scrapy pipeline 管道 (图片,文件)_files_result_field

一.scrapy的图片管道可以方便的快速的批量的 下载图片连接

  一. 普通使用方法

(1)settings. py
'scrapy. pipelines. imges. ImagesPipeline':300
FILES_ STORE = 'D:\\ cnblogs'      存放位置
FILES_ URLS_ FIELD = 'file_ urls'  下载图片url
FILES_ RESULT_ FIELD = 'files'     图片名字
FILES_ EXPIRES = 30                 #30天过期
 
(2)在item.py中添加两个字段
img_urls = scrapy. Field()
name= scrapy. Field()

二.通过继承使用图片管道 

  1.普通的单组

在item_completed(self, results, item, info):方法中   是图片下载完后进行操作result  包含 图片的url ,存放路径path  检查完     整性 checksum在该方法中可以将 默认的路径path  替换 成新的路径new_path 以便分类保存图片

from .settings import IMAGES_STORE
from scrapy.pipelines.images import ImagesPipeline
from scrapy.http import Request
import os
class DouyuproImagePipeline(ImagesPipeline):
    def get_media_requests(self, item, info):
        image_url = item['vertical_src']
        yield Request(url=image_url)
    def item_completed(self, results, item, info):
        # 老路径
        old_path = IMAGES_STORE + [x['path'] for ok, x in results if ok][0]
        # 新路径
        new_path = IMAGES_STORE + item['nickname'] + '.jpg'
        # 防止图片重复
        try:
            os.renames(old_path, new_path)
        except Exception as e:
 
           print('替换完成!')
        return item
'''
result=[  
        (True,  {'url': 'https://rpic.douyucdn.cn/asrpic/190725/6587811_2142.png/dy1', 
        'path': 'full/ab811811c57efac2ef5a354265e692eb44e0adb6.jpg',
        'checksum': 'cb171aeba651caab1b7827da664ef7c0'})
       ]
'''

   在get_media_requests 方法中构造下载图片的请求 

    二.修改名字图片默认名字

    没有item中的名字命名图片时  图片顺序混乱

    def file_path(self, request, response=None, info=None):
        image_guid = hashlib.sha1(to_bytes(request.url)).hexdigest()
        return 'full/%s.jpg' % (image_guid)

        原默认名字是以sha1  进行命名   重写这个方法也可以  修改图片名字

         下面这个演示了该方法的 一组item中有多个图片链接时  该如何处理:

class ManhuaPipeline(ImagesPipeline):
    name=0
    def get_media_requests(self, item, info):
        image_url_list = item['url_list']
        for url in image_url_list:
            yield Request(url=url,meta={'big_name':item['name']})
        self.name=0
    def file_path(self, request, response=None, info=None):
        self.name+=1
        big_name=request.meta['big_name']
        file_path=big_name+'/'+str(self.name)+'.jpg'
        return file_path
 
'''
result=[  
        (True,  {'url': 'https://rpic.douyucdn.cn/asrpic/190725/6587811_2142.png/dy1', 
        'path': 'full/ab811811c57efac2ef5a354265e692eb44e0adb6.jpg',
        'checksum': 'cb171aeba651caab1b7827da664ef7c0'}),
        (True,  {'url': 'https://rpic.douyucdn.cn/asrpic/190725/6587811_2142.png/dy1', 
        'path': 'full/ab811811c57efac2ef5a354265e692eb44e0adb6.jpg',
        'checksum': 'cb171aeba651caab1b7827da664ef7c0'}),
         (True,  {'url': 'https://rpic.douyucdn.cn/asrpic/190725/6587811_2142.png/dy1', 
        'path': 'full/ab811811c57efac2ef5a354265e692eb44e0adb6.jpg',
        'checksum': 'cb171aeba651caab1b7827da664ef7c0'})
       ]
'''

       当下载漫画这种大量图片  并排序时

class ManhuaPipeline(ImagesPipeline):
    name=0
    def get_media_requests(self, item, info):
        image_url_list = item['url_list']
        for url in image_url_list:
            self.name+=1
            yield Request(url=url,meta={'small_name':item['name'],'big_name':item['big_name'],'name':self.name})
    def file_path(self, request, response=None, info=None):
        small_name=request.meta['small_name']
        big_name=request.meta['big_name']
        name=request.meta['name']
        file_path=big_name+'/'+small_name+'/'+str(name)+'.jpg'
        print(file_path+'下载完成!')
        return file_path

 二.文件管道

(1)
settings. py
'scrapy. pipelines. files. FilesPipeline':300
 
(2)在item中添加两个字段
file_ urls = scrapy. Field()
files = scrapy. Field()
 
(3)settings. py
FILES_ STORE = 'D:\\ cnblogs'      存放位置
FILES_ URLS_ FIELD = 'file_ urls'  下载文件url
FILES_ RESULT_ FIELD = 'files'     文件信息字段
FILES_ EXPIRES = 30                 #30天过期

 
from scrapy.pipelines.files import FilesPipeline
from scrapy.http import Request
class LolPipeline(FilesPipeline):
    base_url='https://qt.qq.com/php_cgi/cod_video/php/get_video_url.php?game_id=2103041&vid='
    def get_media_requests(self, item, info):
        url=self.base_url+item['vid']
        return Request(url=url,meta={'view':item['view'],'name':item['game_name']})
 
    def file_path(self, request, response=None, info=None):
        view=request.meta['view']
        name=request.meta['name']
        path=str(view)+name+'.mp4'
        return path

   重点 :

      在下载文件有出现重定向url时,下载时日志信息会输出 

            downloader/response_status_count/200': 42,
           'downloader/response_status_count/302': 41,

     这时 在需要在setting  添加    MEDIA_ALLOW_REDIRECTS =True