使用完成处理程序通过NSURLConnection sendAsynchronousRequest进行身份验证

Question

一般来说,我喜欢使用完成处理程序块使用NSURL的sendAsynchronousRequest类方法"触发并忘记",但似乎在需要身份验证时可能不是一个选项.

使用完成处理程序样式请求时,如下所示:

[NSURLConnection sendAsynchronousRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.mysite.com/"]]
                                       queue:[NSOperationQueue mainQueue]
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {


                            //Do Stuff   

                           }];

处理身份验证的正确方法是什么？我是否需要分配和初始化NSURLConnection并设置委托而不是使用此类方法样式？我想我理解如何使用委托函数正确验证,但我想弄清楚我是否可以在completionHandler块中包含它,或者是否有更好的方法来执行此操作.

- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{

    if ([challenge previousFailureCount] > 0) {
        NSLog(@"Authentication Failure");
        [connection cancel];
    }
    else
    {

        NSURLCredential *credential = [NSURLCredential credentialWithUser:self.username
                                                                 password:self.password
                                                              persistence:NSURLCredentialPersistenceForSession];
        [[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
    }

}

Answer 1

我认为completionHandler方法适用于基本请求.也许您可以考虑使用AFNetworking,因为我使用块方法和身份验证.

编辑....您是否尝试将身份验证标头添加到NSURLRequest？创建NSMutableURLRequest:

NSMutableURLRequest *urlRequest = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"http://www.example.com/"]];

并添加如下身份验证标头:

NSString *basicAuthCredentials = [NSString stringWithFormat:@"%@:%@", userName, password];
NSString *authValue = [NSString stringWithFormat:@"Basic %@", AFBase64EncodedStringFromString(basicAuthCredentials)];
[urlRequest setValue:authValue forHTTPHeaderField:@"Authorization"];

AFBase64EncodedStringFromString函数是这样的:

static NSString * AFBase64EncodedStringFromString(NSString *string) {
    NSData *data = [NSData dataWithBytes:[string UTF8String] length:[string lengthOfBytesUsingEncoding:NSUTF8StringEncoding]];
    NSUInteger length = [data length];
    NSMutableData *mutableData = [NSMutableData dataWithLength:((length + 2) / 3) * 4];

    uint8_t *input = (uint8_t *)[data bytes];
    uint8_t *output = (uint8_t *)[mutableData mutableBytes];

    for (NSUInteger i = 0; i < length; i += 3) {
        NSUInteger value = 0;
        for (NSUInteger j = i; j < (i + 3); j++) {
            value <<= 8;
            if (j < length) {
                value |= (0xFF & input[j]);
            }
        }

        static uint8_t const kAFBase64EncodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

        NSUInteger idx = (i / 3) * 4;
        output[idx + 0] = kAFBase64EncodingTable[(value >> 18) & 0x3F];
        output[idx + 1] = kAFBase64EncodingTable[(value >> 12) & 0x3F];
        output[idx + 2] = (i + 1) < length ? kAFBase64EncodingTable[(value >> 6)  & 0x3F] : '=';
        output[idx + 3] = (i + 2) < length ? kAFBase64EncodingTable[(value >> 0)  & 0x3F] : '=';
    }

    return [[NSString alloc] initWithData:mutableData encoding:NSASCIIStringEncoding];
}

然后调用之前调用的函数,但使用新的NSURLRequest:

[NSURLConnection sendAsynchronousRequest:urlRequest
  queue:[NSOperationQueue mainQueue]
  completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {

}];

Answer 2

即使问题已经解决了一段时间,我想添加一个不需要第三方库的解决方案:

//HTTP Authentication
NSString *authStr = [NSString stringWithFormat:@"%@:%@", @"Username", @"Password"]];
NSData *authData = [authStr dataUsingEncoding:NSASCIIStringEncoding];
NSString *authValue = [authData base64Encoding];

//Set up Request:
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]init];
[request setURL:[NSURL URLWithString:url]];
//...
// Pack in the user credentials
[request setValue:[NSString stringWithFormat:@"Basic %@",authValue] forHTTPHeaderField:@"Authorization"];

// Send the asynchronous request as usual
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *responseCode, NSData *responseData, NSError *error) {

    // Do stuff..

}