l go: import shortener via htgen

lass/2configs/go.nix

@@ -15,5 +15,67 @@
       ];
     };
   };
+  krebs.htgen.go = {
+    port = 3333;
+    script = ''. ${pkgs.writeDash "go" ''
+      find_item() {
+        if test ''${#1} -ge 7; then
+          set -- "$(find "$STATEDIR/items" -mindepth 1 -maxdepth 1 \
+              -regex "$STATEDIR/items/$1[0-9A-Za-z]*$")"
+          if test -n "$1" && test $(echo "$1" | wc -l) = 1; then
+            echo "$1"
+            return 0
+          fi
+        fi
+        return 1
+      }
+
+      STATEDIR=$HOME
+      mkdir -p $STATEDIR/items
+
+      case "$Method $Request_URI" in
+        "GET /"*)
+          if item=$(find_item ''${Request_URI#/}); then
+            uri=$(cat "$item")
+            printf 'HTTP/1.1 302 Found\r\n'
+            printf 'Content-Type: text/plain\r\n'
+            printf 'Connection: closed\r\n'
+            printf 'Location: %s\r\n' "$uri"
+            printf '\r\n'
+            exit
+          fi
+        ;;
+        "POST /") #{ "uri": "http://nixos.org" }
+          uri=$(mktemp -t htgen.$$.content.XXXXXXXX)
+          trap "rm $uri >&2" EXIT
+
+          head -c $req_content_length \
+            | grep -Eo 'https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)' \
+            > $uri
+          sha256=$(sha256sum -b $uri | cut -d\  -f1)
+          base32=$(${pkgs.nixStable}/bin/nix-hash --to-base32 --type sha256 $sha256)
+          item=$STATEDIR/items/$base32
+          ref=http://$req_host/$base32
+
+          if ! test -e $item; then
+            mkdir -v -p $STATEDIR/items >&2
+            cp -v $uri $item >&2
+          fi
+
+          base32short=$(echo $base32 | cut -b-7)
+          if item=$(find_item $base32short); then
+            ref=$(echo "http://$req_host/$base32short")
+          fi
+
+          printf 'HTTP/1.1 200 OK\r\n'
+          printf 'Content-Type: text/plain; charset=UTF-8\r\n'
+          printf 'Connection: close\r\n'
+          printf '\r\n'
+          printf '%s\n' "$ref"
+          exit
+        ;;
+      esac
+    ''}'';
+  };
 }