fix(api,imports): force parameter-free Content-Type on multipart file part

[dgilperez]

Caught during a live smoke test of imports preflight --file against a real Sure instance: the upload was rejected with

{"error":"invalid_file_type","message":"Invalid file type. Please upload a CSV file."}

…even though Sure's Import::ALLOWED_CSV_MIME_TYPES accepts text/csv, text/plain, application/vnd.ms-excel, application/csv.

Root cause

resty's default SetFile uses Go's http.DetectContentType on the first 512 bytes. For an ASCII CSV that returns **text/plain; charset=utf-8\**. Sure does an exact-match include?` on the allow-list, so the charset suffix breaks the check.

Confirmed with an httptest probe:

field=file filename=test-import.csv content-type=text/plain; charset=utf-8

--raw-file-content was a workaround (different code path; server picks the type from the controller's hardcoded "import.csv" filename).

Fix

Layer	Change
internal/api/client.go	PostMultipart gains a fileContentType string param. When non-empty it switches from SetFile to SetMultipartField, setting the Content-Type on the file part explicitly. Empty preserves prior detection behavior.
cmd/sure-cli/root/imports_cmd.go	New mimeForImportFile(path) helper maps extensions to parameter-free MIME types: .csv → text/csv, .ndjson → application/x-ndjson, .json → application/json, other → "".
imports create + imports preflight	Thread the computed type through.

Tests

• TestClient_PostMultipart_ExplicitContentType captures the file part's Content-Type header via httptest and asserts it equals text/csv when passed explicitly. Locks the fix in.
• TestClient_PostMultipart_DefaultContentType confirms "" preserves resty's auto-detection (non-empty value, prior behavior).
• Existing TestClient_PostMultipart updated to the new signature.
• TestMimeForImportFile unit-tests the extension→MIME map across case-insensitive matches, absolute paths, unknown extensions.

go test ./... -race green across the suite.

Live verification

Before (against live Sure): 422 invalid_file_type.

After:

{
  "data": {
    "data": {
      "content": {
        "byte_size": 41,
        "content_type": "text/csv",
        "filename": "test-import.csv"
      },
      "errors": [],
      "headers": ["Date", "Name", "Amount"],
      "valid": true,
      ...

Scope

5 files, +154/-7. Caller signature change is contained — only imports_cmd.go and imports_preflight_cmd.go use PostMultipart.

Refs the post-merge smoke test against sure.h.dgilperez.com.

Summary by CodeRabbit

• Improvements

  • Imports now explicitly specify content-type headers based on file extension (.csv, .ndjson, .json) for improved reliability and compatibility.

• Tests

  • Expanded test coverage for multipart upload content-type handling to ensure consistent behavior across formats.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 9c084542-e1ab-473c-ab43-8a3c5d41a094

📥 Commits

Reviewing files that changed from the base of the PR and between 8eb3455 and 9c8d4b7.

📒 Files selected for processing (5)

• cmd/sure-cli/root/imports_cmd.go
• cmd/sure-cli/root/imports_preflight_cmd.go
• cmd/sure-cli/root/imports_preflight_cmd_test.go
• internal/api/client.go
• internal/api/client_test.go

---

📝 Walkthrough

Walkthrough

CLI import commands now send multipart uploads with explicit MIME types derived from file extensions. A new mimeForImportFile helper selects appropriate types for CSV, NDJSON, and JSON files. The Client.PostMultipart API is extended to accept an optional fileContentType parameter that, when provided, instructs the client to use SetMultipartField with explicit content-type instead of relying on resty's default detection.

Changes

Explicit MIME type handling for multipart imports

Layer / File(s)	Summary
MIME type resolution helper cmd/sure-cli/root/imports_cmd.go, cmd/sure-cli/root/imports_preflight_cmd_test.go	New mimeForImportFile function returns parameter-free MIME types for .csv, .ndjson, .json extensions with case-insensitive matching and absolute-path handling; empty string fallback for unknown extensions. Tests verify extension resolution and edge cases.
Client.PostMultipart API extension internal/api/client.go, internal/api/client_test.go	Client.PostMultipart signature extended with fileContentType parameter. When non-empty, client opens file and uses SetMultipartField with explicit Content-Type; when empty, falls back to SetFile for default behavior. New tests verify explicit and default content-type handling.
CLI command integration cmd/sure-cli/root/imports_cmd.go, cmd/sure-cli/root/imports_preflight_cmd.go	Both imports create and imports preflight commands updated to compute and pass explicit MIME type from file path to PostMultipart, replacing reliance on resty's default multipart detection.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• we-promise/sure-cli#2: Both PRs modify the same import/multipart upload flow—adding imports CLI support and the Client.PostMultipart helper—and this PR further extends PostMultipart/imports preflight to set explicit multipart Content-Type based on file extension, so they are directly connected.

Suggested labels

codex

Poem

🐰 A rabbit hops through file uploads bright,
Specifying MIME types with delight—
No guessing games from resty's detection,
Just explicit types in every direction,
CSV, NDJSON, JSON take flight! 🎉

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/imports-multipart-content-type

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[dgilperez]

@jjmata hey, I think this PR is the last of the bunch - I tested the cli a bit against my local sure and all seems to work as expected. I think it's time to release 0.2.0, but you probably want to do that yourself?

[jjmata]

@jjmata hey, I think this PR is the last of the bunch - I tested the cli a bit against my local sure and all seems to work as expected. I think it's time to release 0.2.0, but you probably want to do that yourself?

Sure, but would love @JSONbored to give this a go as well before we cut a new CLI release. Can you do that? 🙏