Issue in sending POST parameter from iOS

Question

I want to send imageUrl in POST parameter which can have &.e.g. imageUrl can be http://www.url.com?param1=edfef&param2=erfregreg.

Now If I send this directly to server then it will not consider any params after &. Other answers on SO suggest to replace & with %26. But that is not working. Because when I escape the whole POST param string then it will replace % in %26 with %25. i.e.http://www.url.com?param1=edfef%2526param2=erfregreg which makes url invalid.

Code to escape params :

NSMutableString *postParams = [NSMutableString stringWithFormat:@"imageUrl=%@&realName=%@, imageUrl, realName];
NSMutableString *escapeParams = (NSMutableString*)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,  (CFStringRef)postParams, NULL,(CFStringRef)@" !%?$#[]/+:@;*()'\"",kCFStringEncodingUTF8));   
self.postParameters = escapeParams;

Update : I tried below code, but not working.

// URL
NSString * url = [NSString stringWithFormat:@"https://graph.facebook.com/%@/picture?width=250&height=250", fbId];

NSString *escapedString = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(
    NULL,
   (__bridge CFStringRef) url,
    NULL,
    CFSTR("!*'();:@&=+$,/?%#[]\" "),
    kCFStringEncodingUTF8));

url = escapedString;

// Making REST API call to store user details in table.
NSMutableString *postParams = [NSMutableString stringWithFormat:@"imageUrl=%@&realName=%@", imageUrl, realName];
NSMutableString *escapeParams = (NSMutableString*)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,  (CFStringRef)postParams, NULL,(CFStringRef)@" !%?$#[]/+:@;*()'\"",kCFStringEncodingUTF8));
postParams = escapeParams;
NSString * getParams = ...;

// Code to call API.
.
.   // Setting up url and NSMutableURLRequest
.
NSData *myRequestData = [NSData dataWithBytes:[postParams UTF8String] length:[postParams length]];
[request setHTTPBody:myRequestData];

Answer 1

Here is a copy-paste code snippet that I use in all my projects it encodes perfectly

- (NSString *)urlencode:(NSString *)val {
    NSMutableString *output = [NSMutableString string];
    const unsigned char *source = (const unsigned char *)[val UTF8String];
    int sourceLen = strlen((const char *)source);
    for (int i = 0; i < sourceLen; ++i) {
        const unsigned char thisChar = source[i];
        if (thisChar == ' '){
            [output appendString:@"+"];
        } else if (thisChar == '.' || thisChar == '-' || thisChar == '_' || thisChar == '~' ||
                   (thisChar >= 'a' && thisChar <= 'z') ||
                   (thisChar >= 'A' && thisChar <= 'Z') ||
                   (thisChar >= '0' && thisChar <= '9')) {
            [output appendFormat:@"%c", thisChar];
        } else {
            [output appendFormat:@"%%%02X", thisChar];
        }
    }
    return output;
}

I suggest you to use a NSString Categroy

Header

//#import "NSString+UrlEncode.h"
#import <Foundation/Foundation.h>

@interface NSString (UrlEncode)
- (NSString *)urlencode;
@end

Implementation

//#import "NSString+UrlEncode.m"
#import "NSString+UrlEncode.h"

@implementation NSString (UrlEncode)
- (NSString *)urlencode {
    NSMutableString *output = [NSMutableString string];
    const unsigned char *source = (const unsigned char *)[self UTF8String];
    int sourceLen = strlen((const char *)source);
    for (int i = 0; i < sourceLen; ++i) {
        const unsigned char thisChar = source[i];
        if (thisChar == ' '){
            [output appendString:@"+"];
        } else if (thisChar == '.' || thisChar == '-' || thisChar == '_' || thisChar == '~' ||
                   (thisChar >= 'a' && thisChar <= 'z') ||
                   (thisChar >= 'A' && thisChar <= 'Z') ||
                   (thisChar >= '0' && thisChar <= '9')) {
            [output appendFormat:@"%c", thisChar];
        } else {
            [output appendFormat:@"%%%02X", thisChar];
        }
    }
    return output;
}
@end

Usage: import the category

#import "NSString+UrlEncode.h"

then

  param.urlencode