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我有一個自定義的NSURLProtocol（「UrlProtocol」），用於在導航到特定網站時攔截來自UIWebView的請求，並在發送之前應用額外的HTTP標頭。我跟着https://www.raywenderlich.com/59982/nsurlprotocol-tutorial工作。我的問題是從已棄用的NSURLConnection切換到NSURLSession：我測試了一個非常簡單的單文件html頁面，該頁面已成功加載。然而，像js文件，圖像等資源稍微複雜的網站將超時，而使用NSURLConnection整個網站將在幾秒鐘內加載。將NSURLConnection切換到NSURLSession後自定義NSURLProtocol
我將使用NSURLConnection粘貼原始UrlProtocol，然後使用NSURLSession的新類。原：
#import "UrlProtocol.h"
#import "Globals.h"
@implementation UrlProtocol
+ (BOOL)canInitWithRequest:(NSURLRequest *)request {
if (![request.URL.absoluteString hasPrefix:@"http"]) return NO; //No need to intercept non-http requests
if ([NSURLProtocol propertyForKey:@"handled" inRequest:request]) {
return NO;
}
return YES;
}
+ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request {
NSString* key = @"custom-auth-header";
Globals* globals = [Globals getInstance];
NSString* token = [globals token];
NSMutableURLRequest *newRequest = [request mutableCopy]; //Create a mutable copy that can be modified
[newRequest setValue:token forHTTPHeaderField:key];
return [newRequest copy]; //return a non-mutable copy
}
+ (BOOL)requestIsCacheEquivalent:(NSURLRequest *)a toRequest:(NSURLRequest *)b {
return [super requestIsCacheEquivalent:a toRequest:b];
}
- (void)startLoading {
NSMutableURLRequest *newRequest = [self.request mutableCopy];
[NSURLProtocol setProperty:@YES forKey:@"handled" inRequest:newRequest];
self.connection = [NSURLConnection connectionWithRequest:newRequest delegate:self];
}
- (void)stopLoading {
NSLog(@"stopLoading");
[self.connection cancel];
self.connection = nil;
}
- (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];
}
@end
新UrlProtocol使用NSURLSessionDataTasks爲每一個請求：
#import "UrlProtocol.h"
#import "Globals.h"
@implementation UrlProtocol
+ (BOOL)canInitWithRequest:(NSURLRequest * _Nonnull) request {
if (![request.URL.absoluteString hasPrefix:@"http"]) return NO; //No need to intercept non-http requests
if ([NSURLProtocol propertyForKey:@"handled" inRequest:request]) {
return NO;
}
return YES;
}
+ (NSURLRequest * _Nonnull)canonicalRequestForRequest:(NSURLRequest * _Nonnull)request {
NSString* key = @"custom-auth-header";
Globals* globals = [Globals getInstance];
NSString* token = [globals token];
NSMutableURLRequest *newRequest = [request mutableCopy]; //Create a mutable copy that can be modified
[newRequest setValue:token forHTTPHeaderField:key];
return [newRequest copy]; //return a non-mutable copy
}
+ (BOOL)requestIsCacheEquivalent:(NSURLRequest * _Nonnull)a toRequest:(NSURLRequest * _Nonnull)b {
return [super requestIsCacheEquivalent:a toRequest:b];
}
- (void)startLoading {
NSMutableURLRequest *newRequest = [self.request mutableCopy];
[NSURLProtocol setProperty:@YES forKey:@"handled" inRequest:newRequest];
[Globals setUrlSessionDelegate:self];
Globals* globals = [Globals getInstance];
self.dataTask = [globals.session dataTaskWithRequest:newRequest];
[self.dataTask resume];
}
- (void)URLSession:(NSURLSession * _Nonnull)session dataTask:(NSURLSessionDataTask * _Nullable)dataTask didReceiveData:(NSData * _Nullable)data{
[self.client URLProtocol:self didLoadData:data];
}
- (void)URLSession:(NSURLSession * _Nonnull)session dataTask:(NSURLSessionDataTask * _Nullable)dataTask didReceiveResponse:(NSURLResponse * _Nullable)response
completionHandler:(void (^ _Nullable)(NSURLSessionResponseDisposition))completionHandler{
[self.client URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
completionHandler(NSURLSessionResponseAllow);
}
- (void)URLSession:(NSURLSession * _Nonnull)session task:(NSURLSessionTask * _Nonnull)task didCompleteWithError:(NSError * _Nullable)error{
if (error){
[self.client URLProtocol:self didFailWithError:error];
} else {
[self.client URLProtocolDidFinishLoading:self];
}
}
- (void)URLSession:(NSURLSession * _Nonnull)session task:(NSURLSessionTask * _Nonnull)task willPerformHTTPRedirection:(NSHTTPURLResponse * _Nonnull)response
newRequest:(NSURLRequest * _Nonnull)request completionHandler:(void (^ _Nonnull)(NSURLRequest * _Nullable))completionHandler {
completionHandler(request);
}
- (void)stopLoading {
[self.dataTask cancel];
self.dataTask = nil;
}
@end
「全局」是我已經初始化一個NSURLSession意味着整個應用程序的運行時要使用的單。它還包含我設置爲所有請求自定義HTTP標頭中的令牌：
#import "Globals.h"
#import "UrlProtocol.h"
@implementation Globals
@synthesize token;
@synthesize session;
static Globals *instance = nil;
+(Globals*) getInstance
{
@synchronized(self)
{
if (instance == nil)
{
instance = [Globals new];
}
}
return instance;
}
//UrlProtocol class has no init method, so the NSURLSession delegate is being set on url load. We will ensure only one NSURLSession is created.
+(void) setUrlSessionDelegate:(UrlProtocol*) urlProtocol{
Globals* globals = [Globals getInstance];
if (!globals.session){
globals.session = [NSURLSession sessionWithConfiguration:NSURLSessionConfiguration.defaultSessionConfiguration delegate:urlProtocol delegateQueue:nil];
}
}
@end