From 3e50ce65a721ee6a8f930613dd196f92a9126c1d Mon Sep 17 00:00:00 2001
From: Lukas Senionis <warliukz@gmail.com>
Date: Sat, 3 Aug 2024 20:24:25 +0300
Subject: [PATCH] fix: fetchNoCors and http_request data handling (#664)

---
 backend/decky_loader/utilities.py | 12 +++++++-----
 frontend/src/plugin-loader.tsx    | 16 ++++++++++------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/backend/decky_loader/utilities.py b/backend/decky_loader/utilities.py
index f7f22517d..a90244a1b 100644
--- a/backend/decky_loader/utilities.py
+++ b/backend/decky_loader/utilities.py
@@ -141,10 +141,10 @@ async def uninstall_plugin(self, name: str):
 
     # Loosely based on https://gist.github.com/mosquito/4dbfacd51e751827cda7ec9761273e95#file-proxy-py
     async def http_request(self, req: Request) -> StreamResponse:
-        if req.headers.get('X-Decky-Auth', '') != helpers.get_csrf_token() and req.query.get('auth', '') != helpers.get_csrf_token():
+        if req.query['auth'] != helpers.get_csrf_token():
             return Response(text='Forbidden', status=403)
 
-        url = req.headers["X-Decky-Fetch-URL"] if "X-Decky-Fetch-URL" in req.headers else unquote(req.query.get('fetch_url', ''))
+        url = unquote(req.query['fetch_url'])
         self.logger.info(f"Preparing {req.method} request to {url}")
 
         headers = dict(req.headers)
@@ -180,7 +180,11 @@ async def http_request(self, req: Request) -> StreamResponse:
 
         body = await req.read() # TODO can this also be streamed?
 
-        async with ClientSession() as web:
+        # We disable auto-decompress so that the body is completely forwarded to the
+        # JS engine for it to do the decompression. Otherwise we need need to clear
+        # the Content-Encoding header in the response headers, however that would
+        # defeat the point of this proxy.
+        async with ClientSession(auto_decompress=False) as web:
             async with web.request(req.method, url, headers=headers, data=body, ssl=helpers.get_ssl_context()) as web_res:
                 res = StreamResponse(headers=web_res.headers, status=web_res.status)
                 if web_res.headers.get('Transfer-Encoding', '').lower() == 'chunked':
@@ -190,8 +194,6 @@ async def http_request(self, req: Request) -> StreamResponse:
                 self.logger.debug(f"Starting stream for {url}")
                 async for data in web_res.content.iter_any():
                     await res.write(data)
-                    if data:
-                        await res.drain()
                 self.logger.debug(f"Finished stream for {url}")
         return res
 
diff --git a/frontend/src/plugin-loader.tsx b/frontend/src/plugin-loader.tsx
index 6b954d69c..f7d362a7b 100644
--- a/frontend/src/plugin-loader.tsx
+++ b/frontend/src/plugin-loader.tsx
@@ -528,18 +528,22 @@ class PluginLoader extends Logger {
 
   // Same syntax as fetch but only supports the url-based syntax and an object for headers since it's the most common usage pattern
   fetchNoCors(input: string, init?: DeckyRequestInit | undefined): Promise<Response> {
-    const headers: { [name: string]: string } = {
-      ...(init?.headers as { [name: string]: string }),
-      'X-Decky-Auth': deckyAuthToken,
-      'X-Decky-Fetch-URL': input,
+    const { headers: initHeaders = {}, ...restOfInit } = init || {};
+    const getPrefixedHeaders = () => {
+      let prefixedInitHeaders: { [name: string]: any } = {};
+      for (const [key, value] of Object.entries(initHeaders)) {
+        prefixedInitHeaders[`X-Decky-Header-${key}`] = value;
+      }
+      return prefixedInitHeaders;
     };
+    const headers: { [name: string]: string } = getPrefixedHeaders();
 
     if (init?.excludedHeaders) {
       headers['X-Decky-Fetch-Excluded-Headers'] = init.excludedHeaders.join(', ');
     }
 
-    return fetch('http://127.0.0.1:1337/fetch', {
-      ...init,
+    return fetch(this.getExternalResourceURL(input), {
+      ...restOfInit,
       credentials: 'include',
       headers,
     });