updates

- support chmod socket
- fix content-encoding if upstream sets it to gzip
- support conditionally replacing for a specific hostname

app.py

@@ -3,6 +3,7 @@
 
 import io
 import os
+import sys
 import asyncio
 import aiohttp
 import contextlib
@@ -23,9 +24,15 @@ class ContextVar:
 
 pattern = os.environ['PATTERN'].encode()
 repl = os.environ['REPL'].encode()
-upstream = 'http://' + os.environ['UPSTREAM']
-bind = os.environ['BIND']
-port = int(os.environ.get('PORT', '8080'))
+# TODO support upstream unix sockets
+upstream = os.environ['UPSTREAM']
+bind = sys.argv[1]
+socket_mod = int(os.environ.get('SOCKET_MODE', '775'), 8)
+replace_for = os.environ.get('REPLACE_FOR_HOST')
+try:
+	port = int(sys.argv[2])
+except IndexError:
+	port = 8080
 http = ContextVar('http')
 
 async def handler(request):
@@ -38,10 +45,16 @@ async def handler(request):
 		# proxy redirects as-is
 		allow_redirects=False,
 	) as upstream_resp:
-		resp = web.StreamResponse(status=upstream_resp.status, headers=upstream_resp.headers)
+		headers = upstream_resp.headers.copy()
+		# we're not using gzip here so don't confuse our client
+		with contextlib.suppress(KeyError): del headers['Content-Encoding']
+		resp = web.StreamResponse(status=upstream_resp.status, headers=headers)
 		await resp.prepare(request)
 
-		if upstream_resp.content_type == 'text/html':
+		if (
+			upstream_resp.content_type == 'text/html'
+			and (replace_for is None or request.host == replace_for)
+		):
 			# iter_lines when
 			while (line := await upstream_resp.content.readline()):
 				await resp.write(line.replace(pattern, repl))
@@ -63,6 +76,9 @@ async def amain():
 	async with aiohttp.ClientSession() as http_:
 		http.set(http_)
 		await site.start()
+		if '/' in bind:
+			with contextlib.suppress(KeyError):
+				os.chmod(bind, socket_mod)
 		await asyncio.sleep(float('inf'))
 
 def main():
@@ -71,4 +87,3 @@ def main():
 
 if __name__ == '__main__':
 	main()
-