Add MIME Type for .msg

[rd-botan-kansiray]

Add MIME Type for .msg

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Add msg extension to list of files used by static file middleware.

Description

Adds support for the .msg file extension (used for Outlook email files) to the FileExtensionContentTypeProvider in the Microsoft.AspNetCore.StaticFiles package. The MIME type application/vnd.ms-outlook is now returned when .msg files are encountered.

This improves developer experience by eliminating the need to manually add this mapping in every project that handles .msg files.

Fixes #63019

[Copilot]

Pull Request Overview

This PR adds MIME type support for .msg files (Outlook email files) to ASP.NET Core's static file middleware by mapping the .msg extension to the "application/vnd.ms-outlook" MIME type.

• Adds .msg extension mapping to FileExtensionContentTypeProvider in StaticFiles middleware
• Adds .msg extension mapping to FileExtensionContentTypeProvider in WebView component
• Improves developer experience by eliminating manual MIME type configuration for .msg files

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/Middleware/StaticFiles/src/FileExtensionContentTypeProvider.cs	Adds .msg extension mapping to static files MIME type provider
src/Components/WebView/WebView/src/FileExtensionContentTypeProvider.cs	Adds .msg extension mapping to WebView MIME type provider

Comments suppressed due to low confidence (2)

src/Middleware/StaticFiles/src/FileExtensionContentTypeProvider.cs:196

• The new .msg MIME type mapping lacks test coverage. Consider adding a unit test to verify that the .msg extension correctly maps to 'application/vnd.ms-outlook'.

                { ".msg", "application/vnd.ms-outlook" },

src/Components/WebView/WebView/src/FileExtensionContentTypeProvider.cs:202

• The new .msg MIME type mapping lacks test coverage. Consider adding a unit test to verify that the .msg extension correctly maps to 'application/vnd.ms-outlook'.

                { ".msg", "application/vnd.ms-outlook" },

[rd-botan-kansiray]

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[BrennanConroy]

Thanks for the contribution, but this is not something we will be pursuing. See the issue.