scala · adriaanm · Apr 24, 2019 · Mar 8, 2019 · adriaanm · Mar 8, 2019
diff --git a/src/scaladoc/scala/tools/nsc/doc/Settings.scala b/src/scaladoc/scala/tools/nsc/doc/Settings.scala
@@ -220,6 +220,13 @@ class Settings(error: String => Unit, val printMsg: String => Unit = println(_))
     "Prevents parsing and inclusion of comments from java sources."
   )
 
+  val docCanonicalBaseUrl = StringSetting (
+    "-doc-canonical-base-url",
+    "url",
+    s"A base URL to use as prefix and add `canonical` URLs to all pages. The canonical URL may be used by search engines to choose the URL that you want people to see in search results. If unset no canonical URLs are generated.",
+    ""
+  )
+
   // For improved help output.
   def scaladocSpecific = Set[Settings#Setting](
     docformat, doctitle, docfooter, docversion, docUncompilable, docsourceurl, docgenerator, docRootContent,

diff --git a/src/scaladoc/scala/tools/nsc/doc/html/page/Entity.scala b/src/scaladoc/scala/tools/nsc/doc/html/page/Entity.scala
@@ -45,8 +45,15 @@ trait EntityPage extends HtmlPage {
   def headers: Elems = {
     def extScript(str: String) = Script(`type` = "text/javascript", src = str)
     def libScript(value: String) = extScript(relativeLinkTo(List(value, "lib")))
-
-    List(HtmlTags.Link(href = relativeLinkTo(List("index.css", "lib")), media = "screen", `type` = "text/css", rel = "stylesheet"),
+    val canonicalSetting = universe.settings.docCanonicalBaseUrl
+    val canonicalLink =  if (canonicalSetting.isSetByUser) {
+      val canonicalUrl =
+        if (canonicalSetting.value.endsWith("/")) canonicalSetting.value
+        else canonicalSetting.value + "/"
+      List(HtmlTags.Link(href = canonicalUrl + Page.relativeLinkTo(List("."), path), rel = "canonical"))
+    } else Nil
+    canonicalLink ++ List(
+      HtmlTags.Link(href = relativeLinkTo(List("index.css", "lib")), media = "screen", `type` = "text/css", rel = "stylesheet"),
     HtmlTags.Link(href = relativeLinkTo(List("template.css", "lib")), media = "screen", `type` = "text/css", rel = "stylesheet"),
     HtmlTags.Link(href = relativeLinkTo(List("diagrams.css", "lib")), media = "screen", `type` = "text/css", rel = "stylesheet", id = "diagrams-css"),
     libScript("jquery.js"),

diff --git a/test/scaladoc/resources/canonical.scala b/test/scaladoc/resources/canonical.scala
@@ -0,0 +1,15 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package p
+
+class Canonical
diff --git a/test/scaladoc/run/canonical-unset.check b/test/scaladoc/run/canonical-unset.check
@@ -0,0 +1,2 @@
+As expected, no canonical URL found.
+Done.
diff --git a/test/scaladoc/run/canonical-unset.scala b/test/scaladoc/run/canonical-unset.scala
@@ -0,0 +1,43 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+import scala.tools.nsc.{ScalaDocReporter, doc, io}
+import scala.tools.nsc.doc.DocFactory
+import scala.tools.nsc.doc.model._
+import scala.tools.nsc.reporters.ConsoleReporter
+import scala.tools.partest.ScaladocModelTest
+
+object Test extends ScaladocModelTest {
+
+  override def resourceFile: String = "test/scaladoc/resources/canonical.scala"
+
+  def destinationDir = "target/canonical-unset"
+
+  override def scaladocSettings =
+    s"-d ${destinationDir}"
+
+  override def code = ""
+
+  def testModel(rootPackage: Package): Unit = {
+    val dir = new java.io.File(destinationDir)
+    dir.mkdirs()
+    newDocFactory.document(List(resourceFile))
+    val Pattern = """<link href="([^"]*)" rel="canonical"/>""".r
+    val s = io.File(s"${dir.getAbsolutePath}/p/Canonical.html").slurp()
+    Pattern.findFirstIn(s) match {
+      case Some(s) =>
+        println(s)
+      case _ =>
+        println("As expected, no canonical URL found.")
+    }
+  }
+}
diff --git a/test/scaladoc/run/canonical.check b/test/scaladoc/run/canonical.check
@@ -0,0 +1,2 @@
+<link href="https://www.scala-lang.org/files/archive/nightly/2.13.x/api/2.13.x/p/Canonical.html" rel="canonical"/>
+Done.
diff --git a/test/scaladoc/run/canonical.scala b/test/scaladoc/run/canonical.scala
@@ -0,0 +1,44 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+import scala.tools.nsc.{ScalaDocReporter, doc, io}
+import scala.tools.nsc.doc.DocFactory
+import scala.tools.nsc.doc.model._
+import scala.tools.nsc.reporters.ConsoleReporter
+import scala.tools.partest.ScaladocModelTest
+
+object Test extends ScaladocModelTest {
+
+  override def resourceFile: String = "test/scaladoc/resources/canonical.scala"
+
+  def destinationDir = "target/canonical-unset"
+
+  override def scaladocSettings =
+    s"-doc-canonical-base-url https://www.scala-lang.org/files/archive/nightly/2.13.x/api/2.13.x/ -d $destinationDir"
+
+  override def code = ""
+
+  def testModel(rootPackage: Package): Unit = {
+    val dir = new java.io.File(destinationDir)
+    dir.mkdirs()
+    newDocFactory.document(List(resourceFile))
+    val Pattern = """<link href="([^"]*)" rel="canonical"/>""".r
+    val s = io.File(s"${dir.getAbsolutePath}/p/Canonical.html").slurp()
+    Pattern.findFirstIn(s) match {
+      case Some(s) =>
+        println(s)
+      case _ =>
+        println("No canonical URL found.")
+        println(s.substring(0, Math.min(1000, s.length)))
+    }
+  }
+}
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		<link href="https://www.scala-lang.org/files/archive/nightly/2.13.x/api/2.13.x/p/Canonical.html" rel="canonical"/>
		Done.