From ff87aeed7f642fd14010aca84f9bcee666ae343d Mon Sep 17 00:00:00 2001
From: James Hillyerd <james@hillyerd.com>
Date: Thu, 9 May 2024 11:16:52 -0700
Subject: [PATCH] rename option, add tests, always warn

Signed-off-by: James Hillyerd <james@hillyerd.com>
---
 envelope.go      | 15 +++++++++------
 envelope_test.go | 45 +++++++++++++++++++++++++++++++++++++++++++++
 options.go       | 14 +++++++-------
 parser.go        |  2 +-
 4 files changed, 62 insertions(+), 14 deletions(-)

diff --git a/envelope.go b/envelope.go
index f0e7c78..bfade4f 100644
--- a/envelope.go
+++ b/envelope.go
@@ -196,16 +196,19 @@ func (p Parser) EnvelopeFromPart(root *Part) (*Envelope, error) {
 	}
 
 	// Down-convert HTML to text if necessary
-	if e.Text == "" && e.HTML != "" && !p.skipHTML2TextDownConversion {
+	if e.Text == "" && e.HTML != "" {
 		// We always warn when this happens
 		e.Root.addWarning(
 			ErrorPlainTextFromHTML,
 			"Message did not contain a text/plain part")
-		var err error
-		if e.Text, err = html2text.FromString(e.HTML); err != nil {
-			e.Text = "" // Down-conversion shouldn't fail
-			p := e.Root.BreadthMatchFirst(matchHTMLBodyPart)
-			p.addError(ErrorPlainTextFromHTML, "Failed to downconvert HTML: %v", err)
+
+		if !p.disableTextConversion {
+			var err error
+			if e.Text, err = html2text.FromString(e.HTML); err != nil {
+				e.Text = "" // Down-conversion shouldn't fail
+				p := e.Root.BreadthMatchFirst(matchHTMLBodyPart)
+				p.addError(ErrorPlainTextFromHTML, "Failed to downconvert HTML: %v", err)
+			}
 		}
 	}
 
diff --git a/envelope_test.go b/envelope_test.go
index bc19759..bc351e6 100644
--- a/envelope_test.go
+++ b/envelope_test.go
@@ -516,6 +516,51 @@ func TestParseHTMLOnlyInline(t *testing.T) {
 	}
 }
 
+func TestParseHTMLOnlyInlineTextDisabled(t *testing.T) {
+	msg := test.OpenTestData("mail", "html-only-inline.raw")
+
+	parser := enmime.NewParser(enmime.DisableTextConversion(true))
+	e, err := parser.ReadEnvelope(msg)
+	if err != nil {
+		t.Fatal("Failed to parse MIME:", err)
+	}
+
+	if len(e.Errors) == 1 {
+		want := enmime.ErrorPlainTextFromHTML
+		got := e.Errors[0].Name
+		if got != want {
+			t.Errorf("e.Errors[0] got: %v, want: %v", got, want)
+		}
+	} else {
+		t.Errorf("len(e.Errors) got: %v, want: 1", len(e.Errors))
+	}
+
+	if e.Text != "" {
+		t.Errorf("Downconverted Text was %q, should be empty", e.Text)
+	}
+
+	want := ">Test of HTML section<"
+	if !strings.Contains(e.HTML, want) {
+		t.Errorf("HTML: %q should contain %q", e.HTML, want)
+	}
+
+	if len(e.Inlines) != 1 {
+		t.Error("Should one inline, got:", len(e.Inlines))
+	}
+	if len(e.Attachments) > 0 {
+		t.Fatal("Should have no attachments, got:", len(e.Attachments))
+	}
+
+	want = "favicon.png"
+	got := e.Inlines[0].FileName
+	if got != want {
+		t.Error("FileName got:", got, "want:", want)
+	}
+	if !bytes.HasPrefix(e.Inlines[0].Content, []byte{0x89, 'P', 'N', 'G'}) {
+		t.Error("Inline should have correct content")
+	}
+}
+
 func TestParseInlineMultipart(t *testing.T) {
 	msg := test.OpenTestData("mail", "inlinemultipart.raw")
 	e, err := enmime.ReadEnvelope(msg)
diff --git a/options.go b/options.go
index 61f6123..b7e6fd2 100644
--- a/options.go
+++ b/options.go
@@ -89,14 +89,14 @@ func StripMediaTypeInvalidCharacters(stripMediaTypeInvalidCharacters bool) Optio
 	return stripMediaTypeInvalidCharactersOption(stripMediaTypeInvalidCharacters)
 }
 
-type skipHTML2TextDownConversionOption bool
+type disableTextConversionOption bool
 
-func (o skipHTML2TextDownConversionOption) apply(p *Parser) {
-	p.skipHTML2TextDownConversion = bool(o)
+func (o disableTextConversionOption) apply(p *Parser) {
+	p.disableTextConversion = bool(o)
 }
 
-// SkipHTML2TextDownConversion sets skipHTML2TextDownConversion option. If true, there will be no automatic down conversion
-// of HTML 2 Text.
-func SkipHTML2TextDownConversion(skipHTML2TextDownConversion bool) Option {
-	return skipHTML2TextDownConversionOption(skipHTML2TextDownConversion)
+// DisableTextConversion sets the disableTextConversion option. When true, there will be no
+// automated down conversion of HTML to text when a plain/text body is missing.
+func DisableTextConversion(disableTextConversion bool) Option {
+	return disableTextConversionOption(disableTextConversion)
 }
diff --git a/parser.go b/parser.go
index 2fd01cd..2ca6939 100644
--- a/parser.go
+++ b/parser.go
@@ -26,7 +26,7 @@ type Parser struct {
 	rawContent                      bool
 	customParseMediaType            CustomParseMediaType
 	stripMediaTypeInvalidCharacters bool
-	skipHTML2TextDownConversion     bool
+	disableTextConversion           bool
 }
 
 // defaultParser is a Parser with default configuration.