[Python] A translation applet implemented by calling Baidu Translate API

Beginning to learn Python, I want to try to write a few small programs. Accidentally found that the Baidu Translate Open Platform provides an API that can provide us with high-quality translation services. This is the first applet I wrote in Python, and this article is also my first blog, so I'm excited to think about it. Now let's introduce the method of writing online translation program by calling Baidu Translate API.

Now Baidu Translate Open Platform provides free translation services of 2 million characters per month. As long as you have a Baidu account and apply to become a developer, you can get the required account and password. Here is the developer application link:

http://api.fanyi.baidu.com/api/trans/product/index

For the convenience of use, Baidu Translate Open Platform provides detailed access documents, the links are as follows:

http://api.fanyi.baidu.com/api/trans/product/apidoc

Program demo:

The detailed usage method is listed in the translation document. The following is the original text of the access document:

Example: Translate apple from English to Chinese:

Request parameters:

q=apple

from=en

to=zh

appid=2015063000000001

salt=1435660288

Platform Assigned Key: 12345678

Generate sign:

>concatenated string 1

Splicing appid=2015063000000001 + q=apple + salt=1435660288 + key=12345678

get string 1 = 2015063000000001 apple 1435660288 12345678

>Calculate signature sign (encrypt string 1 with md5, note that string 1 must be UTF-8 encoded before calculating md5)

sign=md5(2015063000000001apple143566028812345678)

sign=f89f9594663708c1605f3d736d01d2d4

The full request is:

http://api.fanyi.baidu.com/api/trans/vip/translate?q=apple&from=en&to=zh&appid=2015063000000001&salt=1435660288&sign=f89f9594663708c1605f3d736d01d2d4

Generation of signature

Signature calculation can be achieved through hashlib.md5() in the hashlib module provided by Python

Take the string in the access document as an example:

import hashlib

m = '2015063000000001apple143566028812345678'
m_MD5 = hashlib.md5(m)
sign = m_MD5.hexdigest()
print 'm = ',m
print 'sign = ',sign

After the signature is obtained, a URL request is generated according to the requirements in the access document, and the translation result can be returned after submission. The following is a screenshot of the fields provided by the access document and their corresponding descriptions:

Parse the return result

The return value after submitting the URL is in json format, and the result can be parsed using the json module:

{"from":"en","to":"zh","trans_result":[{"src":"apple","dst":"\u82f9\u679c"}]}

import json

result = '{"from":"en","to":"zh","trans_result":[{"src":"apple","dst":"\u82f9\u679c"}]}'
data = json.loads(result)
print data['trans_result'][0]['dst']

至此，我们完成了有关API调用的所有关键步骤。

以下为全部代码：

# -*- coding: utf-8 -*-

import urllib2
import hashlib
import json
import random


class Baidu_Translation:
    def __init__(self):
        self._q = ''
        self._from = ''
        self._to = ''
        self._appid = 0
        self._key = ''
        self._salt = 0
        self._sign = ''
        self._dst = ''
        self._enable = True
        
    def GetResult(self):
        self._q.encode('utf8')
        m = str(Trans._appid)+Trans._q+str(Trans._salt)+Trans._key
        m_MD5 = hashlib.md5(m)
        Trans._sign = m_MD5.hexdigest()        
        Url_1 = 'http://api.fanyi.baidu.com/api/trans/vip/translate?'
        Url_2 = 'q='+self._q+'&from='+self._from+'&to='+self._to+'&appid='+str(Trans._appid)+'&salt='+str(Trans._salt)+'&sign='+self._sign
        Url = Url_1+Url_2
        PostUrl = Url.decode()
        TransRequest = urllib2.Request(PostUrl)
        TransResponse = urllib2.urlopen(TransRequest)
        TransResult = TransResponse.read()
        data = json.loads(TransResult)
        if 'error_code' in data:
            print 'Crash'
            print 'error:',data['error_code']
            return data['error_msg']
        else:
            self._dst = data['trans_result'][0]['dst']
            return self._dst

    def ShowResult(self,result):
        print result
        
    def Welcome(self):
        self._q = 'Welcome to use icedaisy online translation tool'
        self._from = 'auto'
        self._to = 'zh'
        self._appid = 201609240000*****
        self._key = '******'
        self._salt = random.randint(10001,99999)
        welcome = self.GetResult()
        self.ShowResult(welcome)
        
    def StartTrans(self):
        while self._enable:
            self._q = raw_input()
            if cmp(self._q, '!quit') == 0:
                self._enable = False
                print 'Thanks for using!'
                break
            _q_len = len(self._q)
            if _q_len < 4096:
                result = self.GetResult()
                self.ShowResult(result)
            else:
                print 'Exceeds the maximum limit of 4096 characters'


#----------- 程序的入口 -----------
print u"""  
---------------------------------------  
    程序：icedaisy的在线翻译工具  
    版本：0.2  
    作者：icedaisy  
    日期：2016-09-25  
    语言：Python 2.7 
    功能：输入原文后得到翻译结果
    原理：调用百度翻译API
    退出：输入!quit
---------------------------------------  
"""
Trans = Baidu_Translation()
Trans.Welcome()
Trans.StartTrans()