]> git.mxchange.org Git - simgear.git/blobdiff - simgear/io/HTTPClient.cxx
Don't use object returned from vector::end()
[simgear.git] / simgear / io / HTTPClient.cxx
index a51fb2f43e4e89ea6daf5a5acf97ee0a63c90efe..d5ef1ea5108039ff2dd8e01eea27f0141d69be03 100644 (file)
@@ -21,6 +21,7 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
 
+
 #include "HTTPClient.hxx"
 #include "HTTPFileRequest.hxx"
 
 #include <boost/foreach.hpp>
 #include <boost/algorithm/string/case_conv.hpp>
 
+#include <simgear/simgear_config.h>
+
+#if defined(ENABLE_CURL)
+  #include <curl/multi.h>
+#else
+    #include <simgear/io/HTTPContentDecode.hxx>
+#endif
+
 #include <simgear/io/sg_netChat.hxx>
-#include <simgear/io/HTTPContentDecode.hxx>
+
 #include <simgear/misc/strutils.hxx>
 #include <simgear/compiler.h>
 #include <simgear/debug/logstream.hxx>
@@ -59,7 +68,6 @@ namespace HTTP
 
 extern const int DEFAULT_HTTP_PORT = 80;
 const char* CONTENT_TYPE_URL_ENCODED = "application/x-www-form-urlencoded";
-const unsigned int MAX_INFLIGHT_REQUESTS = 32;
 
 class Connection;
 typedef std::multimap<std::string, Connection*> ConnectionDict;
@@ -68,31 +76,58 @@ typedef std::list<Request_ptr> RequestList;
 class Client::ClientPrivate
 {
 public:
+#if defined(ENABLE_CURL)
+    CURLM* curlMulti;
+
+    void createCurlMulti()
+    {
+        curlMulti = curl_multi_init();
+        // see https://curl.haxx.se/libcurl/c/CURLMOPT_PIPELINING.html
+        // we request HTTP 1.1 pipelining
+        curl_multi_setopt(curlMulti, CURLMOPT_PIPELINING, 1 /* aka CURLPIPE_HTTP1 */);
+        curl_multi_setopt(curlMulti, CURLMOPT_MAX_TOTAL_CONNECTIONS, (long) maxConnections);
+        curl_multi_setopt(curlMulti, CURLMOPT_MAX_PIPELINE_LENGTH,
+                          (long) maxPipelineDepth);
+        curl_multi_setopt(curlMulti, CURLMOPT_MAX_HOST_CONNECTIONS,
+                          (long) maxHostConnections);
+
+
+    }
+
+    typedef std::map<Request_ptr, CURL*> RequestCurlMap;
+    RequestCurlMap requests;
+#else
+    NetChannelPoller poller;
+// connections by host (potentially more than one)
+    ConnectionDict connections;
+#endif
+
     std::string userAgent;
     std::string proxy;
     int proxyPort;
     std::string proxyAuth;
-    NetChannelPoller poller;
     unsigned int maxConnections;
-    
+    unsigned int maxHostConnections;
+    unsigned int maxPipelineDepth;
+
     RequestList pendingRequests;
-    
-// connections by host (potentially more than one)
-    ConnectionDict connections;
-    
+
     SGTimeStamp timeTransferSample;
     unsigned int bytesTransferred;
     unsigned int lastTransferRate;
     uint64_t totalBytesDownloaded;
 };
-  
+
+#if !defined(ENABLE_CURL)
 class Connection : public NetChat
 {
 public:
-    Connection(Client* pr) :
+    Connection(Client* pr, const std::string& conId) :
         client(pr),
         state(STATE_CLOSED),
-        port(DEFAULT_HTTP_PORT)
+        port(DEFAULT_HTTP_PORT),
+        _connectionId(conId),
+        _maxPipelineLength(255)
     {
     }
 
@@ -109,7 +144,7 @@ public:
 
       // force the state to GETTING_BODY, to simplify logic in
       // responseComplete and handleClose
-      state = STATE_GETTING_BODY;
+        setState(STATE_GETTING_BODY);
       responseComplete();
     }
 
