Add *.eml files support

README.md

@@ -15,6 +15,9 @@ Support input formats:
 
 * **.zip** file: zipped dmarc report in xml format
 
+* **.eml** file: an electronic mail format or email saved in plain text - dovecot-report-converter
+  tries to extract .xml, .gz or .zip attachments from found eml files to `input.dir`
+
 Support output formats:
 
 * **html_static** output file is a HTML, generated from builtin template htmlStaticTmpl (consts.go).

cmd/dmarc-report-converter/files.go

@@ -54,6 +54,37 @@ func (c *filesConverter) ConvertWrite() error {
 }
 
 func (c *filesConverter) find() error {
+	emlFiles, err := filepath.Glob(filepath.Join(c.cfg.Input.Dir, "*.eml"))
+	if err != nil {
+		return err
+	}
+	if len(emlFiles) > 0 {
+		log.Printf("[INFO] files: found %d eml file(s), extract attachments to %v", len(emlFiles), c.cfg.Input.Dir)
+		for _, eml := range emlFiles {
+			br, err := os.Open(eml)
+			if err != nil {
+				log.Printf("[ERROR] files: unable to extract attachments from %v", eml)
+				continue
+			}
+
+			isSuccess, err := extractAttachment(br, c.cfg.Input.Dir)
+			if err != nil {
+				log.Printf("[ERROR] files: %v, skip", err)
+				continue
+			}
+
+			if isSuccess && c.cfg.Input.Delete {
+				log.Printf("[DEBUG] files: delete %v", eml)
+				err := os.Remove(eml)
+				if err != nil {
+					log.Printf("[ERROR] files: %v", err)
+					continue
+				}
+			}
+			br.Close()
+		}
+	}
+
 	files, err := filepath.Glob(filepath.Join(c.cfg.Input.Dir, "*.*"))
 	if err != nil {
 		return err

cmd/dmarc-report-converter/imap.go

@@ -86,53 +86,10 @@ func fetchIMAPAttachments(cfg *config) error {
 			return fmt.Errorf("server didn't return message body")
 		}
 
-		// create a new mail reader
-		mr, err := mail.CreateReader(br)
+		isSuccess, err := extractAttachment(br, cfg.Input.Dir)
 		if err != nil {
-			return err
-		}
-
-		// process each message's part
-		isSuccess := false
-		for {
-			p, err := mr.NextPart()
-			if err == io.EOF {
-				break
-			} else if err != nil {
-				log.Printf("[ERROR] imap: can't read next part: %v, skip", err)
-				break
-			}
-
-			switch h := p.Header.(type) {
-			case *mail.AttachmentHeader:
-				// this is an attachment
-				filename, err := h.Filename()
-				if err != nil {
-					log.Printf("[ERROR] imap: %v, skip", err)
-					continue
-				}
-				log.Printf("[INFO] imap: found attachment: %v", filename)
-
-				outFile := filepath.Join(cfg.Input.Dir, filename)
-				log.Printf("[INFO] imap: save attachment to: %v", outFile)
-				f, err := os.Create(outFile)
-				if err != nil {
-					log.Printf("[ERROR] imap: %v, skip", err)
-					continue
-				}
-
-				_, err = io.Copy(f, p.Body)
-				if err != nil {
-					log.Printf("[ERROR] imap: %v, skip", err)
-					continue
-				}
-				err = f.Close()
-				if err != nil {
-					log.Printf("[ERROR] imap: %v, skip", err)
-					continue
-				}
-				isSuccess = true
-			}
+			log.Printf("[ERROR] imap: %v, skip", err)
+			continue
 		}
 
 		if isSuccess && cfg.Input.IMAP.Delete {
@@ -168,3 +125,61 @@ func fetchIMAPAttachments(cfg *config) error {
 
 	return nil
 }
+
+func extractAttachment(r io.Reader, inputDir string) (bool, error) {
+	// Create a new mail reader
+	mr, err := mail.CreateReader(r)
+	if err != nil {
+		return false, err
+	}
+
+	// process each message's part
+	isSuccess := false
+	for {
+		p, err := mr.NextPart()
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			log.Printf("[ERROR] imap: can't read next part: %v, skip", err)
+			break
+		}
+
+		switch h := p.Header.(type) {
+		case *mail.AttachmentHeader:
+			// this is an attachment
+			filename, err := h.Filename()
+			if err != nil {
+				log.Printf("[ERROR] extractAttachment: %v, skip", err)
+				continue
+			}
+			if filename == "" {
+				log.Printf("[WARN] extractAttachment: found attachment with empty filename, skip")
+				continue
+			}
+
+			log.Printf("[INFO] extractAttachment: found attachment: %v", filename)
+
+			outFile := filepath.Join(inputDir, filename)
+			log.Printf("[INFO] extractAttachment: save attachment to: %v", outFile)
+			f, err := os.Create(outFile)
+			if err != nil {
+				log.Printf("[ERROR] extractAttachment: %v, skip", err)
+				continue
+			}
+
+			_, err = io.Copy(f, p.Body)
+			if err != nil {
+				log.Printf("[ERROR] extractAttachment: %v, skip", err)
+				continue
+			}
+			err = f.Close()
+			if err != nil {
+				log.Printf("[ERROR] extractAttachment: %v, skip", err)
+				continue
+			}
+			isSuccess = true
+		}
+	}
+
+	return isSuccess, err
+}