NSURLProtocol简介
NSURLProtocol是URL Loading System的重要组成部分。它是一个抽象类。可以拦截网络请求。可以拦截的网络请求包括NSURLSession，NSURLConnection以及UIWebvIew。现也支持WKWebview框架，本文就是采用WKWebview。
方式
拦截做替换的方式有两种
- 重定向到本地资源，利用canonicalRequestForRequest实现
- 根据url，自定义response。
下面先说第一种实现方式：
1、无论哪种实现方式都必须注册NSURLProtocol
我这里在AppDelegate的didFinishLaunchingWithOptions方法里面进行注册，代码如下
- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
//注册
[NSURLProtocol registerClass:[BaseOnRedirectRequestURLProtocol class]];
//实现拦截功能
Class cls = NSClassFromString(@"WKBrowsingContextController");
SEL sel = NSSelectorFromString(@"registerSchemeForCustomProtocol:");
if([(id)clsrespondsToSelector:sel]) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored"-Warc-performSelector-leaks"
[(id)cls performSelector:sel withObject:@"myapp"];
#pragma clang diagnostic pop
}
return YES;
}
2、创建NSURLProtocol子类BaseOnRedirectRequestURLProtocol
- 在.m文件中 遵循协议<NSURLSessionDelegate>
- 创建 NSURLSessionDataTask 对象
@property (nonnull,strong) NSURLSessionDataTask *task; - 下面是NSURLSession代理方法
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler {
[[self client] URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageAllowed];
completionHandler(NSURLSessionResponseAllow);
}
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
[[self client] URLProtocol:self didLoadData:data];
}
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(nullable NSError *)error {
[self.client URLProtocolDidFinishLoading:self];
}
3、准备就绪后，下面开始实现拦截功能
- 注册NSURLProtocol后，客户端所有请求都将走+ (BOOL)canInitWithRequest:(NSURLRequest *)request。
下面是代码片段：
+ (BOOL)canInitWithRequest:(NSURLRequest *)request
{
NSLog(@"request.URL.absoluteString = %@",request.URL.absoluteString);
NSString *scheme = [[request URL] scheme];
if ( ([scheme caseInsensitiveCompare:@"http"] == NSOrderedSame ||
[scheme caseInsensitiveCompare:@"https"] == NSOrderedSame ))
{
//看看是否已经处理过了，防止无限循环
if ([NSURLProtocol propertyForKey:BaseOnRedirectRequestURLProtocolKey inRequest:request])
return NO;
return YES;
}
return NO;
}
- request 重定向方法 下面代码中的地址，改为你需要拦截的地址，本地路径也改为你需要替换的本地资源
+ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request
{
NSMutableURLRequest *mutableReqeust = [request mutableCopy];
NSLog(@"url ---[%@]\n\n",request.URL.absoluteString);
//request截取重定向
if ([request.URL.absoluteString isEqualToString:@"http://xxx/xxx.js"])
{
NSString * filePath = [[NSBundle mainBundle] pathForResource:@"NewProject" ofType:@"js"];
NSURL * url = [NSURL fileURLWithPath:filePath];
mutableReqeust.URL = url;
}
return mutableReqeust;
}
- 在startLoading中开始加载
- (void)startLoading{
NSMutableURLRequest* request = self.request.mutableCopy;
[NSURLProtocol setProperty:@YES forKey:BaseOnRedirectRequestURLProtocolKey inRequest:request];
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:nil];
self.task = [session dataTaskWithRequest:self.request];
[self.task resume];
}
- stopLoading中记得销毁
- (void)stopLoading
{
if (self.task != nil) {
[self.task cancel];
}
}
至此第一种拦截替换本地资源的方式已实现，控制器加载WKWebView在本文末尾写
下面先说第二种实现方式：
1、首先同第一种方式，都需要注册
- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
//注册
[NSURLProtocol registerClass:[BaseOnResponseURLProtocol class]];
//实现拦截功能
Class cls = NSClassFromString(@"WKBrowsingContextController");
SEL sel = NSSelectorFromString(@"registerSchemeForCustomProtocol:");
if([(id)clsrespondsToSelector:sel]) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored"-Warc-performSelector-leaks"
[(id)cls performSelector:sel withObject:@"myapp"];
#pragma clang diagnostic pop
}
return YES;
}
2、创建NSURLProtocol子类BaseOnResponseURLProtocol
- 在.m文件中 遵循协议<NSURLConnectionDelegate>
- 创建 NSURLConnection 对象
@property (nonatomic, strong) NSURLConnection *connection; - 下面是NSURLConnection代理方法
#pragma mark - NSURLConnectionDelegate
- (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];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[self.client URLProtocol:self didFailWithError:error];
}
3、准备就绪后，下面开始实现拦截功能
- 注册NSURLProtocol后，客户端所有请求都将走+ (BOOL)canInitWithRequest:(NSURLRequest *)request。
