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我正在尝试从此 url 中提取数据，但遇到了一些问题。为什么会在上NSJSONSerialization线时崩溃？有没有更好的方法从这个网站下载信息？

编辑：我将 jsonArray 从 NSArray 更改为 NSDictionary，但它仍然在同一个地方崩溃。有没有其他方法可以下载这些数据？

NSString *url=@"https://api.p04.simcity.com/simcity/rest/users/search/J3d1.json";

NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];

NSURLResponse *resp = nil;
NSError *err = nil;

NSData *response = [NSURLConnection sendSynchronousRequest: theRequest returningResponse: &resp error: &err];

NSDictionary *jsonArray = [NSJSONSerialization JSONObjectWithData: response options: NSJSONReadingMutableContainers error: &err];

NSLog(@"%@",jsonArray);

作为参考，JSON 是：

{
    "users": [
        {
            "uri": "/rest/user/20624",
            "tutorialState": 0,
            "nucleusId": 20624,
            "id": 20624,
            "screenName": "R3DEYEJ3D1",
            "lastLogin": 1362666027000,
            "isOnline": "true",
            "avatarImage": "https://api.p04.simcity.com/simcity/rest/user/20624/avatar",
            "cities_count": 0,
            "canChat": "true"
        },
        {
            "uri": "/rest/user/46326",
            "tutorialState": 0,
            "nucleusId": 46326,
            "id": 46326,
            "screenName": "J3D1_WARR10R",
            "lastLogin": 1363336534000,
            "isOnline": "false",
            "avatarImage": "https://api.p04.simcity.com/simcity/rest/user/46326/avatar",
            "cities_count": 0,
            "canChat": "true"
        }
    ]
}
4

3 回答 3

3

您的服务器提供了一个不受操作系统信任的证书 - 我必须在您的 JSON 中使用该-k标志，curl所以应该早点想到这一点。

为了解决这个问题，您需要切换到使用异步NSURLConnection并实现其委托方法。请参阅此堆栈溢出问题中的此答案，以实施针对您的解析问题的有效解决方案。我在应用程序委托中实现了它，但是您可以例如将它放在异步中NSOperation并在那里使用它。

警告：此代码将连接到任何服务器，无论信任如何。这是要求一个人在中间攻击。启用此类信任时，请勿将敏感信息发送到服务器。您必须实现代码来验证您的服务器的身份，并用针对该检查结果的测试替换if (YES)in 。- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge

我目前的理解是，这应该通过将您的证书的公钥作为 DER 文件包含在应用程序包中来完成，并使用SecCertificateCreateWithData创建一个SecCertficiateRef将用作SecTrustSetAnchorCertificates. 然后，SecTrustEvaluate应该用来验证身份。我基于阅读证书、密钥和信任服务参考以及在这篇博客文章中找到的关于如何信任您自己的证书的示例代码来理解这一点。

@interface AppDelegate () <NSURLConnectionDelegate, NSURLConnectionDataDelegate>

//  This is needed to collect the response as it comes back from the server
@property (nonatomic, strong) NSMutableData *mutableResponseData;

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Xcode template code for setting up window, ignore...
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
        self.viewController = [[ViewController alloc] initWithNibName:@"ViewController_iPhone" bundle:nil];
    } else {
        self.viewController = [[ViewController alloc] initWithNibName:@"ViewController_iPad" bundle:nil];
    }
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];

    //  Instantiate our connection 
    NSString *urlString = @"https://api.p04.simcity.com/simcity/rest/users/search/J3d1.json";
    NSURL *url = [NSURL URLWithString:urlString];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    if(![NSURLConnection connectionWithRequest:request delegate:self]) {
        NSLog(@"Handle an error case here.");
    }

    return YES;
}


- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    //  Prepare to recevie data from the connection
    NSLog(@"did receive response: %@", response);
    self.mutableResponseData = [NSMutableData data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    //  Handle an error case here
    NSLog(@"did fail with error: %@", error);
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    //  Build up the response data
    [self.mutableResponseData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSError *error = nil;
    id JSONObject = [NSJSONSerialization JSONObjectWithData:self.mutableResponseData options: NSJSONReadingMutableContainers error:&error];
    if (!JSONObject) {
        //  Handle error here
        NSLog(@"error with JSON object");
    }
    else if ([JSONObject isKindOfClass:[NSDictionary class]]) {
        //we're in business
        NSDictionary *dict = JSONObject;
        NSLog(@"dict is %@", dict);
    }
    else {
        //  Handle case of other root JSON object class...
    }
}


//  The following two methods allow any credential to be used. THIS IS VULNERABLE TO MAN IN THE MIDDLE ATTACK IN ITS CURRENT FORM
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
{
    return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
}

- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
    if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
        // WE ARE POTENTIALLY TRUSTING ANY CERTIFICATE HERE. Replace YES with verification of YOUR server's identity to avoid man in the middle attack.
        //  FOR ALL THAT'S GOOD DON'T SHIP THIS CODE
#warning Seriously, don't ship this.
        if (YES) {
            [challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
        }
    }

    [challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];   
}

@end
于 2013-03-17T19:34:57.237 回答
0

如果数据为零，NSJSONSerialization 总是会崩溃。您需要输入条件以查看该 URL 是否包含任何数据。

于 2013-03-17T19:31:12.207 回答
0

尝试将 url 放在浏览器中以确保为您提供有效的 JSON，并确保解析的数据是 Array 或 NSDictionary

于 2013-03-17T19:32:22.737 回答