Render nested Action Text attachment content

internal/htmlutil/htmlutil.go

@@ -106,8 +106,9 @@ func walkNode(b *strings.Builder, n *html.Node, depth int) {
 			if isImageContentType(getAttr(n, "content-type")) && isDecorativeImage(getAttr(n, "width"), getAttr(n, "height")) {
 				return
 			}
-			filename := getAttr(n, "filename")
-			if filename != "" {
+			if doc := parseEmbeddedActionText(n, depth); doc != nil {
+				walkNode(b, doc, depth+1)
+			} else if filename := getAttr(n, "filename"); filename != "" {
 				fmt.Fprintf(b, "\n[%s]\n", filename)
 			}
 			return
@@ -172,6 +173,13 @@ func walkMessageSourceNode(b *strings.Builder, n *html.Node, depth int) {
 		case "hr":
 			writeMessageSourceBoundary(b)
 			return
+		case "action-text-attachment":
+			if doc := parseEmbeddedActionText(n, depth); doc != nil {
+				writeMessageSourceBoundary(b)
+				walkMessageSourceNode(b, doc, depth+1)
+				writeMessageSourceBoundary(b)
+			}
+			return
 		case "template":
 			if depth == 0 || n.Parent == nil || n.Parent.Data != "shadow-content" {
 				return
@@ -206,7 +214,7 @@ func elementProvidesMessageSourceText(n *html.Node) bool {
 		return false
 	}
 	switch n.Data {
-	case "script", "style", "noscript", "head", "action-text-attachment":
+	case "script", "style", "noscript", "head":
 		return false
 	case "dialog":
 		return hasAttr(n, "open")
@@ -305,6 +313,24 @@ func parseTrixAttachment(n *html.Node) *trixAttachment {
 	return &att
 }
 
+// embeddedActionTextContent returns the markup an unnamed text/html attachment carries
+// in its content attribute. HEY renders any other attachment as itself, whatever
+// content it carries.
+func embeddedActionTextContent(n *html.Node) string {
+	if getAttr(n, "filename") != "" || !isHTMLContentType(getAttr(n, "content-type")) {
+		return ""
+	}
+	return getAttr(n, "content")
+}
+
+func parseEmbeddedActionText(n *html.Node, depth int) *html.Node {
+	content := embeddedActionTextContent(n)
+	if content == "" {
+		return nil
+	}
+	return parseEmbeddedContent(content, depth)
+}
+
 func getAttr(n *html.Node, key string) string {
 	for _, a := range n.Attr {
 		if a.Key == key {
@@ -455,7 +481,9 @@ func findImages(n *html.Node, urls *[]string, depth int) {
 			if isImageContentType(getAttr(n, "content-type")) && isDecorativeImage(getAttr(n, "width"), getAttr(n, "height")) {
 				return
 			}
-			if imageURL := getAttr(n, "url"); isImageContentType(getAttr(n, "content-type")) && imageURL != "" {
+			if doc := parseEmbeddedActionText(n, depth); doc != nil {
+				findImages(doc, urls, depth+1)
+			} else if imageURL := getAttr(n, "url"); isImageContentType(getAttr(n, "content-type")) && imageURL != "" {
 				*urls = append(*urls, imageURL)
 			}
 		case "figure":

internal/htmlutil/htmlutil_test.go

@@ -105,6 +105,13 @@ func TestMessageSourceTextIncludesEmbeddedEmailBody(t *testing.T) {
 	}
 }
 
+func TestMessageSourceTextIncludesEmbeddedActionTextAttachment(t *testing.T) {
+	html := `<action-text-attachment content-type="text/html" content="<p>External confirmation: BLUE-42</p>"></action-text-attachment>`
+	if got := strings.Join(strings.Fields(MessageSourceText(html)), " "); got != "External confirmation: BLUE-42" {
+		t.Errorf("MessageSourceText = %q", got)
+	}
+}
+
 func TestMessageSourceTextFailsClosedWhenHTMLExceedsParserDepth(t *testing.T) {
 	html := strings.Repeat("<div>", 1_000) + "not selectable" + strings.Repeat("</div>", 1_000)
 	if got := MessageSourceText(html); got != "" {
@@ -176,6 +183,13 @@ func TestToTextActionTextAttachment(t *testing.T) {
 	}
 }
 
