     return false;
 194 }
 195
 196 /** Initialize ACL list for HTTP server */
 197 static bool InitHTTPAllowList()
 198 {
 199     rpc_allow_subnets.clear();
 200     CNetAddr localv4;
 201     CNetAddr localv6;
 202     LookupHost("127.0.0.1", localv4, false);
 203     LookupHost("::1", localv6, false);
 204     rpc_allow_subnets.push_back(CSubNet(localv4, 8));      // always allow IPv4 local subnet
 205     rpc_allow_subnets.push_back(CSubNet(localv6));         // always allow IPv6 localhost
 206     if (mapMultiArgs.count("-rpcallowip")) {
 207         const std::vector<std::string>& vAllow = mapMultiArgs["-rpcallowip"];
 208         for (std::string strAllow : vAllow) {
 209             CSubNet subnet;
 210             LookupSubNet(strAllow.c_str(), subnet);
 211             if (!subnet.IsValid()) {
 212                 uiInterface.ThreadSafeMessageBox(
 213                     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),
 214                     "", CClientUIInterface::MSG_ERROR);
 215                 return false;
 216             }
 217             rpc_allow_subnets.push_back(subnet);
 218         }
 219     }
 220     std::string strAllowed;
 221     for (const CSubNet& subnet : rpc_allow_subnets)
 222         strAllowed += subnet.ToString() + " ";
 223     LogPrint("http", "Allowing HTTP connections from: %s\n", strAllowed);
 224     return true;
 225 }
 226
 227 /** HTTP request method as string - use for logging only */
 228 static std::string RequestMethodString(HTTPRequest::RequestMethod m)
 229 {
 230     switch (m) {
 231     case HTTPRequest::GET:
 232         return "GET";
 233         break;
 234     case HTTPRequest::POST:
 235         return "POST";
 236         break;
 237     case HTTPRequest::HEAD:
 238         return "HEAD";
 239         break;
 240     case HTTPRequest::PUT:
 241         return "PUT";
 242         break;
 243     default:
 244         return "unknown";
 245     }
 246 }
 247
 248 /** HTTP request callback */
 249 static void http_request_cb(struct evhttp_request* req, void* arg)
 250 {
 251     std::unique_ptr<HTTPRequest> hreq(new HTTPRequest(req));
 252
 253     LogPrint("http", "Received a %s request for %s from %s\n",
 254              RequestMethodString(hreq->GetRequestMethod()), hreq->GetURI(), hreq->GetPeer().ToString());
 255
 256     // Early address-based allow check
 257     if (!ClientAllowed(hreq->GetPeer())) {
 258         hreq->WriteReply(HTTP_FORBIDDEN);
 259         return;
 260     }
 261
 262     // Early reject unknown HTTP methods
 263     if (hreq->GetRequestMethod() == HTTPRequest::UNKNOWN) {
 264         hreq->WriteReply(HTTP_BADMETHOD);
 265         return;
 266     }
 267
 268     // Find registered handler for prefix
 269     std::string strURI = hreq->GetURI();
 270     std::string path;
 271     std::vector<HTTPPathHandler>::const_iterator i = pathHandlers.begin();
 272     std::vector<HTTPPathHandler>::const_iterator iend = pathHandlers.end();
 273     for (; i != iend; ++i) {
 274         bool match = false;
 275         if (i->exactMatch)
 276             match = (strURI == i->prefix);
 277         else
 278             match = (strURI.substr(0, i->prefix.size()) == i->prefix);
 279         if (match) {
 280             path = strURI.substr(i->prefix.size());
 281             break;
 282         }
 283     }
 284
 285     // Dispatch to worker thread
 286     if (i != iend) {
 287         std::unique_ptr<HTTPWorkItem> item(new HTTPWorkItem(std::move(hreq), path, i->handler));
 288         assert(workQueue);
 289         if (workQueue->Enqueue(item.get()))
 290             item.release(); /* if true, queue took ownership */
