Check the shape of FTP_SERVER before handing it to the FTP client (#15)

Check the shape of FTP_SERVER before handing it to the FTP client

Author: niteeshkanna-sh

.github/workflows/deploy-admin.yml

@@ -81,6 +81,50 @@ jobs:
               ;;
           esac
 
+          # FTP_SERVER is a bare host -- an IP or a hostname -- and nothing
+          # else. hPanel displays it as ftp://1.2.3.4, and pasting that whole
+          # string makes the FTP client look up a *hostname* of "ftp://1.2.3.4",
+          # which fails as ENOTFOUND: an error that reads like the server is
+          # missing rather than like the value has a prefix on it.
+          #
+          # Nothing below prints the value. This repository is public, so the
+          # logs are public; only derived facts are reported, never the secret
+          # or anything that reconstructs it.
+          bad=0
+          case "$FTP_SERVER" in
+            *://*)  echo "::error::FTP_SERVER contains '://'. Remove the ftp:// prefix -- just the host."; bad=1 ;;
+          esac
+          case "$FTP_SERVER" in
+            */*)    echo "::error::FTP_SERVER contains '/'. It is a host, not a URL or a path."; bad=1 ;;
+          esac
+          case "$FTP_SERVER" in
+            *:*)    echo "::error::FTP_SERVER contains ':'. Drop the port -- 21 is the default."; bad=1 ;;
+          esac
+          case "$FTP_SERVER" in
+            *[[:space:]]*) echo "::error::FTP_SERVER contains a space. A trailing space survives a paste and breaks the lookup."; bad=1 ;;
+          esac
+
+          echo "FTP_SERVER length: ${#FTP_SERVER} characters"
+          echo "(a bare IPv4 address is 7 to 15 characters)"
+
+          # Only hostnames get the lookup. An IP literal needs no DNS, and
+          # checking one with getent is a reverse lookup that fails whenever
+          # the address has no PTR record -- which is normal for shared
+          # hosting, so it would reject the correct value.
+          if [ "$bad" -eq 0 ]; then
+            if echo "$FTP_SERVER" | grep -Eq '^[0-9]{1,3}(\.[0-9]{1,3}){3}$'; then
+              echo "FTP_SERVER is an IP address; no lookup needed."
+            elif getent hosts "$FTP_SERVER" >/dev/null 2>&1; then
+              echo "FTP_SERVER resolves."
+            else
+              echo "::error::FTP_SERVER is neither an IP address nor a hostname DNS knows about."
+              echo "Check it against hPanel -> Files -> FTP Accounts."
+              bad=1
+            fi
+          fi
+
+          [ "$bad" -eq 0 ] || exit 1
+
       - name: Deploy over FTPS
         uses: SamKirkland/FTP-Deploy-Action@v4.3.5
         with: