OPeNDAP Hyrax Back End Server (BES) Updated for version 3.8.3
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00001 // BESStreamResponseHandler.cc 00002 00003 // This file is part of bes, A C++ back-end server implementation framework 00004 // for the OPeNDAP Data Access Protocol. 00005 00006 // Copyright (c) 2004-2009 University Corporation for Atmospheric Research 00007 // Author: Patrick West <pwest@ucar.edu> and Jose Garcia <jgarcia@ucar.edu> 00008 // 00009 // This library is free software; you can redistribute it and/or 00010 // modify it under the terms of the GNU Lesser General Public 00011 // License as published by the Free Software Foundatiion; either 00012 // version 2.1 of the License, or (at your option) any later version. 00013 // 00014 // This library is distributed in the hope that it will be useful, 00015 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00016 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00017 // Lesser General Public License for more details. 00018 // 00019 // You should have received a copy of the GNU Lesser General Public 00020 // License along with this library; if not, write to the Free Software 00021 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 00022 // 00023 // You can contact University Corporation for Atmospheric Research at 00024 // 3080 Center Green Drive, Boulder, CO 80301 00025 00026 // (c) COPYRIGHT University Corporation for Atmospheric Research 2004-2005 00027 // Please read the full copyright statement in the file COPYRIGHT_UCAR. 00028 // 00029 // Authors: 00030 // pwest Patrick West <pwest@ucar.edu> 00031 // jgarcia Jose Garcia <jgarcia@ucar.edu> 00032 00033 #include <cerrno> 00034 #include <iostream> 00035 #include <fstream> 00036 #include <string> 00037 #include <cstring> 00038 00039 using std::ifstream ; 00040 using std::ios ; 00041 using std::endl ; 00042 using std::string ; 00043 00044 #include "BESStreamResponseHandler.h" 00045 #include "BESRequestHandlerList.h" 00046 #include "BESNotFoundError.h" 00047 #include "BESInternalError.h" 00048 #include "BESDataNames.h" 00049 #include "BESContainer.h" 00050 00051 #define BES_STREAM_BUFFER_SIZE 4096 00052 00053 BESStreamResponseHandler::BESStreamResponseHandler( const string &name ) 00054 : BESResponseHandler( name ) 00055 { 00056 } 00057 00058 BESStreamResponseHandler::~BESStreamResponseHandler( ) 00059 { 00060 } 00061 00072 void 00073 BESStreamResponseHandler::execute( BESDataHandlerInterface &dhi ) 00074 { 00075 _response = 0 ; 00076 00077 // What if there is a special way to stream back a data file? 00078 // Should we pass this off to the request handlers and put 00079 // this code into a different class for reuse? For now 00080 // just keep it here. pcw 10/11/06 00081 00082 // I thought about putting this in the transmit method below 00083 // but decided that this is like executing a non-buffered 00084 // request, so kept it here. Plus the idea expressed above 00085 // led me to leave the code in the execute method. 00086 // pcw 10/11/06 00087 if( dhi.containers.size() != 1 ) 00088 { 00089 string err = (string)"Unable to stream file: " 00090 + "no container specified" ; 00091 throw BESInternalError( err, __FILE__, __LINE__ ) ; 00092 } 00093 00094 dhi.first_container() ; 00095 BESContainer *container = dhi.container ; 00096 string filename = container->access() ; 00097 if( filename.empty() ) 00098 { 00099 string err = (string)"Unable to stream file: " 00100 + "filename not specified" ; 00101 throw BESInternalError( err, __FILE__, __LINE__ ) ; 00102 } 00103 00104 int bytes = 0 ; 00105 ifstream os ; 00106 os.open( filename.c_str(), ios::in ) ; 00107 int myerrno = errno ; 00108 if( !os ) 00109 { 00110 string serr = (string)"Unable to stream file: " 00111 + "cannot open file " 00112 + filename + ": " ; 00113 char *err = strerror( myerrno ) ; 00114 if( err ) 00115 serr += err ; 00116 else 00117 serr += "Unknown error" ; 00118 00119 throw BESNotFoundError( err, __FILE__, __LINE__ ) ; 00120 } 00121 00122 int nbytes ; 00123 char block[BES_STREAM_BUFFER_SIZE] ; 00124 os.read( block, sizeof block ) ; 00125 nbytes = os.gcount() ; 00126 while( nbytes ) 00127 { 00128 bytes += nbytes ; 00129 dhi.get_output_stream().write( (char*)block, nbytes ) ; 00130 os.read( block, sizeof block ) ; 00131 nbytes = os.gcount() ; 00132 } 00133 os.close() ; 00134 } 00135 00143 void 00144 BESStreamResponseHandler::transmit( BESTransmitter *transmitter, 00145 BESDataHandlerInterface &dhi ) 00146 { 00147 // The Data is transmitted when it is read, dumped to stdout, so there is nothing 00148 // to transmot here. 00149 } 00150 00157 void 00158 BESStreamResponseHandler::dump( ostream &strm ) const 00159 { 00160 strm << BESIndent::LMarg << "BESStreamResponseHandler::dump - (" 00161 << (void *)this << ")" << endl ; 00162 BESIndent::Indent() ; 00163 BESResponseHandler::dump( strm ) ; 00164 BESIndent::UnIndent() ; 00165 } 00166 00167 BESResponseHandler * 00168 BESStreamResponseHandler::BESStreamResponseBuilder( const string &name ) 00169 { 00170 return new BESStreamResponseHandler( name ) ; 00171 } 00172