 291         else {
 292             LogPrintf("WARNING: request rejected because http work queue depth exceeded, it can be increased with the -rpcworkqueue= setting\n");
 293             item->req->WriteReply(HTTP_INTERNAL, "Work queue depth exceeded");
 294         }
 295     } else {
 296         hreq->WriteReply(HTTP_NOTFOUND);
 297     }
 298 }
 299
 300 /** Callback to reject HTTP requests after shutdown. */
 301 static void http_reject_request_cb(struct evhttp_request* req, void*)
 302 {
 303     LogPrint("http", "Rejecting request while shutting down\n");
 304     evhttp_send_error(req, HTTP_SERVUNAVAIL, NULL);
 305 }
 306
 307 /** Event dispatcher thread */
 308 static bool ThreadHTTP(struct event_base* base, struct evhttp* http)
 309 {
 310     RenameThread("bitcoin-http");
 311     LogPrint("http", "Entering http event loop\n");
 312     event_base_dispatch(base);
 313     // Event loop will be interrupted by InterruptHTTPServer()
 314     LogPrint("http", "Exited http event loop\n");
 315     return event_base_got_break(base) == 0;
 316 }
 317
 318 /** Bind HTTP server to specified addresses */
 319 static bool HTTPBindAddresses(struct evhttp* http)
 320 {
 321     int defaultPort = GetArg("-rpcport", BaseParams().RPCPort());
 322     std::vector<std::pair<std::string, uint16_t> > endpoints;
 323
 324     // Determine what addresses to bind to
 325     if (!mapArgs.count("-rpcallowip")) { // Default to loopback if not allowing external IPs
 326         endpoints.push_back(std::make_pair("::1", defaultPort));
 327         endpoints.push_back(std::make_pair("127.0.0.1", defaultPort));
 328         if (mapArgs.count("-rpcbind")) {
 329             LogPrintf("WARNING: option -rpcbind was ignored because -rpcallowip was not specified, refusing to allow everyone to connect\n");
 330         }
 331     } else if (mapArgs.count("-rpcbind")) { // Specific bind address
 332         const std::vector<std::string>& vbind = mapMultiArgs["-rpcbind"];
 333         for (std::vector<std::string>::const_iterator i = vbind.begin(); i != vbind.end(); ++i) {
 334             int port = defaultPort;
 335             std::string host;
 336             SplitHostPort(*i, port, host);
 337             endpoints.push_back(std::make_pair(host, port));
 338         }
 339     } else { // No specific bind address specified, bind to any
 340         endpoints.push_back(std::make_pair("::", defaultPort));
 341         endpoints.push_back(std::make_pair("0.0.0.0", defaultPort));
 342     }
 343
 344     // Bind addresses
 345     for (std::vector<std::pair<std::string, uint16_t> >::iterator i = endpoints.begin(); i != endpoints.end(); ++i) {
 346         LogPrint("http", "Binding RPC on address %s port %i\n", i->first, i->second);
 347         evhttp_bound_socket *bind_handle = evhttp_bind_socket_with_handle(http, i->first.empty() ? NULL : i->first.c_str(), i->second);
 348         if (bind_handle) {
 349             boundSockets.push_back(bind_handle);
 350         } else {
 351             LogPrintf("Binding RPC on address %s port %i failed.\n", i->first, i->second);
 352         }
 353     }
 354     return !boundSockets.empty();
 355 }
 356
 357 /** Simple wrapper to set thread name and run work queue */
 358 static void HTTPWorkQueueRun(WorkQueue<HTTPClosure>* queue)
 359 {
 360     RenameThread("bitcoin-httpworker");
 361     queue->Run();
 362 }
 363
 364 /** libevent event log callback */
 365 static void libevent_log_cb(int severity, const char *msg)
 366 {
 367 #ifndef EVENT_LOG_WARN
 368 // EVENT_LOG_WARN was added in 2.0.19; but before then _EVENT_LOG_WARN existed.