@@ -119,10 +154,20 @@ public:
         port = p;
     }
 
+    void setMaxPipelineLength(unsigned int m)
+    {
+        _maxPipelineLength = m;
+    }
+
     // socket-level errors
     virtual void handleError(int error)
     {
         const char* errStr = strerror(error);
+        SG_LOG(SG_IO, SG_WARN, _connectionId << " handleError:" << error << " ("
+               << errStr << ")");
+
+        debugDumpRequests();
+
         if (!activeRequest)
         {
         // connection level failure, eg name lookup or routing
@@ -148,7 +193,12 @@ public:
             _contentDecoder.reset();
         }
 
-        state = STATE_SOCKET_ERROR;
+        setState(STATE_SOCKET_ERROR);
+    }
+
+    void handleTimeout()
+    {
+        handleError(ETIMEDOUT);
     }
 
     virtual void handleClose()
@@ -157,13 +207,33 @@ public:
 
     // closing of the connection from the server side when getting the body,
         bool canCloseState = (state == STATE_GETTING_BODY);
+        bool isCancelling = (state == STATE_CANCELLING);
+
         if (canCloseState && activeRequest) {
+            // check bodyTransferSize matches how much we actually transferred
+            if (bodyTransferSize > 0) {
+                if (_contentDecoder.getTotalReceivedBytes() != bodyTransferSize) {
+                    SG_LOG(SG_IO, SG_WARN, _connectionId << " saw connection close while still receiving bytes for:" << activeRequest->url()
+                           << "\n\thave:" << _contentDecoder.getTotalReceivedBytes() << " of " << bodyTransferSize);
+                }
+            }
+
         // force state here, so responseComplete can avoid closing the
         // socket again
-            state =  STATE_CLOSED;
+            SG_LOG(SG_IO, SG_DEBUG, _connectionId << " saw connection close after getting:" << activeRequest->url());
+            setState(STATE_CLOSED);
             responseComplete();
         } else {
-            if (activeRequest) {
+            if (state == STATE_WAITING_FOR_RESPONSE) {
+                SG_LOG(SG_IO, SG_DEBUG, _connectionId << ":close while waiting for response, front request is:"
+                       << sentRequests.front()->url());
+                assert(!sentRequests.empty());
+                sentRequests.front()->setFailure(500, "server closed connection unexpectedly");
+                // no active request, but don't restore the front sent one
+                sentRequests.erase(sentRequests.begin());
+            }
+
+            if (activeRequest && !isCancelling) {
                 activeRequest->setFailure(500, "server closed connection");
                 // remove the failed request from sentRequests, so it does
                 // not get restored
@@ -176,7 +246,7 @@ public:
                 _contentDecoder.reset();
             }
 
-            state = STATE_CLOSED;
+            setState(STATE_CLOSED);
         }
 
       if (sentRequests.empty()) {
@@ -190,25 +260,45 @@ public:
       sentRequests.clear();
     }
 
-    void handleTimeout()
-    {
-        NetChat::handleError(ETIMEDOUT);
-        if (activeRequest) {
-            SG_LOG(SG_IO, SG_DEBUG, "HTTP socket timeout");
-            activeRequest->setFailure(ETIMEDOUT, "socket timeout");
-            activeRequest = NULL;
-            _contentDecoder.reset();
-        }
-
-        state = STATE_SOCKET_ERROR;
-    }
-
     void queueRequest(const Request_ptr& r)
     {
         queuedRequests.push_back(r);
         tryStartNextRequest();
     }
 
+    void cancelRequest(const Request_ptr& r)
+    {
+        RequestList::iterator it = std::find(sentRequests.begin(),
+                                             sentRequests.end(), r);
+        if (it != sentRequests.end()) {
+            sentRequests.erase(it);
+
+            if ((r == activeRequest) || !activeRequest) {
+                // either the cancelling request is active, or we're in waiting
+                // for response state - close now
+                setState(STATE_CANCELLING);
+                close();
+
+                setState(STATE_CLOSED);
+                activeRequest = NULL;
+                _contentDecoder.reset();
+            } else if (activeRequest) {
+                SG_LOG(SG_IO, SG_INFO, "con:" << _connectionId << " cancelling non-active: " << r->url());
+
+                // has been sent but not active, let the active finish and
+                // then close. Otherwise cancelling request #2 would mess up
+                // active transfer #1
+                activeRequest->setCloseAfterComplete();
+            }
+        } // of request has been sent
+
+        // simpler case, not sent yet just remove from the queue
+        it = std::find(queuedRequests.begin(), queuedRequests.end(), r);
+        if (it != queuedRequests.end()) {
+            queuedRequests.erase(it);
+        }
+    }
+
     void beginResponse()
     {
         assert(!sentRequests.empty());
@@ -216,13 +306,14 @@ public:
 
