在 iOS 上发送 HTTP POST 请求

我正在尝试用我正在开发的 iOS 应用程序发送一个 HTTP Post，但是推送永远不会到达服务器，尽管我得到了一个代码200作为响应(来自 urlconnect)。我从未从服务器得到响应，服务器也没有检测到我的帖子(服务器确实检测到来自 android 的帖子)

我确实使用了 ARC，但是将 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];

这是我对委托人的代码

#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

控制台总是打印下列行，并且只打印下列行:

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 <>
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最佳答案

The following code describes a simple example using POST method.(How one can pass data by POST method)

Here, I describe how one can use of POST method.

1. Set post string with actual username and password.

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

2. Encode the post string using NSASCIIStringEncoding and also the post string you need to send in NSData format. 

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

You need to send the actual length of your data. Calculate the length of the post string.

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

3. Create a Urlrequest with all the properties like HTTP method, http header field with length of the post string. Create URLRequest object and initialize it. 

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

Set the Url for which your going to send the data to that request.

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

Now, set HTTP method (POST or GET). Write this lines as it is in your code.

[request setHTTPMethod:@"POST"];

Set HTTP header field with length of the post data. 

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

Also set the Encoded value for HTTP header Field.

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

Set the HTTPBody of the urlrequest with postData.

[request setHTTPBody:postData];

4. Now, create URLConnection object. Initialize it with the URLRequest.

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

It returns the initialized url connection and begins to load the data for the url request. You can check that whether you URL connection is done properly or not using just if/else statement as below.

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

5. To receive the data from the HTTP request , you can use the delegate methods provided by the URLConnection Class Reference. Delegate methods are as below. 

// 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

Also Refer This and This documentation for POST method.

And here is best example with source code of HTTPPost Method.

小开

I am not really sure why, but as soon as I comment out the following method it works:

connectionDidFinishDownloading:destinationURL:

Furthermore, I don't think you need the methods from the NSUrlConnectionDownloadDelegate protocol, only those from NSURLConnectionDataDelegate, unless you want some download information.

小开

Heres the method I used in my logging library: https://github.com/goktugyil/QorumLogs

This method fills html forms inside Google Forms. Hope it helps someone using Swift.

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)
小开 
-(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];
}
小开

Objective C

Post API with parameters and validate with url to navigate if json
response key with status:"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 Response : {"status":"success","user_id":"58","user_name":"dilip","result":"You have been logged in successfully"} Working code

**

小开

Sending an HTTP POST request on iOS (Objective c):

-(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];
}
小开

Using Swift 3 or 4 you can access these http request for sever communication.

// For POST data to request

 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() }

// For get the data from request

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()
}
}

// For get the download content like image or video from request

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()


}

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