Python爬虫天猫店铺全部商品一记

1、前言

最近小姐姐工作需要，需要爬取天猫某店的全部商品，正好小哥学习了Python几个月，就答应上手试试！结果第一道题就难住了，天猫登陆需要账号密码和验证码！！！虽然知道可以通过模拟和Session操作，但是，始终是新手开车，还没有学习那么高深，感觉会走很多弯路！！另外，也想想，有没有什么更简单的方法？？？

不出意思，还真发现啦！天猫的手机版可以不用登陆，全部数据访问！！！就这样~

开始吧！

2、遇到的坑点

本文主要是在 利用Python爬虫爬取指定天猫店铺全店商品信息 - 晴空行 - 博客园 这个大哥的基础上，踩坑填坑，然后增加自己一些数据要求~

• 坑一

File "/Users/HTC/Documents/Programing/Python/WebCrawlerExample/WebCrawler/Tmall_demo.py", line 63, in get_products
    writer.writerows(products)
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/csv.py", line 158, in writerows
    return self.writer.writerows(map(self._dict_to_list, rowdicts))
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/csv.py", line 151, in _dict_to_list
    + ", ".join([repr(x) for x in wrong_fields]))
ValueError: dict contains fields not in fieldnames: 'titleUnderIconList'

writer.writerows 没有找到这个'titleUnderIconList'字段，这个字段应该是天猫的接口后来返回的数据，在代码里只能删除掉：

del product['titleUnderIconList']del product['titleUnderIconList']

• 坑二

File "/Users/HTC/Documents/Programing/Python/WebCrawlerExample/WebCrawler/Tmall_demo.py", line 65, in get_products
    writer.writerows(products)
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/csv.py", line 158, in writerows
    return self.writer.writerows(map(self._dict_to_list, rowdicts))
UnicodeEncodeError: 'ascii' codec can't encode characters in position 26-27: ordinal not in range(128)

熟悉的人儿，看到python3与python2的区别，就知道，'ascii' codec can't encode 就是编码问题，问题就出来这里writer.writerows, python3处理、解析或转换和保存时，最好都指定一下使用 utf-8编码吧，特别是遇到中文的情况！

最后指定编码用utf-8：

with open(self.filename, 'a', encoding="utf-8", newline='') as f:
    writer = csv.DictWriter(f, fieldnames=title)
    writer.writerows(products)

• 坑三

035009803B0
图片下载错误 ： http//img.alicdn.com/bao/uploaded/i4/821705368/TB1Sht8cfQs8KJjSZFEXXc9RpXa_!!0-item_pic.jpg Invalid URL '035009803B0': No schema supplied. Perhaps you meant http://035009803B0?
02100713003
图片下载错误 ： http//img.alicdn.com/bao/uploaded/i1/821705368/TB1_OIkXQfb_uJkSmRyXXbWxVXa_!!0-item_pic.jpg Invalid URL '02100713003': No schema supplied. Perhaps you meant http://02100713003?
02800614023
图片下载错误 ： http//img.alicdn.com/bao/uploaded/i3/821705368/TB1kKK6cInI8KJjSsziXXb8QpXa_!!0-item_pic.jpg Invalid URL '02800614023': No schema supplied. Perhaps you meant http://02800614023?

下图图片失败的提示，原因是天猫接口返回的商品数据如下：

{
item_id: 14292263734,
title: "XXXXXX",
img: "//img.alicdn.com/bao/uploaded/i2/821705368/TB1Us3Qcr_I8KJjy1XaXXbsxpXa_!!0-item_pic.jpg",
sold: "3",
quantity: 0,
totalSoldQuantity: 2937,
url: "//detail.m.tmall.com/item.htm?id=xxxxx",
price: "188.00",
titleUnderIconList: [ ]
},

不带协议名字！！！不知道是什么时候的历史留下的坑点吧！！！大厂也是有坑的！！

3、总结

具体的代码，可参考我github代码：

• iHTCboy/WebCrawlerExample: 网页爬虫实践示例

代码详细的解析还是参考这位大神的 利用Python爬虫爬取指定天猫店铺全店商品信息 - 晴空行 - 博客园，写的非常的详细！

整体来说，因为天猫的商品数据通过js来获取，所以比较容易获取到数据，而不用大量的爬取页面的商品，这个很赞！所以，爬虫这技术活，有很多方法，能找到好的方法，才是爬虫的最高境界啊！加油~