         activeRequest = sentRequests.front();
         try {
+            SG_LOG(SG_IO, SG_DEBUG, "con:" << _connectionId << " saw start of response for " << activeRequest->url());
             activeRequest->responseStart(buffer);
         } catch (sg_exception& e) {
             handleError(EIO);
             return;
         }
 
-      state = STATE_GETTING_HEADERS;
+      setState(STATE_GETTING_HEADERS);
       buffer.clear();
       if (activeRequest->responseCode() == 204) {
         noMessageBody = true;
@@ -248,18 +339,19 @@ public:
         return;
       }
 
-      if (sentRequests.size() > MAX_INFLIGHT_REQUESTS) {
+      if (sentRequests.size() >= _maxPipelineLength) {
         return;
       }
 
       if (state == STATE_CLOSED) {
           if (!connectToHost()) {
-
+              setState(STATE_SOCKET_ERROR);
               return;
           }
 
+          SG_LOG(SG_IO, SG_DEBUG, "connection " << _connectionId << " connected.");
           setTerminator("\r\n");
-          state = STATE_IDLE;
+          setState(STATE_IDLE);
       }
 
       Request_ptr r = queuedRequests.front();
@@ -339,13 +431,13 @@ public:
           }
         }
 
-      //   SG_LOG(SG_IO, SG_INFO, "did start request:" << r->url() <<
-      //       "\n\t @ " << reinterpret_cast<void*>(r.ptr()) <<
-      //      "\n\t on connection " << this);
+        SG_LOG(SG_IO, SG_DEBUG, "con:" << _connectionId << " did send request:" << r->url());
       // successfully sent, remove from queue, and maybe send the next
       queuedRequests.pop_front();
       sentRequests.push_back(r);
-      state = STATE_WAITING_FOR_RESPONSE;
+      if (state == STATE_IDLE) {
+          setState(STATE_WAITING_FOR_RESPONSE);
+      }
 
       // pipelining, let's maybe send the next request right away
       tryStartNextRequest();
@@ -386,7 +478,7 @@ public:
 
         case STATE_GETTING_CHUNKED_BYTES:
             setTerminator("\r\n");
-            state = STATE_GETTING_CHUNKED;
+            setState(STATE_GETTING_CHUNKED);
             buffer.clear();
             break;
 
@@ -406,21 +498,23 @@ public:
 
     bool hasIdleTimeout() const
     {
-        if (state != STATE_IDLE) {
+        if ((state != STATE_IDLE) && (state != STATE_CLOSED)) {
             return false;
         }
 
         assert(sentRequests.empty());
-        return idleTime.elapsedMSec() > 1000 * 10; // ten seconds
+        bool isTimedOut = (idleTime.elapsedMSec() > (1000 * 10)); // 10 seconds
+        return isTimedOut;
     }
 
     bool hasErrorTimeout() const
     {
-      if (state == STATE_IDLE) {
+      if ((state == STATE_IDLE) || (state == STATE_CLOSED)) {
         return false;
       }
 
-      return idleTime.elapsedMSec() > (1000 * 30); // 30 seconds
+        bool isTimedOut = (idleTime.elapsedMSec() > (1000 * 30)); // 30 seconds
+        return isTimedOut;
     }
 
     bool hasError() const
@@ -430,24 +524,71 @@ public:
 
     bool shouldStartNext() const
     {
-      return !queuedRequests.empty() && (sentRequests.size() < MAX_INFLIGHT_REQUESTS);
+      return !queuedRequests.empty() && (sentRequests.size() < _maxPipelineLength);
     }
 
