NSURLRequest：发布数据并阅读发布的页面

本文介绍了NSURLRequest：发布数据并阅读发布的页面的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

在iOS（当前目标5.0，Base SDK 5.1）中，如何向服务器发送帖子请求，然后阅读页面内容。例如，页面采用用户名和密码，然后回显true或false。这只是为了更好地理解NSURLRequest。

In iOS (current target 5.0, Base SDK 5.1) how can I send a post request to a server, and then read the contents of the page. For example, the page takes a username and password, and then echos true or false. This is just for a better understanding of NSURLRequest.

提前致谢！

推荐答案

首先要做的事情

• 决定如何对数据进行编码 - JSON或url编码是一个良好的开端。
• 确定一个返回值 - 它是1，TRUE还是0，FALSE，甚至YES / non-nil nothing / nil。
• 阅读 URL加载系统，这是你的朋友。

• Decide how you want to encode your data - JSON or url-encoding are a good start.
• Decide upon a return value - will it be 1, TRUE or 0, FALSE, or even YES/non-nil nothing/nil.
• Read up on the URL Loading System, it's your friend.

旨在使所有网址连接异步，以便您的UI保持响应。您可以使用NSURLConnectionDelegate回调执行此操作。 NSURLConnection有一个小缺点：您的代码必须解耦。您希望委托函数中可用的任何变量都需要保存到ivars或请求的userInfo dict中。

Aim to make all your url connections asynchronous so your UI remains responsive. You can do this with NSURLConnectionDelegate callbacks. NSURLConnection has a small drawback: your code must be decoupled. Any variables you want available in the delegate functions will need to be saved to ivars or in your request's userInfo dict.

或者您可以使用GCD，当与__block限定符结合使用时，允许您在声明它时指定错误/返回代码 - 对于一次提取非常有用。

Alternatively you can use GCD, which, when coupled with the __block qualifiers, allows you to specify error/return code at the point you declare it - useful for one off fetches.

不用多说，这里有一个快速而又脏的网址编码器：

Without further ado, here's a quick and dirty url-encoder:

- (NSData*)encodeDictionary:(NSDictionary*)dictionary { NSMutableArray *parts = [[NSMutableArray alloc] init]; for (NSString *key in dictionary) { NSString *encodedValue = [[dictionary objectForKey:key] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; NSString *encodedKey = [key stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; NSString *part = [NSString stringWithFormat: @"%@=%@", encodedKey, encodedValue]; [parts addObject:part]; } NSString *encodedDictionary = [parts componentsJoinedByString:@"&"]; return [encodedDictionary dataUsingEncoding:NSUTF8StringEncoding]; }

使用像 JSONKit 使编码变得更容易，考虑它！

Using a JSON library like JSONKit makes encoding things easier, consider it!

// .h @interface ViewController : UIViewController<NSURLConnectionDelegate> @end // .m @interface ViewController () { NSMutableData *receivedData_; } @end ... - (IBAction)asyncButtonPushed:(id)sender { NSURL *url = [NSURL URLWithString:@"localhost/"]; NSDictionary *postDict = [NSDictionary dictionaryWithObjectsAndKeys:@"user", @"username", @"password", @"password", nil]; NSData *postData = [self encodeDictionary:postDict]; // Create the request NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url]; [request setHTTPMethod:@"POST"]; [request setValue:[NSString stringWithFormat:@"%d", postData.length] forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded charset=utf-8" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody:postData]; NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; [connection start]; } - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { [receivedData_ setLength:0]; } - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { [receivedData_ appendData:data]; } - (void)connectionDidFinishLoading:(NSURLConnection *)connection { NSLog(@"Succeeded! Received %d bytes of data", [receivedData_ length]); NSString *responeString = [[NSString alloc] initWithData:receivedData_ encoding:NSUTF8StringEncoding]; // Assume lowercase if ([responeString isEqualToString:@"true"]) { // Deal with true return; } // Deal with an error }

方法2 - Grand Central Dispatch async功能：

Method 2 - Grand Central Dispatch async function:

// .m - (IBAction)dispatchButtonPushed:(id)sender { NSURL *url = [NSURL URLWithString:@"www.apple/"]; NSDictionary *postDict = [NSDictionary dictionaryWithObjectsAndKeys:@"user", @"username", @"password", @"password", nil]; NSData *postData = [self encodeDictionary:postDict]; // Create the request NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url]; [request setHTTPMethod:@"POST"]; [request setValue:[NSString stringWithFormat:@"%d", postData.length] forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded charset=utf-8" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody:postData]; dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ // Peform the request NSURLResponse *response; NSError *error = nil; NSData *receivedData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error]; if (error) { // Deal with your error if ([response isKindOfClass:[NSHTTPURLResponse class]]) { NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse*)response; NSLog(@"HTTP Error: %d %@", httpResponse.statusCode, error); return; } NSLog(@"Error %@", error); return; } NSString *responeString = [[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding]; // Assume lowercase if ([responeString isEqualToString:@"true"]) { // Deal with true return; } // Deal with an error // When dealing with UI updates, they must be run on the main queue, ie: // dispatch_async(dispatch_get_main_queue(), ^(void){ // // }); }); }

方法3 - 使用NSURLConnection便利功能

Method 3 - Use an NSURLConnection convenience function

+ (void)sendAsynchronousRequest:(NSURLRequest *)request queue:(NSOperationQueue *)queue completionHandler:(void (^)(NSURLResponse*, NSData*, NSError*))handler

希望这有帮助。