Convert python signing code to javascript

Question

I'm currently working on a code generator and porting it over to javascript, however I can't seem to get the same results?

The code which I've got in Python is the following:

def sign(self, cs, api):
    temp_string = ""
    cs_length = len(cs)
    api_length = len(api)

    if api_length > 0:
        for index in range(0, cs_length):
            temp_char = cs[index]
            temp_code = ord(temp_char)
            temp_code_2 = ord(api[index % api_length])
            new_code = self.get_code(temp_code, 47, 57, temp_code_2)
            new_char = ""
            if new_code != cs[index]:
                new_char = chr(new_code)
                try:
                    temp_string += new_char
                except:
                    xbmc.log("Unprintable character => %s" % new_char)

            xbmc.log("Index: %i	Character %i:%s		Modulus %i		Modulus Code %i:%s		New Code %i:%s" %
                     (index, temp_code, temp_char, (index % api_length), temp_code_2, chr(temp_code_2), new_code,
                      new_char))
    else:
        xbmc.log("Signature cannot be blank")

    # xbmc.log("
Target Signature: 7a74G7m23Vrp0o5c")
    xbmc.log("Result signature: %s" % temp_string[0:16])

    return temp_string[0:16]

def get_code(self, char_code, const_1, const_2, char_result):
    if const_1 < char_code <= const_2:
        char_code += char_result % (const_2 - const_1)
        if char_code > const_2:
            char_code = char_code - const_2 + const_1

    return char_code

And here's what I've wrote in Javascript:

get_code(char_code, const_1, const_2, char_result) {
    if(const_1 < char_code <= const_2) {
        char_code += char_result % (const_2 - const_1);
        if(char_code > const_2) {
            char_code = char_code - const_2 + const_1;
        }
    }
    return char_code;
}

sign(cs, api) {
    let temp_string = '';
    let cs_length = cs.length;
    let api_length = api.length;
    if(api_length > 0) {
        for(let index in this.range(0, cs_length)) {
            let temp_char = cs[index];
            let temp_code = temp_char.charCodeAt(0);
            let temp_code_2 = api[index % api_length].charCodeAt(0);
            let new_code = this.get_code(temp_code, 47, 57, temp_code_2);
            let new_char = "";
            if(new_code != cs[index]) {
                try {
                    new_char = new_code.charCodeAt(0);
                    temp_string += new_char;
                } catch(error) {
                    console.log('"Unprintable character => ' + new_char);
                }
            }
        }
    }
    return temp_string.substring(0, 16);
}

When running it in Javascript, I'm just getting a ton of "Unprintable character => results being thrown?

user_2904896 · Answer

Your issue appears to be your conversion from this Python code

new_char = chr(new_code)

To JavaScript

new_char = new_code.charCodeAt(0);

Given that chr in Python takes an int and return a single length str, while String.charCodeAt does the exact opposite - also given that the value of new_code appears to be an Number or int (in JavaScript and Python respectively), that will simply not work as that is not a method available for the Number type.

It would have been clear had the code logged the actual error inside the catch block - the nature of the exception should have revealed that TypeError: new_code.charCodeAt is not a function.

You were probably looking for String.fromCharCode, so that problematic line should be:

new_char = String.fromCharCode(new_code);

Convert python signing code to javascript

1 Answers