     bool isActive() const
     {
         return !queuedRequests.empty() || !sentRequests.empty();
     }
+
+    std::string connectionId() const
+    {
+        return _connectionId;
+    }
+
+    void debugDumpRequests() const
+    {
+        SG_LOG(SG_IO, SG_DEBUG, "requests for:" << host << ":" << port << " (conId=" << _connectionId
+               << "; state=" << state << ")");
+        if (activeRequest) {
+            SG_LOG(SG_IO, SG_DEBUG, "\tactive:" << activeRequest->url());
+        } else {
+            SG_LOG(SG_IO, SG_DEBUG, "\tNo active request");
+        }
+
+        BOOST_FOREACH(Request_ptr req, sentRequests) {
+            SG_LOG(SG_IO, SG_DEBUG, "\tsent:" << req->url());
+        }
+
+        BOOST_FOREACH(Request_ptr req, queuedRequests) {
+            SG_LOG(SG_IO, SG_DEBUG, "\tqueued:" << req->url());
+        }
+    }
 private:
+    enum ConnectionState {
+        STATE_IDLE = 0,
+        STATE_WAITING_FOR_RESPONSE,
+        STATE_GETTING_HEADERS,
+        STATE_GETTING_BODY,
+        STATE_GETTING_CHUNKED,
+        STATE_GETTING_CHUNKED_BYTES,
+        STATE_GETTING_TRAILER,
+        STATE_SOCKET_ERROR,
+        STATE_CANCELLING,        ///< cancelling an acitve request
+        STATE_CLOSED             ///< connection should be closed now
+    };
+
+    void setState(ConnectionState newState)
+    {
+        if (state == newState) {
+            return;
+        }
+
+        state = newState;
+    }
+
     bool connectToHost()
     {
         SG_LOG(SG_IO, SG_DEBUG, "HTTP connecting to " << host << ":" << port);
 
         if (!open()) {
-            SG_LOG(SG_ALL, SG_WARN, "HTTP::Connection: connectToHost: open() failed");
+            SG_LOG(SG_IO, SG_WARN, "HTTP::Connection: connectToHost: open() failed");
             return false;
         }
 
         if (connect(host.c_str(), port) != 0) {
+            SG_LOG(SG_IO, SG_WARN, "HTTP::Connection: connectToHost: connect() failed");
             return false;
         }
 
@@ -523,11 +664,11 @@ private:
 
         buffer.clear();
         if (chunkSize == 0) {  //  trailer start
-            state = STATE_GETTING_TRAILER;
+            setState(STATE_GETTING_TRAILER);
             return;
         }
 
-        state = STATE_GETTING_CHUNKED_BYTES;
+        setState(STATE_GETTING_CHUNKED_BYTES);
         setByteCount(chunkSize);
     }
 
@@ -548,16 +689,21 @@ private:
         activeRequest->responseHeadersComplete();
         _contentDecoder.initWithRequest(activeRequest);
 
+        if (!activeRequest->serverSupportsPipelining()) {
+            SG_LOG(SG_IO, SG_DEBUG, _connectionId << " disabling pipelining since server does not support it");
+            _maxPipelineLength = 1;
+        }
+
         if (chunkedTransfer) {
-            state = STATE_GETTING_CHUNKED;
+            setState(STATE_GETTING_CHUNKED);
         } else if (noMessageBody || (bodyTransferSize == 0)) {
             // force the state to GETTING_BODY, to simplify logic in
             // responseComplete and handleClose
-            state = STATE_GETTING_BODY;
+            setState(STATE_GETTING_BODY);
             responseComplete();
         } else {
             setByteCount(bodyTransferSize); // may be -1, that's fine
-            state = STATE_GETTING_BODY;
+            setState(STATE_GETTING_BODY);
         }
     }
 
@@ -573,6 +719,7 @@ private:
 
         if ((state == STATE_GETTING_BODY) || (state == STATE_GETTING_TRAILER)) {
             if (doClose) {
+                SG_LOG(SG_IO, SG_DEBUG, _connectionId << " doClose requested");
           // this will bring us into handleClose() above, which updates
           // state to STATE_CLOSED
               close();
@@ -583,30 +730,17 @@ private:
         }
 
         if (state != STATE_CLOSED)  {
-            state = sentRequests.empty() ? STATE_IDLE : STATE_WAITING_FOR_RESPONSE;
+            setState(sentRequests.empty() ? STATE_IDLE : STATE_WAITING_FOR_RESPONSE);
         }
 
