src/filter_query_rewrite.cpp

   1 /* $Id: filter_query_rewrite.cpp,v 1.7 2006-03-27 12:53:05 adam Exp $
   2    Copyright (c) 2005-2006, Index Data.
   3
   4 %LICENSE%
   5  */
   6
   7
   8 #include "config.hpp"
   9 #include "filter.hpp"
  10 #include "package.hpp"
  11
  12 #include "util.hpp"
  13 #include "filter_query_rewrite.hpp"
  14
  15 #include <yaz/zgdu.h>
  16 #include <yaz/xmlquery.h>
  17 #include <yaz/diagbib1.h>
  18
  19 #include <libxslt/xsltutils.h>
  20 #include <libxslt/transform.h>
  21
  22 namespace mp = metaproxy_1;
  23 namespace yf = mp::filter;
  24
  25 namespace metaproxy_1 {
  26     namespace filter {
  27         class QueryRewrite::Rep {
  28         public:
  29             Rep();
  30             ~Rep();
  31             void process(mp::Package &package) const;
  32             void configure(const xmlNode * ptr);
  33         private:
  34             xsltStylesheetPtr m_stylesheet;
  35         };
  36     }
  37 }
  38
  39 yf::QueryRewrite::Rep::Rep()
  40 {
  41     m_stylesheet = 0;
  42 }
  43
  44 yf::QueryRewrite::Rep::~Rep()
  45 {
  46     if (m_stylesheet)
  47         xsltFreeStylesheet(m_stylesheet);
  48 }
  49
  50 yf::QueryRewrite::QueryRewrite() : m_p(new Rep)
  51 {
  52 }
  53
  54 yf::QueryRewrite::~QueryRewrite()
  55 {  // must have a destructor because of boost::scoped_ptr
  56 }
  57
  58 void yf::QueryRewrite::process(mp::Package &package) const
  59 {
  60     m_p->process(package);
  61 }
  62
  63 void mp::filter::QueryRewrite::configure(const xmlNode *ptr)
  64 {
  65     m_p->configure(ptr);
  66 }
  67
  68 void yf::QueryRewrite::Rep::process(mp::Package &package) const
  69 {
  70     Z_GDU *gdu = package.request().get();
  71
  72     if (gdu && gdu->which == Z_GDU_Z3950)
  73     {
  74         Z_APDU *apdu_req = gdu->u.z3950;
  75         if (apdu_req->which == Z_APDU_searchRequest)
  76         {
  77             int error_code = 0;
  78             const char *addinfo = 0;
  79             mp::odr odr;
  80             Z_SearchRequest *req = apdu_req->u.searchRequest;
  81
  82             xmlDocPtr doc_input = 0;
  83             yaz_query2xml(req->query, &doc_input);
  84
  85             if (!doc_input)
  86             {
  87                 error_code = YAZ_BIB1_MALFORMED_QUERY;
  88                 addinfo = "converion from Query to XML failed";
  89             }
  90             else
  91             {
  92                 if (m_stylesheet)
  93                 {
  94                     xmlDocPtr doc_res = xsltApplyStylesheet(m_stylesheet,
  95                                                             doc_input, 0);
  96                     if (!doc_res)
  97                     {
  98                         error_code = YAZ_BIB1_MALFORMED_QUERY;
  99                         addinfo = "XSLT transform failed for query";
 100                     }
 101                     else
 102                     {
 103                         const xmlNode *root_element = xmlDocGetRootElement(doc_res);
 104                         yaz_xml2query(root_element, &req->query, odr,
 105                                       &error_code, &addinfo);
 106                         xmlFreeDoc(doc_res);
 107                     }
 108                 }
 109                 xmlFreeDoc(doc_input);
 110             }
 111             package.request() = gdu;
 112             if (error_code)
 113             {
 114                 Z_APDU *f_apdu =
 115                     odr.create_searchResponse(apdu_req, error_code, addinfo);
 116                 package.response() = f_apdu;
 117                 return;
 118             }
 119         }
 120     }
 121     package.move();
 122 }
 123
 124 void mp::filter::QueryRewrite::Rep::configure(const xmlNode *ptr)
 125 {
 126     for (ptr = ptr->children; ptr; ptr = ptr->next)
 127     {
 128         if (ptr->type != XML_ELEMENT_NODE)
 129             continue;
 130         if (!strcmp((const char *) ptr->name, "xslt"))
 131         {
 132             if (m_stylesheet)
 133             {
 134                 throw mp::filter::FilterException
 135                     ("Only one xslt element allowed in query_rewrite filter");
 136             }
 137
 138             std::string fname = mp::xml::get_text(ptr);
 139             m_stylesheet = xsltParseStylesheetFile(BAD_CAST fname.c_str());
 140             if (!m_stylesheet)
 141             {
 142                 throw mp::filter::FilterException
 143                     ("Failed to read stylesheet "
 144                      + fname
 145                      + " in query_rewrite filter");
 146             }
 147         }
 148         else
 149         {
 150             throw mp::filter::FilterException
 151                 ("Bad element "
 152                  + std::string((const char *) ptr->name)
 153                  + " in query_rewrite filter");
 154         }
 155     }
 156 }
 157
 158 static mp::filter::Base* filter_creator()
 159 {
 160     return new mp::filter::QueryRewrite;
 161 }
 162
 163 extern "C" {
 164     struct metaproxy_1_filter_struct metaproxy_1_filter_query_rewrite = {
 165         0,
 166         "query_rewrite",
 167         filter_creator
 168     };
 169 }
 170
 171 /*
 172  * Local variables:
 173  * c-basic-offset: 4
 174  * indent-tabs-mode: nil
 175  * c-file-style: "stroustrup"
 176  * End:
 177  * vim: shiftwidth=4 tabstop=8 expandtab
 178  */