@aikidosec/firewall
Version:
Zen by Aikido is an embedded Application Firewall that autonomously protects Node.js apps against common and critical attacks, provides rate limiting, detects malicious traffic (including bots), and more.
54 lines (53 loc) • 1.66 kB
JavaScript
;
const RE_PLUS = /\+/g;
const HEX = [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
];
function Decoder() {
this.buffer = undefined;
}
Decoder.prototype.write = function (str) {
// Replace '+' with ' ' before decoding
str = str.replace(RE_PLUS, " ");
let res = "";
let i = 0;
let p = 0;
const len = str.length;
for (; i < len; ++i) {
if (this.buffer !== undefined) {
if (!HEX[str.charCodeAt(i)]) {
res += "%" + this.buffer;
this.buffer = undefined;
--i; // retry character
}
else {
this.buffer += str[i];
++p;
if (this.buffer.length === 2) {
res += String.fromCharCode(parseInt(this.buffer, 16));
this.buffer = undefined;
}
}
}
else if (str[i] === "%") {
if (i > p) {
res += str.substring(p, i);
p = i;
}
this.buffer = "";
++p;
}
}
if (p < len && this.buffer === undefined) {
res += str.substring(p);
}
return res;
};
Decoder.prototype.reset = function () {
this.buffer = undefined;
};
module.exports = Decoder;