     // notify request after we change state, so this connection is idle
     // if completion triggers other requests (which is likely)
-        //   SG_LOG(SG_IO, SG_INFO, "*** responseComplete:" << activeRequest->url());
         completedRequest->responseComplete();
         client->requestFinished(this);
 
         setTerminator("\r\n");
     }
 
-    enum ConnectionState {
-        STATE_IDLE = 0,
-        STATE_WAITING_FOR_RESPONSE,
-        STATE_GETTING_HEADERS,
-        STATE_GETTING_BODY,
-        STATE_GETTING_CHUNKED,
-        STATE_GETTING_CHUNKED_BYTES,
-        STATE_GETTING_TRAILER,
-        STATE_SOCKET_ERROR,
-        STATE_CLOSED             ///< connection should be closed now
-    };
-
     Client* client;
     Request_ptr activeRequest;
     ConnectionState state;
@@ -622,36 +756,116 @@ private:
     RequestList sentRequests;
 
     ContentDecoder _contentDecoder;
+    std::string _connectionId;
+    unsigned int _maxPipelineLength;
 };
+#endif // of !ENABLE_CURL
 
 Client::Client() :
     d(new ClientPrivate)
 {
     d->proxyPort = 0;
     d->maxConnections = 4;
+    d->maxHostConnections = 4;
     d->bytesTransferred = 0;
     d->lastTransferRate = 0;
     d->timeTransferSample.stamp();
     d->totalBytesDownloaded = 0;
-    
+    d->maxPipelineDepth = 5;
     setUserAgent("SimGear-" SG_STRINGIZE(SIMGEAR_VERSION));
+#if defined(ENABLE_CURL)
+    static bool didInitCurlGlobal = false;
+    if (!didInitCurlGlobal) {
+      curl_global_init(CURL_GLOBAL_ALL);
+      didInitCurlGlobal = true;
+    }
+
+    d->createCurlMulti();
+#endif
 }
 
 Client::~Client()
 {
+#if defined(ENABLE_CURL)
+  curl_multi_cleanup(d->curlMulti);
+#endif
 }
 
 void Client::setMaxConnections(unsigned int maxCon)
 {
-    if (maxCon < 1) {
-        throw sg_range_exception("illegal HTTP::Client::setMaxConnections value");
-    }
-    
     d->maxConnections = maxCon;
+#if defined(ENABLE_CURL)
+    curl_multi_setopt(d->curlMulti, CURLMOPT_MAX_TOTAL_CONNECTIONS, (long) maxCon);
+#endif
+}
+
+void Client::setMaxHostConnections(unsigned int maxHostCon)
+{
+    d->maxHostConnections = maxHostCon;
+#if defined(ENABLE_CURL)
+    curl_multi_setopt(d->curlMulti, CURLMOPT_MAX_HOST_CONNECTIONS, (long) maxHostCon);
+#endif
+}
+
+void Client::setMaxPipelineDepth(unsigned int depth)
+{
+    d->maxPipelineDepth = depth;
+#if defined(ENABLE_CURL)
+    curl_multi_setopt(d->curlMulti, CURLMOPT_MAX_PIPELINE_LENGTH, (long) depth);
+#else
+    ConnectionDict::iterator it = d->connections.begin();
+    for (; it != d->connections.end(); ) {
+        it->second->setMaxPipelineLength(depth);
+    }
+#endif
 }
 
