Quickie Java pipe out to wkhtmltopdf to create a pdf from a string with html

wkhtmltopdf.java

public byte[] getPdf(String html) {
  byte[] results = null;
  try {   
    // For piping in and out, we need separate args for this for some reason
    String[] command = {"/usr/local/bin/wkhtmltopdf", "-", "-"};
    ProcessBuilder builder = new ProcessBuilder(command);
    // this eats up stderr but prevents us from having to handle it ourselves
    builder.redirectErrorStream(false);

    Process process = builder.start();
    
    try (BufferedOutputStream stdin = new BufferedOutputStream(process.getOutputStream())) {
        stdin.write(html.getBytes());
    }

    try(BufferedInputStream stdout = new BufferedInputStream(process.getInputStream()); ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); ) {
      // Couldn't get a buffered read working properly without knowing the length of the result, so reading byte by byte instead.
      // BufferedInputStream should be buffering internally with 8192 bytes, and 
      // ByteArrayOutputStream works similar to a vector with an internal byte array, so performance shouldn't be too bad.
      // TODO: properly buffer this
      while (true) {
          int x = stdout.read();
          if (x == -1) {
              break;
          }
          outputStream.write(x);
      }
      results = outputStream.toByteArray();
      process.waitFor();
    }
  }
  catch(Exception e) {
      log.error("Exception thrown while converting to pdf: " + e);
      return null;
  }
  return results;
}