 369 # define EVENT_LOG_WARN _EVENT_LOG_WARN
 370 #endif
 371     if (severity >= EVENT_LOG_WARN) // Log warn messages and higher without debug category
 372         LogPrintf("libevent: %s\n", msg);
 373     else
 374         LogPrint("libevent", "libevent: %s\n", msg);
 375 }
 376
 377 bool InitHTTPServer()
 378 {
 379     struct evhttp* http = 0;
 380     struct event_base* base = 0;
 381
 382     if (!InitHTTPAllowList())
 383         return false;
 384
 385     if (GetBoolArg("-rpcssl", false)) {
 386         uiInterface.ThreadSafeMessageBox(
 387             "SSL mode for RPC (-rpcssl) is no longer supported.",
 388             "", CClientUIInterface::MSG_ERROR);
 389         return false;
 390     }
 391
 392     // Redirect libevent's logging to our own log
 393     event_set_log_callback(&libevent_log_cb);
 394 #if LIBEVENT_VERSION_NUMBER >= 0x02010100
 395     // If -debug=libevent, set full libevent debugging.
 396     // Otherwise, disable all libevent debugging.
 397     if (LogAcceptCategory("libevent"))
 398         event_enable_debug_logging(EVENT_DBG_ALL);
 399     else
 400         event_enable_debug_logging(EVENT_DBG_NONE);
 401 #endif
 402 #ifdef WIN32
 403     evthread_use_windows_threads();
 404 #else
 405     evthread_use_pthreads();
 406 #endif
 407
 408     base = event_base_new(); // XXX RAII
 409     if (!base) {
 410         LogPrintf("Couldn't create an event_base: exiting\n");
 411         return false;
 412     }
 413
 414     /* Create a new evhttp object to handle requests. */
 415     http = evhttp_new(base); // XXX RAII
 416     if (!http) {
 417         LogPrintf("couldn't create evhttp. Exiting.\n");
 418         event_base_free(base);
 419         return false;
 420     }
 421
 422     evhttp_set_timeout(http, GetArg("-rpcservertimeout", DEFAULT_HTTP_SERVER_TIMEOUT));
 423     evhttp_set_max_headers_size(http, MAX_HEADERS_SIZE);
 424     evhttp_set_max_body_size(http, MAX_SIZE);
 425     evhttp_set_gencb(http, http_request_cb, NULL);
 426
 427     if (!HTTPBindAddresses(http)) {
 428         LogPrintf("Unable to bind any endpoint for RPC server\n");
 429         evhttp_free(http);
 430         event_base_free(base);
 431         return false;
 432     }
 433
 434     LogPrint("http", "Initialized HTTP server\n");
 435     int workQueueDepth = std::max((long)GetArg("-rpcworkqueue", DEFAULT_HTTP_WORKQUEUE), 1L);
 436     LogPrintf("HTTP: creating work queue of depth %d\n", workQueueDepth);
 437
 438     workQueue = new WorkQueue<HTTPClosure>(workQueueDepth);
 439     eventBase = base;
 440     eventHTTP = http;
 441     return true;
 442 }
 443
 444 std::thread threadHTTP;
 445 std::future<bool> threadResult;
 446
 447 bool StartHTTPServer()
 448 {
 449     LogPrint("http", "Starting HTTP server\n");
 450     int rpcThreads = std::max((long)GetArg("-rpcthreads", DEFAULT_HTTP_THREADS), 1L);
 451     LogPrintf("HTTP: starting %d worker threads\n", rpcThreads);
 452     std::packaged_task<bool(event_base*, evhttp*)> task(ThreadHTTP);
 453     threadResult = task.get_future();
 454     threadHTTP = std::thread(std::move(task), eventBase, eventHTTP);
 455
 456     for (int i = 0; i < rpcThreads; i++) {
 457         std::thread rpc_worker(HTTPWorkQueueRun, workQueue);
 458         rpc_worker.detach();
 459     }
 460     return true;
 461 }
 462
 463 void InterruptHTTPServer()
 464 {
 465     LogPrint("http", "Interrupting HTTP server\n");
 466     if (eventHTTP) {
 467         // Unlisten sockets
 468         for (evhttp_bound_socket *socket : boundSockets) {
 469             evhttp_del_accept_socket(eventHTTP, socket);
 470         }
 471         // Reject requests on current connections
 472         evhttp_set_gencb(eventHTTP, http_reject_request_cb, NULL);
 473     }
 474     if (workQueue)
 475         workQueue->Interrupt();
 476 }
 477
 478 void StopHTTPServer()
 479 {
 480     LogPrint("http", "Stopping HTTP server\n");
 481     if (workQueue) {
 482         LogPrint("http", "Waiting for HTTP worker threads to exit\n");
 483         workQueue->WaitExit();
 484         delete workQueue;
 485     }
 486     if (eventBase) {
 487         LogPrint("http", "Waiting for HTTP event thread to exit\n");
 488         // Give event loop a few seconds to exit (to send back last RPC responses), then break it
 489         // Before this was solved with event_base_loopexit, but that didn't work as expected in
 490         // at least libevent 2.0.21 and always introduced a delay. In libevent
 491         // master that appears to be solved, so in the future that solution
 492         // could be used again (if desirable).
