Make XrdHTTP able to forward HTTP requests to an external, optional p…

…lugin (conceptually similar to CGI). Various stability fixes and improvements.

src/XrdHeaders.cmake

@@ -104,6 +104,7 @@ set( XROOTD_PUBLIC_HEADERS
   XrdXrootd/XrdXrootdMonData.hh
   XrdXrootd/XrdXrootdBridge.hh
   XrdHttp/XrdHttpSecXtractor.hh
+  XrdHttp/XrdHttpExtHandler.hh
 )
 
 set( XROOTD_PRIVATE_HEADERS

src/XrdHttp.cmake

@@ -21,6 +21,7 @@ if( BUILD_HTTP )
     XrdHttp/XrdHttpProtocol.cc    XrdHttp/XrdHttpProtocol.hh
     XrdHttp/XrdHttpReq.cc         XrdHttp/XrdHttpReq.hh
                                   XrdHttp/XrdHttpSecXtractor.hh
+    XrdHttp/XrdHttpExtHandler.cc  XrdHttp/XrdHttpExtHandler.hh
                                   XrdHttp/XrdHttpStatic.hh
     XrdHttp/XrdHttpTrace.cc       XrdHttp/XrdHttpTrace.hh
     XrdHttp/XrdHttpUtils.cc       XrdHttp/XrdHttpUtils.hh )

src/XrdHttp/XrdHttpExtHandler.cc

@@ -0,0 +1,68 @@
+//------------------------------------------------------------------------------
+// This file is part of XrdHTTP: A pragmatic implementation of the
+// HTTP/WebDAV protocol for the Xrootd framework
+//
+// Copyright (c) 2017 by European Organization for Nuclear Research (CERN)
+// Author: Fabrizio Furano <furano@cern.ch>
+// File Date: May 2017
+//------------------------------------------------------------------------------
+// XRootD is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// XRootD is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with XRootD.  If not, see <http://www.gnu.org/licenses/>.
+//------------------------------------------------------------------------------
+
+
+
+#include "XrdHttpExtHandler.hh"
+#include "XrdHttpReq.hh"
+#include "XrdHttpProtocol.hh"
+
+/// Sends a basic response. If the length is < 0 then it is calculated internally
+int XrdHttpExtReq::SendSimpleResp(int code, char* desc, char* header_to_add, char* body, long long int bodylen)
+{
+  if (!prot) return -1;
+
+  return prot->SendSimpleResp(code, desc, header_to_add, body, bodylen);
+}
+
+int XrdHttpExtReq::BuffgetData(int blen, char **data, bool wait) {
+
+  if (!prot) return -1;
+  int nb = prot->BuffgetData(blen, data, wait);
+
+  return nb;
+}
+
+
+XrdHttpExtReq::XrdHttpExtReq(XrdHttpReq *req, XrdHttpProtocol *pr): prot(pr),
+verb(req->requestverb), headers(req->allheaders) {
+  // Here we fill the request summary with all the fields we can
+  resource = req->resource.c_str();
+
+  // These fields usually identify the client that connected
+
+
+  if (prot->SecEntity.moninfo) {
+    clientdn = prot->SecEntity.moninfo;
+    trim(clientdn);
+  }
+  if (prot->SecEntity.host) {
+    clienthost = prot->SecEntity.host;
+    trim(clienthost);
+  }
+  if (prot->SecEntity.vorg) {
+    clientgroups = prot->SecEntity.vorg;
+    trim(clientgroups);
+  }
+
+  length = req->length;
+}

