golang/go

net/http: FileServer: Content-Length is not set when Content-Encoding was set

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#66,735 opened on Apr 9, 2024

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Description

Go version

go version go1.22.2 darwin/arm64

Output of go env in your module/workspace:

N/A

What did you do?

I am trying to set Content-Encoding for .br brotli compressed files with http.FileServer.

This code then skips setting Content-Length because Content-Encoding is set: https://github.com/golang/go/blob/9f13665088012298146c573bc2a7255b1caf2750/src/net/http/fs.go#L377

This causes my httptest to fail with an empty Content-Length, as well as other cases where I call ServeHTTP without using the full http client: https://go.dev/play/p/2UvgBSH8FWx

When using http.Get it works correctly, so the client must be filling in the Content-Length: https://go.dev/play/p/xp08V07UrtQ

What did you see happen?

The content-length header is not set when the content-encoding header is set.

What did you expect to see?

I expect the content-length header to be set even if the content-encoding header is set.

Contributor guide

Research direction
Investigate the HTTP specification (RFC 7230) regarding Content Length and Content Encoding. Examine the net/http/fs.go code around line 377 to understand why Content Length is skipped when Content Encoding is set. Determine if the current behavior is a bug or intentional, and propose a fix to set Content Length even when Content Encoding is present.
Tech stack
go
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GoHTTP
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65