 493         // (see discussion in https://github.com/bitcoin/bitcoin/pull/6990)
 494         if (threadResult.valid() && threadResult.wait_for(std::chrono::milliseconds(2000)) == std::future_status::timeout) {
 495             LogPrintf("HTTP event loop did not exit within allotted time, sending loopbreak\n");
 496             event_base_loopbreak(eventBase);
 497         }
 498         threadHTTP.join();
 499     }
 500     if (eventHTTP) {
 501         evhttp_free(eventHTTP);
 502         eventHTTP = 0;
 503     }
 504     if (eventBase) {
 505         event_base_free(eventBase);
 506         eventBase = 0;
 507     }
 508     LogPrint("http", "Stopped HTTP server\n");
 509 }
 510
 511 struct event_base* EventBase()
 512 {
 513     return eventBase;
 514 }
 515
 516 static void httpevent_callback_fn(evutil_socket_t, short, void* data)
 517 {
 518     // Static handler: simply call inner handler
 519     HTTPEvent *self = ((HTTPEvent*)data);
 520     self->handler();
 521     if (self->deleteWhenTriggered)
 522         delete self;
 523 }
 524
 525 HTTPEvent::HTTPEvent(struct event_base* base, bool _deleteWhenTriggered, const std::function<void(void)>& _handler):
 526     deleteWhenTriggered(_deleteWhenTriggered), handler(_handler)
 527 {
 528     ev = event_new(base, -1, 0, httpevent_callback_fn, this);
 529     assert(ev);
 530 }
 531 HTTPEvent::~HTTPEvent()
 532 {
 533     event_free(ev);
 534 }
 535 void HTTPEvent::trigger(struct timeval* tv)
 536 {
 537     if (tv == NULL)
 538         event_active(ev, 0, 0); // immediately trigger event in main thread
 539     else
 540         evtimer_add(ev, tv); // trigger after timeval passed
 541 }
 542 HTTPRequest::HTTPRequest(struct evhttp_request* _req) : req(_req),
 543                                                        replySent(false)
 544 {
 545 }
 546 HTTPRequest::~HTTPRequest()
 547 {
 548     if (!replySent) {
 549         // Keep track of whether reply was sent to avoid request leaks
 550         LogPrintf("%s: Unhandled request\n", __func__);
 551         WriteReply(HTTP_INTERNAL, "Unhandled request");
 552     }
 553     // evhttpd cleans up the request, as long as a reply was sent.
