Testing: Add POP3 integration tests

internal/pop3client/client.go

@@ -0,0 +1,448 @@
+// Package pop3client is borrowed directly from https://github.com/knadh/go-pop3 to reduce dependencies.
+// This is used solely for testing the POP3 server
+package pop3client
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net"
+	"net/mail"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Client implements a Client e-mail client.
+type Client struct {
+	opt    Opt
+	dialer Dialer
+}
+
+// Conn is a stateful connection with the POP3 server/
+type Conn struct {
+	conn net.Conn
+	r    *bufio.Reader
+	w    *bufio.Writer
+}
+
+// Opt represents the client configuration.
+type Opt struct {
+	Host string `json:"host"`
+	Port int    `json:"port"`
+
+	// Default is 3 seconds.
+	DialTimeout time.Duration `json:"dial_timeout"`
+	Dialer      Dialer        `json:"-"`
+
+	TLSEnabled    bool `json:"tls_enabled"`
+	TLSSkipVerify bool `json:"tls_skip_verify"`
+}
+
+// Dialer interface
+type Dialer interface {
+	Dial(network, address string) (net.Conn, error)
+}
+
+// MessageID contains the ID and size of an individual message.
+type MessageID struct {
+	// ID is the numerical index (non-unique) of the message.
+	ID   int
+	Size int
+
+	// UID is only present if the response is to the UIDL command.
+	UID string
+}
+
+var (
+	lineBreak = []byte("\r\n")
+
+	respOK      = []byte("+OK")   // `+OK` without additional info
+	respOKInfo  = []byte("+OK ")  // `+OK <info>`
+	respErr     = []byte("-ERR")  // `-ERR` without additional info
+	respErrInfo = []byte("-ERR ") // `-ERR <info>`
+)
+
+// New returns a new client object using an existing connection.
+func New(opt Opt) *Client {
+	if opt.DialTimeout < time.Millisecond {
+		opt.DialTimeout = time.Second * 3
+	}
+
+	c := &Client{
+		opt:    opt,
+		dialer: opt.Dialer,
+	}
+
+	if c.dialer == nil {
+		c.dialer = &net.Dialer{Timeout: opt.DialTimeout}
+	}
+
+	return c
+}
+
+// NewConn creates and returns live POP3 server connection.
+func (c *Client) NewConn() (*Conn, error) {
+	var (
+		addr = fmt.Sprintf("%s:%d", c.opt.Host, c.opt.Port)
+	)
+
+	conn, err := c.dialer.Dial("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	// No TLS.
+	if c.opt.TLSEnabled {
+		// Skip TLS host verification.
+		tlsCfg := tls.Config{}
+		if c.opt.TLSSkipVerify {
+			tlsCfg.InsecureSkipVerify = c.opt.TLSSkipVerify
+		} else {
+			tlsCfg.ServerName = c.opt.Host
+		}
+
+		conn = tls.Client(conn, &tlsCfg)
+	}
+
+	pCon := &Conn{
+		conn: conn,
+		r:    bufio.NewReader(conn),
+		w:    bufio.NewWriter(conn),
+	}
+
+	// Verify the connection by reading the welcome +OK greeting.
+	if _, err := pCon.ReadOne(); err != nil {
+		return nil, err
+	}
+
+	return pCon, nil
+}
+
+// Send sends a POP3 command to the server. The given comand is suffixed with "\r\n".
+func (c *Conn) Send(b string) error {
+	if _, err := c.w.WriteString(b + "\r\n"); err != nil {
+		return err
+	}
+	return c.w.Flush()
+}
+
+// Cmd sends a command to the server. POP3 responses are either single line or multi-line.
+// The first line always with -ERR in case of an error or +OK in case of a successful operation.
+// OK+ is always followed by a response on the same line which is either the actual response data
+// in case of single line responses, or a help message followed by multiple lines of actual response
+// data in case of multiline responses.
+// See https://www.shellhacks.com/retrieve-email-pop3-server-command-line/ for examples.
