[FIX] Save and serve files with correct Content-Type

[kwerie]

Description

PDFs were served with application/octet-stream, causing Chromium-based browsers to download them instead of opening them in a new tab. Add application/pdf to the MIME type mapping so PDFs are served with the correct Content-Type header.

Also when saving files to an S3 bucket, the content type wasn't being set.

Breaking changes

No

Screenshots

N/A

Checklist

📌 Always:

• I have set a clear title
• My PR is small and contains a single feature
• I have checked my own PR

👍 Most of the time:

• I have added or updated test cases
• I have updated the README if needed

Fixes #4403

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Project	Deployment	Actions	Updated (UTC)
vendure-storybook	Ready	Preview, Comment	Mar 25, 2026 9:18am

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

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Run ID: 6f542874-9a66-435d-9b22-494f4aabfa7f

📥 Commits

Reviewing files that changed from the base of the PR and between 4f8cc9d and 388f85e.

📒 Files selected for processing (1)

• packages/asset-server-plugin/src/asset-server.ts

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📝 Walkthrough

Walkthrough

Adds PDF MIME-type handling to the asset-server-plugin: getMimeType now returns application/pdf for .pdf files. The plugin dependency list includes mime-types, and S3 uploads set ContentType using mime.lookup(fileName) || 'application/octet-stream'. The end-to-end tests were extended to upload test.pdf and assert the MIME type is application/pdf.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: fixing Content-Type headers for file serving, particularly for PDFs.
Description check	✅ Passed	The description covers the main problem, solution, breaking changes status, and relevant checklist items per the template requirements.
Linked Issues check	✅ Passed	The PR implementation fully addresses both requirements from #4403: PDF MIME type mapping added and S3 content type handling implemented with tests.
Out of Scope Changes check	✅ Passed	All changes directly support the stated objectives of fixing PDF Content-Type handling and S3 uploads; no out-of-scope modifications detected.

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[biggamesmallworld]

Great fix! The S3 ContentType addition is a valuable improvement beyond just the serving-side fix. Thanks for the contribution.