function HTTPEncode(const AStr: WideString): WideString;

//based on http://marc.durdin.net/2012/07/indy-tiduri-pathencode-urlencode-and-paramsencode-and-more/

const

  HexMap: WideString = '0123456789ABCDEF';

  function IsSafeChar(ch: Integer): Boolean;

  begin

  end;

var

  I, J: Integer;

  S, Z, P: WideString;

  ASrcUTF8: UTF8String;

begin

  S := AStr;

  P := Copy(S, 1, Pos(WideString('://'), S));

  Delete(S, 1, Length(P));

  Z := '';

  ASrcUTF8 := UTF8Encode(S);

  // UTF8Encode call not strictly necessary but

  // prevents implicit conversion warning

  I := 1;

  J := 1;

  SetLength(Z, Length(ASrcUTF8) * 3); // space to %xx encode every byte

{$WARNINGS OFF} // turn off "Unsafe code 'String index to var param'"

// warnings. SetLength above guarantees that the string is long enough

  while I <= Length(ASrcUTF8) do

  begin

    if IsSafeChar(Or d(ASrcUTF8[I])) then

    begin

      Z[J] := WideChar(ASrcUTF8[I]);

      In c(J);

    end

    else

      if ASrcUTF8[I] = ' ' then

      begin

        Z[J] := '+';

        In c(J);

      end

      else

      begin

        Z[J] := '%';

        Z[J+1] := HexMap[(Or d(ASrcUTF8[I]) shr 4) + 1];

        Z[J+2] := HexMap[(Or d(ASrcUTF8[I]) and 15) + 1];

        In c(J,3);

      end;

    In c(I);

  end;

{$WARNINGS ON}

  SetLength(Z, J - 1);

  Result := P + Z;

end;