 void Client::update(int waitTimeout)
 {
+#if defined(ENABLE_CURL)
+    int remainingActive, messagesInQueue;
+    curl_multi_perform(d->curlMulti, &remainingActive);
+
+    CURLMsg* msg;
+    while ((msg = curl_multi_info_read(d->curlMulti, &messagesInQueue))) {
+      if (msg->msg == CURLMSG_DONE) {
+        Request* rawReq = 0;
+        CURL *e = msg->easy_handle;
+        curl_easy_getinfo(e, CURLINFO_PRIVATE, &rawReq);
+
+        // ensure request stays valid for the moment
+        // eg if responseComplete cancels us
+        Request_ptr req(rawReq);
+
+        long responseCode;
+        curl_easy_getinfo(e, CURLINFO_RESPONSE_CODE, &responseCode);
+
+          // remove from the requests map now,
+          // in case the callbacks perform a cancel. We'll use
+          // the absence from the request dict in cancel to avoid
+          // a double remove
+          ClientPrivate::RequestCurlMap::iterator it = d->requests.find(req);
+          assert(it != d->requests.end());
+          assert(it->second == e);
+          d->requests.erase(it);
+
+        if (msg->data.result == 0) {
+          req->responseComplete();
+        } else {
+          SG_LOG(SG_IO, SG_WARN, "CURL Result:" << msg->data.result << " " << curl_easy_strerror(msg->data.result));
+          req->setFailure(msg->data.result, curl_easy_strerror(msg->data.result));
+        }
+
+        curl_multi_remove_handle(d->curlMulti, e);
+        curl_easy_cleanup(e);
+      } else {
+          // should never happen since CURLMSG_DONE is the only code
+          // defined!
+          SG_LOG(SG_IO, SG_ALERT, "unknown CurlMSG:" << msg->msg);
+      }
+    } // of curl message processing loop
+    SGTimeStamp::sleepForMSec(waitTimeout);
+#else
     if (!d->poller.hasChannels() && (waitTimeout > 0)) {
         SGTimeStamp::sleepForMSec(waitTimeout);
     } else {
@@ -697,6 +911,7 @@ void Client::update(int waitTimeout)
             makeRequest(req);
         }
     }
+#endif
 }
 
 void Client::makeRequest(const Request_ptr& r)
@@ -709,18 +924,100 @@ void Client::makeRequest(const Request_ptr& r)
         return;
     }
 
+    r->_client = this;
+
+#if defined(ENABLE_CURL)
+    ClientPrivate::RequestCurlMap::iterator rit = d->requests.find(r);
+    assert(rit == d->requests.end());
+
+    CURL* curlRequest = curl_easy_init();
+    curl_easy_setopt(curlRequest, CURLOPT_URL, r->url().c_str());
+
+    d->requests[r] = curlRequest;
+
+    curl_easy_setopt(curlRequest, CURLOPT_PRIVATE, r.get());
+    // disable built-in libCurl progress feedback
+    curl_easy_setopt(curlRequest, CURLOPT_NOPROGRESS, 1);
+
+    curl_easy_setopt(curlRequest, CURLOPT_WRITEFUNCTION, requestWriteCallback);
+    curl_easy_setopt(curlRequest, CURLOPT_WRITEDATA, r.get());
+    curl_easy_setopt(curlRequest, CURLOPT_HEADERFUNCTION, requestHeaderCallback);
+    curl_easy_setopt(curlRequest, CURLOPT_HEADERDATA, r.get());
+
+    curl_easy_setopt(curlRequest, CURLOPT_USERAGENT, d->userAgent.c_str());
+    curl_easy_setopt(curlRequest, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
+
+    if (!d->proxy.empty()) {
+      curl_easy_setopt(curlRequest, CURLOPT_PROXY, d->proxy.c_str());
+      curl_easy_setopt(curlRequest, CURLOPT_PROXYPORT, d->proxyPort);
+
+      if (!d->proxyAuth.empty()) {
+        curl_easy_setopt(curlRequest, CURLOPT_PROXYAUTH, CURLAUTH_BASIC);
+        curl_easy_setopt(curlRequest, CURLOPT_PROXYUSERPWD, d->proxyAuth.c_str());
+      }
+    }
+
+    std::string method = boost::to_lower_copy(r->method());
+    if (method == "get") {
+      curl_easy_setopt(curlRequest, CURLOPT_HTTPGET, 1);
+    } else if (method == "put") {
+      curl_easy_setopt(curlRequest, CURLOPT_PUT, 1);
+      curl_easy_setopt(curlRequest, CURLOPT_UPLOAD, 1);
+    } else if (method == "post") {
+      // see http://curl.haxx.se/libcurl/c/CURLOPT_POST.html
+      curl_easy_setopt(curlRequest, CURLOPT_HTTPPOST, 1);
+
+      std::string q = r->query().substr(1);
+      curl_easy_setopt(curlRequest, CURLOPT_COPYPOSTFIELDS, q.c_str());
+
+      // reset URL to exclude query pieces
+      std::string urlWithoutQuery = r->url();
+      std::string::size_type queryPos = urlWithoutQuery.find('?');
+      urlWithoutQuery.resize(queryPos);
+      curl_easy_setopt(curlRequest, CURLOPT_URL, urlWithoutQuery.c_str());
+    } else {
+      curl_easy_setopt(curlRequest, CURLOPT_CUSTOMREQUEST, r->method().c_str());
+    }
+
+    struct curl_slist* headerList = NULL;
+    if (r->hasBodyData() && (method != "post")) {
+      curl_easy_setopt(curlRequest, CURLOPT_UPLOAD, 1);
+      curl_easy_setopt(curlRequest, CURLOPT_INFILESIZE, r->bodyLength());
+      curl_easy_setopt(curlRequest, CURLOPT_READFUNCTION, requestReadCallback);
+      curl_easy_setopt(curlRequest, CURLOPT_READDATA, r.get());
+      std::string h = "Content-Type:" + r->bodyType();
+      headerList = curl_slist_append(headerList, h.c_str());
+    }
+
+    StringMap::const_iterator it;
+    for (it = r->requestHeaders().begin(); it != r->requestHeaders().end(); ++it) {
+      std::string h = it->first + ": " + it->second;
+      headerList = curl_slist_append(headerList, h.c_str());
+    }
+
+    if (headerList != NULL) {
+      curl_easy_setopt(curlRequest, CURLOPT_HTTPHEADER, headerList);
+    }
+
+    curl_multi_add_handle(d->curlMulti, curlRequest);
+
+// this seems premature, but we don't have a callback from Curl we could
+// use to trigger when the requst is actually sent.
+    r->requestStart();
+
+#else
     if( r->url().find("http://") != 0 ) {
         r->setFailure(EINVAL, "only HTTP protocol is supported");
         return;
     }
-    
+
     std::string host = r->host();
     int port = r->port();
     if (!d->proxy.empty()) {
         host = d->proxy;
         port = d->proxyPort;
     }
-    
+
     Connection* con = NULL;
     std::stringstream ss;
     ss << host << "-" << port;
@@ -754,26 +1051,64 @@ void Client::makeRequest(const Request_ptr& r)
         }
     }
 
