python利用xpath爬取网上数据并存储到django模型中

时间：2021-03-18 python爬虫查看: 1188

帮朋友制作一个网站，需要一些产品数据信息，因为是代理其他公司产品，直接爬取代理公司产品数据

1.设计数据库

from django.db import models
from uuslug import slugify
import uuid
import os


def products_directory_path(instance, filename):
  ext = filename.split('.')[-1]
  filename = '{}.{}'.format(uuid.uuid4().hex[:8], ext)
  # return the whole path to the file
  return os.path.join('images', "products", instance.title, filename)


def product_relatedimage_directory_path(instance, filename):
  ext = filename.split('.')[-1]
  filename = '{}.{}'.format(uuid.uuid4().hex[:8], ext)
  # return the whole path to the file
  return os.path.join('images', "product_relatedimage", instance.product.title, filename)


class ProductsCategory(models.Model):
  """产品分类"""
  name = models.CharField('产品分类名', max_length=80, unique=True)
  description = models.TextField('产品分类描述', blank=True, null=True)
  slug = models.SlugField('slug', max_length=80, blank=True, null=True)
  parent_category = models.ForeignKey('self', verbose_name="父级分类", blank=True, null=True, on_delete=models.CASCADE)

  def save(self, *args, **kwargs):
    if not self.id or not self.slug:
      self.slug = slugify(self.name)
    super().save(*args, **kwargs)

  def __str__(self):
    return self.name

  class Meta:
    ordering = ['name']
    verbose_name = "产品分类"
    verbose_name_plural = verbose_name


class ProductsTag(models.Model):
  """产品标签"""
  name = models.CharField('产品标签名', max_length=30, unique=True)
  slug = models.SlugField('slug', max_length=40)

  def __str__(self):
    return self.name

  def save(self, *args, **kwargs):
    if not self.id or not self.slug:
      self.slug = slugify(self.name)
    super().save(*args, **kwargs)

  class Meta:
    ordering = ['name']
    verbose_name = "产品标签"
    verbose_name_plural = verbose_name


class Product(models.Model):
  title = models.CharField('标题', max_length=255, unique=True)
  slug = models.SlugField('slug', max_length=255, blank=True, null=True)
  jscs = models.TextField('技术参数', blank=True, null=True)
  image = models.ImageField(upload_to=products_directory_path, verbose_name="产品图片")
  views = models.PositiveIntegerField('浏览量', default=0)
  category = models.ForeignKey('ProductsCategory', verbose_name='分类', on_delete=models.CASCADE, blank=True, null=True)
  tags = models.ManyToManyField('ProductsTag', verbose_name='标签集合', blank=True)

  def save(self, *args, **kwargs):
    if not self.id or not self.slug:
      self.slug = slugify(self.title)
    super().save(*args, **kwargs)

  def update_views(self):
    self.views += 1
    self.save(update_fields=['views'])

  def get_pre(self):
    return Product.objects.filter(id__lt=self.id).order_by('-id').first()

  def get_next(self):
    return Product.objects.filter(id__gt=self.id).order_by('id').first()

  def __str__(self):
    return self.title

  class Meta:
    verbose_name = "产品"
    verbose_name_plural = verbose_name


class ProductAdvantage(models.Model):
  content = models.TextField('产品优势', blank=True, null=True)
  product = models.ForeignKey(Product, on_delete=models.CASCADE, blank=True, null=True)

  def __str__(self):
    return self.content

  class Meta:
    verbose_name = "产品优势"
    verbose_name_plural = verbose_name


class ProductBody(models.Model):
  body = models.CharField('产品内容', max_length=256, blank=True, null=True)
  product = models.ForeignKey(Product, on_delete=models.CASCADE, blank=True, null=True)

  def __str__(self):
    return self.product.title

  class Meta:
    verbose_name = "产品内容"
    verbose_name_plural = verbose_name

2.脚本编写

2.1编写获取网页源代码函数

def get_one_page(url):
  try:
    headers = {
      "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36"}
    res = requests.get(url=url, headers=headers)
    res.encoding = 'utf-8'
    if res.status_code == 200:
      return res.text
    else:
      return None
  except Exception:
    return None

2.2根据base页面获取所有产品分类页面链接

if __name__ == '__main__':
  content = get_one_page(url)
  tree = etree.HTML(content)
  # 产品分类url
  catgory_urls = tree.xpath('//div[@class="fdh-01-nav"]/div/h3/a/@href')
  # 处理catgory_urls
  for url in catgory_urls:
    url = 'http://www.kexinjianji.com' + url
    print(url)

