AJAX POST and Plus Sign ( + ) -- How to Encode?

I'm POSTing the contents of a form field via AJAX to a PHP script and using JavaScript to escape(field_contents). The problem is that any plus signs are being stripped out and replaced by spaces. How can I safely 'encode' the plus sign and then appropriately 'decode' it on the PHP side?

Solution 1:

Use encodeURIComponent() in JS and in PHP you should receive the correct values.

Note: When you access $_GET, $_POST or $_REQUEST in PHP, you are retrieving values that have already been decoded.

Example:

In your JS:

// url encode your string
var string = encodeURIComponent('+'); // "%2B"
// send it to your server
window.location = 'http://example.com/?string='+string; // http://example.com/?string=%2B

On your server:

echo $_GET['string']; // "+"

It is only the raw HTTP request that contains the url encoded data.

For a GET request you can retrieve this from the URI. $_SERVER['REQUEST_URI'] or $_SERVER['QUERY_STRING']. For a urlencoded POST, file_get_contents('php://stdin')

NB:

decode() only works for single byte encoded characters. It will not work for the full UTF-8 range.

eg:

text = "\u0100"; // Ā
// incorrect
escape(text); // %u0100 
// correct
encodeURIComponent(text); // "%C4%80"

Note: "%C4%80" is equivalent to: escape('\xc4\x80')

Which is the byte sequence (\xc4\x80) that represents Ā in UTF-8. So if you use encodeURIComponent() your server side must know that it is receiving UTF-8. Otherwise PHP will mangle the encoding.

Solution 2:

In JavaScript try:

encodeURIComponent() 

and in PHP:

urldecode($_POST['field']);

Solution 3:

The hexadecimal value you are looking for is %2B

To get it automatically in PHP run your string through urlencode($stringVal). And then run it rhough urldecode($stringVal) to get it back.

If you want the JavaScript to handle it, use escape( str )

Edit

After @bobince's comment I did more reading and he is correct. Use encodeURIComponent(str) and decodeURIComponent(str). Escape will not convert the characters, only escape them with \'s

Solution 4:

To make it more interesting and to hopefully enable less hair pulling for someone else. Using python, built dictionary for a device which we can use curl to configure.

Problem: {"timezone":"+5"} //throws an error " 5"

Solution: {"timezone":"%2B"+"5"} //Works

So, in a nutshell:

var = {"timezone":"%2B"+"5"}
json = JSONEncoder().encode(var)
subprocess.call(["curl",ipaddress,"-XPUT","-d","data="+json])

Thanks to this post!