Error handling: Handle 404 error.

2 files changed, 29 insertions, 2 deletions

diff --git a/gn_auth/errors.py b/gn_auth/errors.py
index bd2c5eb..52fc489 100644
--- a/gn_auth/errors.py
+++ b/gn_auth/errors.py
@@ -1,8 +1,21 @@
 """Handle application level errors."""
-from flask import Flask, jsonify, current_app
+from werkzeug.exceptions import NotFound
+from flask import Flask, request, jsonify, current_app, render_template
 
 from gn_auth.auth.authorisation.errors import AuthorisationError
 
+def page_not_found(exc):
+    """404 handler."""
+    content_type = request.content_type
+    if bool(content_type) and content_type.lower() == "application/json":
+        return jsonify({
+            "error": exc.name,
+            "error_description": (f"The page '{request.url}' does not exist on "
+                                  "this server.")
+        }), 404
+
+    return render_template("404.html", page=request.url)
+
 def handle_authorisation_error(exc: AuthorisationError):
     """Handle AuthorisationError if not handled anywhere else."""
     current_app.logger.error(exc)
@@ -12,7 +25,8 @@ def handle_authorisation_error(exc: AuthorisationError):
     }), exc.error_code
 
 __error_handlers__ = {
-    AuthorisationError: handle_authorisation_error
+    AuthorisationError: handle_authorisation_error,
+    NotFound: page_not_found
 }
 def register_error_handlers(app: Flask):
     """Register ALL defined error handlers"""
diff --git a/gn_auth/templates/404.html b/gn_auth/templates/404.html
new file mode 100644
index 0000000..e17bfe8
--- /dev/null
+++ b/gn_auth/templates/404.html
@@ -0,0 +1,13 @@
+{%extends "base.html"%}
+
+{%block title%}404: Page Not Found{%endblock%}
+
+{%block pagetitle%}404: Could Not Find the Requested Page{%endblock%}
+
+{%block content%}
+
+<p>
+  The page "<strong>{{page}}</strong>" does not exist on this server.
+</p>
+
+{%endblock%}