preview website on PR

from JuliaPluto/computational-thinking-template#11

.github/workflows/ExportNotebooks.yml

@@ -57,9 +57,21 @@ jobs:
                 mv _site www/Fall23
                 mv extra_outputs/* www
 
-            - name: 🚀 Deploy to GitHub Pages
+            - name: 🚀 Deploy to GitHub Pages (main)
+              if: github.event_name == 'push' && github.ref == 'refs/heads/main'
               uses: JamesIves/github-pages-deploy-action@releases/v3
               with:
-                  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-                  BRANCH: output
-                  FOLDER: www
+                GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+                BRANCH: output
+                FOLDER: www
+                CLEAN_EXCLUDE: |
+                  previews/*
+    
+            - name: Deploy PR preview
+              if: github.event_name == 'pull_request' && github.repository == github.event.pull_request.head.repo.full_name # if this build is a PR build and the PR is NOT from a fork
+              uses: JamesIves/github-pages-deploy-action@releases/v3
+              with:
+                GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+                BRANCH: output
+                FOLDER: www
+                TARGET_FOLDER: "previews/PR${{ github.event.number }}" # The website preview is going to be stored in the previews subfolder

.github/workflows/PRCleanup.yml

@@ -0,0 +1,29 @@
+# from https://github.com/CliMA/ClimaTimeSteppers.jl
+# and  https://github.com/JuliaPluto/computational-thinking-template
+
+name: Site Preview Cleanup
+
+on:
+  pull_request:
+    types: [closed]
+
+jobs:
+  doc-preview-cleanup:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout gh-pages branch
+        uses: actions/checkout@v2
+        with:
+          ref: output
+      - name: Delete preview and history + push changes
+        run: |
+            if [ -d "previews/PR$PRNUM" ]; then
+              git config user.name "Documenter.jl"
+              git config user.email "[email protected]"
+              git rm -rf "previews/PR$PRNUM"
+              git commit -m "delete preview"
+              git branch output-new $(echo "delete history" | git commit-tree HEAD^{tree})
+              git push --force origin output-new:output
+            fi
+        env:
+            PRNUM: ${{ github.event.number }}

.github/workflows/PRComment.yml

@@ -0,0 +1,14 @@
+name: PR Comment # Write a comment in the PR with a link to the preview of the given website
+ on:
+   pull_request:
+     types: [opened, reopened]
+ jobs:
+   pr_comment:
+     runs-on: ubuntu-latest
+     steps:
+       - name: Create PR comment
+         if: github.event_name == 'pull_request' && github.repository == github.event.pull_request.head.repo.full_name # if this is a pull request build AND the pull request is NOT made from a fork
+         uses: thollander/actions-comment-pull-request@71efef56b184328c7ef1f213577c3a90edaa4aff
+         with:
+           message: 'Once the build has completed, you can preview your PR at this URL: https://${{ github.event.pull_request.base.repo.owner.login }}.github.io/${{ github.event.pull_request.base.repo.name }}/previews/PR${{ github.event.number }}/'
+           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}