 554 }
 555
 556 std::pair<bool, std::string> HTTPRequest::GetHeader(const std::string& hdr)
 557 {
 558     const struct evkeyvalq* headers = evhttp_request_get_input_headers(req);
 559     assert(headers);
 560     const char* val = evhttp_find_header(headers, hdr.c_str());
 561     if (val)
 562         return std::make_pair(true, val);
 563     else
 564         return std::make_pair(false, "");
 565 }
 566
 567 std::string HTTPRequest::ReadBody()
 568 {
 569     struct evbuffer* buf = evhttp_request_get_input_buffer(req);
 570     if (!buf)
 571         return "";
 572     size_t size = evbuffer_get_length(buf);
 573     /** Trivial implementation: if this is ever a performance bottleneck,
 574      * internal copying can be avoided in multi-segment buffers by using
 575      * evbuffer_peek and an awkward loop. Though in that case, it'd be even
 576      * better to not copy into an intermediate string but use a stream
 577      * abstraction to consume the evbuffer on the fly in the parsing algorithm.
 578      */
 579     const char* data = (const char*)evbuffer_pullup(buf, size);
 580     if (!data) // returns NULL in case of empty buffer
 581         return "";
 582     std::string rv(data, size);
 583     evbuffer_drain(buf, size);
 584     return rv;
 585 }
 586
 587 void HTTPRequest::WriteHeader(const std::string& hdr, const std::string& value)
 588 {
 589     struct evkeyvalq* headers = evhttp_request_get_output_headers(req);
 590     assert(headers);
 591     evhttp_add_header(headers, hdr.c_str(), value.c_str());
 592 }
 593
 594 /** Closure sent to main thread to request a reply to be sent to
 595  * a HTTP request.
 596  * Replies must be sent in the main loop in the main http thread,
 597  * this cannot be done from worker threads.
 598  */
 599 void HTTPRequest::WriteReply(int nStatus, const std::string& strReply)
 600 {
 601     assert(!replySent && req);
 602     // Send event to main http thread to send reply message
 603     struct evbuffer* evb = evhttp_request_get_output_buffer(req);
 604     assert(evb);
 605     evbuffer_add(evb, strReply.data(), strReply.size());
 606     HTTPEvent* ev = new HTTPEvent(eventBase, true,
 607         std::bind(evhttp_send_reply, req, nStatus, (const char*)NULL, (struct evbuffer *)NULL));
 608     ev->trigger(0);
 609     replySent = true;
 610     req = 0; // transferred back to main thread
 611 }
 612
 613 CService HTTPRequest::GetPeer()
 614 {
 615     evhttp_connection* con = evhttp_request_get_connection(req);
 616     CService peer;
 617     if (con) {
 618         // evhttp retains ownership over returned address string
 619         const char* address = "";
 620         uint16_t port = 0;
 621         evhttp_connection_get_peer(con, (char**)&address, &port);
 622         peer = LookupNumeric(address, port);
 623     }
 624     return peer;
 625 }
 626
 627 std::string HTTPRequest::GetURI()
 628 {
 629     return evhttp_request_get_uri(req);
 630 }
 631
 632 HTTPRequest::RequestMethod HTTPRequest::GetRequestMethod()
 633 {
 634     switch (evhttp_request_get_command(req)) {
 635     case EVHTTP_REQ_GET:
 636         return GET;
 637         break;
 638     case EVHTTP_REQ_POST:
 639         return POST;
 640         break;
 641     case EVHTTP_REQ_HEAD:
 642         return HEAD;
 643         break;
 644     case EVHTTP_REQ_PUT:
 645         return PUT;
 646         break;
 647     default:
 648         return UNKNOWN;
 649         break;
 650     }
 651 }
 652
 653 void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler)
 654 {
 655     LogPrint("http", "Registering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
 656     pathHandlers.push_back(HTTPPathHandler(prefix, exactMatch, handler));
 657 }
 658
 659 void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch)
 660 {
 661     std::vector<HTTPPathHandler>::iterator i = pathHandlers.begin();
 662     std::vector<HTTPPathHandler>::iterator iend = pathHandlers.end();
 663     for (; i != iend; ++i)
 664         if (i->prefix == prefix && i->exactMatch == exactMatch)
 665             break;
 666     if (i != iend)
 667     {
 668         LogPrint("http", "Unregistering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
 669         pathHandlers.erase(i);
 670     }
 671 }
 672