added comments

src/app/api/proxy/functions.ts

@@ -38,8 +38,8 @@ export async function redirectRequest(
     })
 }
 
-/// Browsers send OPTIONS request sometimes to check webserver allowed headers and methods.
-/// My backend doesn't support such requests so use proxy to answer to it that all headers and methods are allowed
+/// Browsers send OPTIONS request sometimes to check webserver's allowed headers and methods.
+/// My C# backend doesn't support OPTIONS, so the proxy answer to OPTIONS request that all headers and methods are allowed.
 export async function responseToOPTIONS(req: NextRequest): Promise<NextResponse> {
     // console.log('proxy responding to CORS OPTIONS', req.url)
 
@@ -48,8 +48,8 @@ export async function responseToOPTIONS(req: NextRequest): Promise<NextResponse>
         headers: {
             'Access-Control-Allow-Origin': '*',
             'Access-Control-Allow-Methods': 'GET, POST, PUT, PATCH, DELETE, HEAD',
-            'Access-Control-Allow-Headers':
-                req.headers.get('access-control-request-headers') || 'Content-Type, Authorization',
+            'Access-Control-Allow-Headers': '*',
+            // req.headers.get('access-control-request-headers') || 'Content-Type, Authorization'
         },
     })
 }

src/app/api/proxy/paths.ts

@@ -1,3 +1,5 @@
+// Directories in src/api/proxy/ are routes.
+// Their paths are stored here to simplify refactoring.
 export const PROXY_PATHS = {
     saveParserBackend: '/api/proxy/saveParserBackend',
 }

src/app/api/proxy/saveParserBackend/[[...path]]/route.ts

@@ -4,10 +4,12 @@ import { redirectRequest, responseToOPTIONS as respondToOPTIONS } from '@/app/ap
 import { PROXY_PATHS } from '@/app/api/proxy/paths'
 import { appConfig } from '@/lib/configLoader'
 
+// Forwards the incoming request to the save parser backend.
 async function redirect(req: NextRequest): Promise<NextResponse> {
     return await redirectRequest(req, PROXY_PATHS.saveParserBackend, appConfig.services.saveParserBackend.url)
 }
 
+// handlers for each request method on this route
 export const GET = redirect
 export const POST = redirect
 export const PUT = redirect