在iOS上发送HTTP POST请求

Question

我正在开发的iOS应用程序中尝试发送HTTP Post请求，但推送从未到达服务器，尽管我收到代码200作为响应（来自urlconnection）。我从未从服务器获得响应，服务器也没有检测到我的贴子（服务器确实检测到来自Android的帖子）。

我使用ARC，但已将pd和urlConnection设置为strong。

这是我发送请求的代码：

 NSMutableURLRequest *request = [[NSMutableURLRequest alloc]
                                    initWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@",dk.baseURL,@"daantest"]]];
    [request setHTTPMethod:@"POST"];
    [request setValue:@"text/xml"
   forHTTPHeaderField:@"Content-type"];

    NSString *sendString = @"<data><item>Item 1</item><item>Item 2</item></data>";

    [request setValue:[NSString stringWithFormat:@"%d", [sendString length]] forHTTPHeaderField:@"Content-length"];

    [request setHTTPBody:[sendString dataUsingEncoding:NSUTF8StringEncoding]];
    PushDelegate *pushd = [[PushDelegate alloc] init];
    pd = pushd;
    urlConnection = [[NSURLConnection alloc] initWithRequest:request delegate:pd];
    [urlConnection start];

这是我的委托代码

#import "PushDelegate.h"

@implementation PushDelegate
@synthesize data;

-(id) init
{
    if(self = [super init])
    {
        data = [[NSMutableData alloc]init];
        [data setLength:0];
    }
    return self;
}


- (void)connection:(NSURLConnection *)connection didWriteData:(long long)bytesWritten totalBytesWritten:(long long)totalBytesWritten
{
    NSLog(@"didwriteData push");
}
- (void)connectionDidResumeDownloading:(NSURLConnection *)connection totalBytesWritten:(long long)totalBytesWritten expectedTotalBytes:(long long)expectedTotalBytes
{
    NSLog(@"connectionDidResumeDownloading push");
}

- (void)connectionDidFinishDownloading:(NSURLConnection *)connection destinationURL:(NSURL *)destinationURL
{
    NSLog(@"didfinish push @push %@",data);
}

- (void)connection:(NSURLConnection *)connection didSendBodyData:(NSInteger)bytesWritten totalBytesWritten:(NSInteger)totalBytesWritten totalBytesExpectedToWrite:(NSInteger)totalBytesExpectedToWrite
{
    NSLog(@"did send body");
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    [self.data setLength:0];
    NSHTTPURLResponse *resp= (NSHTTPURLResponse *) response;
    NSLog(@"got response with status @push %d",[resp statusCode]);
}

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

    NSLog(@"recieved data @push %@", data);
}

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

    NSLog(@"didfinishLoading%@",responseText);

}

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

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

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

@end

控制台总是打印以下行，且仅打印以下行：

2013-04-01 20:35:04.341 ApprenticeXM[3423:907] did send body
2013-04-01 20:35:04.481 ApprenticeXM[3423:907] got response with status @push 200
2013-04-01 20:35:04.484 ApprenticeXM[3423:907] didfinish push @push <>

- Daan Luttik

Answer 1

以下代码描述了一个使用 POST 方法的简单示例。(如何使用 POST 方法传递数据)

在这里，我描述了如何使用 POST 方法。

1. 将实际的用户名和密码设置为 post 字符串。

NSString *post = [NSString stringWithFormat:@"Username=%@&Password=%@",@"username",@"password"]; 

2. 使用 NSASCIIStringEncoding 编码帖子字符串，同时将要发送的帖子字符串转换为 NSData 格式。

NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; 

你需要发送数据的实际长度。计算邮件字符串的长度。

NSString *postLength = [NSString stringWithFormat:@"%d",[postData length]]; 

3. 使用所有属性创建一个Urlrequest，如HTTP方法、http头字段和帖子字符串长度。创建URLRequest对象并进行初始化。

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init]; 

设置您要将数据发送到该请求的Url。

[request setURL:[NSURL URLWithString:@"http://www.abcde.com/xyz/login.aspx"]]; 

现在，设置HTTP方法（POST或GET）。将这行代码原封不动地写入你的代码中。

[request setHTTPMethod:@"POST"]; 

设置HTTP头部字段，包括POST数据的长度。

[request setValue:postLength forHTTPHeaderField:@"Content-Length"]; 

同时设置HTTP标头字段的编码值。

[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];

使用postData设置urlrequest的HTTPBody。

[request setHTTPBody:postData];

4. 现在创建一个URLConnection对象，使用URLRequest进行初始化。

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

它返回初始化的URL连接并开始加载URL请求的数据。您可以使用以下if/else语句仅检查URL连接是否正常完成。

if(conn) {
    NSLog(@"Connection Successful");
} else {
    NSLog(@"Connection could not be made");
}

