Objective-C Powerschool login

gistfile1.txt

#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonCrypto.h>
#import "NSString+MyAdditions.h"

#define POWERSCHOOL_TOKEN_DATA 0
#define POWERSCHOOL_CONTEXT_DATA 1

NSArray* getAuthData()
{
    NSMutableArray *authData = [NSMutableArray array];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://psgk.schoolname.org:8081/guardian/home.html"]];
    [request setHTTPShouldHandleCookies:YES];
    [request setHTTPMethod:@"GET"];
    NSURLResponse *response;
    NSError *connectionError;
    NSString *dataString = nil;
    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&connectionError];
    if (!connectionError)
    {
        NSArray *findHiddenValuesWithIds = @[@"pstoken", @"contextData"];
        dataString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        for (NSString *hiddenValueId in findHiddenValuesWithIds)
        {
            NSString *pattern = [NSString stringWithFormat:@"<input type=\"hidden\" name=\"%@\" value=\"(.*?)\" \\/>", hiddenValueId];
            NSError *regexError;
            NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:0 error:&regexError];
            if (!regexError)
            {
                NSArray *matches = [regex matchesInString:dataString options:0 range:NSMakeRange(0, [dataString length])];
                for (NSTextCheckingResult *match in matches)
                {
                    NSRange matchRange = [match rangeAtIndex:1];
                    NSString *matchString = [dataString substringWithRange:matchRange];
                    [authData addObject:matchString];
                }
            }
        }
    }
    return authData;
}

void doPCASLogin(NSString *username, NSString* password)
{
    password = [password lowercaseString];
    NSArray *authData = getAuthData();
    NSMutableString *hmacPassword = [NSMutableString stringWithString:[password hmacMD5WithData:[authData objectAtIndex:POWERSCHOOL_CONTEXT_DATA]]];
    [hmacPassword replaceOccurrencesOfString:@"=" withString:@"" options:0 range:NSMakeRange(0, [hmacPassword length])];
    NSMutableDictionary *fields = [NSMutableDictionary dictionary];
    [fields setValue:[authData objectAtIndex:POWERSCHOOL_TOKEN_DATA] forKey:@"pstoken"];
    [fields setValue:[authData objectAtIndex:POWERSCHOOL_CONTEXT_DATA] forKey:@"contextData"];
    [fields setValue:@"guardian/home.html" forKey:@"returnUrl"];
    [fields setValue:@"PS Parent Portal" forKey:@"serviceName"];
    [fields setValue:@"" forKey:@"serviceTicket"];
    [fields setValue:@"/" forKey:@"pcasServerUrl"];
    [fields setValue:@"User Id and Password Credential" forKey:@"credentialType"];
    [fields setValue:username forKey:@"account"];
    [fields setValue:hmacPassword forKey:@"pw"];
    
    NSArray *postStringOrder = @[@"pstoken", @"contextData", @"returnUrl", @"serviceName", @"serviceTicket", @"pcasServerUrl", @"credentialType", @"account", @"pw"];
    NSMutableString *postString = [NSMutableString string];
    for (NSString *fieldName in postStringOrder)
    {
        [postString appendFormat:@"%@=%@&", fieldName, [fields objectForKey:fieldName]];
    }
    postString = [NSMutableString stringWithString:[postString substringToIndex:[postString length] - 1]];
    
    NSURL *loginUrl = [NSURL URLWithString:@"http://psgk.schoolname.org:8081/guardian/home.html"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:loginUrl];
    request.timeoutInterval = 10;
    request.HTTPShouldHandleCookies = YES;
    request.HTTPMethod = @"POST";
    request.HTTPBody = [postString dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];

    NSURLResponse *response;
    NSError *responseError;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&responseError];
    if (responseData != nil)
    {
        NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
        NSLog(@"%@", responseString);
    }
}