Fixing overwrite Blob/File type as Content-Type in browser. (#1773)

[MitchLewis930]

PR_027

[greptile-apps]

Greptile Overview

Greptile Summary

Added logic to delete the Content-Type header when sending Blob or File objects that have a type property, allowing the browser to automatically set the correct MIME type based on the file's type property.

• Mirrors existing FormData handling pattern (lines 17-19)
• Prevents incorrect Content-Type header from overriding the file's natural MIME type
• Note: This exact change was previously reverted in PR Revert "Fixing overwrite Blob/File type as Content-Type in browser." axios/axios#3289 (commit 9a78465) - verify that the original revert reason has been addressed
• No tests included for this functionality

Confidence Score: 3/5

• This PR has moderate risk due to being a previously reverted change without clear documentation of what issue caused the original revert
• The code change itself is logical and mirrors the existing FormData pattern, but this exact change was reverted in PR Revert "Fixing overwrite Blob/File type as Content-Type in browser." axios/axios#3289. Without understanding why it was reverted or what has changed to make it safe now, there's uncertainty about potential edge cases or breaking changes
• No files require special attention beyond verifying the historical revert reason

Important Files Changed

Filename	Overview
lib/adapters/xhr.js	Added Content-Type header deletion for Blob/File objects with type property to allow browser to set correct MIME type

Sequence Diagram

sequenceDiagram
    participant User
    participant axios
    participant xhrAdapter
    participant Browser
    participant Server

    User->>axios: Send request with Blob/File data
    axios->>xhrAdapter: xhrAdapter(config)
    xhrAdapter->>xhrAdapter: Check if data is FormData
    alt data is FormData
        xhrAdapter->>xhrAdapter: Delete Content-Type header
    end
    xhrAdapter->>xhrAdapter: Check if data is Blob/File with type property
    alt data is Blob/File AND has type property
        xhrAdapter->>xhrAdapter: Delete Content-Type header
    end
    xhrAdapter->>Browser: Create XMLHttpRequest
    xhrAdapter->>Browser: Set headers (excluding Content-Type if deleted)
    Browser->>Browser: Automatically set Content-Type from Blob.type
    Browser->>Server: Send XHR with correct Content-Type
    Server-->>Browser: Response
    Browser-->>xhrAdapter: Response data
    xhrAdapter-->>axios: Resolved Promise
    axios-->>User: Response

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