+func TestToTextRendersEmbeddedActionTextAttachment(t *testing.T) {
+	got := ToText(`<action-text-attachment content-type="text/html" content="<p>Inside</p>"></action-text-attachment>`)
+	if got != "Inside" {
+		t.Errorf("ToText = %q, want %q", got, "Inside")
+	}
+}
+
 func TestToTextTrixFigure(t *testing.T) {
 	got := ToText(`<p>Before</p><figure data-trix-attachment='{"filename":"photo.png","url":"/img.png","contentType":"image/png"}'></figure><p>After</p>`)
 	if !strings.Contains(got, "[photo.png]") {
@@ -204,6 +218,75 @@ func TestExtractImageURLsInsideEmbeddedHTMLAttachment(t *testing.T) {
 	}
 }
 
+func TestExtractImageURLsInsideEmbeddedActionTextAttachment(t *testing.T) {
+	urls := ExtractImageURLs(`<action-text-attachment content-type="text/html" content="<img src=&quot;https://example.com/logo.png&quot;>"></action-text-attachment>`)
+	if len(urls) != 1 || urls[0] != "https://example.com/logo.png" {
+		t.Errorf("ExtractImageURLs = %v, want the image inside the embedded body", urls)
+	}
+}
+
+func embeddedActionTextAttachment(content string) string {
+	return `<action-text-attachment content-type="text/html" content="` + stdhtml.EscapeString(content) + `"></action-text-attachment>`
+}
+
+func TestEmbeddedActionTextAttachmentStopsRecursing(t *testing.T) {
+	withinLimit := `<p>innermost</p><img src="https://example.com/innermost.png">`
+	for range embeddedContentDepthLimit {
+		withinLimit = embeddedActionTextAttachment(withinLimit)
+	}
+	beyondLimit := embeddedActionTextAttachment(withinLimit)
+
+	for name, text := range map[string]func(string) string{"ToText": ToText, "MessageSourceText": MessageSourceText} {
+		if got := text(withinLimit); !strings.Contains(got, "innermost") {
+			t.Errorf("%s = %q, want the body at the nesting limit", name, got)
+		}
+		if got := text(beyondLimit); strings.Contains(got, "innermost") {
+			t.Errorf("%s = %q, should stop before the body beyond the nesting limit", name, got)
+		}
+	}
+	if urls := ExtractImageURLs(withinLimit); len(urls) != 1 {
+		t.Errorf("ExtractImageURLs = %v, want the image at the nesting limit", urls)
+	}
+	if urls := ExtractImageURLs(beyondLimit); len(urls) != 0 {
+		t.Errorf("ExtractImageURLs = %v, should stop before the image beyond the nesting limit", urls)
+	}
+}
+
+// HEY renders an attachment's content as HTML only when its content type is HTML; any
+// other attachment is itself, whatever content it carries.
+func TestNonHTMLActionTextAttachmentContentIsNotABody(t *testing.T) {
+	image := `<action-text-attachment content-type="image/png" url="https://example.com/floor-plan.png" caption="Floor plan" content="<img src=&quot;https://example.com/not-the-image.png&quot;>"></action-text-attachment>`
+	if urls := ExtractImageURLs(image); len(urls) != 1 || urls[0] != "https://example.com/floor-plan.png" {
+		t.Errorf("ExtractImageURLs = %v, want the attachment's own image", urls)
+	}
+
+	untyped := `<p>Visible</p><action-text-attachment content="<p>not the body</p>"></action-text-attachment>`
+	if got := ToText(untyped); strings.Contains(got, "not the body") {
+		t.Errorf("ToText = %q, should not render a non-HTML attachment's content", got)
+	}
+	if got := strings.Join(strings.Fields(MessageSourceText(untyped)), " "); got != "Visible" {
+		t.Errorf("MessageSourceText = %q, want only the visible text", got)
+	}
+}
+
+// Only an unnamed HTML attachment is an email body; a named one is a file, even when it is HTML.
+func TestNamedHTMLActionTextAttachmentIsAFile(t *testing.T) {
+	file := `<action-text-attachment filename="itinerary.html" content-type="text/html" content="<p>Flight to Lisbon departs at 09:40</p><img src=&quot;https://example.com/boarding-pass.png&quot;>"></action-text-attachment>`
+
+	if got := toMarkdown(file); got != "📄 itinerary.html" {
+		t.Errorf("ToMarkdown = %q, want the file row", got)
+	}
+	if got := ToText(file); got != "[itinerary.html]" {
+		t.Errorf("ToText = %q, want the filename", got)
+	}
+	if got := MessageSourceText(file); got != "" {
+		t.Errorf("MessageSourceText = %q, want no source text from a file", got)
+	}
+	if urls := ExtractImageURLs(file); len(urls) != 0 {
+		t.Errorf("ExtractImageURLs = %v, want no image from inside a file", urls)
+	}
+}
+
 func TestExtractAttachmentsSkipsEmbeddedHTMLAttachment(t *testing.T) {
 	attachments := ExtractAttachments(`<figure data-trix-attachment='{"contentType":"text/html","content":"<p>body</p>"}'></figure>`)
 	if len(attachments) != 0 {

