ci: fix link check for files.nordicsemi.com

Files.nordicsemi.com doesnt allow downloading just header
Escape characters on regex expression caused errors

Signed-off-by: Thomas Stilwell <[email protected]>

Author: thst-nordic

.github/workflows/compliance.yml

@@ -106,7 +106,7 @@ jobs:
     - name: Check added or updated links
       working-directory: ncs/nrf
       run: |
-        RE=".. _\`(.*)\`: (.*)"
+        RE='.. _`(.*)`: (.*)'
         LINKS=$(git diff --unified=0 "${{ github.event.pull_request.base.sha }}..HEAD" -- "doc/nrf/links.txt" | \
                 grep "^+" || true | \
                 grep -Ev "^(---|\+\+\+)" || true)
@@ -117,13 +117,18 @@ jobs:
             URL=${BASH_REMATCH[2]}
 
             echo -n "Checking URL for '$NAME' ($URL)... "
-            status=$(curl --write-out "%{http_code}" --output /dev/null --silent --head "$URL" || true)
+            if [[ "$URL" == *"files.nordicsemi.com"* ]]; then
+              # files.nordicsemi.com server does not allow downloading only headers
+              status=$(curl --write-out "%{http_code}" --output /dev/null --silent "$URL" || true)
+            else
+              status=$(curl --write-out "%{http_code}" --output /dev/null --silent --head "$URL" || true)
+            fi
 
             if [[ "$status" -ne 200 ]]; then
               echo "FAIL (HTTP code: ${status})"
-                exit 1
-              else
-                echo "OK"
-              fi
+              exit 1
+            else
+              echo "OK"
+            fi
           fi
         done <<< "$LINKS"