akka/akka-http

Bug: Server responses with 431 when uri length exceeds headers length limit

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#2,472 opened on Mar 15, 2019

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Description

I use Akka = "2.5.19" and AkkaHttp = "10.1.7". server config:

akka {
  http {
    parsing {
      max-uri-length = 96k
      max-header-value-length = 16k
    }
  }
}

I need to send relatively long query(more than 16k (list of ~ 300-500 uuids)). I was getting 414 status code when akka.http.parsing.max-uri-length was 8k. To fix that I've increased value up to 96k and it partially solved problem. Now server responses with (431,HttpEntity.Strict(text/plain; charset=UTF-8,HTTP header value exceeds the configured limit of 16384 characters)) which seems weird cause I send only only Auth header with short String value. To fix that I've increased akka.http.parsing.max-header-value-length up to 32k. This change has solved issue but it looks like an Akka bug.

Contributor guide

Research direction
Investigate the HTTP request parsing code in Akka HTTP to find where the URI length is being counted towards the max header value length limit. Check the parsing of the request line and headers.
Tech stack
scala
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
ScalaAkka HTTP
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55