+func (c *Conn) Cmd(cmd string, isMulti bool, args ...interface{}) (*bytes.Buffer, error) {
+	var cmdLine string
+
+	// Repeat a %v to format each arg.
+	if len(args) > 0 {
+		format := " " + strings.TrimRight(strings.Repeat("%v ", len(args)), " ")
+
+		// CMD arg1 argn ...\r\n
+		cmdLine = fmt.Sprintf(cmd+format, args...)
+	} else {
+		cmdLine = cmd
+	}
+
+	if err := c.Send(cmdLine); err != nil {
+		return nil, err
+	}
+
+	// Read the first line of response to get the +OK/-ERR status.
+	b, err := c.ReadOne()
+	if err != nil {
+		return nil, err
+	}
+
+	// Single line response.
+	if !isMulti {
+		return bytes.NewBuffer(b), err
+	}
+
+	buf, err := c.ReadAll()
+	return buf, err
+}
+
+// ReadOne reads a single line response from the conn.
+func (c *Conn) ReadOne() ([]byte, error) {
+	b, _, err := c.r.ReadLine()
+	if err != nil {
+		return nil, err
+	}
+
+	r, err := parseResp(b)
+	return r, err
+}
+
+// ReadAll reads all lines from the connection until the POP3 multiline terminator "." is encountered
+// and returns a bytes.Buffer of all the read lines.
+func (c *Conn) ReadAll() (*bytes.Buffer, error) {
+	buf := &bytes.Buffer{}
+
+	for {
+		b, _, err := c.r.ReadLine()
+		if err != nil {
+			return nil, err
+		}
+
+		// "." indicates the end of a multi-line response.
+		if bytes.Equal(b, []byte(".")) {
+			break
+		}
+
+		if _, err := buf.Write(b); err != nil {
+			return nil, err
+		}
+		if _, err := buf.Write(lineBreak); err != nil {
+			return nil, err
+		}
+	}
+
+	return buf, nil
+}
+
+// Auth authenticates the given credentials with the server.
+func (c *Conn) Auth(user, password string) error {
+	if err := c.User(user); err != nil {
+		return err
+	}
+
+	if err := c.Pass(password); err != nil {
+		return err
+	}
+
+	// Issue a NOOP to force the server to respond to the auth.
+	// Courtesy: github.com/TheCreeper/go-pop3
+	return c.Noop()
+}
+
+// User sends the username to the server.
+func (c *Conn) User(s string) error {
+	_, err := c.Cmd("USER", false, s)
+	return err
+}
+
+// Pass sends the password to the server.
+func (c *Conn) Pass(s string) error {
+	_, err := c.Cmd("PASS", false, s)
+	return err
+}
+
+// Stat returns the number of messages and their total size in bytes in the inbox.
+func (c *Conn) Stat() (int, int, error) {
+	b, err := c.Cmd("STAT", false)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	// count size
+	f := bytes.Fields(b.Bytes())
+
+	// Total number of messages.
+	count, err := strconv.Atoi(string(f[0]))
+	if err != nil {
+		return 0, 0, err
+	}
+	if count == 0 {
+		return 0, 0, nil
+	}
+
+	// Total size of all messages in bytes.
+	size, err := strconv.Atoi(string(f[1]))
+	if err != nil {
+		return 0, 0, err
+	}
+
+	return count, size, nil
+}
+
+// List returns a list of (message ID, message Size) pairs.
+// If the optional msgID > 0, then only that particular message is listed.
+// The message IDs are sequential, 1 to N.
+func (c *Conn) List(msgID int) ([]MessageID, error) {
+	var (
+		buf *bytes.Buffer
+		err error
+	)
+
+	if msgID <= 0 {
+		// Multiline response listing all messages.
+		buf, err = c.Cmd("LIST", true)
+	} else {
+		// Single line response listing one message.
