iOS HTTP 请求发送 JSON 格式

Question

我正在尝试使用以下参数调用Web服务：

{"Class":"Authorization","method":"login","user":"","pass":""}

如下

NSString *user = [NSString stringWithFormat:@"username=%@",_username.text];
NSString *pass = [NSString stringWithFormat:@"password=%@",_password.text];
NSString *Class = @"Authorization";
NSString *method = @"login";
//NSString *post = [NSString stringWithFormat:@"%@&%@&%@&%@", user, pass, Class, method ];
    
NSString *jsonPostBody = [NSString stringWithFormat:@"'json' = '{"Class":"
                              ""%@""
                              ","method":"
                              ""%@""
                              ","pass":"
                              ""%@""
                              ","user":"
                              ""%@""
                              "}'",
                              [Class stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding],
                              [method stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding],
                              [pass stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding],
                              [user stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
    NSData *postData = [jsonPostBody dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
   
    NSURL *url = [NSURL URLWithString:@"http://212.119.87.45:8080/IktissabServices/index.php/service"];
    NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                                       timeoutInterval:180.0];
    
    [request setHTTPMethod:@"POST"];
    [request setValue:@"application/x-www-form-urlencoded"   forHTTPHeaderField:@"Content-Type"];
    [request setHTTPBody:[[jsonPostBody stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]
                          dataUsingEncoding:NSUTF8StringEncoding
                          allowLossyConversion:YES]];
    
    [request setHTTPBody:postData];
    
    NSString* postDataLengthString = [[NSString alloc] initWithFormat:@"%d", [postData length]];
    [request setValue:postDataLengthString forHTTPHeaderField:@"Content-Length"];
    
    NSURLResponse *response;
    NSError *err;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];
    NSError *error;
    NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableContainers error:&error];//
    if (! error) {
        NSLog(@"%@",jsonDict);
    }else{
        NSLog(@"%@",error.localizedDescription);
    } 

每次结果是：

由于未捕获的异常而终止应用'NSInvalidArgumentException'， reason： 'data parameter is nil'

网络服务具有：

输入内容类型：文本/JSON

输出内容类型：文本/JSON

任何帮助或示例将不胜感激。

Answer 1

以下代码没有任何异常（尽管显然我无法访问您的服务器，所以我无法端到端地测试它）：

NSDictionary *dictionary = @{
    @"Class"  : @"Authorization",
    @"method" : @"login",
    @"pass"   : _password.text,
    @"user"   : _username.text
};
NSError *error;
NSData *postData = [NSJSONSerialization dataWithJSONObject:dictionary
                                                   options:0
                                                     error:&error];
if (error)
    NSLog(@"Failure to serialize JSON object %@", error);
NSURL *url = [NSURL URLWithString:@"http://212.119.87.45:8080/IktissabServices/index.php/service"];
NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:url
                                                       cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                                   timeoutInterval:180.0];
[request setHTTPMethod:@"POST"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];    
[request setHTTPBody:postData];
NSURLResponse *response;
NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
if (error)
    NSLog(@"%s sendSynchronousRequest error %@", __FUNCTION__, error);
NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableContainers error:&error];//
if (!error) {
    NSLog(@"%@",jsonDict);
} else {
    NSLog(@"%s JSONObjectWithData error %@", __FUNCTION__, error);
} 

或者，如果您没有使用最新的 Xcode，并且无法访问字典的 Modern Objective C 定义，则显然可以用传统方式定义字典：

NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:
                            @"Authorization", @"Class",
                            @"login",         @"method",
                            _password.text,   @"pass",
                            _username.text,   @"user",
                            nil];

---

编辑：

从您的jsonPostBody推断，字典条目可能需要：

NSDictionary *dictionary = @{
    @"json" : @{
        @"Class"  : @"Authorization",
        @"method" : @"login",
        @"pass"   : _password.text,
        @"user"   : _username.text
    }
};

或者可能（尽管可能性更小），从您的user和pass定义中推断：

NSDictionary *dictionary = @{
    @"json" : @{
        @"Class"  : @"Authorization",
        @"method" : @"login",
        @"pass"   : [NSString stringWithFormat:@"password=%@",_password.text],
        @"user"   : [NSString stringWithFormat:@"username=%@",_username.text]
    }
};

这是需要如何为您的服务器格式化 JSON 的问题。