iOS 中的 HTTP POST 请求 [关闭]

嗨，我是 ios 新手，直到现在我还没有向 php 发送任何调用，今天我尝试了以下代码

-(void)sendRequest
{

NSString *vali = @"$uppl!3r$";

NSString *post = [NSString stringWithFormat:@"key1=%@",vali];
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]];
NSLog(@"%@",postLength);
NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
[request setURL:[NSURL URLWithString:@"http://www.ddemo3.enerjinet.com/webservices/ios/suppliers.php"]];
[request setHTTPMethod:@"POST"];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:postData];

NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

if (theConnection) {
    webData = [[NSMutableData data] retain];
    NSLog(@"%@",webData);
}
else
{

}
}

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

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

}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
[connection release];
[webData release];

}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSString *loginStatus = [[NSString alloc] initWithBytes: [webData mutableBytes] length:                       [webData length] encoding:NSUTF8StringEncoding];
NSLog(@"%@",loginStatus);
//greeting.text = loginStatus;
[loginStatus release];
[connection release];
[webData release];
}

它应该返回 76 条记录的数组，但它返回了我<>谁能帮帮我吗 ？ Web 服务已准备就绪，我需要获取数组响应并将其显示在我的表格视图中，请帮助我执行此操作

有几点想法：

1. You NSLog your webData，这将始终显示<>（因为您在实例化后立即记录它）。我不确定你为什么要记录它。

问题是你是否看到了<>， 或者NSLog in connectionDidFinishLoading.

2. 我这么问是因为你没有记录error in connection:didFailWithError:，如果失败了，你永远不知道为什么。你真的应该记录error in connection:didFailWithError:这样你就知道它是否失败了，如果失败了，为什么：

    NSLog(@"%s: %@", __FUNCTION__, error);
   

3. In your connection:didReceiveResponse:，你真的应该看看HTTP 状态码 http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html:

    if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
        NSInteger statusCode = [(NSHTTPURLResponse *)response statusCode];
   
        if (statusCode != 200)
            NSLog(@"%s: status code is %d; should be 200", __FUNCTION__, statusCode);
    }
   

如果不是 200，你真的很想知道。

4. 您在您所看到的评论之一中报告了connectionDidFinishLoading:打电话过，但从来没有didReceiveData叫。这意味着（毫不奇怪）没有收到数据。所以，你应该：

• 确认connection:didReceiveResponse:报告了一个statusCode of 200; and

• 确认服务器代码正常工作。我可以想象如果您的服务器 PHP 代码中有错误（由于服务器经常有错误而加剧了这种错误），我可以想象得到您所描述的行为display_errors关闭他们的php.ini file).

顺便说一句，如果可能与关联的值key1可能包含任何保留字符（如中定义第2节 https://www.rfc-editor.org/rfc/rfc3986#section-2RFC 3986），您应该使用百分比转义字符串CFURLCreateStringByAddingPercentEscapes. Thus:

NSString *post = [NSString stringWithFormat:@"key1=%@", [self percentEscapeString:vali]];

哪里，根据W3C 规范 http://www.w3.org/TR/html5/forms.html#application/x-www-form-urlencoded-encoding-algorithm for application/x-www-form-urlencoded，您不仅可以百分比转义，还可以将空格替换为+字符，因此：

- (NSString *)percentEscapeString:(NSString *)string
{ 
    NSString *result = CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                                                 (CFStringRef)string,
                                                                                 (CFStringRef)@" ",
                                                                                 (CFStringRef)@":/?@!$&'()*+,;=",
                                                                                 kCFStringEncodingUTF8));
    return [result stringByReplacingOccurrencesOfString:@" " withString:@"+"];
}