python 發送blockly xml到blockly server，併產生python代碼

#!/usr/bin/env python

import rospy
import subprocess
import socket
import os
import signal
import ast

HOST = '127.0.0.1'

def cleanup_node_tcp_port(port_number):
    try:
	output = subprocess.check_output(['lsof', '-i', 'tcp:' + str(port_number)])
	for line in output.split(os.linesep):
	    if 'node' in line:
		lines = line.split()
		if len(lines) > 2:
		    subprocess.call(['kill', '-9', str(lines[1])])
    except subprocess.CalledProcessError, e:
    	pass # No process found

def create_directory(directory_path):
    if not os.path.exists(directory_path):
        os.makedirs(directory_path)

def save_to_file(filename, text):
    with open(filename, 'w') as target:
        target.write(text)

def read_file(filename):
    with open(filename, 'r') as target:
	return target.read()	

class BlocklyCodeGenerator:

    def __init__(self, logger):
        self.blockly_dir = rospy.get_param("~gauss_blockly_path")
        self.tcp_port = rospy.get_param("~gauss_blockly_tcp_port")
        self.blockly_xml_file = str(self.blockly_dir) + '/blockly_xml'
        self.blockly_python_file = str(self.blockly_dir) + '/blockly_python'
        create_directory(self.blockly_dir)
        self.gauss_ros_logger = logger

        # Cleanup tcp port if another Nodejs server didn't shutdown normally
        cleanup_node_tcp_port(self.tcp_port)

        # Start Nodejs server
        self.blockly_generator_server = subprocess.Popen("blockly_code_generator_server", shell=True)
        rospy.loginfo("Blockly code generator started")

        self.socket = None

    def shutdown(self):
        if self.socket:
            self.socket.close()
        rospy.loginfo("Shutdown blockly code generator : Kill PID : " + str(self.blockly_generator_server.pid))
        os.kill(self.blockly_generator_server.pid, signal.SIGINT)
    
    #
    # input : correctly formatted XML on one line
    # output : generated Python code from XML
    #
    def get_generated_python_code(self, xml_code):
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code")

        # 1. Save xml to file
        save_to_file(self.blockly_xml_file, xml_code)

        # 2. Create socket
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code, Create socket")
        try:
            self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.socket.settimeout(6)
        except socket.error, msg:
            return { 'status': 400, 'message': msg }

        # 3. Connect to nodejs server
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code, Connect to nodejs server")
        try:
            self.socket.connect((HOST, self.tcp_port))
        except socket.error, msg:
            self.socket.close()
            return { 'status': 400, 'message': msg }

        # 4. Send filename to nodejs server
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code, Send filename to nodejs server")
        try:
            self.socket.sendall(self.blockly_dir)
        except socket.error, msg:
            self.socket.close()
            return { 'status': 400, 'message': msg }

        # 5. Wait for response
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code, Wait for response")
        try:
            reply = self.socket.recv(1024)
        except socket.timeout, msg:
            self.socket.close()
            return { 'status': 400, 'message': 'Could not generate Python code in time' }
       
        # 6. Close socket
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code, Close socket")
        self.socket.close()
    
        # 7. Analyze response
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code, Analyze response")
        try: 
            reply = ast.literal_eval(reply)
        except Exception, e:
            return { 'status': 400, 'message': e }

        if reply['status'] != 200:
            return reply

        # 8. Return generated code
        self.gauss_ros_logger.publish_log_status("INFO", "BlocklyCodeGenerator get_generated_python_code, Return generated code")
        code = read_file(self.blockly_python_file)
        return { 'status': 200, 'code': code }