+		buf, err = c.Cmd("LIST", false, msgID)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	var (
+		out   []MessageID
+		lines = bytes.Split(buf.Bytes(), lineBreak)
+	)
+
+	for _, l := range lines {
+		// id size
+		f := bytes.Fields(l)
+		if len(f) == 0 {
+			break
+		}
+
+		id, err := strconv.Atoi(string(f[0]))
+		if err != nil {
+			return nil, err
+		}
+
+		size, err := strconv.Atoi(string(f[1]))
+		if err != nil {
+			return nil, err
+		}
+
+		out = append(out, MessageID{ID: id, Size: size})
+	}
+
+	return out, nil
+}
+
+// Uidl returns a list of (message ID, message UID) pairs. If the optional msgID
+// is > 0, then only that particular message is listed. It works like Top() but only works on
+// servers that support the UIDL command. Messages size field is not available in the UIDL response.
+func (c *Conn) Uidl(msgID int) ([]MessageID, error) {
+	var (
+		buf *bytes.Buffer
+		err error
+	)
+
+	if msgID <= 0 {
+		// Multiline response listing all messages.
+		buf, err = c.Cmd("UIDL", true)
+	} else {
+		// Single line response listing one message.
+		buf, err = c.Cmd("UIDL", false, msgID)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	var (
+		out   []MessageID
+		lines = bytes.Split(buf.Bytes(), lineBreak)
+	)
+
+	for _, l := range lines {
+		// id size
+		f := bytes.Fields(l)
+		if len(f) == 0 {
+			break
+		}
+
+		id, err := strconv.Atoi(string(f[0]))
+		if err != nil {
+			return nil, err
+		}
+
+		out = append(out, MessageID{ID: id, UID: string(f[1])})
+	}
+
+	return out, nil
+}
+
+// Retr downloads a message by the given msgID, parses it and returns it as a *mail.Message.
+func (c *Conn) Retr(msgID int) (*mail.Message, error) {
+	b, err := c.Cmd("RETR", true, msgID)
+	if err != nil {
+		return nil, err
+	}
+
+	m, err := mail.ReadMessage(b)
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}
+
+// RetrRaw downloads a message by the given msgID and returns the raw []byte
+// of the entire message.
+func (c *Conn) RetrRaw(msgID int) (*bytes.Buffer, error) {
+	b, err := c.Cmd("RETR", true, msgID)
+	return b, err
+}
+
+// Top retrieves a message by its ID with full headers and numLines lines of the body.
+func (c *Conn) Top(msgID int, numLines int) (*mail.Message, error) {
+	b, err := c.Cmd("TOP", true, msgID, numLines)
+	if err != nil {
+		return nil, err
+	}
+
+	m, err := mail.ReadMessage(b)
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}
+
+// Dele deletes one or more messages. The server only executes the
+// deletions after a successful Quit().
+func (c *Conn) Dele(msgID ...int) error {
+	for _, id := range msgID {
+		_, err := c.Cmd("DELE", false, id)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Rset clears the messages marked for deletion in the current session.
+func (c *Conn) Rset() error {
+	_, err := c.Cmd("RSET", false)
+	return err
+}
+
+// Noop issues a do-nothing NOOP command to the server. This is useful for
+// prolonging open connections.
+func (c *Conn) Noop() error {
+	_, err := c.Cmd("NOOP", false)
+	return err
+}
+
+// Quit sends the QUIT command to server and gracefully closes the connection.
+// Message deletions (DELE command) are only executed by the server on a graceful
+// quit and close.
+func (c *Conn) Quit() error {
+	defer c.conn.Close()
+
+	if _, err := c.Cmd("QUIT", false); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// parseResp checks if the response is an error that starts with `-ERR`
+// and returns an error with the message that succeeds the error indicator.
+// For success `+OK` messages, it returns the remaining response bytes.
