STWebArchiver.m

// 
// Copyright (c) 2011 Shun Takebayashi
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
// 

#import "STWebArchiver.h"
#import <libxml/HTMLparser.h>

@interface STWebArchiver ()

@end

@implementation STWebArchiver

- (void)archiveHTMLData:(NSData *)aData
		   textEncoding:(NSString *)anEncoding
				baseURL:(NSURL *)anURL
        completionBlock:(void (^)(NSData *))completion {
    
	htmlDocPtr doc = htmlParseDoc((xmlChar *)[aData bytes], [anEncoding UTF8String]);
	NSArray *pathsForImagesAndScripts = [self valueForAttributeName:@"src" withEvaluatingXPath:@"//script[@src]|//img[@src]" inDocument:doc];
	NSArray *pathsForStylesheets = [self valueForAttributeName:@"href" withEvaluatingXPath:@"//link[@rel='stylesheet'][@href]" inDocument:doc];
	NSArray *resourcesPaths = [pathsForImagesAndScripts arrayByAddingObjectsFromArray:pathsForStylesheets];
	NSArray *resourceUrls = [self absoluteURLsForPaths:resourcesPaths baseURL:anURL];
    NSLog(@"urls==%@",resourceUrls);
    //GCD dispatch_async dispatch_queue_create
	dispatch_async(dispatch_queue_create("Downloads", 0), ^{
        
		NSMutableDictionary *resources = [NSMutableDictionary dictionary];
        //GCD dispatch_apply dispatch_get_global_queue
		dispatch_apply([resourceUrls count], dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0), ^(size_t i) {
      NSURL *url = [resourceUrls objectAtIndex:i];
			NSString *urlString = [url absoluteString];
			BOOL unfetched = NO;
			@synchronized (resources) {
				unfetched = ![resources objectForKey:urlString];
				if (unfetched) {
					[resources setObject:[NSNull null] forKey:urlString];
				}
			}
			if (unfetched) {
                
				NSURLResponse *response;
				NSError *error;
				NSURLRequest *request = [NSURLRequest requestWithURL:url];
                //同步请求UI冻结
				NSData *data = [NSURLConnection sendSynchronousRequest:request
													 returningResponse:&response
																 error:&error];
				NSMutableDictionary *resourceArchive = [NSMutableDictionary dictionaryWithObjectsAndKeys:
														urlString, @"WebResourceURL",
														[response MIMEType], @"WebResourceMIMEType",
														data, @"WebResourceData", nil];
				if ([response textEncodingName]) {
					[resourceArchive setObject:[response textEncodingName] forKey:@"WebResourceTextEncodingName"];
				}
				@synchronized (resources) {
					[resources setObject:resourceArchive forKey:urlString];
				}
			}
		});
        
		NSMutableDictionary *archiveSource = [NSMutableDictionary dictionaryWithObject:[resources allValues] forKey:@"WebSubresources"];
		NSMutableDictionary *mainResource = [NSMutableDictionary dictionary];
		[mainResource setObject:aData forKey:@"WebResourceData"];
		[mainResource setObject:@"" forKey:@"WebResourceFrameName"];
		[mainResource setObject:@"text/html" forKey:@"WebResourceMIMEType"];
		[mainResource setObject:anEncoding forKey:@"WebResourceTextEncodingName"];
		[mainResource setObject:[anURL absoluteString] forKey:@"WebResourceURL"];
		[archiveSource setObject:mainResource forKey:@"WebMainResource"];
    NSData *webArchive =
    [NSPropertyListSerialization
     dataFromPropertyList:archiveSource
     format:NSPropertyListBinaryFormat_v1_0
     errorDescription:NULL];
    completion(webArchive);
	});
	xmlFreeDoc(doc);
}

- (NSArray *)valueForAttributeName:(NSString *)attributeName
			   withEvaluatingXPath:(NSString *)xpathExpression
						inDocument:(xmlDocPtr)document {
	xmlXPathContextPtr context = xmlXPathNewContext(document);
	xmlXPathObjectPtr xpathObject = xmlXPathEvalExpression((xmlChar *)[xpathExpression UTF8String], context);
	xmlNodeSetPtr nodes = xpathObject->nodesetval;
	NSMutableArray *results = nil;
	if (!xmlXPathNodeSetIsEmpty(nodes)) {
		results = [NSMutableArray arrayWithCapacity:nodes->nodeNr];
		for (int i = 0; i < nodes->nodeNr; i++) {
			xmlNodePtr node = nodes->nodeTab[i];
			char *attributeChars = (char *)xmlGetProp(node, (xmlChar *)[attributeName UTF8String]);
			NSString *attributeString = [NSString stringWithUTF8String:attributeChars];
			xmlFree(attributeChars);
			[results addObject:attributeString];
		}
	}
	xmlXPathFreeObject(xpathObject);
	xmlXPathFreeContext(context);
	return results;
}

- (NSArray *)absoluteURLsForPaths:(NSArray *)paths baseURL:(NSURL *)base
{
	NSMutableArray *results = [NSMutableArray arrayWithCapacity:[paths count]];
	for (NSString *path in paths)
  {
		[results addObject:[NSURL URLWithString:[path stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] relativeToURL:base]];
	}
	return results;
}

@end