internal/htmlutil/markdown.go

@@ -730,7 +730,8 @@ func (m *markdownizer) embedded(content string) {
 	m.depth--
 }
 
-// actionTextAttachment writes an attachment node — or nothing, for a decorative image.
+// actionTextAttachment writes an attachment node — or nothing, for a decorative image,
+// or the markup an unnamed text/html one carries inline, which is an email body.
 // HEY rewrites an inbound email's <img> tags into these nodes, so a notification
 // email's avatars and icons arrive as image attachments declaring icon-sized
 // dimensions, decoration beside the text that already says who or what they show. A
@@ -740,6 +741,10 @@ func (m *markdownizer) actionTextAttachment(n *html.Node) {
 	if isImageContentType(getAttr(n, "content-type")) && isDecorativeImage(getAttr(n, "width"), getAttr(n, "height")) {
 		return
 	}
+	if content := embeddedActionTextContent(n); content != "" {
+		m.embedded(content)
+		return
+	}
 	filename := getAttr(n, "filename")
 	if filename == "" {
 		filename = getAttr(n, "caption")

internal/htmlutil/markdown_test.go

@@ -529,6 +529,47 @@ func TestToMarkdownEmbeddedHTMLAttachment(t *testing.T) {
 	}
 }
 
+// A nested action-text-attachment carries its HTML in a content attribute.
+func TestToMarkdownEmbeddedActionTextAttachment(t *testing.T) {
+	got := toMarkdown(`<figure data-trix-attachment='{"contentType":"text/html","content":"<action-text-attachment content-type=\"text/html\" content=\"<p>Dear customer,</p><p>Please <a href=&amp;quot;https://example.com/sign&amp;quot;>sign the document</a>.</p>\"></action-text-attachment>"}'></figure>`)
+
+	want := "Dear customer,\n\nPlease [sign the document](https://example.com/sign)."
+	if got != want {
+		t.Errorf("ToMarkdown = %q, want %q", got, want)
+	}
+}
+
+func TestToMarkdownNamedActionTextAttachmentIgnoresInlineContent(t *testing.T) {
+	got := toMarkdown(`<action-text-attachment filename="report.pdf" content-type="application/pdf" content="<p>not the body</p>"></action-text-attachment>`)
+	want := "📄 report.pdf"
+	if got != want {
+		t.Errorf("ToMarkdown = %q, want %q", got, want)
+	}
+}
+
+// HEY renders an attachment's content as HTML only when its content type is HTML.
+func TestToMarkdownNonHTMLActionTextAttachmentIgnoresInlineContent(t *testing.T) {
+	got := toMarkdown(`<action-text-attachment content-type="image/png" url="https://example.com/floor-plan.png" caption="Floor plan" content="<p>not the body</p>"></action-text-attachment>`)
+	want := "![Floor plan](https://example.com/floor-plan.png)"
+	if got != want {
+		t.Errorf("ToMarkdown = %q, want %q", got, want)
+	}
+}
+
+func TestToMarkdownEmbeddedActionTextAttachmentStopsRecursing(t *testing.T) {
+	withinLimit := "<p>innermost</p>"
+	for range embeddedContentDepthLimit {
+		withinLimit = embeddedActionTextAttachment(withinLimit)
+	}
+	if got := toMarkdown(withinLimit); got != "innermost" {
+		t.Errorf("ToMarkdown = %q, want the body at the nesting limit", got)
+	}
+
+	if got := toMarkdown(embeddedActionTextAttachment(withinLimit)); strings.Contains(got, "innermost") {
+		t.Errorf("ToMarkdown = %q, should stop before the body beyond the nesting limit", got)
+	}
+}
+
 func TestToMarkdownEmbeddedContentStopsRecursing(t *testing.T) {
 	nested := "<p>innermost</p>"
 	for range embeddedContentDepthLimit + 1 {