pydot: handle multiple dot images in one file

incorporealcms/mdx/pydot.py

@@ -25,9 +25,12 @@ class InlinePydotPreprocessor(markdown.preprocessors.Preprocessor):
     def run(self, lines):
         """Match and generate diagrams from dot code blocks."""
         text = '\n'.join(lines)
-        for match in self.BLOCK_RE.finditer(text):
-            filename = match.group(1)
-            dot_string = match.group(2)
+        out = text
+        for block_match in self.BLOCK_RE.finditer(text):
+            filename = block_match.group(1)
+            dot_string = block_match.group(2)
+            logger.debug("matched markdown block: %s", dot_string)
+            logger.debug("match start/end: %s/%s", block_match.start(), block_match.end())
 
             # use pydot to turn the text into pydot
             graphs = pydot.graph_from_dot_data(dot_string)
@@ -41,9 +44,9 @@ class InlinePydotPreprocessor(markdown.preprocessors.Preprocessor):
             inline_image = f'![{filename}]({data_path})'
 
             # replace the image in the output markdown
-            text = f'{text[:match.start()]}\n{inline_image}\n{text[match.end():]}'
+            out = out.replace(block_match.group(0), inline_image)
 
-        return text.split('\n')
+        return out.split('\n')
 
 
 def makeExtension(*args, **kwargs):

tests/functional_markdown_tests.py

@@ -29,6 +29,17 @@ def test_graphviz_is_rendered():
     assert b'data:image/png;base64' in response.data
 
 
+def test_two_graphviz_are_rendered():
+    """Test two images are rendered."""
+    app = app_with_pydot()
+    client = app.test_client()
+
+    response = client.get('/test-two-graphviz')
+    assert response.status_code == 200
+    assert b'~~~pydot' not in response.data
+    assert b'data:image/png;base64' in response.data
+
+
 def test_invalid_graphviz_is_not_rendered():
     """Check that invalid graphviz doesn't blow things up."""
     app = app_with_pydot()

tests/instance/config.py

@@ -15,6 +15,10 @@ LOGGING = {
         },
     },
     'loggers': {
+        'incorporealcms.mdx': {
+            'level': 'DEBUG',
+            'handlers': ['console'],
+        },
         'incorporealcms.pages': {
             'level': 'DEBUG',
             'handlers': ['console'],

tests/instance/pages/test-two-graphviz.md

@@ -0,0 +1,25 @@
+# test
+
+test
+
+~~~pydot:attack-plan
+digraph G {
+    rankdir=LR
+    Earth
+    Mars
+    Earth -> Mars
+}
+~~~
+
+more test
+
+~~~pydot:new-attack-plan
+digraph H {
+    rankdir=LR
+    Venus
+    Mars
+    Venus -> Mars
+}
+~~~
+
+done