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//
// XPathQuery.m
//
// Created by Matt Gallagher on 4/08/08.
// Modified by Matt Bauman on 12/01/09 to ignore attributes and simplify the
// created data structure (depends upon the NSDictionary Category method
// - (void)addObject:forKey: below).
// Copyright 2008 Matt Gallagher. All rights reserved.
//
// Permission is given to use this source code file, free of charge, in any
// project, commercial or otherwise, entirely at your risk, with the condition
// that any redistribution (in part or whole) of source code must retain
// this copyright and permission notice. Attribution in compiled projects is
// appreciated but not required.
//
#import "XPathQuery.h"
#import "NSMutableDictionary+MBAddObject.h"
#import <libxml/tree.h>
#import <libxml/parser.h>
#import <libxml/HTMLparser.h>
#import <libxml/xpath.h>
#import <libxml/xpathInternals.h>
id ElementForNode(xmlNodePtr currentNode, NSMutableDictionary *currentDictionary)
{
if (!currentNode->name) return nil;
NSString *currentNodeName = [NSString stringWithCString:(const char *)currentNode->name
encoding:NSUTF8StringEncoding];
if (currentNode->children && currentNode->children == currentNode->last &&
(currentNode->children->type == XML_TEXT_NODE || currentNode->children->type == XML_CDATA_SECTION_NODE) ) {
/* We have a simple element; add it to the existing dictionary */
NSString *currentNodeText = [NSString stringWithCString:(const char *)currentNode->children->content
encoding:NSUTF8StringEncoding];
currentNodeText = [currentNodeText stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
if ([currentNodeText length] > 0) {
/* Note that currentDictionary may be null; in that case addObject:forKey:
* falls flat and the returned object should suffice. */
[currentDictionary addObject:currentNodeText forKey:currentNodeName];
return currentNodeText;
}
return nil;
}
if (currentNode->type == XML_ELEMENT_NODE) {
/* create a new dictionary for this node */
NSMutableDictionary *nodeDictionary = [NSMutableDictionary dictionary];
[currentDictionary addObject:nodeDictionary forKey:currentNodeName];
/* And go through its children */
xmlNodePtr childNode = currentNode->children;
do {
ElementForNode(childNode, nodeDictionary);
} while (childNode = childNode->next);
return nodeDictionary;
}
return nil;
}
NSArray *PerformXPathQuery(xmlDocPtr doc, NSString *query) {
xmlXPathContextPtr xpathCtx;
xmlXPathObjectPtr xpathObj;
/* Create xpath evaluation context */
xpathCtx = xmlXPathNewContext(doc);
if(xpathCtx == NULL) {
NSLog(@"Unable to create XPath context.");
return nil;
}
/* Evaluate xpath expression */
xpathObj = xmlXPathEvalExpression((xmlChar *)[query cStringUsingEncoding:NSUTF8StringEncoding], xpathCtx);
if(xpathObj == NULL) {
NSLog(@"Unable to evaluate XPath.");
return nil;
}
xmlNodeSetPtr nodes = xpathObj->nodesetval;
if (!nodes) {
NSLog(@"Nodes was nil.");
return nil;
}
NSMutableArray *resultNodes = [NSMutableArray array];
for (NSInteger i = 0; i < nodes->nodeNr; i++) {
id nodeElement = ElementForNode(nodes->nodeTab[i], nil);
if (nodeElement) {
[resultNodes addObject:nodeElement];
}
}
/* Cleanup */
xmlXPathFreeObject(xpathObj);
xmlXPathFreeContext(xpathCtx);
return resultNodes;
}
NSArray *PerformHTMLXPathQuery(NSData *document, NSString *query) {
xmlDocPtr doc;
/* Load XML document */
doc = htmlReadMemory([document bytes], [document length], "", NULL, HTML_PARSE_NOWARNING | HTML_PARSE_NOERROR);
if (doc == NULL) {
NSLog(@"Unable to parse.");
return nil;
}
NSArray *result = PerformXPathQuery(doc, query);
xmlFreeDoc(doc);
return result;
}
NSArray *PerformXMLXPathQuery(NSData *document, NSString *query) {
xmlDocPtr doc;
/* Load XML document */
doc = xmlReadMemory([document bytes], [document length], "", NULL, XML_PARSE_RECOVER);
if (doc == NULL) {
NSLog(@"Unable to parse.");
return nil;
}
NSArray *result = PerformXPathQuery(doc, query);
xmlFreeDoc(doc);
return result;
}
// --
//
// NSMutableDictionary+MBAddObject
//
// Created by Matt Bauman on 12/1/09.
// Copyright 2008 Matt Bauman. All rights reserved.
//
// Permission is given to use this source code file, free of charge, in any
// project, commercial or otherwise, entirely at your risk, with the condition
// that any redistribution (in part or whole) of source code must retain
// this copyright and permission notice. Attribution in compiled projects is
// appreciated but not required.
#import <Cocoa/Cocoa.h>
@interface NSMutableDictionary (MBAddObject)
/* Adds the object for a given key. If the key already exists, it adds the
* object to an array at the given key location. */
- (void)addObject:(id)anObject forKey:(id)aKey;
@end
@implementation NSMutableDictionary (MBAddObject)
- (void)addObject:(id)anObject forKey:(id)aKey {
id existingObject = [self objectForKey:aKey];
if (!existingObject) {
[self setObject:anObject forKey:aKey];
} else {
/* We already have a key for this element. If it's not an array, create
* one, and add the existing element back into the new array. */
if (![existingObject isKindOfClass:[NSMutableArray class]]) {
NSMutableArray *newArray = [NSMutableArray arrayWithObject:existingObject];
[self setObject:newArray forKey:aKey];
existingObject = newArray;
}
[(NSMutableArray *)existingObject addObject:anObject];
}
}
@end
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