吴裕雄--天生自然PYTHON爬虫：使用Scrapy抓取股票行情

Scrapy框架它能够帮助提升爬虫的效率，从而更好地实现爬虫。Scrapy是一个为了抓取网页数据、提取结构性数据而编写的应用框架，该框架是封装的，包含request异步调度和处理、下载器（多线程的Downloader）、解析器selector和twisted(异步处理)等。对于网站的内容爬取，其速度非常快捷。

下面将使用Scrapy框架抓取某证券网站A股行情，爬取过程分为以下五步：

一：创建Scrapy爬虫项目；

二：定义一个item容器；

三：定义settings文件进行基本爬虫设置；

四：编写爬虫逻辑；

五：代码调试。

1、创建Scrapy爬虫项目

调出CMD，输入下面代码：(我在F盘下的pywork文件夹下创建的)

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

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.html

import scrapy
from scrapy.loader import ItemLoader
from scrapy.loader.processors import TakeFirst

class StockstarItemLoader(ItemLoader):
    #自定义itemloader
    default_output_processor = TakeFirst()

class StockstarItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    code = scrapy.Field()  # 股票代码
    abbr = scrapy.Field()  # 股票简称
    last_trade = scrapy.Field()  # 最新价
    chg_ratio = scrapy.Field()   # 涨跌幅
    chg_amt = scrapy.Field()     # 涨跌额
    chg_ratio_5min = scrapy.Field() # 5分钟涨幅
    volumn = scrapy.Field()  # 成交量
    turn_over = scrapy.Field()  # 成交额

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

# Scrapy settings for stockstar project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://docs.scrapy.org/en/latest/topics/settings.html
#     https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://docs.scrapy.org/en/latest/topics/spider-middleware.html

from scrapy.exporters import JsonLinesItemExporter

# 默认显示的中文是阅读性较差的Unicode字符
# 需要定义子类显示出原来的字符集(将父类的ensure_ascii属性设置为False即可)
class CustomJsonLinesItemExporter(JsonLinesItemExporter):
    def __init__(self, file, **kwargs):
        super(CustomJsonLinesItemExporter, self).__init__(file, ensure_ascii=False, **kwargs)

# 启用新定义的Exporter类
FEED_EXPORTERS = {
    'json': 'stockstar.settings.CustomJsonLinesItemExporter',
}

BOT_NAME = 'stockstar'

SPIDER_MODULES = ['stockstar.spiders']
NEWSPIDER_MODULE = 'stockstar.spiders'

# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'stockstar (+http://www.yourdomain.com)'

# Obey robots.txt rules
ROBOTSTXT_OBEY = True

# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32

# Configure a delay for requests for the same website (default: 0)
# See https://docs.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
DOWNLOAD_DELAY = 0.25
#DOWNLOAD_DELAY = 3
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16

# Disable cookies (enabled by default)
#COOKIES_ENABLED = False

# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False

# Override the default request headers:
#DEFAULT_REQUEST_HEADERS = {
#   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
#   'Accept-Language': 'en',
#}

# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'stockstar.middlewares.StockstarSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'stockstar.middlewares.StockstarDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
#ITEM_PIPELINES = {
#    'stockstar.pipelines.StockstarPipeline': 300,
#}

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False

# Enable and configure HTTP caching (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'

scrapy genspider stock quote.stockstar.com

# -*- coding: utf-8 -*-
import scrapy
from items import StockstarItem, StockstarItemLoader

class StockSpider(scrapy.Spider):
    #爬虫名称
    name = 'stock'
    #爬虫领域
    allowed_domains = ['quote.stockstar.com']
    # start_urls = ['http://quote.stockstar.com/']
    #爬虫开始链接
    start_urls = ['http://quote.stockstar.com/stock/industry_I_0_0_1.html']

    #编写爬虫逻辑
    def parse(self, response):
        #获取页码
        page = int(response.url.split("_")[-1].split(".")[0])
        item_nodes = response.css('#datalist tr')
        for item_node in item_nodes:
            #根据item_node定义的字段内容来按照里面的字段获取
            item_loader = StockstarItemLoader(item=StockstarItem(), selector=item_node)
            item_loader.add_css("code", "td:nth-child(1) a::text")
            item_loader.add_css("abbr", "td:nth-child(2) a::text")
            item_loader.add_css("last_trade", "td:nth-child(3) ::text")
            item_loader.add_css("chg_ratio", "td:nth-child(4) ::text")
            item_loader.add_css("chg_amt", "td:nth-child(5) ::text")
            item_loader.add_css("chg_ratio_5min", "td:nth-child(6) ::text")
            item_loader.add_css("volumn", "td:nth-child(7)::text")
            item_loader.add_css("turn_over", "td:nth-child(8)::text")
            stock_item = item_loader.load_item()
            yield stock_item
        if item_nodes:
            next_page = page + 1
            next_url = response.url.replace("{0}.html".format(page), "{0}.html".format(next_page))
            yield scrapy.Request(url=next_url, callback=self.parse)

5、接下来在stockstar文件下创建一个main.py文件用来方便调试爬虫代码。

from scrapy.cmdline import execute

execute(["scrapy", "crawl", "stock", "-o", "items.json"])

上面这条命令等价与在CMD中进入到scrapy文件中执行：

scrapy crawl stock -o items.json
这样爬虫得到的内容就都保存到items.json这个文件里面了