爬虫源码1

# -*- coding: utf-8 -*-
import re
import scrapy
import datetime
from scrapy.http import Request
from urllib import parse
from scrapy.loader import ItemLoader
import time

from ArticleSpider.items import JobBoleArticleItem, ArticleItemLoader

from ArticleSpider.utils.common import get_md5


class JobboleSpider(scrapy.Spider):
    name = "jobbole"
    allowed_domains = ["python.jobbole.com"]
    start_urls = ['http://python.jobbole.com/all-posts/']

    def parse(self, response):
        """
        1. 获取文章列表页中的文章url并交给scrapy下载后并进行解析
        2. 获取下一页的url并交给scrapy进行下载， 下载完成后交给parse
        """

        #解析列表页中的所有文章url并交给scrapy下载后并进行解析
        post_nodes = response.css("#archive .floated-thumb .post-thumb a")
        for post_node in post_nodes:
            image_url = post_node.css("img::attr(src)").extract_first("")
            post_url = post_node.css("::attr(href)").extract_first("")
            yield Request(url=parse.urljoin(response.url, post_url), meta={"front_image_url":image_url}, callback=self.parse_detail)

        #提取下一页并交给scrapy进行下载
        next_url = response.css(".next.page-numbers::attr(href)").extract_first("")
        if next_url:
            yield Request(url=parse.urljoin(response.url, next_url), callback=self.parse)

    def parse_detail(self, response):
        article_item = JobBoleArticleItem()

        #提取文章的具体字段
        # title = response.xpath('//div[@class="entry-header"]/h1/text()').extract_first("")
        # create_date = response.xpath("//p[@class='entry-meta-hide-on-mobile']/text()").extract()[0].strip().replace("·","").strip()
        # praise_nums = response.xpath("//span[contains(@class, 'vote-post-up')]/h10/text()").extract()[0]
        # fav_nums = response.xpath("//span[contains(@class, 'bookmark-btn')]/text()").extract()[0]
        # match_re = re.match(".*?(d+).*", fav_nums)
        # if match_re:
        #     fav_nums = match_re.group(1)
        #
        # comment_nums = response.xpath("//a[@href='#article-comment']/span/text()").extract()[0]
        # match_re = re.match(".*?(d+).*", comment_nums)
        # if match_re:
        #     comment_nums = match_re.group(1)
        #
        # content = response.xpath("//div[@class='entry']").extract()[0]
        #
        # tag_list = response.xpath("//p[@class='entry-meta-hide-on-mobile']/a/text()").extract()
        # tag_list = [element for element in tag_list if not element.strip().endswith("评论")]
        # tags = ",".join(tag_list)

        #通过css选择器提取字段
        # front_image_url = response.meta.get("front_image_url", "")  #文章封面图
        # title = response.css(".entry-header h1::text").extract()[0]
        # create_date = response.css("p.entry-meta-hide-on-mobile::text").extract()[0].strip().replace("·","").strip()
        # praise_nums = response.css(".vote-post-up h10::text").extract()[0]
        # fav_nums = response.css(".bookmark-btn::text").extract()[0]
        # match_re = re.match(".*?(d+).*", fav_nums)
        # if match_re:
        #     fav_nums = int(match_re.group(1))
        # else:
        #     fav_nums = 0
        #
        # comment_nums = response.css("a[href='#article-comment'] span::text").extract()[0]
        # match_re = re.match(".*?(d+).*", comment_nums)
        # if match_re:
        #     comment_nums = int(match_re.group(1))
        # else:
        #     comment_nums = 0
        #
        # content = response.css("div.entry").extract()[0]
        #
        # tag_list = response.css("p.entry-meta-hide-on-mobile a::text").extract()
        # tag_list = [element for element in tag_list if not element.strip().endswith("评论")]
        # tags = ",".join(tag_list)
        #
        # article_item["url_object_id"] = get_md5(response.url)
        # article_item["title"] = title
        # article_item["url"] = response.url
        # try:
        #     create_date = datetime.datetime.strptime(create_date, "%Y/%m/%d").date()
        # except Exception as e:
        #     create_date = datetime.datetime.now().date()
        # article_item["create_date"] = create_date
        # article_item["front_image_url"] = [front_image_url]
        # article_item["praise_nums"] = praise_nums
        # article_item["comment_nums"] = comment_nums
        # article_item["fav_nums"] = fav_nums
        # article_item["tags"] = tags
        # article_item["content"] = content


