test: add multipart/form-data rerouting regression coverage for #714 by rodri-oliveira-dev · Pull Request #2421 · ThreeMammals/Ocelot

rodri-oliveira-dev · 2026-08-31T17:18:05Z

Closes #714

Multipart/form-data is not rerouted (error 404) #714

Summary

Adds regression coverage and a real browser sample for #714 against the current develop branch.

The original issue reported that multipart/form-data requests containing a file returned 404 instead of being rerouted. After validating the current request pipeline, the original issue is no longer reproducible for regular, non-aggregated routes: Ocelot streams the raw request body and preserves the original Content-Type, including the multipart boundary.

No production-code change under src/ is required for the regular rerouting scenario. This PR documents and protects that behavior.

Coverage added

Acceptance coverage that reroutes POST /upload to /api/files using multipart/form-data
Verifies that the downstream route is reached successfully
Verifies the downstream path
Verifies the multipart Content-Type and boundary
Verifies a regular form field
Verifies the file field name, original filename, file content type, and exact file contents
Unit coverage for RequestMapper confirming that the multipart body and Content-Type boundary are preserved unchanged
Unit coverage for the multiplexer context clone confirming that a cloned multipart request body can still be read as form data without copying Request.Form

Real sample

Adds samples/MultipartFormData with two small apps:

ApiGateway: serves a valid HTML page containing a real enctype="multipart/form-data" form with a text field and file input, then forwards POST /upload through Ocelot
DownstreamService: handles POST /api/files, reads the request using ReadFormAsync, and returns the received form field, file metadata, file contents, and request content type

The sample README includes the run instructions and uses only the existing ASP.NET Core/Ocelot project setup.

Review follow-up

The one-test constants in the acceptance test were moved to local variables and passed into helpers where needed.
The requested real sample/browser form scenario was added with an actual HTML upload page.
I reviewed the Form = from.Form idea from Add 'multipart/form-data' support for file uploads #1372. It was not technically necessary for this PR: the regular route works through the existing raw-body streaming path, and the multiplexer clone can read multipart form data from the cloned body plus copied content headers. Therefore this PR intentionally does not add Form = from.Form.
POST aggregation/multiplexing support remains out of scope and should be treated as a future feature/design discussion.

Validation

Validated locally with .NET SDK 10.0.400:

dotnet restore Ocelot.slnx passed
dotnet restore Ocelot.Samples.slnx passed, with existing ServiceFabric/Steeltoe dependency warnings outside this PR
dotnet build Ocelot.slnx --no-restore passed with 0 warnings/errors
dotnet build Ocelot.Samples.slnx --no-restore passed, with the same existing ServiceFabric/Steeltoe warnings
dotnet format Ocelot.slnx --no-restore --verify-no-changes --include acceptance/Request/MultipartFormDataTests.cs unit/Multiplexing/MultiplexingMiddlewareTests.cs unit/Request/Mapper/RequestMapperTests.cs passed
dotnet format Ocelot.Samples.slnx --no-restore --verify-no-changes --include samples/MultipartFormData/ApiGateway/Program.cs samples/MultipartFormData/DownstreamService/Program.cs passed
Issue Multipart/form-data is not rerouted (error 404) #714 unit tests passed on net8.0 and net10.0
Issue Multipart/form-data is not rerouted (error 404) #714 acceptance test passed on net8.0 and net10.0
Full unit suite passed on net8.0 and net10.0 with --culture invariant (1901 passed per TFM)
Full acceptance suite on net10.0 was run; it had one unrelated ClientWebSocketTests.Http20ClientWhenDirectConnectionThenShouldConnect HTTP/2 WebSocket timeout. Rerunning the suite excluding only that test passed (358 passed, 3 skipped).
The new sample was run manually: GET http://localhost:5567/ returned 200, and a real multipart POST /upload through the gateway returned 200 with the expected text field, file metadata, exact file contents, and multipart boundary received downstream.

Local note: net9.0 builds successfully, but the .NET 9 runtime is not installed in this environment, so local test execution was limited to net8.0 and net10.0.

Production impact

No production files under src/ are changed.

The current implementation already supports the regular multipart/form-data rerouting scenario, so this PR adds regression coverage and a real executable sample to prevent that behavior from being unintentionally broken in the future.

Refs #714

codecov · 2026-08-31T17:22:19Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.69%. Comparing base (c279f81) to head (ac52775).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2421      +/-   ##
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+ Coverage    95.55%   95.69%   +0.14%     
===========================================
  Files          264      264              
  Lines         6970     6970              
  Branches       761      761              
===========================================
+ Hits          6660     6670      +10     
+ Misses         201      193       -8     
+ Partials       109      107       -2

Flag	Coverage Δ
unit	`95.69% <ø> (+0.14%)`	⬆️

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see 1 file with indirect coverage changes

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coveralls · 2026-08-31T17:23:02Z

coverage: 97.231% (+0.1%) from 97.116% — rodri-oliveira-dev:test/issue-714-multipart-regression into ThreeMammals:develop

raman-m

Production impact

No production files under src/ are changed.

