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对Requests和sqlite3进行封装

对Requests和sqlite3进行封装

作者: 小温侯 | 来源:发表于2018-07-21 23:13 被阅读26次

    封装了两个库,简化一下代码。第一个不是最终版,先用着,比如说,L30那里关于请求的参数,只列出了常用的几个。到时候有需求了再改。

    ohRequests.py

    这个封装会对请求失败的URL默认重新请求3次,避免网络波动导致抓取失败。

    import requests
    from faker import Faker
    
    
    class ohRequests(object):
        def __init__(self, retries = 1):
            self.faker = Faker()
            self.GET = 'get'
            self.POST = 'post'
            self.RETRIES = retries
    
        def __request(self,
                    method,
                    url,
                    headers = {},
                    cookies = None,
                    proxies = None,
                    params  = None,
                    data    = None,
                    timeout = 5):
    
            # FIXME: 
            # 没有检测User-Agent, user-Agent之类的key名
            headers['user-agent'] = self.faker.user_agent()
    
            for i in range(self.RETRIES):
                req_methond = requests.post if method == 'post' else requests.get
                response = None
                try:
                    response = req_methond(url, 
                                    headers = headers,
                                    cookies = cookies,
                                    proxies = proxies,
                                    data    = data,
                                    timeout = timeout, 
                                    params  = params
                                )
                    response.encoding = 'utf-8'
                    return response
    
                except Exception:
                    print ('HTTPError, Status Code: {}'.format(response.status_code))
    
                print ("Requests Error. Retry[{}], max retries[{}]".format(i+1, self.RETRIES))
    
            return None
    
        def get(self, url, **kwargs):
            return self.__request('get', url, **kwargs)
    
        def post(self, url, **kwargs):
            return self.__request('post', url, **kwargs)
    
        def faker_user_agent(self):
            return self.faker.user_agent()
    
    if __name__ == '__main__':
        r = ohRequests()
        req = r.get("http://www.baidu.com")
        print (req)
    

    ohSqlite3.py

    import sqlite3
    import os
    
    class ohSqlite3(object):
        """ APIs for using Sqlite3.
    
        Attributes:
            dbpath: the db file path for manipulation
            conn: connection object returned from sqlite3.connect()
            cursor: cursor object returned from conn
    
            SHOW_SQL_STATEMENT: whether print sql statement, default False
        """
    
        SHOW_SQL_STATEMENT = False
    
        def __init__(self, dbpath):
            """inits ohSqlite3 with dbpath"""
            self.dbpath = dbpath
            self.conn = None
            self.cursor = None
    
        def __enter__(self):
            self.connect()
            return self
    
        def __exit__(self, exc_type, exc_val, exc_tb):
            self.close()
    
        def connect(self):
            """init db connection
            
            Raises:
                sqlite3.Error: An error occurred when attempting to connect sqlite db.
            """
            try:
                self.conn = sqlite3.connect(self.dbpath)
            except sqlite3.Error as e:
                print ("Connect {} failed. Error: {}".foramt(self.dbpath, e.args[0]))
            
            self.cursor = self.conn.cursor()
    
        def execute(self, sql, args = None):
            """execute sql statement
    
            Args:
                sql: the sql statement to be executed
                args: a tuple of fields to be added to sql, default None
    
            Returns:
                result of sql statement execution
    
            Raises:
                Exception: any errors occurred when executing sql statement
    
            """
            if self.SHOW_SQL_STATEMENT:
                print ("[SQL]{}".format(sql))
    
            data = None
            try:
                if args:
                    self.cursor.execute(sql, args)
                else:
                    self.cursor.execute(sql)
                data = self.cursor.fetchall()
            except Exception as e:
                print (e, "[SQL]:" + sql.strip())
                self.conn.rollback()
    
            self.conn.commit()
            if data:
                return data
            return None
    
        def query(self, sql, args = None):
            """Same as execute(), different names"""
            return self.execute(sql, args = None)
    
        def close(self):
            """close all objects"""
            self.cursor.close()
            self.conn.close()
    
    def unitest():
        testdb = "ohSqlite3_test.db"
    
        # test funcs
        db = ohSqlite3(testdb)
        db.connect()
    
        db.execute("CREATE TABLE stocks (date text, trans text, symbol text, qty real, price real)")
    
        db.execute("INSERT INTO stocks VALUES ('2006-01-05','BUY','RHAT',100,35.14)")
        db.execute("INSERT INTO stocks VALUES ('2006-03-28', 'BUY', 'IBM', 1000, 45.00)")
        db.execute("INSERT INTO stocks VALUES ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00)")
        db.execute("INSERT INTO stocks VALUES ('2006-04-06', 'SELL', 'IBM', 500, 53.00)")
    
        assert 4 == db.execute("SELECT count(*) FROM stocks")[0][0]
    
        db.execute("DROP TABLE stocks")
    
        db.close()
    
        # test __with__ statement
        with ohSqlite3(testdb) as db:
            db.query("CREATE TABLE stocks (date text, trans text, symbol text, qty real, price real)")
    
            db.execute("INSERT INTO stocks VALUES ('2006-01-05','BUY','RHAT',100,35.14)")
            db.execute("INSERT INTO stocks VALUES ('2006-03-28', 'BUY', 'IBM', 1000, 45.00)")
            db.execute("INSERT INTO stocks VALUES ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00)")
            db.execute("INSERT INTO stocks VALUES ('2006-04-06', 'SELL', 'IBM', 500, 53.00)")
    
            assert 4 == db.execute("SELECT count(*) FROM stocks")[0][0]
    
            db.execute("DROP TABLE stocks")
    
        os.remove(testdb)
    
    
    if __name__ == "__main__":
        unitest()
    

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