Update README Action in C#

Keep a profile README current with code you understand

This project is a custom Docker container GitHub Action written in C#. It reads recent activity from Medium and Stack Overflow, then replaces only the marked sections in a repository file such as README.md.

The goal was practical and educational: automate a repetitive profile-maintenance task while learning how a container action works from its inputs through to a committed file change.

A small, explicit workflow

Add markers to the file you want to maintain:

<!-- MEDIUM:START -->
<!-- MEDIUM:END -->

<!-- STACKOVERFLOW:START -->
<!-- STACKOVERFLOW:END -->

Then call the action from a workflow:

- name: Refresh recent activity
  uses: ferrywlto/update-readme-action-csharp@v1
  with:
    medium-user-id: ${{ secrets.MEDIUM_USER_ID }}
    stackoverflow-user-id: ${{ secrets.STACKOVERFLOW_USER_ID }}

The action accepts a custom target file through file-to-update, which defaults to README.md.

How it is built

• C# and .NET: load external activity and apply the replacement steps.
• Docker action: publish the .NET application inside the image that GitHub Actions runs.
• Content loaders: separate Medium and Stack Overflow retrieval from replacement logic.
• Marker-based updates: preserve everything outside the named start and end markers.

Adding another source follows the same path: create an IContentLoader, register it in the factory, and add a matching marker section to the target file.

Useful for

• Profile READMEs that show current writing and community activity.
• Repository documentation that includes a curated, generated activity section.
• Learning how a container-based GitHub Action receives inputs and edits a checked-out file.

The project is public and provides its implementation and usage instructions in the source repository.