The current implementation already supports the regular multipart/form-data rerouting scenario, so this PR only adds regression coverage to prevent that behavior from being unintentionally broken in the future.

Refs #714

I'm going to change the requirements. I can't approve this without real improvements.
We need to test it using a sample or via a browser test with an actual HTML page.

raman-m · 2026-09-02T10:53:53Z

Scope

This PR intentionally covers the regular, non-aggregated routing scenario discussed in #714.

Aggregated routes using POST/multiplexing are intentionally out of scope.

As discussed in the issue, aggregation currently has additional constraints around POST requests and raises a broader design question about combining potentially heterogeneous downstream responses such as JSON, XML, HTML, headers/status-only responses, or other payload types.

That scenario should therefore be treated separately from the regular multipart rerouting behavior validated by this PR.

Agreed. This could become a future feature proposal. I'll develop the concept further and probably create an official feature issue during the current release. In cooperation with you or without.

rodri-oliveira-dev · 2026-09-02T13:49:23Z

Thanks, @raman-m. I added the requested real sample in samples/MultipartFormData.

It now includes an actual HTML page served by the gateway with enctype="multipart/form-data", a text field, and a file input. The form posts to POST /upload, Ocelot forwards it to /api/files, and the downstream service reads the request with ReadFormAsync and returns the received field, file metadata, file contents, and multipart content type.

I kept the automated regression coverage as well: the acceptance test validates the forwarded form field, file field name, filename, file content type, exact file contents, downstream path, and multipart boundary; the unit tests cover RequestMapper raw body/content type preservation and the multiplexer clone behavior.

I also reviewed the Form = from.Form idea from #1372. I did not add it because it was not technically necessary for this PR: regular routing already works through the raw body streaming path, and the cloned multiplexer request can parse multipart data from the copied body plus content headers. POST aggregation/multiplexing remains out of scope for this PR.

Validation passed locally for restore/build, sample build, formatting checks, issue #714 unit/acceptance tests on net8/net10, full unit suite on net8/net10 with invariant culture, and full net10 acceptance suite when excluding only the unrelated HTTP/2 WebSocket direct-connection timeout.

…ot.Testing v25.0.1

rodri-oliveira-dev added 9 commits August 31, 2026 13:50

test: validate multipart form-data routing for ThreeMammals#714

d8e1371

ci: validate multipart routing for ThreeMammals#714

fb3a698

test: cover multipart rerouting for ThreeMammals#714

b7c65d0

chore: remove temporary issue 714 workflow

80ecab1

test: preserve multipart boundary and body for ThreeMammals#714

f00d36f

ci: add temporary build and test workflow for ThreeMammals#714

350df32

test: capture mapped downstream path for ThreeMammals#714

ca3f67d

ci: isolate issue 714 acceptance validation

84d6867

chore: remove temporary issue 714 validation workflow

a420e90

rodri-oliveira-dev marked this pull request as ready for review August 31, 2026 17:54

rodri-oliveira-dev mentioned this pull request Aug 31, 2026

Multipart/form-data is not rerouted (error 404) #714

Open

raman-m self-requested a review September 2, 2026 10:29

raman-m assigned rodri-oliveira-dev and raman-m Sep 2, 2026

raman-m added Core Ocelot Core related or system upgrade (not a public feature) Autumn'26 Autumn 2026 release Requester Ocelot feature: Requester labels Sep 2, 2026

raman-m added this to the Autumn'26 milestone Sep 2, 2026

raman-m requested changes Sep 2, 2026

View reviewed changes

Comment thread acceptance/Request/MultipartFormDataTests.cs Outdated

test: harden multipart form regression coverage

4f8d471

rodri-oliveira-dev and others added 3 commits September 3, 2026 12:24

Merge branch 'develop' into test/issue-714-multipart-regression

4f25488

Ref SDK 10.0.401 (Runtime 10.0.12) to release Ocelot v25.0.1 and Ocel…

dd276d4

…ot.Testing v25.0.1

Merge branch 'develop' into test/issue-714-multipart-regression

1fca0ec

raman-m force-pushed the develop branch from dd276d4 to 7ae5de3 Compare September 14, 2026 21:15

raman-m and others added 2 commits September 15, 2026 17:14

Merge branch 'develop' into test/issue-714-multipart-regression

d0c4df0

Merge branch 'develop' into test/issue-714-multipart-regression

ac52775

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test: add multipart/form-data rerouting regression coverage for #714 - #2421

test: add multipart/form-data rerouting regression coverage for #714#2421
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rodri-oliveira-dev commented Aug 31, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Closes #714

Summary

Coverage added

Real sample

Review follow-up

Validation

Production impact

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