broken-link-checker.yml

name: Check for Broken Links
on: [push, pull_request]
jobs:
  build_and_check:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v2

      - name: Install Node.js
        uses: actions/setup-node@v2
        with:
          node-version: 16

      - name: Install dependencies
        run: yarn install

      - name: Build website
        run: yarn build

      - name: Setup Simple HTTP Server
        run: |
          nohup yarn start &

      - name: Check HTTP Server status
        run: sleep 5 && curl -I http://127.0.0.1:8080

      - name: Install Broken Link Checker
        run: npm install -g broken-link-checker

      - name: Execute Link Checker and Show Broken Links
        env:
          TEMPORARY_WEBSITE_URL: "http://127.0.0.1:8080"
          ACTUAL_WEBSITE_URL: "https://ddmal.music.mcgill.ca/Neon"
        run: |
          output=$(blc $TEMPORARY_WEBSITE_URL --filter-level=3 | \
            grep -v -E '├───OK───|└───OK───' | \
            awk '
              BEGIN {
                p=1;
                buf=""
              }

              # The logic between the following two statements ensures lines started with "Getting links from:"
              # and immediately followed by a line starting with "Finished!" and containing "0 broken" get removed
              /^Getting links from:/ {
                buf=$0;
                next
              }
              /^Finished!.*0 broken\./ {
                if (length(buf)>0) {
                  buf="";
                  next
                }
              }

              {
                if(length(buf)>0)
                  print buf;
                if (NF > 0) # ensures only lines with non-zero fields are printed
                  print;
                buf=""
              }

              # Printing an empty line after any single "Finished!" keyword to separate the outputs
              /^Finished!/ {
                print ""
              }
            ' | sed "s|$TEMPORARY_WEBSITE_URL|$ACTUAL_WEBSITE_URL|g")

          echo "$output"

          # Fail the github actions only if there's a single HTTP 404 found
          echo "$output" | grep -Eq 'HTTP_4[0-9]{2}' && flag=1

          if [ "$flag" -eq "1" ]; then
            echo "Broken links were found, exiting with an error."
            exit 1
          else
            echo "No broken links were found (although there may be other HTTP errors - check above), exiting successfully."
            exit 0
          fi