iOS webview加载网页内容,拦截如果本地有资源就先加载本地资源

webiew加载一个网页资源过多,加载速度过慢。可以将部分资源放在本地，拦截webview的链接和请求，本地有的资源直接获取本地的,不去加载网络服务器内容

首先自定义一个继承自NSURLProtocol的类

然后重写+ (BOOL)canInitWithRequest:(NSURLRequest *)request

 

重写

+ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request

- (void)startLoading、

 

然后需要在调用的webview控制器中实现注册

[NSURLProtocol registerClass:[CQURLProtocol class]];

上代码

#import "CQURLProtocol.h"
#import
#import
@implementation CQURLProtocol
+ (BOOL)canInitWithRequest:(NSURLRequest *)request{

    NSLog(@"canInitWithRequest");
    
    NSString *urlPathString = request.URL.absoluteString;
    if ([urlPathString containsString:@"http://"] ) {
        
        urlPathString = [urlPathString stringByReplacingOccurrencesOfString:@"http://" withString:@""];
        
    }else if ([urlPathString containsString:@"https://"]){
        urlPathString = [urlPathString stringByReplacingOccurrencesOfString:@"https://" withString:@""];
    }
    NSString *filePath = [[NSBundle mainBundle] pathForResource:urlPathString ofType:@""];
    if ([NSData dataWithContentsOfFile:filePath]) {
        return YES;
    }
    return NO;

}
+ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request
{
    
    NSLog(@"canInitWithRequest");
    return request;
}

- (void)startLoading{
    
    
    NSLog(@"*****startLoading");
    NSLog(@"%@", super.request.URL);
    
    NSString *urlPathString = super.request.URL.absoluteString;
    if ([urlPathString containsString:@"http://"] ) {
        
        urlPathString = [urlPathString stringByReplacingOccurrencesOfString:@"http://" withString:@""];
        
    }else if ([urlPathString containsString:@"https://"]){
        urlPathString = [urlPathString stringByReplacingOccurrencesOfString:@"https://" withString:@""];
    }
    
    NSString *filePath = [[NSBundle mainBundle] pathForResource:urlPathString ofType:@""];
    
    NSData *imageData = [self DataWithPath:filePath];
    
    if (imageData ) {
        //获取本地资源成功
        NSLog(@"*******--------%@",filePath);
        CFStringRef pathExtension = (__bridge_retained CFStringRef)[filePath pathExtension];
        
        CFStringRef type = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension, NULL);
        
        CFRelease(pathExtension);
        
        // The UTI can be converted to a mime type:
        
        NSString *mimeType = (__bridge_transfer NSString *)UTTypeCopyPreferredTagWithClass(type, kUTTagClassMIMEType);

        NSMutableDictionary *header = [NSMutableDictionary dictionary];
        
        NSString *contentType = [mimeType stringByAppendingString:@";chartset=UTF-8"];
        header[@"Content-type"] = contentType;
        header[@"Content-Length"] = [NSString stringWithFormat:@"%ld",imageData.length];
        
        NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:self.request.URL
                                                                  statusCode:200 HTTPVersion:@"1.1" headerFields:header];
        //回调
        [self.client URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageAllowed];
        [self.client URLProtocol:self didLoadData:imageData];
        [self.client URLProtocolDidFinishLoading:self];
    }else{
        //获取本地资源失败
        [NSURLProtocol setProperty:@(YES) forKey:@"JXProtocol" inRequest:super.request];
        NSMutableURLRequest *newRequset = [self.request mutableCopy];
        NSURLSessionConfiguration *config = [NSURLSessionConfiguration ephemeralSessionConfiguration];
        NSURLSession *session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:[NSOperationQueue mainQueue]];
        NSURLSessionTask *task = [session dataTaskWithRequest:newRequset];
        [task resume];

    }
}
- (void)stopLoading{
    
    NSLog(@"stop******");
}
- (NSData*)DataWithPath:(NSString*)filePath{

    NSData *data = [NSData dataWithContentsOfFile:filePath];
    
    if (data) {
        
        return data;
    }

    return nil;
}
#pragma mark- NSURLConnectionDelegate

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    
    [self.client URLProtocol:self didFailWithError:error];
}

#pragma mark - NSURLConnectionDataDelegate

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    [self.client URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [self.client URLProtocol:self didLoadData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [self.client URLProtocolDidFinishLoading:self];
}

@end