Passing array to PHP using POST from iOS

Question

So I've looked through an endless number of like problems but none of them answered what I was looking for or answered it in a complete manner so hopefully you all can help me out.

I need to pass an array of restaurantID's from iOS to a PHP file using POST or anyway that would work well. I know about ASIHTTPRequest but I'm looking for something built in and it has been abandon by the developer. And lastly, I don't want to pass them through the URL because I don't know how many entries there will be.

So here's what I got so far.

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:theURL]];

[request setHTTPMethod:@"POST"];

NSMutableDictionary *jsonDict = [[NSMutableDictionary alloc] init];
[jsonDict setValue:restaurants forKey:@"restIDs"];
NSLog(@"JSON Dict: %@",jsonDict);//Checking my array here


NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonDict options:kNilOptions error:nil];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
NSLog(@"JSON String: %@",jsonString); //Checking my jsonString here...

[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

[request setValue:@"json" forHTTPHeaderField:@"Data-Type"];
[request setValue:[NSString stringWithFormat:@"%d", [jsonData length]] forHTTPHeaderField:@"Content-Length"];
[request setHTTPBody: jsonData];
NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSLog(@"Return DATA contains: %@", [NSJSONSerialization JSONObjectWithData:returnData options:NSJSONReadingMutableContainers error:nil]);
NSArray *restMenuCount = [NSJSONSerialization JSONObjectWithData:returnData options:NSJSONReadingMutableContainers error:nil];

So, from this end, I've checked everything and it all looks good, but from the PHP end it doesn't even pick it up.

Here's what my PHP file looks like:

$restIDs = $_POST['restIDs'];
echo $restIDs; //Checking to see if it even has anything......but nothing there
for ($i = 0; $i < $restIDs.count; $i++) {
    $query = "SELECT * FROM `MenuItems` WHERE rest_id = '$restID'";
    $result = mysqli_query($connect, $query);
    $number = mysqli_num_rows($result);
    $menuNumber[$i] = $number;
}

echo json_encode($menuNumber);

So finally, what am I doing wrong? Why am I not receiving anything on my PHP end. And most of all, can someone explain to me how to send array's via a POST. Because I feel like that's my real problem here, I don't understand it enough to fix the problem myself. I don't understand how you can put everything in from the iOS side and pick it up on the PHP side.

I hope all of this was clear enough, thanks in advance.

EDIT:
I tried passing the array as a string through the URL then exploding it, luckily it worked...but I'm just under the URL limit, so I'd still like to figure out another solution. At least, now I know the rest of my code was working as expected.

Answer 1

You seem to have a basic misunderstanding of how the $_POST variable is filled in. Specifying the document type as JSON and throwing the JSON string in as the post body will not auto-populate this array. The body has to be in a specific format. Usually, this means url-encoded pairs, eg a=1&b=2&c=2&d=%2fg+y etc. This somewhat limits the kind of data you can send. In particular, an arbitrary JSON object is not possible in this sense, if you want it to show up in the $_POST variable automatically. There are a few options from here:

Option one: Rather than using $_POST, use the post body directly. Use fopen("php://input") and parse that using a PHP JSON parser:

$input = file_get_contents("php://input");
$obj = json_decode($input,true);
$restIDs = $obj['restIDs'];

If you went this route you need not create an object with a field named restIDs though. You can instead simply serialize the array and use $obj as $restIDs

Option two, assuming your objects in restIDs are simply strings, instead of passing the data in as a JSON object, format the body as intended for PHP use:

NSMutableString *bodyStr = [NSMutableString string];
for (NSString *restID in restaurants) {
    [bodyStr appendFormat:@"restIDs[]=%@&",[restID stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}
NSData *body = [bodyStr dataUsingEncoding:NSUTF8StringEncoding];
[request setHTTPBody: body];

Now you should be able to access it using $_POST['restIDs'] as you would expect.

Answer 2

You are passing the array wrong. First you placed it in a JSON string and then you didn't put the JSON String in the post variables but as the body of the HTML message. If you are going to use JSON to transfer data to PHP via a POST message you need to set it as a post variable. Then in PHP, you read the variable and decode the json to get your original variables. Here's an example of how I did it.

Sorry I originally pasted the Java code here. This might make more sense.

-(void) setPath: (NSString *) input
{
    Path=input;
}

-(void) run
{
    NSDictionary* jsonDictionary=[NSDictionary dictionaryWithObject: data1 forKey:@"data"];
    NSString* jsonString = [jsonDictionary JSONRepresentation];
    AFHTTPClient *httpClient=[[AFHTTPClient alloc] initWithBaseURL:url];
    NSDictionary *params =[NSDictionary dictionaryWithObjectsAndKeys:
                           apps,@"app",
                           jsonString,@"smpdata",nil];
    NSMutableURLRequest *request = [httpClient requestWithMethod:@"POST" path:Path parameters:params];

    NSURLResponse *response = nil;
    NSError *error = nil;

    NSData *data=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

    if (error) {
        NSLog(@"Error: %@",error);
    }
    else {
        id JSON = AFJSONDecode(data, &error);
        NSArray *dataarray=[JSON valueForKey:@"Data"];
        status= [NSString stringWithFormat:@"%@",[JSON valueForKeyPath:@"Status"]];
        NSLog(@"%@",status);
        returndata= dataarray;

    }
}

-(NSArray *) returndata {
    return returndata;
}

-(NSString *) status {
    return status;
}

@end

PHP

<?
$jsondata=$_POST['smpdata'];
$data = json_decode($jsondata);
?>