devServer proxy not returning content (when proxied response includes a `content-encoding` header)

[thescientist13]

Type of Change

Bug

Summary

Noticed as part of the v0.29.0 alpha release line that in the projects usingdevServer.proxy configuration, those proxied requests started not returning content anymore.

• https://github.com/AnalogStudiosRI/www.analogstudios.net/pull/89
• https://github.com/ContributaryCommunity/www.contributary.community/pull/124

An example endpoint trying to be proxied to is - https://www.contributary.community/api/topology

Details

Interestingly, I noticed the endpoint worked when using curl locally and bypassing the browser entirely.

curl -v localhost:1984/api/topology
*   Trying 127.0.0.1:1984...
* Connected to localhost (127.0.0.1) port 1984 (#0)
> GET /api/topology HTTP/1.1
> Host: localhost:1984
> User-Agent: curl/8.1.2
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: application/json
< age: 4057
< connection: keep-alive
< content-encoding: gzip
< date: Sat, 07 Oct 2023 14:46:16 GMT
< transfer-encoding: chunked
< vary: Accept-Encoding
< via: 1.1 c772176b119045d2ed52ef4f42db5fe0.cloudfront.net (CloudFront), 1.1 26ba6c8d559dffe51c3f7d9239642222.cloudfront.net (CloudFront)
< x-amz-apigw-id: Mb5QoFtVIAMFf6A=
< x-amz-cf-id: qI75WVTcNy_jlZbR83KTqGA8UenHavmQBUDlWJJHviRgxgIQiYltuw==
< x-amz-cf-pop: IAD79-C2, BOS50-P3
< x-amzn-requestid: b9587ddc-dead-4a24-8dbd-fd5e9db6c97e
< x-amzn-trace-id: Root=1-65216f36-4738a36b702d7cc40c57513c;Sampled=0;lineage=edc229bf:0
< x-cache: Hit from cloudfront
<
* Connection #0 to host localhost left intact
{"language":{"c":{"label":"C","projects":[{"name":"Git","type":"org","repositories":["*"]},{"name":"Torvalds","type":"user","repositories":[{"name":"linux"}]}]},"go":{"label":"Go","projects":[{"name":"evanw","type":"user","repositories":[{"name":"esbuild"}]},{"name":"Docker","type":"org","repositories":["*"]}]},"java":{"label":"Java","projects":[{"name":"JenkinsCI","type":"org","repositories":["*"]},{"name":"KenzanLabs","type":"org","repositories":["*"]},{"name":"Netflix","type":"org","repositories":["*"]}]},"javascript":{"label":"JavaScript","projects":[{"name":"Babel","type":"org","repositories":["*"]},{"name":"ContributaryCommunity","type":"org","repositories":["*"]},{"name":"DevelopIt","type":"user","repositories":["*"]},{"name":"expressjs","type":"org","repositories":["*"]},{"name":"Facebook","type":"org","repositories":["*"]},{"name":"GatsbyJS","type":"org","repositories":["*"]},{"name":"cutenode","type":"org","repositories":["*"]},{"name":"jamiebuilds","type":"user","repositories":["*"]},{"name":"Microsoft","type":"org","repositories":["*"]},{"name":"NodeJS","type":"org","repositories":["*"]},{"name":"npm","type":"org","repositories":["*"]},{"name":"open-wc","type":"org","repositories":["*"]},{"name":"PayPal","type":"org","repositories":["*"]},{"name":"Polymer","type":"org","repositories":["*"]},{"name":"ProjectEvergreen","type":"org","repositories":["*"]},{"name":"ProvidenceGeeks","type":"org","repositories":["*"]},{"name":"TheGreenhouseIO","type":"org","repositories":["*"]},{"name":"thescientist13","type":"user","repositories":[{"name":"copy-dots"},{"name":"gallinago"},{"name":"git-explorer"},{"name":"github-dashboard"}]},{"name":"VueJS","type":"org","repositories":["*"]},{"name":"webpack","type":"org","repositories":["*"]},{"name":"YarnPkg","type":"org","repositories":["*"]}]},"php":{"label":"PHP","projects":[{"name":"composer","type":"org","repositories":["*"]},{"name":"laravel","type":"org","repositories":["*"]}]},"python":{"label":"Python","projects":[{"name":"django","type":"org","repositories":["*"]},{"name":"python","type":"org","repositories":["*"]}]},"rust":{"label":"Rust","projects":[{"name":"entropic-dev","type":"org","repositories":["*"]},{"name":"swc-project","type":"org","repositories":["*"]}]}}}

I dug into the headers a bit and started filtering them out and noticed that the one that fixed was when omitting the content-encoding header

< content-encoding: gzip

Which makes sense, as we are processing the request server side first and returning the full body, so telling the client the response is encoded is probably making it think the browser needs to decode it, when it's not necessary.

---

Haven't quite pinpointed the exact release this broke on (given some periodic rebasing in the release branch, but it does seem to break on the v0.29.0-alpha.0 release which only had this change - https://github.com/ProjectEvergreen/greenwood/pull/1110