Improve error handling and reporting.

- Refactor out common functionality into reusable utilities
- Handle errors from the Authlib library/package
- Handle 4xx errors generically.

3 files changed, 20 insertions, 13 deletions

diff --git a/gn_auth/templates/404.html b/gn_auth/templates/404.html
deleted file mode 100644
index e17bfe8..0000000
--- a/gn_auth/templates/404.html
+++ /dev/null
@@ -1,13 +0,0 @@
-{%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%}
diff --git a/gn_auth/templates/http-error-4xx.html b/gn_auth/templates/http-error-4xx.html
new file mode 100644
index 0000000..16c4581
--- /dev/null
+++ b/gn_auth/templates/http-error-4xx.html
@@ -0,0 +1,20 @@
+{%extends "base.html"%}
+
+{%block title%}{{error.code}}: {{error.name}}{%endblock%}
+
+{%block pagetitle%}{{error.code}}: {{error.name}}{%endblock%}
+
+{%block content%}
+
+<dl>
+  <dt>status code</dt>
+  <dd>{{error.code}}: {{error.name}}</dd>
+
+  <dt><strong>URI</strong></dt>
+  <dd>{{page}}</dd>
+
+  <dt>error description</dt>
+  <dd>{{description}}</dd>
+</dl>
+
+{%endblock%}
diff --git a/gn_auth/templates/50x.html b/gn_auth/templates/http-error-5xx.html
index 859a232..859a232 100644
--- a/gn_auth/templates/50x.html
+++ b/gn_auth/templates/http-error-5xx.html