        #通过item loader加载item
        front_image_url = response.meta.get("front_image_url", "")  # 文章封面图
        item_loader = ArticleItemLoader(item=JobBoleArticleItem(), response=response)
        item_loader.add_css("title", ".entry-header h1::text")
        item_loader.add_value("url", response.url)
        item_loader.add_value("url_object_id", get_md5(response.url))
        item_loader.add_css("create_date", "p.entry-meta-hide-on-mobile::text")
        item_loader.add_value("front_image_url", [front_image_url])
        item_loader.add_css("praise_nums", ".vote-post-up h10::text")
        item_loader.add_css("comment_nums", "a[href='#article-comment'] span::text")
        item_loader.add_css("fav_nums", ".bookmark-btn::text")
        item_loader.add_css("tags", "p.entry-meta-hide-on-mobile a::text")
        item_loader.add_css("content", "div.entry")

        article_item = item_loader.load_item()


        yield article_item

在scrapy中获取属性是::attr(src)

yield Request()中的callback指向需要处理的方法例如self.parse

注意：在scrapy中的items.py就好像django中的models

如下：

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

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

import datetime
import re

import scrapy
from scrapy.loader import ItemLoader
from scrapy.loader.processors import MapCompose, TakeFirst, Join

from utils.common import extract_num
from settings import SQL_DATETIME_FORMAT, SQL_DATE_FORMAT
from w3lib.html import remove_tags


class ArticlespiderItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    pass


def add_jobbole(value):
    return value+"-bobby"


def date_convert(value):
    try:
        create_date = datetime.datetime.strptime(value, "%Y/%m/%d").date()
    except Exception as e:
        create_date = datetime.datetime.now().date()

    return create_date


def get_nums(value):
    match_re = re.match(".*?(d+).*", value)
    if match_re:
        nums = int(match_re.group(1))
    else:
        nums = 0

    return nums

def return_value(value):
    return value


def remove_comment_tags(value):
    #去掉tag中提取的评论
    if "评论" in value:
        return ""
    else:
        return value

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


class JobBoleArticleItem(scrapy.Item):
    title = scrapy.Field()
    create_date = scrapy.Field(
        input_processor=MapCompose(date_convert),
    )
    url = scrapy.Field()
    url_object_id = scrapy.Field()
    front_image_url = scrapy.Field(
        output_processor=MapCompose(return_value)
    )
    front_image_path = scrapy.Field()
    praise_nums = scrapy.Field(
        input_processor=MapCompose(get_nums)
    )
    comment_nums = scrapy.Field(
        input_processor=MapCompose(get_nums)
    )
    fav_nums = scrapy.Field(
        input_processor=MapCompose(get_nums)
    )
    tags = scrapy.Field(
        input_processor=MapCompose(remove_comment_tags),
        output_processor=Join(",")
    )
    content = scrapy.Field()

    def get_insert_sql(self):
        insert_sql = """
            insert into jobbole_article(title, url, create_date, fav_nums, front_image_url, front_image_path,
            praise_nums, comment_nums, tags, content)
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s) ON DUPLICATE KEY UPDATE content=VALUES(fav_nums)
        """

        fron_image_url = ""
        # content = remove_tags(self["content"])

        if self["front_image_url"]:
            fron_image_url = self["front_image_url"][0]
        params = (self["title"], self["url"], self["create_date"], self["fav_nums"],
                  fron_image_url, self["front_image_path"], self["praise_nums"], self["comment_nums"],
                  self["tags"], self["content"])
        return insert_sql, params


class ZhihuQuestionItem(scrapy.Item):
    #知乎的问题 item
    zhihu_id = scrapy.Field()
    topics = scrapy.Field()
    url = scrapy.Field()
    title = scrapy.Field()
    content = scrapy.Field()
    answer_num = scrapy.Field()
    comments_num = scrapy.Field()
    watch_user_num = scrapy.Field()
    click_num = scrapy.Field()
    crawl_time = scrapy.Field()

    def get_insert_sql(self):
        #插入知乎question表的sql语句
        insert_sql = """
            insert into zhihu_question(zhihu_id, topics, url, title, content, answer_num, comments_num,
              watch_user_num, click_num, crawl_time
              )
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
            ON DUPLICATE KEY UPDATE content=VALUES(content), answer_num=VALUES(answer_num), comments_num=VALUES(comments_num),
              watch_user_num=VALUES(watch_user_num), click_num=VALUES(click_num)
        """
        zhihu_id = self["zhihu_id"][0]
        topics = ",".join(self["topics"])
        url = self["url"][0]
        title = "".join(self["title"])
        content = "".join(self["content"])
        answer_num = extract_num("".join(self["answer_num"]))
        comments_num = extract_num("".join(self["comments_num"]))

        if len(self["watch_user_num"]) == 2:
            watch_user_num = int(self["watch_user_num"][0])
            click_num = int(self["watch_user_num"][1])
        else:
            watch_user_num = int(self["watch_user_num"][0])
            click_num = 0

        crawl_time = datetime.datetime.now().strftime(SQL_DATETIME_FORMAT)

        params = (zhihu_id, topics, url, title, content, answer_num, comments_num,
                  watch_user_num, click_num, crawl_time)

