Add extensions.py for Jinja2 extensions

Author: pythoninthegrass

extensions.py

@@ -0,0 +1,73 @@
+from datetime import datetime
+from typing import Dict, Any
+
+from jinja2.ext import Extension
+
+
+class CurrentYearExtension(Extension):
+    """
+    Jinja extension that adds a {{ current_year }} variable containing the current year.
+    """
+
+    def __init__(self, environment):
+        super().__init__(environment)
+        environment.globals["current_year"] = str(datetime.now().year)
+
+
+class GitExtension(Extension):
+    """
+    Jinja extension that adds support for filters:
+    - git_user_name: returns the default user name from git config
+    - git_user_email: returns the default user email from git config
+    """
+
+    def __init__(self, environment):
+        super().__init__(environment)
+
+        try:
+            import subprocess
+
+            stdout = subprocess.check_output(
+                ["git", "config", "--get", "user.name"],
+                text=True,
+                stderr=subprocess.DEVNULL,
+            ).strip()
+            environment.filters["git_user_name"] = lambda default="": stdout or default
+        except (subprocess.SubprocessError, FileNotFoundError):
+            environment.filters["git_user_name"] = lambda default="": default
+
+        try:
+            import subprocess
+
+            stdout = subprocess.check_output(
+                ["git", "config", "--get", "user.email"],
+                text=True,
+                stderr=subprocess.DEVNULL,
+            ).strip()
+            environment.filters["git_user_email"] = lambda default="": stdout or default
+        except (subprocess.SubprocessError, FileNotFoundError):
+            environment.filters["git_user_email"] = lambda default="": default
+
+
+class SlugifyExtension(Extension):
+    """
+    Jinja extension that adds a filter:
+    - slugify: to convert "The text" into "the-text" or "the_text" if underscore=True
+    """
+
+    def __init__(self, environment):
+        super().__init__(environment)
+
+        def slugify(text, underscore=False):
+            import re
+            import unicodedata
+
+            text = unicodedata.normalize("NFKD", text)
+            text = text.encode("ascii", "ignore").decode("ascii")
+            text = text.lower()
+            text = re.sub(r"[^a-z0-9]+", "_" if underscore else "-", text)
+            text = re.sub(r"[-_]+", "_" if underscore else "-", text)
+            text = text.strip("_" if underscore else "-")
+            return text
+
+        environment.filters["slugify"] = slugify