src/XrdHttp/XrdHttpExtHandler.hh

@@ -0,0 +1,142 @@
+//------------------------------------------------------------------------------
+// This file is part of XrdHTTP: A pragmatic implementation of the
+// HTTP/WebDAV protocol for the Xrootd framework
+//
+// Copyright (c) 2017 by European Organization for Nuclear Research (CERN)
+// Author: Fabrizio Furano <furano@cern.ch>
+// File Date: May 2017
+//------------------------------------------------------------------------------
+// XRootD is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// XRootD is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with XRootD.  If not, see <http://www.gnu.org/licenses/>.
+//------------------------------------------------------------------------------
+
+
+
+
+
+
+
+
+
+
+
+#ifndef __XRDHTTPEXTHANDLER_H__
+#define __XRDHTTPEXTHANDLER_H__
+
+#include <map>
+#include <string>
+
+class XrdLink;
+class XrdSecEntity;
+class XrdHttpReq;
+class XrdHttpProtocol;
+
+// This class summarizes the content of a request, for consumption by an external plugin
+class XrdHttpExtReq {
+private:
+  XrdHttpProtocol *prot;
+
+public:
+  XrdHttpExtReq(XrdHttpReq *req, XrdHttpProtocol *pr);
+
+  std::string verb, resource;
+  std::map<std::string, std::string> &headers;
+
+  std::string clientdn, clienthost, clientgroups;
+  long long length;
+
+  /// Get a pointer to data read from the client, valid for up to blen bytes from the buffer. Returns the validity
+  int BuffgetData(int blen, char **data, bool wait);
+
+  /// Sends a basic response. If the length is < 0 then it is calculated internally
+  int SendSimpleResp(int code, char *desc, char *header_to_add, char *body, long long bodylen);
+};
+
+
+/// Base class for a plugin that can handle requests for urls that match
+/// a certain set of prefixes
+class XrdHttpExtHandler {
+
+public:
+
+  /// Tells if the incoming path is recognized as one of the paths that have to be processed
+  // e.g. applying a prefix matching scheme or whatever
+  virtual bool MatchesPath(const char *path) = 0;
+
+  /// Process an HTTP request and send the response using the calling
+  ///  XrdHttpProtocol instance directly
+  /// Returns 0 if ok, non0 if errors
+  virtual int ProcessReq(XrdHttpExtReq &) = 0;
+
+  /// Initializes the external request handler
+  virtual int Init(const char *cfgfile) = 0;
+
+  //------------------------------------------------------------------------------
+  //! Constructor
+  //------------------------------------------------------------------------------
+
+  XrdHttpExtHandler() {}
+
+  //------------------------------------------------------------------------------
+  //! Destructor
+  //------------------------------------------------------------------------------
+
+  virtual     ~XrdHttpExtHandler() {}
+};
+
+/******************************************************************************/
+/*                    X r d H t t p G e t E x t H a n d l e   r               */
+/******************************************************************************/
+
+//------------------------------------------------------------------------------
+//! Obtain an instance of the XrdHttpExtHandler object.
+//!
+//! This extern "C" function is called when a shared library plug-in containing
+//! implementation of this class is loaded. It must exist in the shared library
+//! and must be thread-safe.
+//!
+//! @param  eDest -> The error object that must be used to print any errors or
+//!                  other messages (see XrdSysError.hh).
+//! @param  confg -> Name of the configuration file that was used. This pointer
+//!                  may be null though that would be impossible.
+//! @param  parms -> Argument string specified on the namelib directive. It may
+//!                  be null or point to a null string if no parms exist.
+//!
+//! @return Success: A pointer to an instance of the XrdHttpSecXtractor object.
+//!         Failure: A null pointer which causes initialization to fail.
+//!
+
+//------------------------------------------------------------------------------
+
+class XrdSysError;
+
+#define XrdHttpExtHandlerArgs XrdSysError       *eDest, \
+                              const char        *confg, \
+                              const char        *parms
+
+extern "C" XrdHttpExtHandler *XrdHttpGetExtHandler(XrdHttpExtHandlerArgs);
+
+//------------------------------------------------------------------------------
+//! Declare compilation version.
+//!
+//! Additionally, you *should* declare the xrootd version you used to compile
+//! your plug-in. While not currently required, it is highly recommended to
+//! avoid execution issues should the class definition change. Declare it as:
+//------------------------------------------------------------------------------
+
+/*! #include "XrdVersion.hh"
+ *    XrdVERSIONINFO(XrdHttpGetExtHandler,<name>);
+ * 
+ *    where <name> is a 1- to 15-character unquoted name identifying your plugin.
+ */
+#endif