Scrapy框架系列--数据不保存，就是耍流氓（3）

import scrapy
class Doubantop250Item(scrapy.Item):
    title = scrapy.Field()  # 电影名字
    star = scrapy.Field()  # 电影评分
    quote = scrapy.Field()  # 脍炙人口的一句话
    movieInfo = scrapy.Field()  # 电影的描述信息，包括导演、主演、电影类型

import json
class JsonPipeline(object):
    file_name = base_dir + '/doubanTop250/data.json'  # json 文件路径
    def process_item(self, item, spider):
        file = open(self.file_name, 'r', encoding='utf-8')
        load_data = json.load(file)
        load_data.append({"title": item["title"].strip()}) # 追加数据
        file = open(self.file_name, 'w', encoding='utf-8')
        json.dump(load_data, file, ensure_ascii=False) # 保存数据
        file.close()
        return item

    def appendDta2Csv(self, file_name, new_headers, new_data):
        with open(file_name,'r') as f:
            f_csv = csv.reader(f)
            try:# 如何有源文件没有 headers ，将调用传进来的 headers
                headers = next(f_csv)
            except:
                headers = new_headers
            old_data = list(f_csv)
            old_data.append(new_data) # 追加新的数据
            with open(file_name, 'w') as f2:# 保存数据
                f_csv = csv.writer(f2)
                f_csv.writerow(headers)
                f_csv.writerows(old_data)
                f2.close()
            f.close()

    def process_item(self, item, spider):
        self.appendDta2Csv(self.file_name, ["title"], [item["title"].strip()])
        return item

from pymongo import MongoClient
import os
base_dir = os.getcwd()
class MongoPipeline(object):
    # 实现保存到mongo数据库的类，
    collection = 'douban'  # mongo 数据库的 collection 名字

    def __init__(self, mongo_uri, db_name, db_user, db_pass):
        self.mongo_uri = mongo_uri
        self.db_name = db_name
        self.db_user = db_user
        self.db_pass = db_pass

    @classmethod
    def from_crawler(cls, crawler):
        # scrapy 为我们访问settings提供了这样的一个方法，这里，
        # 我们需要从 settings.py 文件中，取得数据库的URI和数据库名称
        return cls(
            mongo_uri=crawler.settings.get('MONGO_URI'),
            db_name=crawler.settings.get('DB_NAME'),
            db_user=crawler.settings.get('DB_USER'),
            db_pass=crawler.settings.get('DB_PASS'))

    def open_spider(self, spider):  # 爬虫启动时调用，连接到数据库
        self.client = MongoClient(self.mongo_uri)
        self.zfdb = self.client[self.db_name]
        self.zfdb.authenticate(self.db_user, self.db_pass)

    def close_spider(self, spider):  # 爬虫关闭时调用，关闭数据库连接
        self.client.close()

    def process_item(self, item, spider):
        self.zfdb[self.collection].insert({"title": item["title"].strip()})
        return item

from sqlalchemy import create_engine, Column, Integer, String, BIGINT, ForeignKey, UniqueConstraint, Index, and_, \
    or_, inspect
from sqlalchemy.orm import sessionmaker, relationship, contains_eager
class MysqlPipeline(object):
    MYSQL_URI = 'mysql+pymysql://username:password@localhost:3306/db_name'
    # echo 为 True 将会输出 SQL 原生语句
    engine = create_engine(MYSQL_URI, echo=True)
    from sqlalchemy.ext.declarative import declarative_base
    Base = declarative_base()

    # 创建单表
    class Movie(Base):
        __tablename__ = 'movies'
        id = Column(BIGINT, primary_key=True, autoincrement=True)
        title = Column(String(200))
    # 初始化数据库
    def init_db(self):
        self.Base.metadata.create_all(self.engine)
    # 删除数据库
    def drop_db(self):
        self.Base.metadata.drop_all(self.engine)
    def open_spider(self, spider):  # 爬虫启动时调用，连接到数据库
        self.init_db()
        Session = sessionmaker(bind=self.engine)
        self.session = Session()
    def process_item(self, item, spider):
        new_movie = self.Movie(title=item["title"].strip())
        self.session.add(new_movie)
        self.session.commit()
        return item

ITEM_PIPELINES = {
    'doubanTop250.pipelines.MongoPipeline': 300,
    'doubanTop250.pipelines.MysqlPipeline': 301,
    'doubanTop250.pipelines.CsvPipeline': 302,
    'doubanTop250.pipelines.JsonPipeline': 303,
}