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Merge pull request #210 from jayden-sudo/main
Fixed a bug in retrieving the DKIM public key
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Original file line number | Diff line number | Diff line change |
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// DoH servers list | ||
export enum DoHServer { | ||
// Google Public DNS | ||
Google = "https://dns.google/resolve", | ||
// Cloudflare DNS | ||
Cloudflare = "https://cloudflare-dns.com/dns-query", | ||
} | ||
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/** | ||
* DNS over HTTPS (DoH) resolver | ||
* | ||
* @export | ||
* @class DoH | ||
*/ | ||
export class DoH { | ||
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// DNS response codes | ||
static DoHStatusNoError = 0; | ||
// DNS RR types | ||
static DoHTypeTXT = 16; | ||
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/** | ||
* Resolve DKIM public key from DNS | ||
* | ||
* @static | ||
* @param {string} name DKIM record name (e.g. 20230601._domainkey.gmail.com) | ||
* @param {string} DNSServer DNS over HTTPS API URL | ||
* @return {*} {(Promise<string | null>)} DKIM public key or null if not found | ||
* @memberof DoH | ||
*/ | ||
public static async resolveDKIMPublicKey(name: string, DNSServer: string): Promise<string | null> { | ||
if (!DNSServer.startsWith('https://')) { | ||
DNSServer = 'https://' + DNSServer; | ||
} | ||
if (DNSServer.endsWith('/')) { | ||
DNSServer = DNSServer.slice(0, -1); | ||
} | ||
const resp = await fetch( | ||
DNSServer + "?" + | ||
new URLSearchParams({ | ||
name: name, | ||
// DKIM public key record type is TXT | ||
type: DoH.DoHTypeTXT.toString(), | ||
}), | ||
{ | ||
headers: { | ||
"accept": "application/dns-json", | ||
} | ||
} | ||
); | ||
if (resp.status === 200) { | ||
const out = await resp.json(); | ||
if (typeof out === 'object' && out !== null && 'Status' in out && 'Answer' in out) { | ||
const resp = out as DoHResponse; | ||
if (resp.Status === DoH.DoHStatusNoError && resp.Answer.length > 0) { | ||
for (const ans of resp.Answer) { | ||
if (ans.type === DoH.DoHTypeTXT) { | ||
let DKIMRecord = ans.data; | ||
/* | ||
Remove all double quotes | ||
Some DNS providers wrap TXT records in double quotes, | ||
and others like Cloudflare may include them. According to | ||
TXT (potentially multi-line) and DKIM (Base64 data) standards, | ||
we can directly remove all double quotes from the DKIM public key. | ||
*/ | ||
DKIMRecord = DKIMRecord.replace(/"/g, ''); | ||
return DKIMRecord; | ||
} | ||
} | ||
} | ||
} | ||
} | ||
return null; | ||
} | ||
} | ||
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interface DoHResponse { | ||
Status: number; // NOERROR - Standard DNS response code (32 bit integer). | ||
TC: boolean; // Whether the response is truncated | ||
AD: boolean; // Whether all response data was validated with DNSSEC | ||
CD: boolean; // Whether the client asked to disable DNSSEC | ||
Question: Question[]; | ||
Answer: Answer[]; | ||
Comment: string; | ||
} | ||
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interface Question { | ||
name: string; // FQDN with trailing dot | ||
type: number; // A - Standard DNS RR type. 5:CNAME, 16:TXT | ||
} | ||
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interface Answer { | ||
name: string; // Always matches name in the Question section | ||
type: number; // A - Standard DNS RR type. 5:CNAME, 16:TXT | ||
TTL: number; // Record's time-to-live in seconds | ||
data: string; // Record data | ||
} |
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