Class: Nokogiri::XML::XPathContext

Inherits:
Object
  • Object
show all
Defined in:
lib/nokogiri/xml/xpath_context.rb,
ext/nokogiri/xml_xpath_context.c

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.new(node) ⇒ Object

Create a new XPathContext with node as the reference point.



287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
# File 'ext/nokogiri/xml_xpath_context.c', line 287

static VALUE new(VALUE klass, VALUE nodeobj)
{
  xmlNodePtr node;
  xmlXPathContextPtr ctx;
  VALUE self;

  xmlXPathInit();

  Data_Get_Struct(nodeobj, xmlNode, node);

  ctx = xmlXPathNewContext(node->doc);
  ctx->node = node;
  self = Data_Wrap_Struct(klass, 0, deallocate, ctx);
  /*rb_iv_set(self, "@xpath_handler", Qnil); */
  return self;
}

Instance Method Details

#evaluate(search_path, handler = nil) ⇒ Object

Evaluate the search_path returning an XML::XPath object.



208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
# File 'ext/nokogiri/xml_xpath_context.c', line 208

static VALUE evaluate(int argc, VALUE *argv, VALUE self)
{
  VALUE search_path, xpath_handler;
  VALUE thing = Qnil;
  xmlXPathContextPtr ctx;
  xmlXPathObjectPtr xpath;
  xmlChar *query;

  Data_Get_Struct(self, xmlXPathContext, ctx);

  if(rb_scan_args(argc, argv, "11", &search_path, &xpath_handler) == 1)
    xpath_handler = Qnil;

  query = (xmlChar *)StringValuePtr(search_path);

  if(Qnil != xpath_handler) {
    /* FIXME: not sure if this is the correct place to shove private data. */
    ctx->userData = (void *)xpath_handler;
    xmlXPathRegisterFuncLookup(ctx, lookup, (void *)xpath_handler);
  }

  xmlResetLastError();
  xmlSetStructuredErrorFunc(NULL, xpath_exception_handler);

  /* For some reason, xmlXPathEvalExpression will blow up with a generic error */
  /* when there is a non existent function. */
  xmlSetGenericErrorFunc(NULL, xpath_generic_exception_handler);

  xpath = xmlXPathEvalExpression(query, ctx);
  xmlSetStructuredErrorFunc(NULL, NULL);
  xmlSetGenericErrorFunc(NULL, NULL);

  if(xpath == NULL) {
    VALUE xpath = rb_const_get(mNokogiriXml, rb_intern("XPath"));
    VALUE klass = rb_const_get(xpath, rb_intern("SyntaxError"));

    xmlErrorPtr error = xmlGetLastError();
    rb_exc_raise(Nokogiri_wrap_xml_syntax_error(klass, error));
  }

  assert(ctx->doc);
  assert(DOC_RUBY_OBJECT_TEST(ctx->doc));

  switch(xpath->type) {
    case XPATH_STRING:
      thing = NOKOGIRI_STR_NEW2(xpath->stringval);
      xmlFree(xpath->stringval);
      break;
    case XPATH_NODESET:
      if(NULL == xpath->nodesetval) {
        thing = Nokogiri_wrap_xml_node_set(xmlXPathNodeSetCreate(NULL),
          DOC_RUBY_OBJECT(ctx->doc));
      } else {
        thing = Nokogiri_wrap_xml_node_set(xpath->nodesetval,
            DOC_RUBY_OBJECT(ctx->doc));
      }
      break;
    case XPATH_NUMBER:
      thing = rb_float_new(xpath->floatval);
      break;
    case XPATH_BOOLEAN:
      thing = xpath->boolval == 1 ? Qtrue : Qfalse;
      break;
    default:
      thing = Nokogiri_wrap_xml_node_set(xmlXPathNodeSetCreate(NULL),
        DOC_RUBY_OBJECT(ctx->doc));
  }

  xmlXPathFreeNodeSetList(xpath);

  return thing;
}

#register_namespaces(namespaces) ⇒ Object

Register namespaces in namespaces



7
8
9
10
11
12
# File 'lib/nokogiri/xml/xpath_context.rb', line 7

def register_namespaces(namespaces)
  namespaces.each do |k, v|
    k = k.gsub(/.*:/,'') # strip off 'xmlns:' or 'xml:'
    register_ns(k, v)
  end
end

#register_ns(prefix, uri) ⇒ Object

Register the namespace with prefix and uri.



18
19
20
21
22
23
24
25
26
27
28
# File 'ext/nokogiri/xml_xpath_context.c', line 18

static VALUE register_ns(VALUE self, VALUE prefix, VALUE uri)
{
  xmlXPathContextPtr ctx;
  Data_Get_Struct(self, xmlXPathContext, ctx);

  xmlXPathRegisterNs( ctx,
                      (const xmlChar *)StringValuePtr(prefix),
                      (const xmlChar *)StringValuePtr(uri)
  );
  return self;
}

#register_variable(name, value) ⇒ Object

Register the variable name with value.



36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
# File 'ext/nokogiri/xml_xpath_context.c', line 36

static VALUE register_variable(VALUE self, VALUE name, VALUE value)
{
   xmlXPathContextPtr ctx;
   xmlXPathObjectPtr xmlValue;
   Data_Get_Struct(self, xmlXPathContext, ctx);

   xmlValue = xmlXPathNewCString(StringValuePtr(value));

   xmlXPathRegisterVariable( ctx,
      (const xmlChar *)StringValuePtr(name),
      xmlValue
   );

   return self;
}