+func parseResp(b []byte) ([]byte, error) {
+	if len(b) == 0 {
+		return nil, nil
+	}
+
+	if bytes.Equal(b, respOK) {
+		return nil, nil
+	} else if bytes.HasPrefix(b, respOKInfo) {
+		return bytes.TrimPrefix(b, respOKInfo), nil
+	} else if bytes.Equal(b, respErr) {
+		return nil, errors.New("unknown error (no info specified in response)")
+	} else if bytes.HasPrefix(b, respErrInfo) {
+		return nil, errors.New(string(bytes.TrimPrefix(b, respErrInfo)))
+	}
+
+	return nil, fmt.Errorf("unknown response: %s. Neither -ERR, nor +OK", string(b))
+}

server/pop3/pop3_test.go

@@ -0,0 +1,365 @@
+package pop3
+
+import (
+	"bytes"
+	"fmt"
+	"math/rand/v2"
+	"net"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/axllent/mailpit/config"
+	"github.com/axllent/mailpit/internal/auth"
+	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/pop3client"
+	"github.com/axllent/mailpit/internal/storage"
+	"github.com/jhillyerd/enmime"
+)
+
+var (
+	testingPort int
+)
+
+func TestPOP3(t *testing.T) {
+	t.Log("Testing POP3 server")
+	setup()
+	defer storage.Close()
+
+	// connect with bad password
+	t.Log("Testing invalid login")
+	c, err := connectBadAuth()
+	if err == nil {
+		t.Error("invalid login gained access")
+		return
+	}
+
+	t.Log("Testing valid login")
+	c, err = connectAuth()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	count, size, err := c.Stat()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	assertEqual(t, count, 0, "incorrect message count")
+	assertEqual(t, size, 0, "incorrect size")
+
+	// quit else we get old data
+	if err := c.Quit(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	t.Log("Inserting 50 messages")
+
+	insertEmailData(t) // insert 50 messages
+
+	c, err = connectAuth()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	count, size, err = c.Stat()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	assertEqual(t, count, 50, "incorrect message count")
+
+	t.Log("Fetching 20 messages")
+
+	for i := 1; i <= 20; i++ {
+		_, err := c.Retr(i)
+		if err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+	}
+
+	t.Log("Deleting 25 messages")
+
+	for i := 1; i <= 25; i++ {
+		if err := c.Dele(i); err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+	}
+
+	// messages get deleted after a QUIT
+	if err := c.Quit(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	c, err = connectAuth()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	t.Log("Fetching message count")
+
+	count, _, err = c.Stat()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	assertEqual(t, count, 25, "incorrect message count")
+
+	// messages get deleted after a QUIT
+	if err := c.Quit(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	c, err = connectAuth()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	t.Log("Deleting 25 messages")
+
+	for i := 1; i <= 25; i++ {
+		if err := c.Dele(i); err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+	}
+
+	t.Log("Undeleting messages")
+
+	if err := c.Rset(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	if err := c.Quit(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	c, err = connectAuth()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	count, _, err = c.Stat()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	assertEqual(t, count, 25, "incorrect message count")
+
+	if err := c.Quit(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+}
+
+func TestAuthentication(t *testing.T) {
+	// commands only allowed after authentication
+	authCommands := make(map[string]bool)
+	authCommands["STAT"] = false
+	authCommands["LIST"] = true
+	authCommands["NOOP"] = false
+	authCommands["RSET"] = false
+	authCommands["RETR 1"] = true
+
+	t.Log("Testing authenticated commands while not logged in")
