From fc64840b5f009021d64173d81c2f244fb0d8a43d Mon Sep 17 00:00:00 2001
From: Marjus Cako <marios.cako@hpe.com>
Date: Fri, 5 Jan 2024 18:13:26 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=91=8C=20IMPROVE:=20External=20links=20in?=
 =?UTF-8?q?=20new=20tab=20(#856)?=
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Add support to enable external links to open in a new tab. Expose the
configuration option myst_links_external_new_tab, which if set will set
all URL links to open in a new tab on the browser.

Besides that, we allow the user to set the target and rel attributes
when using the extension inline_attrs (#820).

Closes #820
Closes #856

Signed-off-by: Marjus Cako <marios.cako@hpe.com>
---
 myst_parser/config/main.py                    |  8 ++++++++
 myst_parser/mdit_to_docutils/base.py          |  6 +++++-
 tests/test_renderers/fixtures/myst-config.txt | 20 +++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/myst_parser/config/main.py b/myst_parser/config/main.py
index ae29dfad..a3faceb1 100644
--- a/myst_parser/config/main.py
+++ b/myst_parser/config/main.py
@@ -233,6 +233,14 @@ def __repr__(self) -> str:
         },
     )
 
+    links_external_new_tab: bool = dc.field(
+        default=False,
+        metadata={
+            "validator": instance_of(bool),
+            "help": "Open all external links in a new tab",
+        },
+    )
+
     url_schemes: Dict[str, Optional[UrlSchemeType]] = dc.field(
         default_factory=lambda: {
             "http": None,
diff --git a/myst_parser/mdit_to_docutils/base.py b/myst_parser/mdit_to_docutils/base.py
index 4a02459d..c4e59aed 100644
--- a/myst_parser/mdit_to_docutils/base.py
+++ b/myst_parser/mdit_to_docutils/base.py
@@ -952,8 +952,12 @@ def render_link_url(
         """
         ref_node = nodes.reference()
         self.add_line_and_source_path(ref_node, token)
+        attribute_keys = ["class", "id", "reftitle", "target", "rel"]
+        if self.md_config.links_external_new_tab:
+            token.attrs["target"] = "_blank"
+            token.attrs["rel"] = "noreferer noopener"
         self.copy_attributes(
-            token, ref_node, ("class", "id", "reftitle"), aliases={"title": "reftitle"}
+            token, ref_node, attribute_keys, aliases={"title": "reftitle"}
         )
         uri = cast(str, token.attrGet("href") or "")
         implicit_text: str | None = None
diff --git a/tests/test_renderers/fixtures/myst-config.txt b/tests/test_renderers/fixtures/myst-config.txt
index e0e69305..ccac6ea0 100644
--- a/tests/test_renderers/fixtures/myst-config.txt
+++ b/tests/test_renderers/fixtures/myst-config.txt
@@ -301,6 +301,10 @@ a
 [ref]{#id3 .e .f}
 
 [ref]: https://example.com
+
+[text3](https://example.com){target="g"}
+
+[text4](https://example.com){rel="h"}
 .
 <document source="<string>">
     <paragraph>
@@ -319,6 +323,12 @@ a
     <paragraph>
         <reference classes="e f" ids="id3" names="id3" refuri="https://example.com">
             ref
+    <paragraph>
+        <reference refuri="https://example.com" target="g">
+            text3
+    <paragraph>
+        <reference refuri="https://example.com" rel="h">
+            text4
 .
 
 [attrs_inline_image] --myst-enable-extensions=attrs_inline
@@ -507,3 +517,13 @@ content
 <string>:1: (WARNING/2) Unknown directive type: 'unknown' [myst.directive_unknown]
 <string>:6: (WARNING/2) 'admonition': Unknown option keys: ['a'] (allowed: ['class', 'name']) [myst.directive_parse]
 .
+
+[links-external-new-tab] --myst-links-external-new-tab="true"
+.
+[text](https://example.com)
+.
+<document source="<string>">
+    <paragraph>
+        <reference refuri="https://example.com" rel="noreferer noopener" target="_blank">
+            text
+.