smartdns/ts/index.ts

import * as q from 'smartq'
import * as plugins from './dnsly.plugins'

export type TDnsProvider = 'google'
export type TDnsRecordType = 'A'
    | 'AAAA'
    | 'CNAME'
    | 'PTR'
    | 'MX'
    | 'NAPTR'
    | 'NS'
    | 'SOA'
    | 'SRV'
    | 'TXT'

export interface IDnsRecord {
    chunked?: string[]
    name: string
    type: TDnsRecordType
    value: string
}

/**
 * class dnsly offers methods for working with dns from a dns provider like Google DNS
 */
export class Dnsly {
    dnsServerIp: string
    dnsServerPort: number
    /**
     * constructor for class dnsly
     */
    constructor(dnsProviderArg: TDnsProvider = 'google') {
        this._setDnsProvider(dnsProviderArg)
    }

    /**
     * gets a record
     */
    async getRecord(recordNameArg: string, recordTypeArg: TDnsRecordType): Promise<IDnsRecord[]> {
        switch (recordTypeArg) {
            case 'TXT':
                return await this.getRecordTxt(recordNameArg)
            case 'A':
                return await this.getRecordA(recordNameArg)
            case 'AAAA':
                return await this.getRecordAAAA(recordNameArg)
        }
    }

    async checkUntilAvailable(recordNameArg: string, recordTypeArg: TDnsRecordType, expectedValue: string) {
        let cycleArg = 0
        let doCheck = async () => {
            if (cycleArg < 30) {
                cycleArg++
                try {
                    let myRecordArray = await this.getRecord(recordNameArg, recordTypeArg)
                    let myRecord = myRecordArray[0].value
                    if (myRecord === expectedValue) {
                        return true
                    } else {
                        await plugins.smartdelay.delayFor(500)
                        return await doCheck()
                    }
                } catch (err) {
                    await plugins.smartdelay.delayFor(500)
                    return await doCheck()
                }
            } else {
                console.log('failed permanently...')
                return false
            }
        }
        return await doCheck()
    }

    /**
     * get A Dns Record
     */
    async getRecordA(recordNameArg: string): Promise<IDnsRecord[]> {
        return await this.getOrdinaryRecord(recordNameArg, 'A')
    }

    /**
     * get AAAA Record
     */
    async getRecordAAAA(recordNameArg: string) {
        return await this.getOrdinaryRecord(recordNameArg, 'AAAA')
    }

    /**
     * gets a txt record
     */
    getRecordTxt(recordNameArg: string): Promise<IDnsRecord[]> {
        let done = q.defer<IDnsRecord[]>()
        plugins.dns.resolveTxt(recordNameArg, (err, recordsArg) => {
            if (err) {
                done.reject(err)
            }
            let responseArray: IDnsRecord[] = []
            for (let record of recordsArg) {
                let recordAny: any = record // fix wrong typings
                responseArray.push({
                    chunked: recordAny,
                    name: recordNameArg,
                    value: recordAny.join(' '),
                    type: 'TXT'
                })
            }
            done.resolve(responseArray)
        })
        return done.promise
    }

    /**
     * get oridinary record
     */
    private getOrdinaryRecord(recordNameArg: string, recordTypeArg: TDnsRecordType): Promise<IDnsRecord[]> {
        let done = q.defer<IDnsRecord[]>()
        plugins.dns.resolve(recordNameArg, recordTypeArg, (err, recordsArg) => {
            if (err) {
                done.reject(err)
            }
            let responseArray: IDnsRecord[] = []
            for (let record of recordsArg) {
                responseArray.push({
                    name: recordNameArg,
                    value: record,
                    type: recordTypeArg
                })
            }
            done.resolve(responseArray)
        })
        return done.promise
    }

    /**
     * set the DNS provider
     */
    private _setDnsProvider(dnsProvider: TDnsProvider) {
        if (dnsProvider === 'google') {
            this.dnsServerIp = '8.8.8.8'
            this.dnsServerPort = 53
            plugins.dns.setServers(['8.8.8.8', '8.8.4.4'])
        } else {
            throw new Error('unknown dns provider')
        }
    }
}