Check for 404 redirect URLs

.github/scripts/find_redirect_404s.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+# Takes a list of docs.substrate.io URLs from the netlify _redirects file,
+# and checks which of them return 404 response code after following redirects.
+
+# Check if curl is installed
+if ! command -v curl &> /dev/null; then
+    echo "::error::Error: curl is required but not installed"
+    exit 1
+fi
+
+# Check if input file is provided
+if [ "$#" -ne 1 ]; then
+    echo "::error::Usage: $0 <url_list_file>"
+    echo "::error::url_list_file: Invalid number of arguments"
+    exit 1
+fi
+
+input_file="$1"
+
+# Check if input file exists
+if [ ! -f "$input_file" ]; then
+    echo "::error::Error: File '$input_file' not found"
+    exit 1
+fi
+
+# Process each URL
+echo "::warning::The following polkadot.com URLs are missing:"
+while IFS= read -r line || [ -n "$line" ]; do
+    # Skip empty lines
+    [ -z "$line" ] && continue
+
+    # Extract path and destination
+    path=$(echo "$line" | awk '{print $1}' | xargs)
+    destination=$(echo "$line" | awk '{print $2}' | xargs)
+    source_url="https://docs.substrate.io${path}"
+
+    # Get HTTP response code with timeout, following redirects
+    response=$(curl -L -o /dev/null -s -w "%{http_code}" -m 10 "$destination")
+
+    if [ "$response" = "404" ]; then
+        echo "::warning::$destination"
+    fi
+done < "$input_file"

.github/workflows/404_redirect_checker.yml

@@ -0,0 +1,25 @@
+---
+name: Check Redirect 404s
+
+on:
+  push:
+  workflow_dispatch:
+    inputs:
+      redirect_file:
+        description: 'Redirect file to check'
+        required: true
+        type: string
+        default: '.github/scripts/polkadot_com_redirects'
+  schedule:
+    - cron: '0 14 * * 1'  # Every Monday at 2pm UTC
+
+jobs:
+  check-redirects:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Run redirect checker
+        run: .github/scripts/find_redirect_404s.sh .netlify/_redirects