-    if (!con && atConnectionsLimit) {
+    bool atHostConnectionsLimit = (count >= d->maxHostConnections);
+
+    if (!con && (atConnectionsLimit || atHostConnectionsLimit)) {
         // all current connections are busy (active), and we don't
         // have free connections to allocate, so let's assign to
         // an existing one randomly. Ideally we'd used whichever one will
         // complete first but we don't have that info.
         int index = rand() % count;
-        for (it = d->connections.find(connectionId); index > 0; --index) { ; }
+        for (it = d->connections.find(connectionId); index > 0; --index, ++it) { ; }
         con = it->second;
     }
 
     // allocate a new connection object
     if (!con) {
-        con = new Connection(this);
+        static int connectionSuffx = 0;
+
+        std::stringstream ss;
+        ss << connectionId << "-" << connectionSuffx++;
+
+        SG_LOG(SG_IO, SG_DEBUG, "allocating new connection for ID:" << ss.str());
+        con = new Connection(this, ss.str());
         con->setServer(host, port);
+        con->setMaxPipelineLength(d->maxPipelineDepth);
         d->poller.addChannel(con);
         d->connections.insert(d->connections.end(),
             ConnectionDict::value_type(connectionId, con));
     }
 
+    SG_LOG(SG_IO, SG_DEBUG, "queing request for " << r->url() << " on:" << con->connectionId());
     con->queueRequest(r);
+#endif
+}
+
+void Client::cancelRequest(const Request_ptr &r, std::string reason)
+{
+#if defined(ENABLE_CURL)
+    ClientPrivate::RequestCurlMap::iterator it = d->requests.find(r);
+    if(it == d->requests.end()) {
+        // already being removed, presumably inside ::update()
+        // nothing more to do
+        return;
+    }
+
+    CURLMcode err = curl_multi_remove_handle(d->curlMulti, it->second);
+    assert(err == CURLM_OK);
+
+    // clear the request pointer form the curl-easy object
+    curl_easy_setopt(it->second, CURLOPT_PRIVATE, 0);
+
+    curl_easy_cleanup(it->second);
+    d->requests.erase(it);
+#else
+    ConnectionDict::iterator it = d->connections.begin();
+    for (; it != d->connections.end(); ++it) {
+        (it->second)->cancelRequest(r);
+    }
+#endif
+    r->setFailure(-1, reason);
 }
 