5. 要接收来自HTTP请求的数据，可以使用URLConnection类引用提供的代理方法。代理方法如下所示。

// This method is used to receive the data which we get using post method.
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data

// This method receives the error report in case of connection is not made to server. 
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error 

// This method is used to process the data after connection has made successfully.
- (void)connectionDidFinishLoading:(NSURLConnection *)connection

还可以参考：这篇文章 和 这篇文档，了解使用POST方法的相关信息。

以下是使用HTTPPost方法获取数据的最佳示例及其源代码。

- iPatel

---

还要检查是否没有缓存。这可能解释了为什么您收到了“200”，但服务器上没有任何操作。 - Jelle

尽管这个答案已经被接受了很多次，但是其中给出的代码存在许多明显的问题，在实践中会带来麻烦。 - CouchDeveloper

@iPatel 但是我们能否使用上述的POST方法代码发送图像数据呢？ - iHulk

很遗憾，这段代码是不正确的，容易受到注入攻击。如果用户密码中恰好有"&"字符，那么后续所有字符都会被解析为额外的POST参数。这样就可能发生恶意操作。 - ge0rg

如果我需要打开Safari而不是UIWebView，并且需要向浏览器发送POST参数，该怎么办？ - Developer

Answer 2

-(void)sendingAnHTTPPOSTRequestOniOSWithUserEmailId: (NSString *)emailId withPassword: (NSString *)password{
//Init the NSURLSession with a configuration
NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: nil delegateQueue: [NSOperationQueue mainQueue]];

//Create an URLRequest
NSURL *url = [NSURL URLWithString:@"http://www.example.com/apis/login_api"];
NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url];

//Create POST Params and add it to HTTPBody
NSString *params = [NSString stringWithFormat:@"email=%@&password=%@",emailId,password];
[urlRequest setHTTPMethod:@"POST"];
[urlRequest setHTTPBody:[params dataUsingEncoding:NSUTF8StringEncoding]];

//Create task
NSURLSessionDataTask *dataTask = [defaultSession dataTaskWithRequest:urlRequest completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    //Handle your response here
    NSDictionary *responseDict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
     NSLog(@"%@",responseDict);
}];
   [dataTask resume];
}

- Mannam Brahmam

Answer 3

我不是很确定为什么，但只要我注释掉以下方法，它就能正常工作：

connectionDidFinishDownloading:destinationURL:

此外，我认为您只需要NSURLConnectionDataDelegate协议中的方法，除非您需要一些下载信息，不需要NSUrlConnectionDownloadDelegate协议中的方法。

- nickygerritsen

---

我确实想要下载信息，这就是为什么我使用了connectionDidFinishDownloading:destinationURL:函数。 - Daan Luttik

显然，NSURLConnectionDownloadDelegate仅适用于新闻亭应用程序...至少这就是这个线程所说的：https://dev59.com/SWw15IYBdhLWcg3wQpbS - nickygerritsen

Answer 4

这是我在日志记录库中使用的方法：https://github.com/goktugyil/QorumLogs 该方法填充了Google表单中的HTML表单。希望它能帮助那些使用Swift的人。

var url = NSURL(string: urlstring)

var request = NSMutableURLRequest(URL: url!)
request.HTTPMethod = "POST"
request.setValue("application/x-www-form-urlencoded; charset=utf-8", forHTTPHeaderField: "Content-Type")
request.HTTPBody = postData.dataUsingEncoding(NSUTF8StringEncoding)
var connection = NSURLConnection(request: request, delegate: nil, startImmediately: true)

- Esqarrouth

Answer 5

使用Swift 3或4，您可以访问这些HTTP请求以进行服务器通信。

//用于POST数据请求

 func postAction()  {
//declare parameter as a dictionary which contains string as key and value combination. considering inputs are valid
let parameters = ["id": 13, "name": "jack"] as [String : Any]
//create the url with URL
let url = URL(string: "www.requestURL.php")! //change the url
//create the session object
let session = URLSession.shared
//now create the URLRequest object using the url object
var request = URLRequest(url: url)
request.httpMethod = "POST" //set http method as POST
do {
    request.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: .prettyPrinted) // pass dictionary to nsdata object and set it as request body
} catch let error {
    print(error.localizedDescription)
}
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
//create dataTask using the session object to send data to the server
let task = session.dataTask(with: request as URLRequest, completionHandler: { data, response, error in
    guard error == nil else {
        return
    }
    guard let data = data else {
        return
    }
    do {
        //create json object from data
        if let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String: Any] {
            print(json)
            // handle json...
        }
    } catch let error {
        print(error.localizedDescription)
    }
})
task.resume() }

