web全栈应用【爬取（scrapy）数据 -> 通过restful接口存入数据库 -> websocket推送展示到前台】

作为

https://github.com/fanqingsong/web_full_stack_application

子项目的一功能的核心部分，使用scrapy抓取数据，解析完的数据，使用 python requets库，将数据推送到 webservice接口上， webservice接口负责保存数据到mongoDB数据库。

实现步骤：

1、 使用requests库，与webservice接口对接。

2、 使用scrapy抓取数据。

3、 结合1 2 实现完整功能。

Requests库 （Save to DB through restful api）

库的安装和快速入门见：

http://docs.python-requests.org/en/master/user/quickstart/#response-content

给出测试通过示例代码：

insert_to_db.py

import requests

resp = requests.get('http://localhost:3000/api/v1/summary')

# ------------- GET --------------
if resp.status_code != 200:
     # This means something went wrong.
     raise ApiError('GET /tasks/ {}'.format(resp.status_code))

for todo_item in resp.json():
     print('{} {}'.format(todo_item['Technology'], todo_item['Count']))

# ------------- POST --------------
Technology = {"Technology": "Django", "Count": "50" }

resp = requests.post('http://localhost:3000/api/v1/summary', json=Technology)
if resp.status_code != 201:
     raise ApiError('POST /Technologys/ {}'.format(resp.status_code))

print("-------------------")
print(resp.text)

print('Created Technology. ID: {}'.format(resp.json()["_id"])

Python VirutalEnv运行环境

https://realpython.com/python-virtual-environments-a-primer/

Create a new virtual environment inside the directory:

# Python 2:
$ virtualenv env
 
# Python 3
$ python3 -m venv env

Note: By default, this will not include any of your existing site packages.

windows 激活：

env\Scripts\activate

Scrapy（Scratch data）

https://scrapy.org/

An open source and collaborative framework for extracting the data you need from websites.

In a fast, simple, yet extensible way.

https://scrapy-chs.readthedocs.io/zh_CN/0.24/topics/architecture.html

安装和使用参考：

https://www.cnblogs.com/lightsong/p/8732537.html

安装和运行过程报错解决办法：

1、 Scrapy运行ImportError: No module named win32api错误

https://blog.csdn.net/u013687632/article/details/57075514

pip install pypiwin32

2、 error: Microsoft Visual C++ 14.0 is required. Get it with "Microsoft Visual C++ Build Tools": http://landinghub.visualstudio.com/visual-cpp-build-tools

https://www.cnblogs.com/baxianhua/p/8996715.html

1. http://www.lfd.uci.edu/~gohlke/pythonlibs/#twisted 下载twisted对应版本的whl文件（我的Twisted‑17.5.0‑cp36‑cp36m‑win_amd64.whl)，cp后面是python版本，amd64代表64位，

2. 运行命令：

pip install C:\Users\CR\Downloads\Twisted-17.5.0-cp36-cp36m-win_amd64.whl

给出示例代码：

quotes_spider.py

import scrapy

class QuotesSpider(scrapy.Spider):
     name = "quotes"
     start_urls = [
         'http://quotes.toscrape.com/tag/humor/',
     ]

def parse(self, response):
         for quote in response.css('div.quote'):
             yield {
                 'text': quote.css('span.text::text').extract_first(),
                 'author': quote.xpath('span/small/text()').extract_first(),
             }

next_page = response.css('li.next a::attr("href")').extract_first()
         if next_page is not None:
             yield response.follow(next_page, self.parse)

在此目录下，运行

scrapy runspider quotes_spider.py -o quotes.json

输出结果

[
{"text": "\u201cThe person, be it gentleman or lady, who has not pleasure in a good novel, must be intolerably stupid.\u201d", "author": "Jane Austen"},
{"text": "\u201cA day without sunshine is like, you know, night.\u201d", "author": "Steve Martin"},
{"text": "\u201cAnyone who thinks sitting in church can make you a Christian must also think that sitting in a garage can make you a car.\u201d", "author": "Garrison Keillor"},
{"text": "\u201cBeauty is in the eye of the beholder and it may be necessary from time to time to give a stupid or misinformed beholder a black eye.\u201d", "author": "Jim Henson"},
{"text": "\u201cAll you need is love. But a little chocolate now and then doesn't hurt.\u201d", "author": "Charles M. Schulz"},
{"text": "\u201cRemember, we're madly in love, so it's all right to kiss me anytime you feel like it.\u201d", "author": "Suzanne Collins"},
{"text": "\u201cSome people never go crazy. What truly horrible lives they must lead.\u201d", "author": "Charles Bukowski"},
{"text": "\u201cThe trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it.\u201d", "author": "Terry Pratchett"},
{"text": "\u201cThink left and think right and think low and think high. Oh, the thinks you can think up if only you try!\u201d", "author": "Dr. Seuss"},
{"text": "\u201cThe reason I talk to myself is because I\u2019m the only one whose answers I accept.\u201d", "author": "George Carlin"},
{"text": "\u201cI am free of all prejudice. I hate everyone equally. \u201d", "author": "W.C. Fields"},
{"text": "\u201cA lady's imagination is very rapid; it jumps from admiration to love, from love to matrimony in a moment.\u201d", "author": "Jane Austen"}
]

业务全流程实例

https://github.com/fanqingsong/web_data_visualization

由于zhipin网站对爬虫有反制策略， 本例子采用scrapy的官方爬取实例quotes为研究对象。

流程为：

1、 爬取数据，  scrapy 的两个组件 spider & item pipeline

2、 存数据库， requests库的post方法推送数据到 webservice_quotes服务器的api

3、 webservice_quotes将数据保存到mongoDB

4、 浏览器访问vue页面， 与websocket_quotes服务器建立连接

5、 websocket_quotes定期（每隔1s）从mongoDB中读取数据，推送给浏览器端，缓存为Vue应用的data，data绑定到模板视图

scrapy item pipeline 推送数据到webservice接口

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

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://doc.scrapy.org/en/latest/topics/item-pipeline.html

import requests

class ScratchZhipinPipeline(object):
     def process_item(self, item, spider):

print("--------------------")
         print(item['text'])
         print(item['author'])
         print("--------------------")

# save to db through web service
         resp = requests.post('http://localhost:3001/api/v1/quote', json=item)
         if resp.status_code != 201:
             raise ApiError('POST /item/ {}'.format(resp.status_code))
         print(resp.text)
         print('Created Technology. ID: {}'.format(resp.json()["_id"]))

return item

爬虫运行: scrapy crawl quotes

webservice运行: npm run webservice_quotes

websocket运行: npm run websocket_quotes

vue调试环境运行： npm run dev

chrome:

db:

Python生成requirement.text文件

http://www.cnblogs.com/zhaoyingjie/p/6645811.html

快速生成requirement.txt的安装文件
(CenterDesigner) xinghe@xinghe:~/PycharmProjects/CenterDesigner$ pip freeze > requirements.txt

安装所需要的文件
 
pip install -r requirement.txt