16-python爬虫之Requests库爬取海量图片

曾庆林
82 阅读9分钟

Requests 是一个 Python 的 HTTP 客户端库。

Request支持HTTP连接保持和连接池，支持使用cookie保持会话，支持文件上传，支持自动响应内容的编码，支持国际化的URL和POST数据自动编码。

在python内置模块的基础上进行了高度的封装从而使得python进行网络请求时，变得人性化，使用Requests可以轻而易举的完成浏览器可有的任何操作。现代，国际化，友好。

requests会自动实现持久连接keep-alive

开源地址：github.com/kennethreit… 中文文档：docs.python-requests.org/zh_CN/lates…

目录 一、Requests基础 二、发送请求与接收响应（基本GET请求） 三、发送请求与接收响应（基本POST请求） 四、response属性 五、代理 六、cookie和session 七、案例

一、Requests基础

1.安装Requests库

pip install  requests

2.使用Requests库

import requests

二、发送请求与接收响应（基本GET请求）

response = requests.get(url)

1.传送 parmas参数

  • 参数包含在url中
response = requests.get("http://httpbin.org/get?name=zhangsan&age=22")
print(response.text)

image

  • 通过get方法传送参数
data = {
        "name": "zhangsan",
        "age": 30
    }
response = requests.get("http://httpbin.org/get", params=data)
print(response.text)

2.模拟发送请求头（传送headers参数）

headers = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"
}
response = requests.get("http://httpbin.org/get", headers=headers)
print(response.text)

三、发送请求与接收响应（基本POST请求）

response = requests.post(url, data = data, headers=headers)

四、response属性

属性描述
response.text获取str类型（Unicode编码）的响应
response.content获取bytes类型的响应
response.status_code获取响应状态码
response.headers获取响应头
response.request获取响应对应的请求

五、代理

proxies = {
    "http": "https://175.44.148.176:9000",
    "https": "https://183.129.207.86:14002"
}
response = requests.get("https://www.baidu.com/", proxies=proxies)

六、cookie和session

  • 使用的cookie和session好处：很多网站必须登录之后(或者获取某种权限之后)才能能够请求到相关数据。
  • 使用的cookie和session的弊端：一套cookie和session往往和一个用户对应.请求太快，请求次数太多，容易被服务器识别为爬虫，从而使账号收到损害。

1.不需要cookie的时候尽量不去使用cookie。 2.为了获取登录之后的页面，我们必须发送带有cookies的请求，此时为了确保账号安全应该尽量降低数据 采集速度。

1.cookie

（1）获取cookie信息

response.cookies

2.session

（1）构造session回话对象

session = requests.session()

示例：

def login_renren():
    login_url = 'http://www.renren.com/SysHome.do'
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"
    }

    session = requests.session()

    login_data = {
        "email": "账号",
        "password": "密码"
    }

    response = session.post(login_url, data=login_data, headers=headers)

    response = session.get("http://www.renren.com/971909762/newsfeed/photo")
    print(response.text)

login_renren()

七、案例

image

案例1：百度贴吧页面爬取（GET请求）

import requests
import sys

class BaiduTieBa:
    def __init__(self, name, pn, ):
        self.name = name
        self.url = "http://tieba.baidu.com/f?kw={}&ie=utf-8&pn={}".format(name, pn)
        self.headers = {
            # "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"

            # 使用较老版本的请求头，该浏览器不支持js
            "User-Agent": "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)"
        }
        self.url_list = [self.url + str(pn*50) for pn in range(pn)]
        print(self.url_list)

    def get_data(self, url):
        """
        请求数据
        :param url:
        :return:
        """
        response = requests.get(url, headers=self.headers)
        return response.content

    def save_data(self, data, num):
        """
        保存数据
        :param data:
        :param num:
        :return:
        """
        file_name = "./pages/" + self.name + "_" + str(num) + ".html"
        with open(file_name, "wb") as f:
            f.write(data)

    def run(self):
        for url in self.url_list:
            data = self.get_data(url)
            num = self.url_list.index(url)
            self.save_data(data, num)

if __name__ == "__main__":
    name = sys.argv[1]
    pn = int(sys.argv[2])
    baidu = BaiduTieBa(name, pn)
    baidu.run()

