Reverse proxy support for custom server base path

scripts/server_with_rewrites.py

@@ -1,16 +1,22 @@
 from http.server import HTTPServer, SimpleHTTPRequestHandler
 import argparse
 
+BASE_PATH = ''
 
 class RequestHandler(SimpleHTTPRequestHandler):
-
     # mimic firebase hosting's rewrite rules
-    def translate_path(self, path):
-        if path.startswith('/simplified') or path.startswith('/traditional') or path.startswith('/cantonese') or path.startswith('/hsk'):
+    def translate_path(self, request_path):
+        global BASE_PATH
+        slashed_path = request_path.removeprefix(BASE_PATH)
+        crit_blank = slashed_path in ('/', '')
+        crit_specials = any([slashed_path.startswith(f"{candidate}") for candidate in (
+            '/simplified', '/traditional', '/cantonese', '/hsk'
+        )])
+        if crit_blank or crit_specials:
             return 'index.html'
-        # prepend . such that the frontend's use of /whatever results in ./whatever
-        # should maybe just strip the first character, tbh
-        return f".{path}"
+        # now turn the slashed path /foo/bar into ./foo/bar on disk
+        path = f".{slashed_path}"
+        return path
 
 
 if __name__ == '__main__':
@@ -20,8 +26,15 @@ def translate_path(self, path):
         description='Enable URL rewrites without relying on firebase hosting. Intended to be run from the public/ directory.')
     parser.add_argument(
         '--port', help='your choice of port; default 8000', nargs='?', default=8000, type=int)
+    parser.add_argument(
+        '--base-path', help='custom base path, e.g. /app/hanzigraph; useful for reverse proxy', default='')
     args = parser.parse_args()
     port = int(args.port)
+    if args.base_path:
+        BASE_PATH = args.base_path
+        assert BASE_PATH[0] == '/', '--base-path must start with /'
+        if BASE_PATH[-1] == '/':
+            BASE_PATH = BASE_PATH[:-1]
     myServer = HTTPServer(('0.0.0.0', port), RequestHandler)
     print("HanziGraph started")
     try: