Send array to PHP from objective C using POST/GET

Question

I am trying to send an array of strings from Objective C to PHP. I was using GET initially but I got to know that GET is not suitable for sending large amount of data. My array would have approximately 300 entries. Therefore, I am using POST. After going through this page I came up with the following code

 NSDictionary *userconnections = [user objectForKey:@"connections"];
             NSMutableArray *connectionsID = [[NSMutableArray alloc] init];
             for (id foo in [userconnections objectForKey:@"values"]) {

                 [connectionsID addObject:[foo objectForKey:@"id"]];
                 //[User sharedUser].connections = connectionsID;

             }

             NSError *error;
             NSData *jsonData = [NSJSONSerialization dataWithJSONObject:connectionsID options:NSJSONWritingPrettyPrinted error:&error];

             NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
             [User sharedUser].connections = jsonData;
             [User sharedUser].connectionsID = jsonString;

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"http://localhost:8888/API.php"]];

    [request setHTTPMethod:@"POST"];

[request setValue:[[User sharedUser]connectionsID] forKey:@"songs"];
[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[request setValue:[NSString stringWithFormat:@"%lu", (unsigned long)[[[User sharedUser] connections] length]] forHTTPHeaderField:@"Content-Length"];
 [request setHTTPBody: [[User sharedUser] connections]];

NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSLog(@"Return DATA contains: %@", [NSJSONSerialization JSONObjectWithData:returnData options:NSJSONReadingMutableContainers error:nil]);

In my PHP, I receive it like:

    <?php 

header("Content-Type: application/json");
$headers = array_change_key_case(getallheaders());


include "dbconnect.php";

$songs = json_decode(stripcslashes($_GET["songs"]));
echo json_encode($songs);

However, I am not able to receive data in php. Any help or pointers would be appreciated

EDIT: I switched back to using GET since POST was not helping me. Thank you for any help you may offer

if you look at just the body is it form encoded? I think it needs to be to show up in $_POST... otherwise I think you have to get it out of the raw request. — Grady Player
– Grady Player, Commented Mar 21, 2014 at 3:37

Rob · Accepted Answer · 2014-03-21 03:54:23Z

2

A couple of issues:

You are building a Content-Type of application/json request, but your PHP is trying to read the $_POST['songs']. You should do one or the other (either send raw JSON request, or send application/x-www-form-urlencoded request). Let's assume you just wanted to create simple JSON request (as your Objective-C code is largely doing now). In that case, your PHP should read the raw JSON like so:

<?php

// be a good citizen and report that we're going to return JSON response

header("Content-Type: application/json");

// get the lower case rendition of the headers of the request

$headers = array_change_key_case(getallheaders());

// extract the content-type

if (isset($headers["content-type"]))
    $content_type = $headers["content-type"];
else
    $content_type = "";

// if JSON, read and parse it

if ($content_type == "application/json")
{
    // read it

    $handle = fopen("php://input", "rb");
    $raw_post_data = '';
    while (!feof($handle)) {
        $raw_post_data .= fread($handle, 8192);
    }
    fclose($handle);

    // parse it

    $songs = json_decode($raw_post_data, true);
}
else
{
    // report non-JSON request and exit
}

// now use that `$songs` variable here

// if you wanted to report it back to the client for debugging purposes, you should
// recreate JSON response:

$raw_result = json_encode($songs);

// finally, write the body of the response

echo $raw_result;

?>

I would suggest removing the the setValue:forKey: with the @"songs" key in your Objective-C code. Assuming you just wanted to send the raw JSON request like I outlined above, then this is not needed (and, frankly, is the wrong way to send a application/x-www-form-urlencoded request, anyway).

If you intended to make the payload so that you could use $_POST['songs'], then the Objective-C code to do that does not use setValue:forKey:, but consists of manually building a request with a Content-Type of application/x-www-form-urlencoded, and the songs=... would be in the body of the request (and you'd have to use CFURLCreateStringByAddingPercentEscapes to encode the JSON string you'd pass in this request). This is all a bit academic, though, as I think you should stick with the application/json request.

edited Mar 21, 2014 at 3:54

answered Mar 21, 2014 at 3:49

Rob

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2 Comments

Shruti Kapoor Over a year ago

Hi, thanks for your response. I did have the json header in my php. I have updated my php code that should give you a better idea of what my file looks like.

Rob Over a year ago

@ShrutiKapoor That's great. But lack or presence of the JSON header is not the problem. It's that your Objective-C code is creating a JSON request (not a application/x-www-form-urlencoded request), but your PHP was using $_POST, which is intended only for application/x-www-form-urlencoded and similarly encoded requests. Since you're just sending raw JSON in the request body, you should therefore change the PHP to read the raw data of the request body, which it can then convert with json_decode.

Tijn · Accepted Answer · 2014-03-21 20:33:57Z

0

I recommend the widely used AFNetworking library (https://github.com/AFNetworking/AFNetworking). A simple POST request with parameters can be constructed like this:

NSDictionary *p = @{@"foo": @"bar"};
[[AFHTTPRequestOperationManager manager] POST:@"http://example.com/resources.json" parameters:p success:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"JSON: %@", responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error); 
}];

answered Mar 21, 2014 at 20:33

Tijn

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Comments

Yao Li · Accepted Answer · 2016-09-03 06:32:18Z

0

AFNetworking 2.0 has AFHTTPSessionManager class with POST method

(NSURLSessionDataTask *)POST:(NSString *)URLString parameters:(id)parameters constructingBodyWithBlock:(void (^)(id<AFMultipartFormData>))block success:(void (^)(NSURLSessionDataTask *, id))success failure:(void (^)(NSURLSessionDataTask *, NSError *))failure;

pass connectionsID into parameters

NSDictionary *params = @{@"connectionsID": [connectionsID copy]};

which can be accessed in PHP

$_POST['connectionsID']

answered Sep 3, 2016 at 6:32

Yao Li

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