案例2：金山词霸翻译（POST请求）

import requests
import sys
import json

class JinshanCiBa:
    def __init__(self, words):
        self.url = "http://fy.iciba.com/ajax.php?a=fy"
        self.headers = {
            "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 SE 2.X MetaSr 1.0",
            "X-Requested-With": "XMLHttpRequest"
        }
        self.post_data = {
            "f": "auto",
            "t": "auto",
            "w": words
        }

    def get_data(self):
        """
        请求数据
        :param url:
        :return:
        """
        response = requests.post(self.url, data=self.post_data, headers=self.headers)
        return response.text

    def show_translation(self):
        """
        显示翻译结果
        :param data:
        :param num:
        :return:
        """
        response = self.get_data()
        json_data = json.loads(response, encoding='utf-8')
        if json_data['status'] == 0:
            translation = json_data['content']['word_mean']
        elif json_data['status'] == 1:
            translation = json_data['content']['out']
        else:
            translation = None
        print(translation)

    def run(self):
        self.show_translation()

if __name__ == "__main__":
    words = sys.argv[1]
    ciba = JinshanCiBa(words)
    ciba.run()

在这里插入图片描述

案例3：百度贴吧图片爬取

（1）普通版

从已下载页面中提取url来爬取图片（页面下载方法见案例1）

from lxml import etree
import requests

class DownloadPhoto:
    def __init__(self):
        pass

    def download_img(self, url):
        response = requests.get(url)
        index = url.rfind('/')
        file_name = url[index + 1:]
        print("下载图片：" + file_name)
        save_name = "./photo/" + file_name
        with open(save_name, "wb") as f:
            f.write(response.content)

    def parse_photo_url(self, page):
        html = etree.parse(page, etree.HTMLParser())
        nodes = html.xpath("//a[contains(@class, 'thumbnail')]/img/@bpic")
        print(nodes)
        print(len(nodes))
        for node in nodes:
            self.download_img(node)

if __name__ == "__main__":
    download = DownloadPhoto()
    for i in range(6000):
        download.parse_photo_url("./pages/校花_{}.html".format(i))

（2）多线程版

main.py

import requests
from lxml import etree

from file_download import DownLoadExecutioner, file_download

class XiaoHua:
    def __init__(self, init_url):
        self.init_url = init_url
        self.download_executioner = DownLoadExecutioner()

    def start(self):
        self.download_executioner.start()
        self.download_img(self.init_url)

    def download_img(self, url):
        html_text = file_download(url, type='text')
        html = etree.HTML(html_text)
        img_urls = html.xpath("//a[contains(@class,'thumbnail')]/img/@bpic")
        self.download_executioner.put_task(img_urls)

        # 获取下一页的连接
        next_page = html.xpath("//div[@id='frs_list_pager']/a[contains(@class,'next')]/@href")
        next_page = "http:" + next_page[0]
        self.download_img(next_page)

if __name__ == '__main__':
    x = XiaoHua("http://tieba.baidu.com/f?kw=校花&ie=utf-8")
    x.start()

file_download.py

import requests
import threading
from queue import Queue

def file_download(url, type='content'):
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko'
    }
    r = requests.get(url, headers=headers)
    if type == 'text':
        return r.text

    return r.content

class DownLoadExecutioner(threading.Thread):
    def __init__(self):
        super().__init__()
        self.q = Queue(maxsize=50)
        # 图片保存目录
        self.save_dir = './img/'
        # 图片计数
        self.index = 0

    def put_task(self, urls):
        if isinstance(urls, list):
            for url in urls:
                self.q.put(url)
        else:
            self.q.put(urls)

    def run(self):
        while True:
            url = self.q.get()
            content = file_download(url)

            # 截取图片名称
            index = url.rfind('/')
            file_name = url[index+1:]
            save_name = self.save_dir + file_name
            with open(save_name, 'wb+') as f:
                f.write(content)
                self.index += 1
                print(save_name + "下载成功!  当前已下载图片总数：" + str(self.index))

