iOS:如何执行 HTTP POST 请求? [英] iOS: how to perform a HTTP POST request?

问题描述

我正在接触 iOS 开发，我想要我的第一个应用程序来执行 HTTP POST 请求.

据我所知，我应该通过 NSURLConnection 对象来管理处理请求的连接，这迫使我拥有一个委托对象，而该对象又将处理数据事件.

有人可以用一个实际的例子来澄清这个任务吗?

我应该联系 https 端点发送身份验证数据(用户名和密码)并获取纯文本响应.

解决方案

您可以使用 NSURLConnection 如下:

1. 设置您的 NSURLRequest:使用 requestWithURL:(NSURL *)theURL 来初始化请求.

   如果您需要指定 POST 请求和/或 HTTP 标头，请使用 NSMutableURLRequest 和

   • (void)setHTTPMethod:(NSString *)method
   • (void)setHTTPBody:(NSData *)data
   • (void)setValue:(NSString *)value forHTTPHeaderField:(NSString *)field

2. 使用 NSURLConnection 以两种方式发送您的请求:

   • 同步:(NSData *)sendSynchronousRequest:(NSURLRequest *)requestreturningResponse:(NSURLResponse **)response error:(NSError **)error

     这将返回一个您可以处理的 NSData 变量.

     重要提示:请记住在单独的线程中启动同步请求以避免阻塞 UI.

   • 异步:(void)start

不要忘记设置您的 NSURLConnection 的委托来处理连接，如下所示:

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {[self.data setLength:0];}- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)d {[self.data appendData:d];}- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {[[[[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Error", @"")消息:[错误本地化描述]代表:无cancelButtonTitle:NSLocalizedString(@"OK", @"")otherButtonTitles:nil] 自动释放] 显示];}- (void)connectionDidFinishLoading:(NSURLConnection *)connection {NSString *responseText = [[NSString alloc] initWithData:self.data encoding:NSUTF8StringEncoding];//用它做任何你想做的事[响应文本发布];}//如果需要，处理基本身份验证质询- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {NSString *用户名 = @"用户名";NSString *password = @"password";NSURLCredential *credential = [NSURLCredential credentialWithUser:username密码:密码持久性:NSURLCredentialPersistenceForSession];[[挑战发送者] useCredential:credential forAuthenticationChallenge:challenge];}

I'm approaching iOS development and I'd like to have one of my first applications to perform a HTTP POST request.

As far as I can understand, I should manage the connection which handles the request via a NSURLConnection object, which forces me to have a delegate object, which in turn will handle data events.

Could someone please clarify the task with a practical example?

I should contact an https endpoint sending authentication data (username and password) and getting back a plain text response.

解决方案

You can use NSURLConnection as follows:

1. Set your NSURLRequest: Use requestWithURL:(NSURL *)theURL to initialise the request.

   If you need to specify a POST request and/or HTTP headers, use NSMutableURLRequest with

   • (void)setHTTPMethod:(NSString *)method
   • (void)setHTTPBody:(NSData *)data
   • (void)setValue:(NSString *)value forHTTPHeaderField:(NSString *)field

2. Send your request in 2 ways using NSURLConnection:

   • Synchronously: (NSData *)sendSynchronousRequest:(NSURLRequest *)request returningResponse:(NSURLResponse **)response error:(NSError **)error

     This returns a NSData variable that you can process.

     IMPORTANT: Remember to kick off the synchronous request in a separate thread to avoid blocking the UI.

   • Asynchronously: (void)start

Don't forget to set your NSURLConnection's delegate to handle the connection as follows:

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

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

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    [[[[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Error", @"")
                                 message:[error localizedDescription]
                                delegate:nil
                       cancelButtonTitle:NSLocalizedString(@"OK", @"") 
                       otherButtonTitles:nil] autorelease] show];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSString *responseText = [[NSString alloc] initWithData:self.data encoding:NSUTF8StringEncoding];

    // Do anything you want with it 

    [responseText release];
}

// Handle basic authentication challenge if needed
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
    NSString *username = @"username";
    NSString *password = @"password";

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

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