Add support for custom tags

Author: TheTripleV

README.md

@@ -28,6 +28,8 @@ These values are placed in the conf.py of your sphinx project.
     * This is not required. Link to image to show.
 * `ogp_type`
     * This sets the ogp type attribute, for more information on the types available please take a look at https://ogp.me/#types. By default it is set to `website`, which should be fine for most use cases.
+* `ogp_custom_tags`
+    * This is not required. List of custom tags and values to insert into all documents.
 
 ## Example Config
 
@@ -45,4 +47,9 @@ ogp_site_url = "http://example.org/"
 ogp_image = "http://example.org/image.png"
 ogp_description_length = 300
 ogp_type = "article"
+
+ogp_custom_tags = [
+    ("og:ignore_canonical", "true"),
+]
+
 ```

sphinxext/opengraph.py

@@ -184,6 +184,10 @@ def get_tags(context: Dict[str, Any], doctree: nodes.document, config: Dict[str,
     if image_url:
         tags += make_tag("og:image", image_url)
 
+    # custom tags
+    for custom_tag in config['ogp_custom_tags']:
+        tags += make_tag(*custom_tag)
+
     return tags
 
 
@@ -198,6 +202,7 @@ def setup(app: Sphinx) -> Dict[str, Any]:
     app.add_config_value("ogp_image", None, "html")
     app.add_config_value("ogp_type", "website", "html")
     app.add_config_value("ogp_site_name", None, "html")
+    app.add_config_value("ogp_custom_tags", [], "html")
 
     app.connect('html-page-context', html_page_context)
 

tests/roots/test-custom-tags/conf.py

@@ -0,0 +1,12 @@
+extensions = ["sphinxext.opengraph"]
+
+master_doc = "index"
+exclude_patterns = ["_build"]
+
+html_theme = "basic"
+
+ogp_site_url = "http://example.org/"
+
+ogp_custom_tags = [
+    ("og:ignore_canonical", "true"),
+]

tests/roots/test-custom-tags/index.rst

@@ -0,0 +1 @@
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse at lorem ornare, fringilla massa nec, venenatis mi. Donec erat sapien, tincidunt nec rhoncus nec, scelerisque id diam. Orci varius natoque penatibus et magnis dis parturient mauris.

tests/test_options.py

@@ -86,3 +86,7 @@ def test_nested_list_punctuation(og_meta_tags):
 def test_skip_comments(og_meta_tags):
     assert get_tag_content(og_meta_tags, "description") == "This is text."
 
+
+@pytest.mark.sphinx("html", testroot="custom-tags")
+def test_custom_tags(og_meta_tags):
+    assert get_tag_content(og_meta_tags, "ignore_canonical") == "true"