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/**
* Check if a hostname is an IP. You should be aware that this only works
* because `hostname` is already garanteed to be a valid hostname!
*/
function isProbablyIpv4(hostname: string): boolean {
// Cannot be shorted than 1.1.1.1
if (hostname.length < 7) {
return false;
}
// Cannot be longer than: 255.255.255.255
if (hostname.length > 15) {
return false;
}
let numberOfDots = 0;
for (let i = 0; i < hostname.length; i += 1) {
const code = hostname.charCodeAt(i);
if (code === 46 /* '.' */) {
numberOfDots += 1;
} else if (code < 48 /* '0' */ || code > 57 /* '9' */) {
return false;
}
}
return (
numberOfDots === 3 &&
hostname.charCodeAt(0) !== 46 /* '.' */ &&
hostname.charCodeAt(hostname.length - 1) !== 46 /* '.' */
);
}
/**
* Similar to isProbablyIpv4.
*/
function isProbablyIpv6(hostname: string): boolean {
if (hostname.length < 3) {
return false;
}
let start = hostname.startsWith('[') ? 1 : 0;
let end = hostname.length;
if (hostname[end - 1] === ']') {
end -= 1;
}
// We only consider the maximum size of a normal IPV6. Note that this will
// fail on so-called "IPv4 mapped IPv6 addresses" but this is a corner-case
// and a proper validation library should be used for these.
if (end - start > 39) {
return false;
}
let hasColon = false;
for (; start < end; start += 1) {
const code = hostname.charCodeAt(start);
if (code === 58 /* ':' */) {
hasColon = true;
} else if (
!(
(
(code >= 48 && code <= 57) || // 0-9
(code >= 97 && code <= 102) || // a-f
(code >= 65 && code <= 90)
) // A-F
)
) {
return false;
}
}
return hasColon;
}
/**
* Check if `hostname` is *probably* a valid ip addr (either ipv6 or ipv4).
* This *will not* work on any string. We need `hostname` to be a valid
* hostname.
*/
export default function isIp(hostname: string): boolean {
return isProbablyIpv6(hostname) || isProbablyIpv4(hostname);
}
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