Limit on GET request size in Phoenix

cmkarlsson · January 25, 2022, 2:55am

I think this is a property of cowboy: max_request_line_length.

It defaults to 8000 but to change it you can do it like this:

http: [protocol_options: [max_request_line_length: 10_000]]

Reference:

github.com/phoenixframework/phoenix

414 returned for large query string

opened 10:23PM - 15 Apr 21 UTC

closed 06:41AM - 19 Apr 21 UTC

acco

### Environment * Elixir version (elixir -v): 1.11.3 * Phoenix version (mix …deps): 1.5.8 * Operating system: macOS Big Sur 11.1 ### Expected behavior When making a `curl` request with a large query string (>10,000 bytes), the request succeeds. ### Actual behavior Request fails with: ``` > Host: localhost:4000 > User-Agent: curl/7.64.1 > Accept: */* > < HTTP/1.1 414 Request-URI Too Long < connection: close < content-length: 0 < * Closing connection 0 ``` I thought this may have been happening in `Plug.Parsers.fetch_query_params/x` but (a) that function has a default limit of 1M bytes and (b) I can prove that function is never called. I made [this example repo](https://github.com/acco/hit414/blob/master/lib/hit414_web/endpoint.ex#L2-L20) where the first plug called in `Endpoint` prints a "HERE" and halts. Alas, the response is the same (414) and there is no indication that this plug is invoked. Therefore, I have reason to suspect the 414 is coming higher up in the chain.