+ (BOOL)canInitWithRequest:(NSURLRequest *)request
{
NSLog(@"request.URL.absoluteString = %@",request.URL.absoluteString);
if ( ([request.URL.absoluteString hasPrefix:@"http://game.scool.online/cutcake1/"]))
{
//看看是否已经处理过了，防止无限循环
if ([NSURLProtocol propertyForKey:BaseOnResponseURLProtocolKey inRequest:request]) {
return NO;
}
return YES;
}
return NO;
}
- 在startLoading中加载，实现思路：将需要替换的地址重新拼接response返回，再响应本地资源，代码如下：
- (void)startLoading {
//1.获取资源文件路径 ajkyq/index.html
NSURL *url = [self request].URL;
//2.读取资源文件内容
NSString *path = [[NSBundle mainBundle] pathForResource:@"NewProject" ofType:@"js"];
NSFileHandle *file = [NSFileHandle fileHandleForReadingAtPath:path];
NSData *data = [file readDataToEndOfFile];
[file closeFile];
//3.拼接响应Response
NSInteger dataLength = data.length;
NSString *mimeType = [self getMIMETypeWithCAPIAtFilePath:path];
NSString *httpVersion = @"HTTP/1.1";
NSHTTPURLResponse *response = nil;
if (dataLength > 0) {
response = [self jointResponseWithData:data dataLength:dataLength mimeType: mimeType requestUrl:url statusCode:200 httpVersion:httpVersion];
} else {
response = [self jointResponseWithData:[@"404" dataUsingEncoding:NSUTF8StringEncoding] dataLength:3 mimeType:mimeType requestUrl:url statusCode:404 httpVersion:httpVersion];
}
//4.响应
[[self client] URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
[[self client] URLProtocol:self didLoadData:data];
[[self client] URLProtocolDidFinishLoading:self];
}
- jointResponseWithData方法实现如下：
#pragma mark - 拼接响应Response
-(NSHTTPURLResponse *)jointResponseWithData:(NSData *)data dataLength:(NSInteger)dataLength mimeType:(NSString *)mimeType requestUrl:(NSURL *)requestUrl statusCode:(NSInteger)statusCode httpVersion:(NSString *)httpVersion
{
NSDictionary *dict = @{@"Content-type":mimeType,
@"Content-length":[NSString stringWithFormat:@"%ld",dataLength]};
NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:requestUrl statusCode:statusCode HTTPVersion:httpVersion headerFields:dict];
return response;
}
- MIMEType类型获取如下
#pragma mark - 获取mimeType
-(NSString *)getMIMETypeWithCAPIAtFilePath:(NSString *)path
{
if (![[[NSFileManager alloc] init] fileExistsAtPath:path]) {
return @"text/html";
}
CFStringRef UTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (__bridge CFStringRef)[path pathExtension], NULL);
CFStringRef MIMEType = UTTypeCopyPreferredTagWithClass (UTI, kUTTagClassMIMEType);
CFRelease(UTI);
if (!MIMEType) {
return @"application/octet-stream";
}
return (__bridge NSString *)(MIMEType);
}
至此第二种实现方式也已完成，下面贴上控制器中的代码
1、引用#import <WebKit/WebKit.h> 和 #import "NSURLProtocol+WKWebVIew.h" 并遵循<WKNavigationDelegate,WKUIDelegate>
NSURLProtocol+WKWebVIew 是对NSURLProtocol的一个扩展，主要是注册http和https协议，本文不做介绍，demo里会有的。
2、声明WKWebView对象
@property (nonatomic) WKWebView* webView;
3、viewDidLoad中代码
- (void)viewDidLoad {
[super viewDidLoad];
[NSURLProtocol wk_registerScheme:@"http"];
[NSURLProtocol wk_registerScheme:@"https"];
[self.view addSubview:self.webView];
}
4、WKWebView懒加载
- (WKWebView *)webView {
if (!_webView) {
WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc] init];
configuration.userContentController = [WKUserContentController new];
WKPreferences *preferences = [WKPreferences new];
preferences.javaScriptCanOpenWindowsAutomatically = YES;
preferences.minimumFontSize = 30.0;
configuration.preferences = preferences;
_webView = [[WKWebView alloc] initWithFrame:self.view.frame configuration:configuration];
_webView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
if ([_webView respondsToSelector:@selector(setNavigationDelegate:)]) {
[_webView setNavigationDelegate:self];
}
// if ([_webView respondsToSelector:@selector(setDelegate:)]) {
[_webView setUIDelegate:self];
// }
NSURL *url = [NSURL URLWithString:@"http://game.scool.online/cutcake1/"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[_webView loadRequest:request];
}
return _webView;
}
5、别忘记回调哦
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler {
completionHandler();
}
