fix(http): don't force application/json on multipart uploads

[graycyrus]

Summary

RawClient::headers() sets a fixed Content-Type: application/json on every request. On post_multipart that overrode the multipart/form-data; boundary=… reqwest's .multipart(form) must set, so the backend JSON-parsed the multipart body and returned 500 "Unexpected token '-', \"--<boundary>\"... is not valid JSON". This broke all file uploads (OpenHuman storage_upload_file + the whole file→attachment chain).

Fix

Strip Content-Type in post_multipart before .multipart(form) so reqwest owns the multipart content-type. Scoped to the multipart path — every other verb is byte-identical, including body-less POSTs (teams, payments/stripe/portal, auth, channels) that rely on the shared application/json. (A cleaner refactor would move content-type entirely to the body methods, but that would drop the json type from those body-less POSTs — deferred to avoid regressions.)

Proof

Live against the (now-healthy) backend: a plain multipart curl → 200; the identical body with a forced Content-Type: application/json → the exact 500. Masked until now by the separately-fixed storage-bucket 500.

Tests

tests/multipart.rs (wiremock): asserts post_multipart sends a multipart/form-data content-type and NOT application/json, plus a no-regression check that a JSON POST still sends application/json. Full suite green.

Summary by CodeRabbit

• Bug Fixes
  • Fixed multipart uploads to send the correct multipart/form-data content type, including the required boundary.
  • Preserved application/json handling for standard JSON requests.
  • Improved reliability of multipart response processing.

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[coderabbitai]

📝 Walkthrough

Walkthrough

HttpClient::post_multipart now removes the shared JSON Content-Type header before sending multipart data. Tests verify multipart headers and confirm that regular JSON POST requests remain unchanged.

Changes

Multipart request handling

Layer / File(s)	Summary
Header handling and regression coverage src/lib.rs, tests/multipart.rs	post_multipart removes the JSON Content-Type header before applying multipart data. Tests verify the multipart content type, response parsing, and unchanged JSON POST behavior.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• tinyhumansai/sdk#8 — Directly addresses the duplicate JSON and multipart Content-Type problem in post_multipart.

Poem

A rabbit packed a form with care,
And sent it through the boundary air.
JSON stayed on its proper track,
Multipart headers no longer clash.
Hop, hop—clean requests arrive!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the multipart upload content-type fix.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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• Commit on current branch

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[coderabbitai]

🧹 Nitpick comments (1)

tests/multipart.rs (1)

59-66: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Complete the header-regression coverage.

Line 60 accepts multipart/form-data without a boundary= parameter. Assert the boundary parameter because the server needs it to parse the form.

Lines 83-106 send a JSON body. .json() can set application/json independently. Add a body-less RawClient::send(Method::POST, ..., None, ...) test that asserts application/json. This covers the preserved contract stated for body-less POST requests.

Also applies to: 83-106

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@tests/multipart.rs` around lines 59 - 66, Extend the multipart header
assertions near the existing content_type checks to require a boundary=
parameter in the multipart/form-data value. In the body-less POST coverage
around the JSON request in the test flow, add a RawClient::send(Method::POST,
..., None, ...) request and assert its response Content-Type is
application/json, preserving the existing multipart and JSON-body assertions.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@tests/multipart.rs`:
- Around line 59-66: Extend the multipart header assertions near the existing
content_type checks to require a boundary= parameter in the multipart/form-data
value. In the body-less POST coverage around the JSON request in the test flow,
add a RawClient::send(Method::POST, ..., None, ...) request and assert its
response Content-Type is application/json, preserving the existing multipart and
JSON-body assertions.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: ee72cddd-3ec3-409a-bf07-2df995f5f9d0

📥 Commits

Reviewing files that changed from the base of the PR and between 495be81 and a2f26f4.

📒 Files selected for processing (2)

• src/lib.rs
• tests/multipart.rs