added error handling to contributor load

Author: mcloughlan

main.py

@@ -6,9 +6,35 @@
 def define_env(env):
     @env.macro
     def contributors(repo="mcloughlan/algo-notes"):
-        USERS = requests.get(
-            f"https://api.github.com/repos/{repo}/contributors").json()
-        html = ""
-        for u in USERS:
-            html += f'<a href="https://github.com/{u["login"]}"><img src="https://github.com/{u["login"]}.png?size=50" alt="{u["login"]}" style="border-radius: 50%; margin: 5px;"></a>\n'
-        return html
+        try:
+            url = f"https://api.github.com/repos/{repo}/contributors"
+            resp = requests.get(
+                url, headers={"Accept": "application/vnd.github+json"}, timeout=10)
+
+            if resp.status_code == 404:
+                return f"<p style='color:red;'>Error: GitHub repo '{repo}' not found.</p>"
+
+            if resp.status_code == 403:
+                return "<p style='color:red;'>Error: GitHub API rate limit exceeded. Try again later.</p>"
+
+            if not resp.ok:
+                return f"<p style='color:red;'>Error: GitHub API returned status {resp.status_code}.</p>"
+
+            users = resp.json()
+            if not isinstance(users, list):
+                return "<p style='color:red;'>Error: Unexpected response format from GitHub API.</p>"
+
+            html = ""
+            for u in users:
+                if "login" not in u:
+                    continue  # Skip invalid user object
+                username = u["login"]
+                html += (
+                    f'<a href="https://github.com/{username}" title="{username}">'
+                    f'<img src="https://github.com/{username}.png?size=50" alt="{username}" '
+                    f'style="border-radius: 50%; margin: 5px;"></a>\n'
+                )
+            return html or "<p>No contributors found.</p>"
+
+        except requests.exceptions.RequestException as e:
+            return f"<p style='color:red;'>Error contacting GitHub: {e}</p>"