 //------------------------------------------------------------------------------
@@ -829,12 +1164,16 @@ void Client::setProxy( const std::string& proxy,
 
 bool Client::hasActiveRequests() const
 {
+  #if defined(ENABLE_CURL)
+    return !d->requests.empty();
+  #else
     ConnectionDict::const_iterator it = d->connections.begin();
     for (; it != d->connections.end(); ++it) {
         if (it->second->isActive()) return true;
     }
 
     return false;
+#endif
 }
 
 void Client::receivedBytes(unsigned int count)
@@ -874,6 +1213,101 @@ uint64_t Client::totalBytesDownloaded() const
     return d->totalBytesDownloaded;
 }
 
+size_t Client::requestWriteCallback(char *ptr, size_t size, size_t nmemb, void *userdata)
+{
+  size_t byteSize = size * nmemb;
+  Request* req = static_cast<Request*>(userdata);
+  req->processBodyBytes(ptr, byteSize);
+
+  Client* cl = req->http();
+  if (cl) {
+    cl->receivedBytes(byteSize);
+  }
+
+  return byteSize;
+}
+
+size_t Client::requestReadCallback(char *ptr, size_t size, size_t nmemb, void *userdata)
+{
+  size_t maxBytes = size * nmemb;
+  Request* req = static_cast<Request*>(userdata);
+  size_t actualBytes = req->getBodyData(ptr, 0, maxBytes);
+  return actualBytes;
+}
+
+size_t Client::requestHeaderCallback(char *rawBuffer, size_t size, size_t nitems, void *userdata)
+{
+  size_t byteSize = size * nitems;
+  Request* req = static_cast<Request*>(userdata);
+  std::string h = strutils::simplify(std::string(rawBuffer, byteSize));
+
+  if (req->readyState() == HTTP::Request::OPENED) {
+    req->responseStart(h);
+    return byteSize;
+  }
+
+  if (h.empty()) {
+      // got a 100-continue reponse; restart
+      if (req->responseCode() == 100) {
+          req->setReadyState(HTTP::Request::OPENED);
+          return byteSize;
+      }
+
+    req->responseHeadersComplete();
+    return byteSize;
+  }
+
+  if (req->responseCode() == 100) {
+      return byteSize; // skip headers associated with 100-continue status
+  }
+
+  size_t colonPos = h.find(':');
+  if (colonPos == std::string::npos) {
+      SG_LOG(SG_IO, SG_WARN, "malformed HTTP response header:" << h);
+      return byteSize;
+  }
+
+  std::string key = strutils::simplify(h.substr(0, colonPos));
+  std::string lkey = boost::to_lower_copy(key);
+  std::string value = strutils::strip(h.substr(colonPos + 1));
+
+  req->responseHeader(lkey, value);
+  return byteSize;
+}
+
+void Client::debugDumpRequests()
+{
+#if defined(ENABLE_CURL)
+    SG_LOG(SG_IO, SG_INFO, "== HTTP request dump");
+    ClientPrivate::RequestCurlMap::iterator it = d->requests.begin();
+    for (; it != d->requests.end(); ++it) {
+        SG_LOG(SG_IO, SG_INFO, "\t" << it->first->url());
+    }
+    SG_LOG(SG_IO, SG_INFO, "==");
+#else
+    SG_LOG(SG_IO, SG_INFO, "== HTTP connection dump");
+    ConnectionDict::iterator it = d->connections.begin();
+    for (; it != d->connections.end(); ++it) {
+        it->second->debugDumpRequests();
+    }
+    SG_LOG(SG_IO, SG_INFO, "==");
+#endif
+}
+
+void Client::clearAllConnections()
+{
+#if defined(ENABLE_CURL)
+    curl_multi_cleanup(d->curlMulti);
+    d->createCurlMulti();
+#else
+    ConnectionDict::iterator it = d->connections.begin();
+    for (; it != d->connections.end(); ++it) {
+        delete it->second;
+    }
+    d->connections.clear();
+#endif
+}
+
 } // of namespace HTTP
 
 } // of namespace simgear