2.3根据产品分类页面链接获取对应所有产品链接

if __name__ == '__main__':
  content = get_one_page(url)
  tree = etree.HTML(content)
  # 产品分类
  catgory = tree.xpath('//div[@class="cplb-3n-ts-03 b"]/h3/span/text()')
  print("产品分类：" + catgory[0])
  # 该分类下产品url
  urls = tree.xpath('//div[@class="cplb-3n-ts-03-list"]/dl/dt/a/@href')
  # 处理url
  for url in urls:
    url = 'http://www.kexinjianji.com' + url
    print(url)
  print("=====================================================")

两者结合起来就可以打印出所有产品链接

if __name__ == '__main__':
  content = get_one_page(url)
  tree = etree.HTML(content)
  # 产品分类url
  catgory_urls = tree.xpath('//div[@class="fdh-01-nav"]/div/h3/a/@href')
  # 处理catgory_urls
  for url in catgory_urls:
    url = 'http://www.kexinjianji.com' + url
    content = get_one_page(url)
    tree = etree.HTML(content)
    # 产品分类
    catgory = tree.xpath('//div[@class="cplb-3n-ts-03 b"]/h3/span/text()')
    print("产品分类：" + catgory[0])
    # 该分类下产品url
    urls = tree.xpath('//div[@class="cplb-3n-ts-03-list"]/dl/dt/a/@href')
    # 处理url
    for url in urls:
      url = 'http://www.kexinjianji.com' + url
      print(url)
    print("=====================================================")

2.2使用xpath解析函数返回产品链接的内容

if __name__ == '__main__':
  content = get_one_page(url)
  tree = etree.HTML(content)
  # 产品名称
  title = tree.xpath('//*[@id="wrap"]//h1/text()')
  images = tree.xpath('//div[@class="sol_tj_left"]/a/img/@src')
  # 产品图片
  images_url = 'http://www.kexinjianji.com/' + images[0]
  # 性能特点
  xntd = tree.xpath('//div[@class="w"]//div/span/text()|//div[@class="w"]//div/text()')
  # 技术参数
  jscs = tree.xpath('//table')[0]
  jscs_str = etree.tostring(jscs, encoding='utf-8').decode('utf-8')
  # 产品内容
  cpnr = tree.xpath('//div[@class="describe"]/p')
  print('产品名称:' + title[0])
  print('产品图片:' + images_url)
  for td in xntd:
    print('性能特点:' + td)
  print('技术参数:' + jscs_str)
  for cp in cpnr:
    # string(.) 获取当前标签下所有文本内容
    cp = cp.xpath('string(.)')
    print('产品内容:' + cp)
  print('============================================')

将三者结合在一起就可以获取所有产品信息

if __name__ == '__main__':
  content = get_one_page(url)
  tree = etree.HTML(content)
  # 产品分类url
  catgory_urls = tree.xpath('//div[@class="fdh-01-nav"]/div/h3/a/@href')
  # 处理catgory_urls
  for url in catgory_urls:
    url = 'http://www.kexinjianji.com' + url
    content = get_one_page(url)
    tree = etree.HTML(content)
    # 产品分类
    catgory = tree.xpath('//div[@class="cplb-3n-ts-03 b"]/h3/span/text()')
    # 该分类下产品url
    urls = tree.xpath('//div[@class="cplb-3n-ts-03-list"]/dl/dt/a/@href')
    # 处理url
    for url in urls:
      url = 'http://www.kexinjianji.com' + url
      content = get_one_page(url)
      try:
        tree = etree.HTML(content)
        # 产品名称
        title = tree.xpath('//*[@id="wrap"]//h1/text()')
        images = tree.xpath('//div[@class="sol_tj_left"]/a/img/@src')
        # 产品图片
        images_url = 'http://www.kexinjianji.com' + images[0]
        # 性能特点
        xntd = tree.xpath('//div[@class="w"]//div/span/text()|//div[@class="w"]//div/text()')
        # 技术参数
        jscs = tree.xpath('//table')[0]
        jscs_str = etree.tostring(jscs, encoding='utf-8').decode('utf-8')
        # 产品内容
        cpnr = tree.xpath('//div[@class="describe"]/p')
        print("产品分类：" + catgory[0])
        print('产品链接:' + url)
        print('产品名称:' + title[0])
        print('产品图片:' + images_url)
        for td in xntd:
          print('性能特点:' + td.strip())
        # print('技术参数:' + jscs_str)
        for cp in cpnr:
          # string(.) 获取当前标签下所有文本内容
          cp = cp.xpath('string(.)')
          print('产品内容:' + cp)
        print('============================================')
      except Exception as e:
        print(e)
        print('出错url:' + url)
        pass

