使用参数的Http Post请求

Question

使用参数的Http Post请求

3

我有一个简单的asp.net Web服务，它返回json格式的数据。我想发送带参数的http post请求来获取json数据。我该如何发送请求并获取数据？

post请求：

POST /JsonWS.asmx/FirmaGetir HTTP/1.1
Host: localhost
Content-Type: application/x-www-form-urlencoded
Content-Length: length

firID=string

answer:

HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: length    
<?xml version="1.0" encoding="utf-8"?>
<string xmlns="http://tempuri.org/">string</string>

我尝试了一些代码，但它们没有起作用。

NSString *firmadi =@"";
NSMutableData *response;


-(IBAction)buttonClick:(id)sender
{
    NSString *firid = [NSString stringWithFormat:@"800"];

    response = [[NSMutableData data] retain];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://192.168.1.23/testService/JsonWS.asmx?op=FirmaGetir"]];

    NSString *params = [[NSString alloc] initWithFormat:@"firID=%@",firid];
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:[params dataUsingEncoding:NSUTF8StringEncoding]];
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [[NSURLConnection alloc] initWithRequest:request delegate:self];
NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

    if(theConnection)
    {
        response = [[NSMutableData data] retain];

    }
    else 
    {
        NSLog(@"theConnection is null");
    }

}

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

    httpResponse = (NSURLResponse *) responsed;

}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data
{
    [response appendData:data];
    //NSLog(@"webdata: %@", data);

}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError*)error
{
    NSLog(@"error with the connection");
    [connection release];
    [response release];
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{

    response = [[NSMutableData data] retain];

 NSString *responseString = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
    NSLog(@"%@",responseString);

}

- Melih Mucuk

1

你尝试过将请求的 MIME 类型设置为 'application/json' 而不是 'application/x-www-form-urlencoded' 吗？ - George Green

这是来自我的网络服务，为什么我要更改这个设置？ - Melih Mucuk

你发布的代码有什么问题？ - George Green

屏幕上有一个按钮。当我按下按钮时，我想看到我的服务结果。但是没有发生。 - Melih Mucuk

在didFinishLoading中，response = [[NSMutableData data] retain]]会导致你在使用它之前丢失所有已下载的数据，将其放在NSString *responseString之后。 - George Green

2个回答

0

今天早上我遇到了这个问题，现在才解决。我猜你的问题关键在于如何使用带参数的POST方法。实际上，它非常简单。

(1) 首先，您应该确保您要发送的文件已经准备好了。这里我们用一个NSString变量叫stringReady作为我们postRequest方法的参数（这不是我们想要讨论的HTTP POST参数，不用担心）。

// Send JSON to server
- (void) postRequest:(NSString *)stringReady{
// Create a new NSMutableURLRequest
NSMutableURLRequest *req = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"http://www.xxxxxx.io/addcpd.php"]];
[req setHTTPMethod:@"POST"];

(2) 现在，我们说服务器想要获取的参数称为“data”，这是将参数插入HTTP正文的方法。

// Add the [data] parameter
NSString *bodyWithPara = [NSString stringWithFormat:@"data=%@",stringReady];

看，这是在使用POST方法时添加参数的方式。你只需要在要发送的文件之前简单地放置参数即可。如果你已经知道你的参数，那么最好查看一下这个网站：

https://www.hurl.it/

这将帮助您测试是否正确发送文件，并在网站底部显示响应。

(3) 第三步，我们将NSString打包成NSData并发送到服务器。

// Convert the String to NSData
NSData *postData = [bodyWithPara dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
// Set the content length and http body
NSString *postLength = [NSString stringWithFormat:@"%lu",(unsigned long)[postData length]];
[req addValue:postLength forHTTPHeaderField:@"Content-Length"];
[req setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[req setHTTPBody:postData];
// Create an NSURLSession
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest:req
                                        completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                            // Do something with response data here - convert to JSON, check if error exists, etc....
                                            if (!data) {
                                                NSLog(@"No data returned from the sever, error occured: %@", error);
                                                return;
                                            }

                                            NSLog(@"got the NSData fine. here it is...\n%@\n", data);
                                            NSLog(@"next step, deserialising");

                                            NSError *deserr;
                                            NSDictionary *responseDict = [NSJSONSerialization
                                                                          JSONObjectWithData:data
                                                                          options:kNilOptions
                                                                          error:&deserr];
                                            NSLog(@"so, here's the responseDict\n\n\n%@\n\n\n", responseDict);
                                        }];

[task resume];}

希望这能帮助到在这里卡住的人。

- BetterTeng

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- Jaybit · Accepted Answer

你在这里做什么：

[[NSURLConnection alloc] initWithRequest:request delegate:self];

这行代码返回了一个 NSURLConnection，但你没有存储它。这对你没有任何作用。

在读取数据之前，你清除了数据：

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    response = [[NSMutableData data] retain]; // This line is clearing your data get rid of it
    NSString *responseString = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
    NSLog(@"%@",responseString);

}

编辑

-(IBAction)buttonClick:(id)sender {

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://192.168.1.23/testService/JsonWS.asmx?op=FirmaGetir"]
                                                           cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData
                                                       timeoutInterval:15];
    [request setHTTPMethod:@"POST"];
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [request setHTTPBody:[@"firID=800" dataUsingEncoding:NSUTF8StringEncoding]];
    self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    [self.connection start];

}


#pragma NSURLConnection Delegates

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

    if (!self.receivedData){
        self.receivedData = [NSMutableData data];
    }
    [self.receivedData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {

     NSString *responseString = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding];
     NSLog(@"%@",responseString);
}