Question

I am trying to send a POST request to a server using AFNetworking, and everything seems to be working, i.e. the application is successfully pinging the server. However, the parameter values that it is sending are blank when it reaches the server even though after stepping through my code below using the debugger, the values appear to be being passed successfully. Any help on this would be greatly appreciated.

APIClient.m

#import "APIClient.h"
#import "AFJSONRequestOperation.h"

// Removed URL for privacy purposes.
static NSString * const kAPIBaseURLString = @"string goes here";

@implementation APIClient

+ (APIClient *)sharedClient {
    static APIClient *_sharedClient;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _sharedClient = [[APIClient alloc] initWithBaseURL:[NSURL URLWithString:kAPIBaseURLString]];
    });

    return _sharedClient;
}

- (id)initWithBaseURL:(NSURL *)url {
    self = [super initWithBaseURL:url];
    if (self) {
        [self registerHTTPOperationClass:[AFJSONRequestOperation class]];

        // Accept HTTP Header; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
        [self setDefaultHeader:@"Accept" value:@"application/json"];
    }

    return self;
}

@end

Login Method in LoginBrain.m

- (void)loginUsingEmail:(NSString *)email andPassword:(NSString *)password withBlock:(void (^)(NSDictionary *loginResults))block {
    self.email = email;
    self.password = password;

    // Removed path for privacy purposes
    [[APIClient sharedClient] postPath:@"insert path here" parameters:[NSDictionary dictionaryWithObjectsAndKeys:email, @"uname", password, @"pw", nil] success:^(AFHTTPRequestOperation *operation, id responseJSON) {
        if (block) {
            block(responseJSON);
        }
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);

        if (block) {
            block(nil);
        }
    }];

    // Store user data in app?
}

Login Called Method in LoginViewController.m

- (IBAction)loginPressed {
    [self.loginProgressIndicator startAnimating];
    NSString *email = self.emailTextField.text;
    NSString *password = self.passwordTextField.text;

    [self.brain loginUsingEmail:email andPassword:password withBlock:^(NSDictionary *loginResults) {
        [self.loginProgressIndicator stopAnimating];
        [self.delegate uloopLoginViewController:self didLoginUserWithEmail:email andPassword:password];
    }];
}

UPDATE

I tried changing the parameterEncoding as recommended here, but it did not fix the problem.

SECOND UPDATE

Here is the PHP code from the server side that is accessing the POST data. This was written by a co-worker of mine, as I don’t do anything on the server side and am very unfamiliar with how it works.

header('Content-type: application/json');
$username = $_POST['uname'];
$pw = $_POST['pw'];

The server code is pretty straight forward. He has some sort of log script that checks to see what the variable values are, and he says that the client is hitting the server, but the variable values are blank.

THIRD UPDATE

This is a dump of the HTTP request by generating a print_r of the $_REQUEST variable:

Array ( [sid] => FwAqvZrfckw )

And here is a dump of the $_POST variable. As you can see, it’s completely blank:

Array ( )

FOURTH UPDATE

I used Wireshark to capture the packet before it’s being sent to the server, and everything appears to be in order:

Accept: application/json
Content-Type: application/x-www-form-urlencoded; charset=utf-8

And the POST parameters were all there as well. We also created a test file on the server side and just did a test POST to make sure that the code there is working, and it is.

Answer 1

I don’t see anything in particular that would cause a problem here but I’ll start off by giving you the steps I used to solve a similar problem.

To start, checkout the tool, Charles, which is a Debugging Web Proxy that will intercept the response from the server and should give you a more clear idea of what’s going wrong. There’s a 30 day free trial and it really helped me pick out the little bugs. To use it, press the sequence button and filter the results via your server url. From there you can see the request and response sent and received from the server. If the following doesn’t fix your problem, post the request and response that Charles spits out.

Fix wise, try adding [[APIClient sharedClient] setParameterEncoding:AFJSONParameterEncoding] right before you send the POST request. It looks like yall are using JSON as the server-side format.

So in loginUsingEmail:

self.email = email;
self.password = password;

[[APIClient sharedClient] setParameterEncoding:AFJSONParameterEncoding];

[[APIClient sharedClient] postPath:@"insert path here" parameters:[NSDictionary dictionaryWithObjectsAndKeys:email, @"uname", password, @"pw", nil] success:^(AFHTTPRequestOperation *operation, id responseJSON) {
    if (block) {
        block(responseJSON);
    }
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);

    if (block) {
        block(nil);
    }
}];

// Store user data in app?
}