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.



367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
 
# File 'ext/nokogiri/xml_xpath_context.c', line 367

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

  Noko_Node_Get_Struct(nodeobj, xmlNode, node);

#if LIBXML_VERSION < 21000
  /* deprecated in 40483d0 */
  xmlXPathInit();
#endif

  ctx = xmlXPathNewContext(node->doc);
  ctx->node = node;

  xmlXPathRegisterNs(ctx, NOKOGIRI_BUILTIN_PREFIX, NOKOGIRI_BUILTIN_URI);
  xmlXPathRegisterFuncNS(ctx, (const xmlChar *)"css-class", NOKOGIRI_BUILTIN_URI,
                         xpath_builtin_css_class);
  xmlXPathRegisterFuncNS(ctx, (const xmlChar *)"local-name-is", NOKOGIRI_BUILTIN_URI,
                         xpath_builtin_local_name_is);

  self = Data_Wrap_Struct(klass, 0, deallocate, ctx);
  return self;
}

Instance Method Details

#evaluate(search_path, handler = nil) ⇒ Object

Evaluate the search_path returning an XML::XPath object.



312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
 
# File 'ext/nokogiri/xml_xpath_context.c', line 312

static VALUE
evaluate(int argc, VALUE *argv, VALUE self)
{
  VALUE search_path, xpath_handler;
  VALUE retval = 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 *)StringValueCStr(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, Nokogiri_error_raise);

  /* 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) {
    xmlErrorPtr error = xmlGetLastError();
    rb_exc_raise(Nokogiri_wrap_xml_syntax_error(error));
  }

  retval = xpath2ruby(xpath, ctx);
  if (retval == Qundef) {
    retval = noko_xml_node_set_wrap(NULL, DOC_RUBY_OBJECT(ctx->doc));
  }

  xmlXPathFreeNodeSetList(xpath);

  return retval;
}

#register_namespaces(namespaces) ⇒ Object

Register namespaces in namespaces



8
9
10
11
12
13
 
# File 'lib/nokogiri/xml/xpath_context.rb', line 8

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

#register_ns(prefix, uri) ⇒ Object

Register the namespace with prefix and uri.



115
116
117
118
119
120
121
122
123
124
125
126
 
# File 'ext/nokogiri/xml_xpath_context.c', line 115

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

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

#register_variable(name, value) ⇒ Object

Register the variable name with value.



134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
 
# File 'ext/nokogiri/xml_xpath_context.c', line 134

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

  xmlValue = xmlXPathNewCString(StringValueCStr(value));

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

  return self;
}