（3）线程池版

main.py

import requests
from lxml import etree

from file_download_pool import DownLoadExecutionerPool, file_download

class XiaoHua:
    def __init__(self, init_url):
        self.init_url = init_url
        self.download_executioner = DownLoadExecutionerPool()

    def start(self):
        self.download_img(self.init_url)

    def download_img(self, url):
        html_text = file_download(url, type='text')
        html = etree.HTML(html_text)
        img_urls = html.xpath("//a[contains(@class,'thumbnail')]/img/@bpic")
        self.download_executioner.put_task(img_urls)

        # 获取下一页的连接
        next_page = html.xpath("//div[@id='frs_list_pager']/a[contains(@class,'next')]/@href")
        next_page = "http:" + next_page[0]
        self.download_img(next_page)

if __name__ == '__main__':
    x = XiaoHua("http://tieba.baidu.com/f?kw=校花&ie=utf-8")
    x.start()

file_download_pool.py

import requests
import concurrent.futures as futures

def file_download(url, type='content'):
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko'
    }
    r = requests.get(url, headers=headers)
    if type == 'text':
        return r.text

    return r.content

class DownLoadExecutionerPool():
    def __init__(self):
        super().__init__()
        # 图片保存目录
        self.save_dir = './img_pool/'
        # 图片计数
        self.index = 0
        # 线程池
        self.ex = futures.ThreadPoolExecutor(max_workers=30)

    def put_task(self, urls):
        if isinstance(urls, list):
            for url in urls:
                self.ex.submit(self.save_img, url)
        else:
            self.ex.submit(self.save_img, urls)

    def save_img(self, url):
        content = file_download(url)

        # 截取图片名称
        index = url.rfind('/')
        file_name = url[index+1:]
        save_name = self.save_dir + file_name
        with open(save_name, 'wb+') as f:
            f.write(content)
            self.index += 1
            print(save_name + "下载成功!  当前已下载图片总数：" + str(self.index))

作者：Recalcitrant 链接：www.jianshu.com/p/140012f88… 是一个 Python 的 HTTP 客户端库。

Request支持HTTP连接保持和连接池，支持使用cookie保持会话，支持文件上传，支持自动响应内容的编码，支持国际化的URL和POST数据自动编码。 在python内置模块的基础上进行了高度的封装，从而使得python进行网络请求时，变得人性化，使用Requests可以轻而易举的完成浏览器可有的任何操作。现代，国际化，友好。

requests会自动实现持久连接keep-alive ![image](upload-images.jianshu.io/upload_imag…

开源地址：github.com/kennethreit… 中文文档：docs.python-requests.org/zh_CN/lates…

目录 一、Requests基础 二、发送请求与接收响应（基本GET请求） 三、发送请求与接收响应（基本POST请求） 四、response属性 五、代理 六、cookie和session 七、案例

一、Requests基础

1.安装Requests库

pip install  requests

2.使用Requests库

import requests

二、发送请求与接收响应（基本GET请求）

response = requests.get(url)

1.传送 parmas参数

  • 参数包含在url中
response = requests.get("http://httpbin.org/get?name=zhangsan&age=22")
print(response.text)

image

  • 通过get方法传送参数
data = {
        "name": "zhangsan",
        "age": 30
    }
response = requests.get("http://httpbin.org/get", params=data)
print(response.text)

2.模拟发送请求头（传送headers参数）

headers = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"
}
response = requests.get("http://httpbin.org/get", headers=headers)
print(response.text)

三、发送请求与接收响应（基本POST请求）

response = requests.post(url, data = data, headers=headers)

四、response属性

属性描述
response.text获取str类型（Unicode编码）的响应
response.content获取bytes类型的响应
response.status_code获取响应状态码
response.headers获取响应头
response.request获取响应对应的请求

五、代理

proxies = {
    "http": "https://175.44.148.176:9000",
    "https": "https://183.129.207.86:14002"
}
response = requests.get("https://www.baidu.com/", proxies=proxies)

