writeto_test.go

package mail

import (
	"bytes"
	"fmt"
	"io"
	"log"
	"strings"
	"testing"
	"unicode/utf8"

	"github.com/InSitu-Software/pgpmaildriver"
	"golang.org/x/crypto/openpgp/armor"
)

const qwertPub = `-----BEGIN PGP PUBLIC KEY BLOCK-----

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=2HNJ
-----END PGP PUBLIC KEY BLOCK-----`

const qwertPrivate = `-----BEGIN PGP PRIVATE KEY BLOCK-----

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mpvROrdPYketPyNe4FIeP0YinF2qewFRAowRVyATib+hyKcZPS8uEB43xwP0eeOm
CUaWPjIdjkYPb3uwNM14534IxjRll1VFEeLWLKZCqVdHIFLMsIanXexyc9jUqrXH
z9ILOdFm2qH3XJKuoObxMCb8o517D2iNjPpaJUcD09LpWeOgRxN+PCNrPyyvDkOy
5CBBZ5hE4tBuKBtD+DIMba2Y09k4+Tjs1tlVnpVLaTizAP7kcJB7Ek/2nBcj0qwO
kshMdYAFhKoilz3bywyX6dgmKBhBHWOZRmai8sGB2Qb2+NfSiSEkCqYpv902TuzO
6nRR466ipFStt9QTxQa8M9wTYg==
=Z2Y8
-----END PGP PRIVATE KEY BLOCK-----`

const pass = "qwert123"

func mockPublicProvider(k string, scope string) (string, error) {
	switch scope {
	case "public":
		return qwertPub, nil
	case "private":
		return qwertPrivate, nil
	}

	return "", fmt.Errorf("wrong scope")
}

type rot13 struct {
	PlainMessage     *Message
	EncryptedMessage strings.Builder
}

func rotN(c int32, shift int32) rune {
	return rune(c + shift)
}

func rotStringN(s string, shift int32) string {
	var out string
	for _, c := range s {
		out += fmt.Sprintf("%c", rotN(c, shift))
	}

	return out
}

func (r *rot13) String() string {
	var b bytes.Buffer
	w, err := armor.Encode(&b, "ROT13 MESSAGE", nil)
	if err != nil {
		w.Close()
		return ""
	}

	if _, err := w.Write([]byte(r.EncryptedMessage.String())); err != nil {
		log.Fatal(err)
		w.Close()
		return ""
	}

	w.Close()

	return b.String()
}

func (r *rot13) Write(b []byte) (n int, err error) {
	r.EncryptedMessage.Grow(len(b))

	for len(b) > 0 {
		c, size := utf8.DecodeRune(b)
		c = rune(c + 13)
		rn, err := r.EncryptedMessage.WriteRune(c)
		if err != nil {
			return n, err
		}
		b = b[size:]

		n += rn
	}

	return n, nil
}

func (r *rot13) WriteTo(w io.Writer) (int64, error) {
	var buf bytes.Buffer
	_, err := r.PlainMessage.WriteTo(&buf)
	if err != nil {
		log.Fatal(err)
	}

	var written int64

	for _, c := range buf.String() {
		// naive implementation, no real rotation, only shifting, ignoring UTF-8 / rune sizes
		shifted := rotN(c, 13)
		bytedRune := byte(shifted)
		i, err := w.Write([]byte{bytedRune})
		written += int64(i)
		if err != nil {
			return written, err
		}

	}

	return written, nil
}

func TestRot13(t *testing.T) {
	s := "testá\u0061\u0300"
	e := rotStringN(s, 13)
	d := rotStringN(e, -13)

	if d != s {
		fmt.Printf("%s | %s | %s \n", s, e, d)
		fmt.Printf("%+q | %+q | %+q \n", s, e, d)
		t.Fail()
	}
}

func TestWriteTo(t *testing.T) {
	to := []string{"sebastian.gabbert@insitu.de"}
	from := "sender@sender.de"

	secretMail := NewMessage()
	secretMail.SetHeader("To", to...)
	secretMail.SetHeader("From", from)
	secretMail.SetHeader("Subject", "my secret mail subject")
	secretMail.SetBody("text/plain", "my darkest secret is *#12!4//(+")

	pgpWriter := pgpmaildriver.PGPMessageEncryptor{
		KeyProvider: mockPublicProvider,
		To:          to,
	}

	secretMail.SetEncrypted(
		"application/pgp-encrypted",
		"application/octet-stream",
		"Version: 1",
		&pgpWriter,
	)

	var out bytes.Buffer
	if _, err := secretMail.WriteTo(&out); err != nil {
		log.Fatal(err)
	}

	var outString string
	outString = out.String()

	fmt.Println("\n-----------encrptedOutString---------")
	fmt.Printf("%s\n", outString)

}