src/filter_query_rewrite.cpp

   1 /* This file is part of Metaproxy.
   2    Copyright (C) 2005-2008 Index Data
   3
   4 Metaproxy is free software; you can redistribute it and/or modify it under
   5 the terms of the GNU General Public License as published by the Free
   6 Software Foundation; either version 2, or (at your option) any later
   7 version.
   8
   9 Metaproxy is distributed in the hope that it will be useful, but WITHOUT ANY
  10 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18
  19 #include "config.hpp"
  20 #include "filter.hpp"
  21 #include "package.hpp"
  22
  23 #include "util.hpp"
  24 #include "xmlutil.hpp"
  25 #include "filter_query_rewrite.hpp"
  26
  27 #include <yaz/zgdu.h>
  28 #include <yaz/xmlquery.h>
  29 #include <yaz/diagbib1.h>
  30
  31 #include <libxslt/xsltutils.h>
  32 #include <libxslt/transform.h>
  33
  34 namespace mp = metaproxy_1;
  35 namespace yf = mp::filter;
  36
  37 namespace metaproxy_1 {
  38     namespace filter {
  39         class QueryRewrite::Rep {
  40         public:
  41             Rep();
  42             ~Rep();
  43             void process(mp::Package &package) const;
  44             void configure(const xmlNode * ptr);
  45         private:
  46             xsltStylesheetPtr m_stylesheet;
  47         };
  48     }
  49 }
  50
  51 yf::QueryRewrite::Rep::Rep()
  52 {
  53     m_stylesheet = 0;
  54 }
  55
  56 yf::QueryRewrite::Rep::~Rep()
  57 {
  58     if (m_stylesheet)
  59         xsltFreeStylesheet(m_stylesheet);
  60 }
  61
  62 yf::QueryRewrite::QueryRewrite() : m_p(new Rep)
  63 {
  64 }
  65
  66 yf::QueryRewrite::~QueryRewrite()
  67 {  // must have a destructor because of boost::scoped_ptr
  68 }
  69
  70 void yf::QueryRewrite::process(mp::Package &package) const
  71 {
  72     m_p->process(package);
  73 }
  74
  75 void mp::filter::QueryRewrite::configure(const xmlNode *ptr, bool test_only)
  76 {
  77     m_p->configure(ptr);
  78 }
  79
  80 void yf::QueryRewrite::Rep::process(mp::Package &package) const
  81 {
  82     Z_GDU *gdu = package.request().get();
  83
  84     if (gdu && gdu->which == Z_GDU_Z3950)
  85     {
  86         Z_APDU *apdu_req = gdu->u.z3950;
  87         if (apdu_req->which == Z_APDU_searchRequest)
  88         {
  89             int error_code = 0;
  90             const char *addinfo = 0;
  91             mp::odr odr;
  92             Z_SearchRequest *req = apdu_req->u.searchRequest;
  93
  94             xmlDocPtr doc_input = 0;
  95             yaz_query2xml(req->query, &doc_input);
  96
  97             if (!doc_input)
  98             {
  99                 error_code = YAZ_BIB1_MALFORMED_QUERY;
 100                 addinfo = "converion from Query to XML failed";
 101             }
 102             else
 103             {
 104                 if (m_stylesheet)
 105                 {
 106                     xmlDocPtr doc_res = xsltApplyStylesheet(m_stylesheet,
 107                                                             doc_input, 0);
 108                     if (!doc_res)
 109                     {
 110                         error_code = YAZ_BIB1_MALFORMED_QUERY;
 111                         addinfo = "XSLT transform failed for query";
 112                     }
 113                     else
 114                     {
 115                         const xmlNode *root_element = xmlDocGetRootElement(doc_res);
 116                         yaz_xml2query(root_element, &req->query, odr,
 117                                       &error_code, &addinfo);
 118                         xmlFreeDoc(doc_res);
 119                     }
 120                 }
 121                 xmlFreeDoc(doc_input);
 122             }
 123             package.request() = gdu;
 124             if (error_code)
 125             {
 126                 Z_APDU *f_apdu =
 127                     odr.create_searchResponse(apdu_req, error_code, addinfo);
 128                 package.response() = f_apdu;
 129                 return;
 130             }
 131         }
 132     }
 133     package.move();
 134 }
 135
 136 void mp::filter::QueryRewrite::Rep::configure(const xmlNode *ptr)
 137 {
 138     for (ptr = ptr->children; ptr; ptr = ptr->next)
 139     {
 140         if (ptr->type != XML_ELEMENT_NODE)
 141             continue;
 142
 143         if (mp::xml::check_element_mp(ptr, "xslt"))
 144         {
 145             if (m_stylesheet)
 146             {
 147                 throw mp::filter::FilterException
 148                     ("Only one xslt element allowed in query_rewrite filter");
 149             }
 150
 151             std::string fname;// = mp::xml::get_text(ptr);
 152
 153             for (struct _xmlAttr *attr = ptr->properties;
 154                  attr; attr = attr->next)
 155             {
 156                 mp::xml::check_attribute(attr, "", "stylesheet");
 157                 fname = mp::xml::get_text(attr);
 158             }
 159
 160             if (0 == fname.size())
 161                 throw mp::filter::FilterException
 162                     ("Attribute <xslt stylesheet=\""
 163                      + fname
 164                      + "\"> needs XSLT stylesheet path content"
 165                      + " in query_rewrite filter");
 166
 167             m_stylesheet = xsltParseStylesheetFile(BAD_CAST fname.c_str());
 168             if (!m_stylesheet)
 169             {
 170                 throw mp::filter::FilterException
 171                     ("Failed to read XSLT stylesheet '"
 172                      + fname
 173                      + "' in query_rewrite filter");
 174             }
 175         }
 176         else
 177         {
 178             throw mp::filter::FilterException
 179                 ("Bad element "
 180                  + std::string((const char *) ptr->name)
 181                  + " in query_rewrite filter");
 182         }
 183     }
 184 }
 185
 186 static mp::filter::Base* filter_creator()
 187 {
 188     return new mp::filter::QueryRewrite;
 189 }
 190
 191 extern "C" {
 192     struct metaproxy_1_filter_struct metaproxy_1_filter_query_rewrite = {
 193         0,
 194         "query_rewrite",
 195         filter_creator
 196     };
 197 }
 198
 199 /*
 200  * Local variables:
 201  * c-basic-offset: 4
 202  * c-file-style: "Stroustrup"
 203  * indent-tabs-mode: nil
 204  * End:
 205  * vim: shiftwidth=4 tabstop=8 expandtab
 206  */
 207