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Calling HTMLDOC from Java

Java programs are a portable way to add PDF support to your web server. Here is a class called htmldoc that acts as a portal, converting the named file to PDF. It can also be called by your Java servlets to process an HTML file and send the result to the client in PDF format:

    class htmldoc
    {
      // Convert named file to PDF on stdout...
      public static int topdf(String filename)// I - Name of file to convert
      {
        String              command;          // Command string
        Process             process;          // Process for HTMLDOC
        Runtime             runtime;          // Local runtime object
        java.io.InputStream input;            // Output from HTMLDOC
        byte                buffer [];        // Buffer for output data
        int                 bytes;            // Number of bytes


        // First tell the client that we will be sending PDF...
        System.out.print("Content-type: application/pdf\n\n");

        // Construct the command string
        command = "htmldoc --quiet --jpeg --webpage -t pdf --left 36 " +
                  "--header .t. --footer .1. " + filename;

        // Run the process and wait for it to complete...
        runtime = Runtime.getRuntime();

        try
        {
          // Create a new HTMLDOC process...
          process = runtime.exec(command);

          // Get stdout from the process and a buffer for the data...
          input  = process.getInputStream();
          buffer = new byte[8192];

          // Read output from HTMLDOC until we have it all...
          while ((bytes = input.read(buffer)) > 0)
            System.out.write(buffer, 0, bytes);

          // Return the exit status from HTMLDOC...
          return (process.waitFor());
        }
        catch (Exception e)
        {
          // An error occurred - send it to stderr for the web server...
          System.err.print(e.toString() + " caught while running:\n\n");
          System.err.print("    " + command + "\n");
          return (1);
        }
      }

      // Main entry for htmldoc class
      public static void main(String[] args)// I - Command-line args
      {
        String server_name,                 // SERVER_NAME env var
               server_port,                 // SERVER_PORT env var
               path_info,                   // PATH_INFO env var
               query_string,                // QUERY_STRING env var
               filename;                    // File to convert


        if ((server_name = System.getProperty("SERVER_NAME")) != null &&
            (server_port = System.getProperty("SERVER_PORT")) != null &&
            (path_info = System.getProperty("PATH_INFO")) != null)
        {
          // Construct a URL for the resource specified...
          filename = "http://" + server_name + ":" + server_port + path_info;

          if ((query_string = System.getProperty("QUERY_STRING")) != null)
          {
            filename = filename + "?" + query_string;
          }
        }
        else if (args.length == 1)
        {
          // Pull the filename from the command-line...
          filename = args[0];
        }
        else
        {
          // Error - no args or env variables!
          System.err.print("Usage: htmldoc.class filename\n");
          return;
        }

        // Convert the file to PDF and send to the web client...
        topdf(filename);
      }
    }