Needed fix for corsProxy (server operators must read)

Action required

If you are an NSS server operator, please check that your settings use the default "corsProxy": false.
If you have a public facing server with "corsProxy": true, please change it to "corsProxy": false until the suggested fix below is deployed.

Fix

The CORS proxy needs to be changed as follows:

• If no Origin field present in the HTTP request, respond with a 400 or similar.
• If the Origin value in the request is not the server's configured domain (podhost.example) or a direct subdomain thereof (alice.podhost.example), respond with 400 or similar.
• If, after satistying the above two conditions, the response received from the downstream server does not indicate an RDF content type in its headers (such as Turtle, HTML, etc.), respond with 400.
  • In particular, images, videos, PDFs etc. must result in a 400.
  • The connection to the downstream server can and should be closed prematurely if the content type is not RDF.

首先定位 corsProxy 的實作及其要求處理測試；該 issue 未指定任何檔案或測試。驗證缺少 Origin 值或 Origin 值未獲授權時的行為，以及下游回應不包含 RDF 內容類型時的行為。完成的標準是這些情況回傳 400 或類似結果，同時允許的 RDF 回應繼續正常運作。