Rewrite relative links to reflect the base url of the repo.

src/main/scala/view/Asciidoc.scala

@@ -1,17 +1,14 @@
 package view
 
-import util.StringUtil
-import util.ControlUtil._
-import util.Directory._
-import org.parboiled.common.StringUtils
-import org.pegdown._
-import org.pegdown.ast._
-import org.pegdown.LinkRenderer.Rendering
-import java.text.Normalizer
-import java.util.Locale
-import scala.collection.JavaConverters._
-import service.{ RequestCache, WikiService }
-import org.asciidoctor.{ Asciidoctor, Attributes, AttributesBuilder, OptionsBuilder, SafeMode }
+import org.asciidoctor.Asciidoctor
+import org.asciidoctor.AttributesBuilder
+import org.asciidoctor.OptionsBuilder
+import org.asciidoctor.SafeMode
+import org.htmlcleaner.HtmlCleaner
+import org.htmlcleaner.HtmlNode
+import org.htmlcleaner.SimpleHtmlSerializer
+import org.htmlcleaner.TagNode
+import org.htmlcleaner.TagNodeVisitor
 
 object Asciidoc {
 
@@ -20,14 +17,41 @@ object Asciidoc {
   /**
    * Converts Markdown of Wiki pages to HTML.
    */
-  def toHtml(asciidoc: String, repository: service.RepositoryService.RepositoryInfo,
+  def toHtml(asciidoc: String, branch: String, repository: service.RepositoryService.RepositoryInfo,
              enableWikiLink: Boolean, enableRefsLink: Boolean)(implicit context: app.Context): String = {
+
     val options = OptionsBuilder.options()
     options.safe(SafeMode.SECURE)
     val attributes = AttributesBuilder.attributes()
     attributes.showTitle(true)
     options.attributes(attributes.get())
-    asciidoctor.render(asciidoc, options)
+    val rendered = asciidoctor.render(asciidoc, options)
+
+    // this is always relative to the base dir of the repo, as we currently only render README files.
+    val relativeUrlPrefix = s"${helpers.url(repository)}/blob/${branch}/"
+    prefixRelativeUrls(rendered, relativeUrlPrefix)
   }
+
+  def prefixRelativeUrls(html: String, urlPrefix: String): String = {
+    val cleaner = new HtmlCleaner()
+    val node = cleaner.clean(html)
+    node.traverse(new TagNodeVisitor() {
+      override def visit(tagNode: TagNode, htmlNode: HtmlNode): Boolean = {
+        htmlNode match {
+          case tag: TagNode if tag.getName == "a" =>
+            Option(tag.getAttributeByName("href")) foreach { href =>
+              if (!href.startsWith("/") && !href.startsWith("http://") && !href.startsWith("https://")) {
+                tag.addAttribute("href", s"${urlPrefix}${href}")
+              }
+            }
+          case _ =>
+        }
+        // continue traversal
+        true
+      }
+    })
+    new SimpleHtmlSerializer(cleaner.getProperties()).getAsString(node)
+  }
+
 }