如何使用NSURLRequest在Http请求中发送json数据

问题描述

我是objective-c的新手，我开始对最近的请求/响应做出大量的努力。我有一个可以调用url（通过http GET）并解析返回的json的工作示例。

I'm new to objective-c and I'm starting to put a great deal of effort into request/response as of recent. I have a working example that can call a url (via http GET) and parse the json returned.

这个工作示例如下

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    [responseData setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [responseData appendData:data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
  NSLog([NSString stringWithFormat:@"Connection failed: %@", [error description]]);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [connection release];
  //do something with the json that comes back ... (the fun part)
}

- (void)viewDidLoad
{
  [self searchForStuff:@"iPhone"];
}

-(void)searchForStuff:(NSString *)text
{
  responseData = [[NSMutableData data] retain];
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.whatever.com/json"]];
    [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

我的第一个问题是 - 这种方法会放大吗？或者这不是异步（意味着我在应用程序等待响应时阻塞UI线程）

My first question is - will this approach scale up? Or is this not async (meaning I block the UI thread while the app is waiting for the response)

我的第二个问题是 - 我如何修改此部分的请求做一个POST而不是GET？是否只是修改HttpMethod这样？

My second question is - how might I modify the request part of this to do a POST instead of GET? Is it simply to modify the HttpMethod like so?

[request setHTTPMethod:@"POST"];

最后 - 如何添加一组json数据到这个帖子作为一个简单的字符串示例）

And finally - how do I add a set of json data to this post as a simple string (for example)

{
    "magic":{
               "real":true
            },
    "options":{
               "happy":true,
                "joy":true,
                "joy2":true
              },
    "key":"123"
}

预先感谢您

推荐答案

这里是我做的（请注意，到我的服务器的JSON需要是一个字典与一个值（另一个字典）的key =问题。 .ie {：question => {dictionary}}）：

Here's what I do (please note that the JSON going to my server needs to be a dictionary with one value (another dictionary) for key = question..i.e. {:question => { dictionary } } ):

NSArray *objects = [NSArray arrayWithObjects:[[NSUserDefaults standardUserDefaults]valueForKey:@"StoreNickName"],
  [[UIDevice currentDevice] uniqueIdentifier], [dict objectForKey:@"user_question"],     nil];
NSArray *keys = [NSArray arrayWithObjects:@"nick_name", @"UDID", @"user_question", nil];
NSDictionary *questionDict = [NSDictionary dictionaryWithObjects:objects forKeys:keys];

NSDictionary *jsonDict = [NSDictionary dictionaryWithObject:questionDict forKey:@"question"];

NSString *jsonRequest = [jsonDict JSONRepresentation];

NSLog(@"jsonRequest is %@", jsonRequest);

NSURL *url = [NSURL URLWithString:@"https://xxxxxxx.com/questions"];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
             cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];


NSData *requestData = [jsonRequest dataUsingEncoding:NSUTF8StringEncoding];

[request setHTTPMethod:@"POST"];
[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[request setValue:[NSString stringWithFormat:@"%d", [requestData length]] forHTTPHeaderField:@"Content-Length"];
[request setHTTPBody: requestData];

NSURLConnection *connection = [[NSURLConnection alloc]initWithRequest:request delegate:self];
if (connection) {
 receivedData = [[NSMutableData data] retain];
}

然后通过以下方式处理receivedData：

The receivedData is then handled by:

NSString *jsonString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSDictionary *jsonDict = [jsonString JSONValue];
NSDictionary *question = [jsonDict objectForKey:@"question"];

这不是100％清楚，需要重新阅读，但一切都应该在这里让你开始。从我可以告诉，这是异步。我的UI不会锁定，而这些调用。希望有所帮助。

This isn't 100% clear and will take some re-reading, but everything should be here to get you started. And from what I can tell, this is asynchronous. My UI is not locked up while these calls are made. Hope that helps.

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