+	setup()
+	defer storage.Close()
+
+	insertEmailData(t) // insert 50 messages
+
+	// non-authenticated connection
+	c, err := connect()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	for cmd, multi := range authCommands {
+		if _, err := c.Cmd(cmd, multi); err == nil {
+			t.Errorf("%s should require authentication", cmd)
+			return
+		}
+
+		if _, err := c.Cmd(strings.ToLower(cmd), multi); err == nil {
+			t.Errorf("%s should require authentication", cmd)
+			return
+		}
+	}
+
+	if err := c.Quit(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	t.Log("Testing authenticated commands while logged in")
+
+	// authenticated connection
+	c, err = connectAuth()
+	if err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+
+	for cmd, multi := range authCommands {
+		if _, err := c.Cmd(cmd, multi); err != nil {
+			t.Errorf("%s should work when authenticated", cmd)
+			return
+		}
+
+		if _, err := c.Cmd(strings.ToLower(cmd), multi); err != nil {
+			t.Errorf("%s should work when authenticated", cmd)
+			return
+		}
+	}
+
+	if err := c.Quit(); err != nil {
+		t.Errorf(err.Error())
+		return
+	}
+}
+
+func setup() {
+	auth.SetPOP3Auth("username:password")
+	logger.NoLogging = true
+	config.MaxMessages = 0
+	config.Database = os.Getenv("MP_DATABASE")
+	var foundPort bool
+	for !foundPort {
+		testingPort = randRange(1111, 2000)
+		if portFree(testingPort) {
+			foundPort = true
+		}
+	}
+
+	config.POP3Listen = fmt.Sprintf("localhost:%d", testingPort)
+
+	if err := storage.InitDB(); err != nil {
+		panic(err)
+	}
+
+	if err := storage.DeleteAllMessages(); err != nil {
+		panic(err)
+	}
+
+	go Run()
+
+	time.Sleep(time.Second)
+}
+
+// connect and authenticate
+func connectAuth() (*pop3client.Conn, error) {
+	c, err := connect()
+	if err != nil {
+		return c, err
+	}
+
+	err = c.Auth("username", "password")
+
+	return c, err
+}
+
+// connect and authenticate
+func connectBadAuth() (*pop3client.Conn, error) {
+	c, err := connect()
+	if err != nil {
+		return c, err
+	}
+
+	err = c.Auth("username", "notPassword")
+
+	return c, err
+}
+
+// connect but do not authenticate
+func connect() (*pop3client.Conn, error) {
+	p := pop3client.New(pop3client.Opt{
+		Host:       "localhost",
+		Port:       testingPort,
+		TLSEnabled: false,
+	})
+
+	c, err := p.NewConn()
+	if err != nil {
+		return c, err
+	}
+
+	return c, err
+}
+
+func portFree(port int) bool {
+	ln, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", port))
+	if err != nil {
+		return false
+	}
+
+	if err := ln.Close(); err != nil {
+		panic(err)
+	}
+
+	return true
+}
+
+func randRange(min, max int) int {
+	return rand.IntN(max-min) + min
+}
+
+func insertEmailData(t *testing.T) {
+	for i := 0; i < 50; i++ {
+		msg := enmime.Builder().
+			From(fmt.Sprintf("From %d", i), fmt.Sprintf("from-%d@example.com", i)).
+			Subject(fmt.Sprintf("Subject line %d end", i)).
+			Text([]byte(fmt.Sprintf("This is the email body %d <jdsauk;dwqmdqw;>.", i))).
+			To(fmt.Sprintf("To %d", i), fmt.Sprintf("to-%d@example.com", i))
+
+		env, err := msg.Build()
+		if err != nil {
+			t.Log("error ", err)
+			t.Fail()
+		}
+
+		buf := new(bytes.Buffer)
+
+		if err := env.Encode(buf); err != nil {
+			t.Log("error ", err)
+			t.Fail()
+		}
+
+		bufBytes := buf.Bytes()
+
+		id, err := storage.Store(&bufBytes)
+		if err != nil {
+			t.Log("error ", err)
+			t.Fail()
+		}
+
+		if err := storage.SetMessageTags(id, []string{fmt.Sprintf("Test tag %03d", i)}); err != nil {
+			t.Log("error ", err)
+			t.Fail()
+		}
+	}
+}
+
+func assertEqual(t *testing.T, a interface{}, b interface{}, message string) {
+	if a == b {
+		return
+	}
+	message = fmt.Sprintf("%s: \"%v\" != \"%v\"", message, a, b)
+	t.Fatal(message)
+}