代码

python就是利害，一百行代码就搞定！

import os
import requests
import json
import csv
import random
import re
from datetime import datetime
from urllib import request
import time


class TM_producs(object):
    def __init__(self, storename):
        self.storename = storename
        self.url = 'https://{}.m.tmall.com'.format(storename)
        self.headers = {
            "user-agent": "Mozilla/5.0 (iPhone; CPU iPhone OS 9_1 like Mac OS X) AppleWebKit/601.1.46 "
                          "(KHTML, like Gecko) Version/9.0 Mobile/13B143 Safari/601.1"
        }
        datenum = datetime.now().strftime('%Y%m%d_%H%M%S')
        self.filename = '{}_{}.csv'.format(self.storename, datenum)
        self.get_file()

    def get_file(self):
        '''创建一个含有标题的表格'''
        title = ['item_id', 'product_id', 'price', 'quantity', 'sold', 'title', 'totalSoldQuantity', 'url', 'img']
        with open(self.filename, 'w', newline='') as f:
            writer = csv.DictWriter(f, fieldnames=title)
            writer.writeheader()
        return

    def get_totalpage(self):
        '''提取总页码数'''
        num = random.randint(83739921, 87739530)
        endurl = '/shop/shop_auction_search.do?sort=s&p=1&page_size=12&from=h5&ajson=1&_tm_source=tmallsearch&callback=jsonp_{}'
        url = self.url + endurl.format(num)
        html = requests.get(url, headers=self.headers).text
        infos = re.findall('\(({.*})\)', html)[0]
        infos = json.loads(infos)
        totalpage = infos.get('total_page')
        return int(totalpage)

    def get_products(self, page):
        '''提取单页商品列表'''
        num = random.randint(83739921, 87739530)
        endurl = '/shop/shop_auction_search.do?sort=s&p={}&page_size=12&from=h5&ajson=1&_tm_source=tmallsearch&callback=jsonp_{}'
        url = self.url + endurl.format(page, num)
        html = requests.get(url, headers=self.headers).text
        infos = re.findall('\(({.*})\)', html)[0]
        infos = json.loads(infos)
        products = infos.get('items')
        for product in products:
            del product['titleUnderIconList']
            item_id = product['item_id']
            product_id = self.get_product_spm(item_id)
            product['product_id'] = product_id
            imgUrl = 'https:' + product['img']
            self.save_img(imgUrl, product_id)
            item_id = product['item_id']

        # print(products)
        title = ['item_id', 'product_id', 'price', 'quantity', 'sold', 'title', 'totalSoldQuantity', 'url', 'img']
        with open(self.filename, 'a', encoding="utf-8", newline='') as f:
            writer = csv.DictWriter(f, fieldnames=title)
            writer.writerows(products)

    def get_product_spm(self, item_id):
        url = 'https://detail.m.tmall.com/item.htm?id={}'.format(item_id)
        html = requests.get(url, headers=self.headers).text
        # {"货号":"07300318000 "}
        product_id = re.findall(r'"货号":"(.+?)"}', html)[0].strip()
        print(product_id)
        return product_id

    def save_img(self, img_url, file_name):
        try:
            # 获得图片后缀
            file_suffix = os.path.splitext(img_url)[1]
            cwd = os.getcwd()
            save_path = os.path.join(cwd, 'images/')
            if not os.path.exists(save_path):
                os.makedirs(save_path)

            image_path = os.path.join(save_path, file_name + file_suffix)
            # 下载图片
            image = requests.get(img_url, headers=self.headers)
            # 命名并保存图片
            with open(image_path, 'wb') as f:
                f.write(image.content)

        except Exception as e:
            print('图片下载错误 ：', file_name, e)

    def main(self):
        '''循环爬取所有页面宝贝'''
        total_page = self.get_totalpage()
        for i in range(1, total_page + 1):
            self.get_products(i)
            print('总计{}页商品，已经提取第{}页'.format(total_page, i))
            time.sleep(1 + random.random())


if __name__ == '__main__':
    storename = 'mgssp'
    tm = TM_producs(storename)
    tm.main()

参考

• iHTCboy/WebCrawlerExample: 网页爬虫实践示例
• 利用Python爬虫爬取指定天猫店铺全店商品信息 - 晴空行 - 博客园
• Hopetree/E-commerce-crawlers: 电商网站爬虫合集，淘宝京东亚马逊等

• 如有疑问，欢迎在评论区一起讨论！
• 如有不正确的地方，欢迎指导！

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