3.存储到django模型

import requests
from lxml.html import etree
import os
import django
import uuid
from django.core.files.base import ContentFile

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "jiaobanzhan.settings")
django.setup()

from products.models import ProductBody, ProductsCategory, Product, ProductAdvantage

url = 'http://www.kexinjianji.com/product/hzshntjbz_1/'


def get_one_page(url):
  try:
    headers = {
      "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36"}
    res = requests.get(url=url, headers=headers, timeout=10)
    res.encoding = 'utf-8'
    if res.status_code == 200:
      return res.text
    else:
      return None
  except Exception:
    print('aa')
    return None


if __name__ == '__main__':
  content = get_one_page(url)
  tree = etree.HTML(content)
  # 产品分类url
  catgory_urls = tree.xpath('//div[@class="fdh-01-nav"]/div/h3/a/@href')
  # 处理catgory_urls
  for url in catgory_urls:
    url = 'http://www.kexinjianji.com' + url
    content = get_one_page(url)
    tree = etree.HTML(content)
    # 产品分类
    p_catgory = tree.xpath('//div[@class="cplb-3n-ts-03 b"]/h3/span/text()')
    # 该分类下产品url
    urls = tree.xpath('//div[@class="cplb-3n-ts-03-list"]/dl/dt/a/@href')
    # 处理url
    for url in urls:
      url = 'http://www.kexinjianji.com' + url
      content = get_one_page(url)
      try:
        tree = etree.HTML(content)
        # 产品名称
        title = tree.xpath('//*[@id="wrap"]//h1/text()')
        images = tree.xpath('//div[@class="sol_tj_left"]/a/img/@src')
        # 产品图片
        images_url = 'http://www.kexinjianji.com' + images[0]
        # 性能特点
        xntd = tree.xpath('//div[@class="w"]//div/span/text()|//div[@class="w"]//div/text()')
        # 技术参数
        jscs = tree.xpath('//table')[0]
        jscs_str = etree.tostring(jscs, encoding='utf-8').decode('utf-8')
        # 产品内容
        cpnr = tree.xpath('//div[@class="describe"]/p')
        # 判断是否有这分类，没有则新建
        catgory = p_catgory[0]
        products_catgory = ProductsCategory.objects.filter(name=catgory).exists()
        if products_catgory:
          products_catgory = ProductsCategory.objects.get(name=catgory)
        else:
          products_catgory = ProductsCategory(name=catgory)
          products_catgory.save()
        print(products_catgory)

        # 保存产品图片
        image_content = requests.get(url=images_url)
        ext = images_url.split('.')[-1] # 获取图片类型
        filename = '{}.{}'.format(uuid.uuid4().hex[:8], ext) # 随机生成图片名字
        upload_image_file = ContentFile(image_content.content, name=filename) # 将图片保存为django类型
        product = Product(title=title[0], jscs=jscs_str, image=upload_image_file, category=products_catgory)
        product.save()
        for td in xntd:
          product_advantage = ProductAdvantage()
          product_advantage.content = td
          product_advantage.product = product
          product_advantage.save()
        for cp in cpnr:
          cp = cp.xpath('string(.)')
          product_body = ProductBody()
          product_body.body = cp
          product_body.product = product
          product_body.save()
      except Exception as e:
        print(e)
        print('出错url:' + url)

最后自己手动处理出错url（页面没有获取到技术参数，技术参数是一张图片）

4.总结

1.xpath 获取标签内容时，p标签中嵌套span标签，源码如下

<div class="describe" style="position: relative;"> 
   <p><span>板  宽：</span>1500mm</p> 
   <p><span>板  厚：</span>4.5 mm</p> 
   <p><span>出料口：</span>6口</p> 
   <p><span>重  量：</span>6000 kg</p>
</div>

使用xpath获取p标签内容
我想得到的效果如下
板宽：1500mm
板厚：4.5 mm
出料口：6口
重量：6000 kg
使用以下xpath 只能分开获取，不是想要的效果

//div[@class="describe"]/p/span/text()|//div[@class="describe"]/p/text()

百度之后找到的解决办法，使用xpath(‘string(.)')
1.先获取所有p标签

cpnr = tree.xpath('//div[@class="describe"]/p')

2.使用**string(.)**获取所有标签所有文本

cp = cp.xpath('string(.)')

循环遍历所有p标签即可

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