refactor: encapsulate lib functions further

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## v0.2.1
+
+### Changed
+
+- 优化`Parse`、`ParseHeader`、`ParseBody`函数的传参, 进一步封装, 使更易用
+
 ## v0.2.0
 
 ### Added

README.md

@@ -18,7 +18,6 @@ package main
 import (
 	"fmt"
 	"log"
-	"net/mail"
 
 	"github.com/knadh/go-pop3"
 
@@ -58,13 +57,8 @@ func main() {
 			continue
 		}
 
-		m, err := mail.ReadMessage(b)
-		if err != nil {
-			fmt.Println(err)
-			continue
-		}
-
-		res, err := mailparser.Parse(m)
+		// parse email
+		res, err := mailparser.Parse(b)
 		if err != nil {
 			fmt.Println(err)
 			continue

mailparser.go

@@ -17,9 +17,9 @@ import (
 )
 
 const (
-	// multipart/alternative, multipart/mixed, multipart/related
+	// multipart/alternative, multipart/mixed, multipart/related...
 	multipartPrefix = "multipart/"
-	// text/html, text/plain
+	// text/html, text/plain, text/markdown...
 	textPrefix = "text/"
 )
 
@@ -52,13 +52,13 @@ type MailMessage struct {
 }
 
 // Parse mail message.
-func Parse(m *mail.Message) (*MailMessage, error) {
-	header, err := ParseHeader(m)
+func Parse(r io.Reader) (*MailMessage, error) {
+	header, err := ParseHeader(r)
 	if err != nil {
 		return nil, err
 	}
 
-	body, attachments, err := ParseBody(m)
+	body, attachments, err := ParseBody(r)
 	if err != nil {
 		return nil, err
 	}
@@ -71,7 +71,12 @@ func Parse(m *mail.Message) (*MailMessage, error) {
 }
 
 // ParseHeader mail message headers.
-func ParseHeader(m *mail.Message) (*Header, error) {
+func ParseHeader(r io.Reader) (*Header, error) {
+	m, err := mail.ReadMessage(r)
+	if err != nil {
+		return nil, err
+	}
+
 	dec := new(mime.WordDecoder)
 	dec.CharsetReader = charsetReader
 
@@ -130,7 +135,12 @@ func ParseHeader(m *mail.Message) (*Header, error) {
 }
 
 // ParseBody mail message body.
-func ParseBody(m *mail.Message) (string, []*Attachment, error) {
+func ParseBody(r io.Reader) (string, []*Attachment, error) {
+	m, err := mail.ReadMessage(r)
+	if err != nil {
+		return "", nil, err
+	}
+
 	contentType := m.Header.Get("Content-Type")
 	if contentType == "" {
 		contentType = "text/plain"