79 lines
1.5 KiB
JavaScript
79 lines
1.5 KiB
JavaScript
'use strict';
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/**
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* Check if a hostname is an IP. You should be aware that this only works
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* because `hostname` is already garanteed to be a valid hostname!
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*
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* @param {string} hostname
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* @return {boolean}
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*/
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function isProbablyIpv4(hostname) {
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var numberOfDots = 0;
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for (var i = 0; i < hostname.length; i += 1) {
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var code = hostname.charCodeAt(i);
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if (code === 46) { // '.'
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numberOfDots += 1;
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} else if (code < 48 || code > 57) {
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// 48 => '0'
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// 57 => '9'
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return false;
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}
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}
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return (
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numberOfDots === 3 &&
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hostname[0] !== '.' &&
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hostname[hostname.length - 1] !== '.'
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);
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}
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/**
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* Similar to isProbablyIpv4.
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*
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* @param {string} hostname
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* @return {boolean}
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*/
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function isProbablyIpv6(hostname) {
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var hasColon = false;
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for (var i = 0; i < hostname.length; i += 1) {
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var code = hostname.charCodeAt(i);
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if (code === 58) { // ':'
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hasColon = true;
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} else if (!(
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(code >= 48 && code <= 57) || // 0-9
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(code >= 97 && code <= 102) // a-f
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)) {
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return false;
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}
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}
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return hasColon;
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}
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/**
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* Check if `hostname` is *probably* a valid ip addr (either ipv6 or ipv4).
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* This *will not* work on any string. We need `hostname` to be a valid
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* hostname.
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*
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* @param {string} hostname
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* @return {boolean}
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*/
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module.exports = function isIp(hostname) {
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if (typeof hostname !== 'string') {
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return false;
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}
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if (hostname.length === 0) {
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return false;
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}
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return (isProbablyIpv6(hostname) || isProbablyIpv4(hostname));
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};
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