Add redirect example script

CHANGELOG.md

@@ -19,6 +19,8 @@
   (examples/chatroom.py).
 - The jetforce-client tool now supports writing TLS keys to a logfile to
   facilitate debugging TLS connections using tools like Wireshark.
+- Added ``examples/redirect.py`` to show demonstrate extending the static file
+  server with common patterns like redirects and authenticated directories.
 
 
 ### v0.4.0 (2020-06-09)

examples/redirect.py

@@ -0,0 +1,44 @@
+#!/usr/local/env python3
+"""
+This example shows how you can extend the jetforce static directory server to
+support advanced behavior like custom redirects and directory authentication.
+"""
+from jetforce import GeminiServer, Response, StaticDirectoryApplication, Status
+
+app = StaticDirectoryApplication("/var/gemini")
+
+
+# Example of registering a custom file extension
+app.mimetypes.add_type("text/gemini", ".gemlog")
+
+
+@app.route("/old/(?P<route>.*)")
+def redirect_old_regex(request, route):
+    """
+    Redirect any request that starts with "/old/..." to "/new/...".
+    """
+    return Response(Status.REDIRECT_PERMANENT, f"/new/{route}")
+
+
+@app.route("/custom-cgi")
+def custom_cgi(request):
+    """
+    Invoke a CGI script from anywhere in the filesystem.
+    """
+    return app.run_cgi_script("/opt/custom-cgi.sh", request.environ)
+
+
+@app.route("/auth/.*")
+def authenticated(request):
+    """
+    Require a TLS client certificate to access files in the /auth directory.
+    """
+    if request.environ.get("TLS_CLIENT_HASH"):
+        return app.serve_static_file(request)
+    else:
+        return Response(Status.CLIENT_CERTIFICATE_REQUIRED, "Need certificate")
+
+
+if __name__ == "__main__":
+    server = GeminiServer(app, host="127.0.0.1", hostname="localhost")
+    server.run()