reusable-deploy-web-gh-pages.yml

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#         About
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# Reuseable workflow to be called from content repos.
# Build and deploy app to github pages
#
#         Version : 1.0
#
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#         Configuration
# Must enable github pages in settings, e.g.
# https://github.com/{org}/{repo}/settings/pages
# 
# Variables
# 
# GH_PAGES_BASE - url path that pages deployed to.
# If using gh pages domain should be name of repo for page to display at
# https://{org}.github.io/{repo}, e.g. 'my-repo'
# 
# If using a custom domain or subdomain can leave use folder name if deployed
# to a child path, e.g. https://my-domain.com/app, or leave blank if not using
# child folder, e.g. https://my-domain.com
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#         Main Code
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name: Deploy Web GH Pages
# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
concurrency:
  group: "deploy_web_gh_pages"
  cancel-in-progress: true

on:
  workflow_call:
    inputs:
      GH_PAGES_BASE:
        description: 'URL prefix used when deploying to folder path, e.g. /my-repo-name'
        default: ${{vars.GH_PAGES_BASE || ''}}
        required: false
        type: string
      

jobs:
  build:
    uses: ./.github/workflows/reusable-app-build.yml
    secrets: inherit
    with: 
      # If base url provided pass to build command with both initial and trailing '/', i.e. /my-repo/
      # https://stackoverflow.com/a/54409380
      build-flags: ${{inputs.GH_PAGES_BASE && format('--base-href /{0}/',inputs.GH_PAGES_BASE) }}

  # Github pages doesn't support single-page-apps, so use post-build to add 404 workaround
  # https://github.com/isaacs/github/issues/408
  # https://github.com/orgs/community/discussions/64096
  # TODO - could consider populating individual files for all known template paths (for better SEO)
  post_build:
    needs: build
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Download Build Artifact
        uses: actions/download-artifact@v4
        with:
          name: www
      - name: Extract Build folder
        run: |
          mkdir www
          tar -xf artifact.tar --directory www
      - name: Add fallback redirect
        run: |
          cp www/index.html www/404.html
      - name: Upload updated artifact
        uses: actions/upload-pages-artifact@v3
        with:
          path: "www/"        

  deploy:
    needs: post_build
    permissions:
      pages: write     
      id-token: write
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}
    runs-on: ubuntu-latest
    outputs:
      urls: ${{ steps.deploy.outputs.urls }}
    steps:
      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v4

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#         Useful Links
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# https://github.com/marketplace/actions/deploy-github-pages-site