Add ability to convert relative links to absolute

block_test.go

@@ -21,7 +21,7 @@ func runMarkdownBlock(input string, extensions int) string {
 	htmlFlags := 0
 	htmlFlags |= HTML_USE_XHTML
 
-	renderer := HtmlRenderer(htmlFlags, "", "")
+	renderer := HtmlRenderer(htmlFlags, "", "", "")
 
 	return string(Markdown([]byte(input), renderer, extensions))
 }

html.go

@@ -41,6 +41,7 @@ const (
 	HTML_USE_SMARTYPANTS                      // enable smart punctuation substitutions
 	HTML_SMARTYPANTS_FRACTIONS                // enable smart fractions (with HTML_USE_SMARTYPANTS)
 	HTML_SMARTYPANTS_LATEX_DASHES             // enable LaTeX-style dashes (with HTML_USE_SMARTYPANTS)
+	HTML_ABSOLUTE_LINKS                       // convert all links to absolute links
 )
 
 var (
@@ -62,6 +63,7 @@ type Html struct {
 	closeTag       string // how to end singleton tags: either " />\n" or ">\n"
 	title          string // document title
 	css            string // optional css file url (used with HTML_COMPLETE_PAGE)
+	absolutePrefix string
 
 	// table of contents data
 	tocMarker    int
@@ -84,7 +86,7 @@ const (
 // title is the title of the document, and css is a URL for the document's
 // stylesheet.
 // title and css are only used when HTML_COMPLETE_PAGE is selected.
-func HtmlRenderer(flags int, title string, css string) Renderer {
+func HtmlRenderer(flags int, title string, css string, absolutePrefix string) Renderer {
 	// configure the rendering engine
 	closeTag := htmlClose
 	if flags&HTML_USE_XHTML != 0 {
@@ -96,6 +98,7 @@ func HtmlRenderer(flags int, title string, css string) Renderer {
 		closeTag:       closeTag,
 		title:          title,
 		css:            css,
+		absolutePrefix: absolutePrefix,
 
 		headerCount:  0,
 		currentLevel: 0,
@@ -410,7 +413,10 @@ func (options *Html) AutoLink(out *bytes.Buffer, link []byte, kind int) {
 	out.WriteString("<a href=\"")
 	if kind == LINK_TYPE_EMAIL {
 		out.WriteString("mailto:")
+	} else {
+		options.maybeWriteAbsolutePrefix(out, link)
 	}
+
 	entityEscapeWithSkip(out, link, skipRanges)
 
 	if options.flags&HTML_NOFOLLOW_LINKS != 0 && !isRelativeLink(link) {
@@ -459,12 +465,22 @@ func (options *Html) Emphasis(out *bytes.Buffer, text []byte) {
 	out.WriteString("</em>")
 }
 
+func (options *Html) maybeWriteAbsolutePrefix(out *bytes.Buffer, link []byte) {
+	if options.flags&HTML_ABSOLUTE_LINKS != 0 && isRelativeLink(link) {
+		out.WriteString(options.absolutePrefix)
+		if link[0] != '/' {
+			out.WriteByte('/')
+		}
+	}
+}
+
 func (options *Html) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
 	if options.flags&HTML_SKIP_IMAGES != 0 {
 		return
 	}
 
 	out.WriteString("<img src=\"")
+	options.maybeWriteAbsolutePrefix(out, link)
 	attrEscape(out, link)
 	out.WriteString("\" alt=\"")
 	if len(alt) > 0 {
@@ -503,6 +519,7 @@ func (options *Html) Link(out *bytes.Buffer, link []byte, title []byte, content
 	}
 
 	out.WriteString("<a href=\"")
+	options.maybeWriteAbsolutePrefix(out, link)
 	attrEscape(out, link)
 	if len(title) > 0 {
 		out.WriteString("\" title=\"")

inline_test.go

@@ -23,7 +23,7 @@ func runMarkdownInline(input string, extensions, htmlFlags int) string {
 
 	htmlFlags |= HTML_USE_XHTML
 
-	renderer := HtmlRenderer(htmlFlags, "", "")
+	renderer := HtmlRenderer(htmlFlags, "", "", "")
 
 	return string(Markdown([]byte(input), renderer, extensions))
 }

markdown.go

@@ -202,7 +202,7 @@ type parser struct {
 func MarkdownBasic(input []byte) []byte {
 	// set up the HTML renderer
 	htmlFlags := HTML_USE_XHTML
-	renderer := HtmlRenderer(htmlFlags, "", "")
+	renderer := HtmlRenderer(htmlFlags, "", "", "")
 
 	// set up the parser
 	extensions := 0
@@ -237,7 +237,7 @@ func MarkdownCommon(input []byte) []byte {
 	htmlFlags |= HTML_SMARTYPANTS_FRACTIONS
 	htmlFlags |= HTML_SMARTYPANTS_LATEX_DASHES
 	htmlFlags |= HTML_SANITIZE_OUTPUT
-	renderer := HtmlRenderer(htmlFlags, "", "")
+	renderer := HtmlRenderer(htmlFlags, "", "", "")
 
 	// set up the parser
 	extensions := 0
@@ -332,7 +332,7 @@ func firstPass(p *parser, input []byte) []byte {
 				// when last line was none blank and a fenced code block comes after
 				if beg >= lastFencedCodeBlockEnd {
 					// tmp var so we don't modify beyond bounds of `input`
-					var tmp = make([]byte, len(input[beg:]), len(input[beg:]) + 1)
+					var tmp = make([]byte, len(input[beg:]), len(input[beg:])+1)
 					copy(tmp, input[beg:])
 					if i := p.fencedCode(&out, append(tmp, '\n'), false); i > 0 {
 						if !lastLineWasBlank {

upskirtref_test.go

@@ -20,7 +20,7 @@ import (
 )
 
 func runMarkdownReference(input string, flag int) string {
-	renderer := HtmlRenderer(0, "", "")
+	renderer := HtmlRenderer(0, "", "", "")
 	return string(Markdown([]byte(input), renderer, flag))
 }