// 获取请求中的数据

func GetRequest()  {
    let urlString = URL(string: "http://www.requestURL.php") //change the url

    if let url = urlString {
        let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
            if error != nil {
                print(error ?? "")
            } else {
                if let responceData = data {
                    print(responceData) //JSONSerialization
                    do {
                        //create json object from data
                        if let json = try JSONSerialization.jsonObject(with:responceData, options: .mutableContainers) as? [String: Any] {
                            print(json)
                            // handle json...
                        }
                    } catch let error {
                        print(error.localizedDescription)
                    }
                }
            }
        }
        task.resume()
    }
}

// 用于从请求中获取下载内容，例如图像或视频

func downloadTask()  {
    // Create destination URL
    let documentsUrl:URL =  FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first as URL!
    let destinationFileUrl = documentsUrl.appendingPathComponent("downloadedFile.jpg")
    //Create URL to the source file you want to download
    let fileURL = URL(string: "http://placehold.it/120x120&text=image1")
    let sessionConfig = URLSessionConfiguration.default
    let session = URLSession(configuration: sessionConfig)
    let request = URLRequest(url:fileURL!)

    let task = session.downloadTask(with: request) { (tempLocalUrl, response, error) in
        if let tempLocalUrl = tempLocalUrl, error == nil {
            // Success
            if let statusCode = (response as? HTTPURLResponse)?.statusCode {
                print("Successfully downloaded. Status code: \(statusCode)")
            }

            do {
                try FileManager.default.copyItem(at: tempLocalUrl, to: destinationFileUrl)
            } catch (let writeError) {
                print("Error creating a file \(destinationFileUrl) : \(writeError)")
            }

        } else {
            print("Error took place while downloading a file. Error description: %@", error?.localizedDescription ?? "");
        }
    }
    task.resume()

}

- Sunil M.

Answer 6

在iOS（Objective c）上发送HTTP POST请求：

-(NSString *)postexample{

// SEND POST
NSString *url = [NSString stringWithFormat:@"URL"];
NSString *post = [NSString stringWithFormat:@"param=value"];
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:@"%d",[postData length]];


NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setHTTPMethod:@"POST"];
[request setURL:[NSURL URLWithString:url]];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:postData];

NSError *error = nil;
NSHTTPURLResponse *responseCode = nil;

//RESPONDE DATA 
NSData *oResponseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&responseCode error:&error];

if([responseCode statusCode] != 200){
    NSLog(@"Error getting %@, HTTP status code %li", url, (long)[responseCode statusCode]);
    return nil;
}

//SEE RESPONSE DATA
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Response" message:[[NSString alloc] initWithData:oResponseData encoding:NSUTF8StringEncoding] delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
[alert show];

return [[NSString alloc] initWithData:oResponseData encoding:NSUTF8StringEncoding];
}

- Ronny Morán

---

这是新鲜事...在你的问题发布4年后还收到回复 :p - Daan Luttik

这个“postexample”函数比Response更快 :p @DaanLuttik - Ronny Morán

Answer 7

Objective C

使用参数发布API，并通过URL验证以导航到JSON响应键，如果状态为“success”

NSString *string= [NSString stringWithFormat:@"url?uname=%@&pass=%@&uname_submit=Login",self.txtUsername.text,self.txtPassword.text];
    NSLog(@"%@",string);
    NSURL *url = [NSURL URLWithString:string];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [request setHTTPMethod:@"POST"];
    NSURLResponse *response;
    NSError *err;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];
    NSLog(@"responseData: %@", responseData);
    NSString *str = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
    NSLog(@"responseData: %@", str);
        NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseData
                                                         options:kNilOptions
                                                           error:nil];
    NSDictionary* latestLoans = [json objectForKey:@"status"];
    NSString *str2=[NSString stringWithFormat:@"%@", latestLoans];
    NSString *str3=@"success";
    if ([str3 isEqualToString:str2 ])
    {
        [self performSegueWithIdentifier:@"move" sender:nil];
        NSLog(@"successfully.");
    }
    else
    {
        UIAlertController *alert= [UIAlertController
                                 alertControllerWithTitle:@"Try Again"
                                 message:@"Username or Password is Incorrect."
                                 preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction* ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault
                                                   handler:^(UIAlertAction * action){
                                                       [self.view endEditing:YES];
                                                   }
                             ];
        [alert addAction:ok];
        [[UIView appearanceWhenContainedIn:[UIAlertController class], nil] setTintColor:[UIColor redColor]];
        [self presentViewController:alert animated:YES completion:nil];
        [self.view endEditing:YES];
      }

JSON响应：{"status":"success","user_id":"58","user_name":"dilip","result":"您已成功登录"} 工作代码

**

- Dilip Tiwari