Convert relative paths to absolute in og:image. (#48)

Always using absolute/full URLs for og:image as long as
`config["ogp_site_url"]` is set.

Fixes #43

sphinxext/opengraph/__init__.py

@@ -1,10 +1,9 @@
 from typing import Any, Dict
 from urllib.parse import urljoin, urlparse, urlunparse
-from pathlib import Path, PosixPath
+from pathlib import Path
 
 import docutils.nodes as nodes
 from sphinx.application import Sphinx
-from sphinx.util import logger
 
 from .descriptionparser import get_description
 from .titleparser import get_title
@@ -111,6 +110,10 @@ def get_tags(
             ogp_image_alt = first_image.get("alt", None)
 
     if image_url:
+        image_url_parsed = urlparse(image_url)
+        if not image_url_parsed.scheme:
+            # Relative image path detected. Make absolute.
+            image_url = urljoin(config["ogp_site_url"], image_url_parsed.path)
         tags += make_tag("og:image", image_url)
 
         # Add image alt text (either provided by config or from site_name)

tests/conftest.py

@@ -19,8 +19,11 @@ def content(app):
     yield app
 
 
-def _meta_tags(content):
-    c = (content.outdir / "index.html").read_text()
+def _meta_tags(content, subdir=None):
+    if subdir is None:
+        c = (content.outdir / "index.html").read_text()
+    else:
+        c = (content.outdir / subdir / "index.html").read_text()
     return BeautifulSoup(c, "html.parser").find_all("meta")
 
 
@@ -42,5 +45,14 @@ def og_meta_tags(content):
     ]
 
 
+@pytest.fixture()
+def og_meta_tags_sub(content):
+    return [
+        tag
+        for tag in _meta_tags(content, "sub")
+        if tag.get("property", "").startswith("og:")
+    ]
+
+
 def pytest_configure(config):
     config.addinivalue_line("markers", "sphinx")

tests/roots/test-image-rel-paths/conf.py

@@ -0,0 +1,10 @@
+extensions = ["sphinxext.opengraph"]
+
+master_doc = "index"
+exclude_patterns = ["_build"]
+
+html_theme = "basic"
+
+ogp_site_name = "Example's Docs!"
+ogp_site_url = "http://example.org/"
+ogp_use_first_image = True

tests/roots/test-image-rel-paths/index.rst

@@ -0,0 +1,2 @@
+.. image:: img/sample.jpg
+   :alt: Test image alt text

tests/roots/test-image-rel-paths/sub/index.rst

@@ -0,0 +1,6 @@
+========
+Sub Page
+========
+
+.. image:: ../img/sample.jpg
+   :alt: Test image alt text

tests/test_options.py

@@ -37,6 +37,18 @@ def test_image(og_meta_tags):
     assert get_tag_content(og_meta_tags, "image") == "http://example.org/image.png"
 
 
+@pytest.mark.sphinx("html", testroot="image-rel-paths")
+def test_image_rel_paths(og_meta_tags, og_meta_tags_sub):
+    assert (
+        get_tag_content(og_meta_tags, "image")
+        == "http://example.org/_images/sample.jpg"
+    )
+    assert (
+        get_tag_content(og_meta_tags_sub, "image")
+        == "http://example.org/_images/sample.jpg"
+    )
+
+
 @pytest.mark.sphinx("html", testroot="image")
 def test_image_alt(og_meta_tags):
     assert get_tag_content(og_meta_tags, "image:alt") == "Example's Docs!"