        return insert_sql, params


class ZhihuAnswerItem(scrapy.Item):
    #知乎的问题回答item
    zhihu_id = scrapy.Field()
    url = scrapy.Field()
    question_id = scrapy.Field()
    author_id = scrapy.Field()
    content = scrapy.Field()
    parise_num = scrapy.Field()
    comments_num = scrapy.Field()
    create_time = scrapy.Field()
    update_time = scrapy.Field()
    crawl_time = scrapy.Field()

    def get_insert_sql(self):
        #插入知乎question表的sql语句
        insert_sql = """
            insert into zhihu_answer(zhihu_id, url, question_id, author_id, content, parise_num, comments_num,
              create_time, update_time, crawl_time
              ) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
              ON DUPLICATE KEY UPDATE content=VALUES(content), comments_num=VALUES(comments_num), parise_num=VALUES(parise_num),
              update_time=VALUES(update_time)
        """

        create_time = datetime.datetime.fromtimestamp(self["create_time"]).strftime(SQL_DATETIME_FORMAT)
        update_time = datetime.datetime.fromtimestamp(self["update_time"]).strftime(SQL_DATETIME_FORMAT)
        params = (
            self["zhihu_id"], self["url"], self["question_id"],
            self["author_id"], self["content"], self["parise_num"],
            self["comments_num"], create_time, update_time,
            self["crawl_time"].strftime(SQL_DATETIME_FORMAT),
        )

        return insert_sql, params

def replace_splash(value):
    return value.replace("/", "")

def handle_strip(value):
    return value.strip()

def handle_jobaddr(value):
    addr_list = value.split("
")
    addr_list = [item.strip() for item in addr_list if item.strip() != "查看地图"]
    return "".join(addr_list)

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

class LagouJobItem(scrapy.Item):
    #拉勾网职位
    title = scrapy.Field()
    url = scrapy.Field()
    salary = scrapy.Field()
    job_city = scrapy.Field(
        input_processor=MapCompose(replace_splash),
    )
    work_years = scrapy.Field(
        input_processor=MapCompose(replace_splash),
    )
    degree_need = scrapy.Field(
        input_processor=MapCompose(replace_splash),
    )
    job_type = scrapy.Field()
    publish_time = scrapy.Field()
    job_advantage = scrapy.Field()
    job_desc = scrapy.Field(
        input_processor=MapCompose(handle_strip),
    )
    job_addr = scrapy.Field(
        input_processor=MapCompose(remove_tags, handle_jobaddr),
    )
    company_name = scrapy.Field(
        input_processor=MapCompose(handle_strip),
    )
    company_url = scrapy.Field()
    crawl_time = scrapy.Field()
    crawl_update_time = scrapy.Field()

    def get_insert_sql(self):
        insert_sql = """
            insert into lagou_job(title, url, salary, job_city, work_years, degree_need,
            job_type, publish_time, job_advantage, job_desc, job_addr, company_url, company_name, job_id)
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s) ON DUPLICATE KEY UPDATE job_desc=VALUES(job_desc)
        """

        job_id = extract_num(self["url"])
        params = (self["title"], self["url"], self["salary"], self["job_city"], self["work_years"], self["degree_need"],
                  self["job_type"], self["publish_time"], self["job_advantage"], self["job_desc"], self["job_addr"], self["company_url"],
                  self["company_name"], job_id)

        return insert_sql, params

在这个类之中必须继承scrapy.Item

但是他的字段也是只有一种就是scrapy.Field()

在爬虫的文件中实例化之后像字典一样进行传至

是不是和django似曾相识？

注意：在写完之后要加一句：

yield article_item

这时scrapy就会把数据传递到piplines.py中

如何让scrapy自动下载图片？加上一句话！

'scrapy.pipelines.images.ImagesPipeline': 1, #后面的数字越小，表明越先进入管道

还需要告知哪个字段是url图片的字段，在settings中配置

IMAGES_URLS_FIELD = "front_image_url"

这个是固定写法，但是我的下载的图片我保存在哪？？

在settings中再次配置

project_dir = os.path.abspath(os.path.dirname(__file__))
IMAGES_STORE = os.path.join(project_dir, 'images')

完整版看截图：

 那如何将下载到本地文件的路径保存起来？

自定义piplines

from scrapy.pipelines.images import ImagesPipeline
class ArticleImagePipeline(ImagesPipeline):
    def item_completed(self, results, item, info):
        if "front_image_url" in item:
            for ok, value in results:
                image_file_path = value["path"]
            item["front_image_path"] = image_file_path

        return item

那如何过滤掉一些小图片呢？

在settings中配置

IMAGES_MIN_HEIGHT = 100
IMAGES_MIN_WIDTH = 100

 如果想保存到数据库中就需要在piplines中定义一个类，用来处理item的方法是必须使用

process_item(self, item, spider)

    return item  

必须要return回去item，因为以后的piplines可能会需要使用item