careyjames/dns-scout

package dnsinformation

import (
    "fmt"

    "github.com/careyjames/dns-scout/color"
    constants "github.com/careyjames/dns-scout/constant"
)

const (
    DKIMValid = "v=DKIM1"
)

var (
    DKIMSelectors = []string{
        "default._domainkey",
        "google._domainkey",
        "mail._domainkey",
        "selector1._domainkey",
        "selector2._domainkey",
    }
)

// getDKIM fetches the DMARC record for a given domain.
func getDKIM(domain string, selector string) (string, error) {
    txtRecords, _ := GetTXTRecordNSLookup(selector + "." + domain)
    for _, record := range txtRecords {
        if hasDKIMRecord(record) {
            return record, nil
        }
    }
    return "", nil
}

// GetDKIMPrompt fetches the DKIM record for a given domain.
func GetDKIMPrompt(input string) {
    flag := false
    dkimPrompt := ""
    for index, selector := range DKIMSelectors {
        dkim, _ := getDKIM(input, selector)
        if dkim != "" {
            if !flag {
                dkimPrompt = ""
            }
            flag = true
            if isValidDKIM(dkim) {
                formattedDMARC := formatLongText(dkim, 80, " ")
                if index > 0 && len(dkimPrompt) > 0 {
                    dkimPrompt += " " + color.Grey(selector+".") + color.Grey(formattedDMARC) + constants.Newline
                } else {
                    dkimPrompt += color.Blue(" DKIM  ✅: ") + "" + color.Grey(selector+".") + color.Grey(formattedDMARC) + constants.Newline
                }
            } else {
                dkimPrompt += " " + color.Grey(selector+".") + color.Red(dkim[7:]) + constants.Newline
            }
        } else {
            if !flag {
                dkimPrompt = color.Blue(" DKIM  ❌: ") + color.Red("None") + constants.Newline
            }
        }
    }
    fmt.Printf(dkimPrompt)
}

func hasDKIMRecord(record string) bool {
    return (len(record) > 7 && record[:7] == DKIMValid) || (len(record) > 5 && record[:5] == "vDKIM")
}

func isValidDKIM(record string) bool {
    if len(record) > 7 && record[:7] == DKIMValid {
        return true
    }
    return false
}