六、cookie和session

  • 使用的cookie和session好处：很多网站必须登录之后(或者获取某种权限之后)才能能够请求到相关数据。
  • 使用的cookie和session的弊端：一套cookie和session往往和一个用户对应.请求太快，请求次数太多，容易被服务器识别为爬虫，从而使账号收到损害。

1.不需要cookie的时候尽量不去使用cookie。 2.为了获取登录之后的页面，我们必须发送带有cookies的请求，此时为了确保账号安全应该尽量降低数据 采集速度。

1.cookie

（1）获取cookie信息

response.cookies

2.session

（1）构造session回话对象

session = requests.session()

示例：

def login_renren():
    login_url = 'http://www.renren.com/SysHome.do'
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"
    }

    session = requests.session()

    login_data = {
        "email": "账号",
        "password": "密码"
    }

    response = session.post(login_url, data=login_data, headers=headers)

    response = session.get("http://www.renren.com/971909762/newsfeed/photo")
    print(response.text)

login_renren()

七、案例

image

案例1：百度贴吧页面爬取（GET请求）

import requests
import sys

class BaiduTieBa:
    def __init__(self, name, pn, ):
        self.name = name
        self.url = "http://tieba.baidu.com/f?kw={}&ie=utf-8&pn={}".format(name, pn)
        self.headers = {
            # "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"

            # 使用较老版本的请求头，该浏览器不支持js
            "User-Agent": "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)"
        }
        self.url_list = [self.url + str(pn*50) for pn in range(pn)]
        print(self.url_list)

    def get_data(self, url):
        """
        请求数据
        :param url:
        :return:
        """
        response = requests.get(url, headers=self.headers)
        return response.content

    def save_data(self, data, num):
        """
        保存数据
        :param data:
        :param num:
        :return:
        """
        file_name = "./pages/" + self.name + "_" + str(num) + ".html"
        with open(file_name, "wb") as f:
            f.write(data)

    def run(self):
        for url in self.url_list:
            data = self.get_data(url)
            num = self.url_list.index(url)
            self.save_data(data, num)

if __name__ == "__main__":
    name = sys.argv[1]
    pn = int(sys.argv[2])
    baidu = BaiduTieBa(name, pn)
    baidu.run()

案例2：金山词霸翻译（POST请求）

import requests
import sys
import json

class JinshanCiBa:
    def __init__(self, words):
        self.url = "http://fy.iciba.com/ajax.php?a=fy"
        self.headers = {
            "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 SE 2.X MetaSr 1.0",
            "X-Requested-With": "XMLHttpRequest"
        }
        self.post_data = {
            "f": "auto",
            "t": "auto",
            "w": words
        }

    def get_data(self):
        """
        请求数据
        :param url:
        :return:
        """
        response = requests.post(self.url, data=self.post_data, headers=self.headers)
        return response.text

    def show_translation(self):
        """
        显示翻译结果
        :param data:
        :param num:
        :return:
        """
        response = self.get_data()
        json_data = json.loads(response, encoding='utf-8')
        if json_data['status'] == 0:
            translation = json_data['content']['word_mean']
        elif json_data['status'] == 1:
            translation = json_data['content']['out']
        else:
            translation = None
        print(translation)

    def run(self):
        self.show_translation()

if __name__ == "__main__":
    words = sys.argv[1]
    ciba = JinshanCiBa(words)
    ciba.run()

案例3：百度贴吧图片爬取

（1）普通版

从已下载页面中提取url来爬取图片（页面下载方法见案例1）

from lxml import etree
import requests

class DownloadPhoto:
    def __init__(self):
        pass

    def download_img(self, url):
        response = requests.get(url)
        index = url.rfind('/')
        file_name = url[index + 1:]
        print("下载图片：" + file_name)
        save_name = "./photo/" + file_name
        with open(save_name, "wb") as f:
            f.write(response.content)

    def parse_photo_url(self, page):
        html = etree.parse(page, etree.HTMLParser())
        nodes = html.xpath("//a[contains(@class, 'thumbnail')]/img/@bpic")
        print(nodes)
        print(len(nodes))
        for node in nodes:
            self.download_img(node)

if __name__ == "__main__":
    download = DownloadPhoto()
    for i in range(6000):
        download.parse_photo_url("./pages/校花_{}.html".format(i))

