From 4d4b52075e906f77b49a25f7690c936ad5311992 Mon Sep 17 00:00:00 2001
From: Alejandro Alonso <alejandroalonsofernandez@gmail.com>
Date: Fri, 13 Mar 2015 13:03:40 +0100
Subject: [PATCH] Bug 2444 links in rich content editor

---
 taiga/mdrender/extensions/autolink.py    |  1 -
 taiga/mdrender/extensions/target_link.py | 46 ++++++++++++++++++++++++
 taiga/mdrender/service.py                |  5 +--
 tests/unit/test_mdrender.py              |  8 ++---
 4 files changed, 53 insertions(+), 7 deletions(-)
 create mode 100644 taiga/mdrender/extensions/target_link.py

diff --git a/taiga/mdrender/extensions/autolink.py b/taiga/mdrender/extensions/autolink.py
index 7676bd18..4413353a 100644
--- a/taiga/mdrender/extensions/autolink.py
+++ b/taiga/mdrender/extensions/autolink.py
@@ -36,7 +36,6 @@ class AutolinkExtension(markdown.Extension):
     * GitHub only accepts URLs with protocols or "www.", whereas Gruber's regex
       accepts things like "foo.com/bar".
     """
-
     def extendMarkdown(self, md, md_globals):
         url_re = r'(?i)\b((?:(?:ftp|https?)://|www\d{0,3}[.])([^\s<>]+))'
         autolink = AutolinkPattern(url_re, md)
diff --git a/taiga/mdrender/extensions/target_link.py b/taiga/mdrender/extensions/target_link.py
new file mode 100644
index 00000000..26cc6a5f
--- /dev/null
+++ b/taiga/mdrender/extensions/target_link.py
@@ -0,0 +1,46 @@
+# Copyright (C) 2015 Andrey Antukh <niwi@niwi.be>
+# Copyright (C) 2015 Jesús Espino <jespinog@gmail.com>
+# Copyright (C) 2015 David Barragán <bameda@dbarragan.com>
+# Copyright (C) 2015 Alejandro Alonso <alejandro.alonso@kaleidos.net>
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import re
+import markdown
+
+from markdown.treeprocessors import Treeprocessor
+
+from taiga.front import resolve
+
+
+class TargetBlankLinkExtension(markdown.Extension):
+    """An extension that add target="_blank" to all external links."""
+    def extendMarkdown(self, md, md_globals):
+        md.treeprocessors.add("target_blank_links",
+                              TargetBlankLinksTreeprocessor(md),
+                              "<prettify")
+
+
+class TargetBlankLinksTreeprocessor(Treeprocessor):
+    def run(self, root):
+        home_url = resolve("home")
+        links = root.getiterator("a")
+        for a in links:
+            href = a.get("href", "")
+            url = a.get("href", "")
+            if url.endswith("/"):
+                url = url[:-1]
+
+            if not url.startswith(home_url):
+                a.set("target", "_blank")
diff --git a/taiga/mdrender/service.py b/taiga/mdrender/service.py
index 0bac20cb..5b9207c8 100644
--- a/taiga/mdrender/service.py
+++ b/taiga/mdrender/service.py
@@ -49,7 +49,7 @@ from .extensions.wikilinks import WikiLinkExtension
 from .extensions.emojify import EmojifyExtension
 from .extensions.mentions import MentionsExtension
 from .extensions.references import TaigaReferencesExtension
-
+from .extensions.target_link import TargetBlankLinkExtension
 
 # Bleach configuration
 bleach.ALLOWED_TAGS += ["p", "table", "thead", "tbody", "th", "tr", "td", "h1",
@@ -59,7 +59,7 @@ bleach.ALLOWED_TAGS += ["p", "table", "thead", "tbody", "th", "tr", "td", "h1",
 
 bleach.ALLOWED_STYLES.append("background")
 
-bleach.ALLOWED_ATTRIBUTES["a"] = ["href", "title", "alt"]
+bleach.ALLOWED_ATTRIBUTES["a"] = ["href", "title", "alt", "target"]
 bleach.ALLOWED_ATTRIBUTES["img"] = ["alt", "src"]
 bleach.ALLOWED_ATTRIBUTES["*"] = ["class", "style"]
 
@@ -74,6 +74,7 @@ def _make_extensions_list(project=None):
             EmojifyExtension(),
             MentionsExtension(),
             TaigaReferencesExtension(project),
+            TargetBlankLinkExtension(),
             "extra",
             "codehilite",
             "sane_lists",
diff --git a/tests/unit/test_mdrender.py b/tests/unit/test_mdrender.py
index 6e66418c..1de084d8 100644
--- a/tests/unit/test_mdrender.py
+++ b/tests/unit/test_mdrender.py
@@ -133,25 +133,25 @@ def test_render_wikilink_relative_to_absolute():
 
 
 def test_render_reference_links():
-    expected_result = "<p>An <a href=\"http://example.com/\" title=\"Title\">example</a> of reference link</p>"
+    expected_result = "<p>An <a href=\"http://example.com/\" target=\"_blank\" title=\"Title\">example</a> of reference link</p>"
     source = "An [example][id] of reference link\n  [id]: http://example.com/  \"Title\""
     assert render(dummy_project, source) == expected_result
 
 
 def test_render_url_autolinks():
-    expected_result = "<p>Test the <a href=\"http://example.com/\">http://example.com/</a> autolink</p>"
+    expected_result = "<p>Test the <a href=\"http://example.com/\" target=\"_blank\">http://example.com/</a> autolink</p>"
     source = "Test the http://example.com/ autolink"
     assert render(dummy_project, source) == expected_result
 
 
 def test_render_url_autolinks_without_http():
-    expected_result = "<p>Test the <a href=\"http://www.example.com\">www.example.com</a> autolink</p>"
+    expected_result = "<p>Test the <a href=\"http://www.example.com\" target=\"_blank\">www.example.com</a> autolink</p>"
     source = "Test the www.example.com autolink"
     assert render(dummy_project, source) == expected_result
 
 
 def test_render_url_automail():
-    expected_result = "<p>Test the <a href=\"mailto:example@example.com\">example@example.com</a> automail</p>"
+    expected_result = "<p>Test the <a href=\"mailto:example@example.com\" target=\"_blank\">example@example.com</a> automail</p>"
     source = "Test the example@example.com automail"
     assert render(dummy_project, source) == expected_result