（2）多线程版

main.py

import requests
from lxml import etree

from file_download import DownLoadExecutioner, file_download

class XiaoHua:
    def __init__(self, init_url):
        self.init_url = init_url
        self.download_executioner = DownLoadExecutioner()

    def start(self):
        self.download_executioner.start()
        self.download_img(self.init_url)

    def download_img(self, url):
        html_text = file_download(url, type='text')
        html = etree.HTML(html_text)
        img_urls = html.xpath("//a[contains(@class,'thumbnail')]/img/@bpic")
        self.download_executioner.put_task(img_urls)

        # 获取下一页的连接
        next_page = html.xpath("//div[@id='frs_list_pager']/a[contains(@class,'next')]/@href")
        next_page = "http:" + next_page[0]
        self.download_img(next_page)

if __name__ == '__main__':
    x = XiaoHua("http://tieba.baidu.com/f?kw=校花&ie=utf-8")
    x.start()

file_download.py

import requests
import threading
from queue import Queue

def file_download(url, type='content'):
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko'
    }
    r = requests.get(url, headers=headers)
    if type == 'text':
        return r.text

    return r.content

class DownLoadExecutioner(threading.Thread):
    def __init__(self):
        super().__init__()
        self.q = Queue(maxsize=50)
        # 图片保存目录
        self.save_dir = './img/'
        # 图片计数
        self.index = 0

    def put_task(self, urls):
        if isinstance(urls, list):
            for url in urls:
                self.q.put(url)
        else:
            self.q.put(urls)

    def run(self):
        while True:
            url = self.q.get()
            content = file_download(url)

            # 截取图片名称
            index = url.rfind('/')
            file_name = url[index+1:]
            save_name = self.save_dir + file_name
            with open(save_name, 'wb+') as f:
                f.write(content)
                self.index += 1
                print(save_name + "下载成功!  当前已下载图片总数：" + str(self.index))

（3）线程池版

main.py

import requests
from lxml import etree

from file_download_pool import DownLoadExecutionerPool, file_download

class XiaoHua:
    def __init__(self, init_url):
        self.init_url = init_url
        self.download_executioner = DownLoadExecutionerPool()

    def start(self):
        self.download_img(self.init_url)

    def download_img(self, url):
        html_text = file_download(url, type='text')
        html = etree.HTML(html_text)
        img_urls = html.xpath("//a[contains(@class,'thumbnail')]/img/@bpic")
        self.download_executioner.put_task(img_urls)

        # 获取下一页的连接
        next_page = html.xpath("//div[@id='frs_list_pager']/a[contains(@class,'next')]/@href")
        next_page = "http:" + next_page[0]
        self.download_img(next_page)

if __name__ == '__main__':
    x = XiaoHua("http://tieba.baidu.com/f?kw=校花&ie=utf-8")
    x.start()

file_download_pool.py

import requests
import concurrent.futures as futures

def file_download(url, type='content'):
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko'
    }
    r = requests.get(url, headers=headers)
    if type == 'text':
        return r.text

    return r.content

class DownLoadExecutionerPool():
    def __init__(self):
        super().__init__()
        # 图片保存目录
        self.save_dir = './img_pool/'
        # 图片计数
        self.index = 0
        # 线程池
        self.ex = futures.ThreadPoolExecutor(max_workers=30)

    def put_task(self, urls):
        if isinstance(urls, list):
            for url in urls:
                self.ex.submit(self.save_img, url)
        else:
            self.ex.submit(self.save_img, urls)

    def save_img(self, url):
        content = file_download(url)

        # 截取图片名称
        index = url.rfind('/')
        file_name = url[index+1:]
        save_name = self.save_dir + file_name
        with open(save_name, 'wb+') as f:
            f.write(content)
            self.index += 1
            print(save_name + "下载成功!  当前已下载图片总数：" + str(self.index))

作者：Recalcitrant 链接：www.jianshu.com/p/140012f88…

在线练习：https://www.520mg.com/it IT 入门感谢关注

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