一、前言 

1. scrapy依赖包：

二、创建工程

1. 创建scrapy工程：

scrapy staratproject ArticleSpider

 

2. 开始（创建）新的爬虫：

cd ArticleSpiderscrapy genspider jobbole blog.jobbole.com //默认通过 'basic' module创建

 

三、用pycharm调试scrapy

1. 在 ArticleSpider 目录下创建 main.py 文件

 

2. 用到Python提供的一个内置函数，调用这个函数可以执行scrapy脚本

from scrapy.cmdline import executeimport sysimport ossys.path.append(os.path.dirname(os.path.abspath(__file__)))execute(["scrapy", "crawl", "jobbole"])#需要把当前项目目录放到sys.path下，scrapy命令必须在工程目录下运行#__file__:当前文件（main.py文件）#os.path.abspath(__file__): 获取main.py的绝对路径#os.path.dirname(os.path.abspath(__file__)):获取mian.py目录#scrapy启动命令：scrapy crawl jobbole

 

3. 现在就可以在pycharm中打断点使用debug模式了

 

四、Settings.py 配置

1. 在 settings.py 文件中找到 ROBOTSTXT_OBEY , 把其值设为 False。让我们的爬虫不去读取网站的 ROBOTS 协议。

 

五、Xpath语法

 注：尽量不用beautifulsoup，它比Xpath慢许多

表达式	说明
article	选取所有的article元素的所有子节点
/article	选取根元素article
article/a	选取所有属于article的子元素的a元素
//div	选取所有div子元素（不论出现在文档任何地方）
article//div	选取所有属于article元素的后代的div元素，不管它出现在article的任何位置
//@class	选取所有名为class的属性

 

 

 

 

 

 

 

 

 

 

 

表达式	说明
/article/div[1]	选择属于article子元素的第一个div元素
/article/div[last()]	选择属于article子元素的最后一个div元素
/article/div[last()-1]	选择属于article子元素的倒数第二个div元素
//div[@lang]	选择所有拥有lang属性的div元素
//div[@lang='eng']	选取所有lang属性为eng的div元素
/div/*	选取属于div元素的所有子节点
//*	选取所有元素
//div[@*]	选取所有带属性的div元素
/div/a|//div/p	选取所有div元素的a和p元素
//span|//ul	选取文档中的span和ul元素
article/div/p|//span	选取所有属于article元素的div元素的p元素 以及文档中所有的span元素
//h1[@id='test']/text()	获取id为test的h1的文字

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 六、用Xpath和CSS爬取伯乐在线文章页面元素

 

# jobbole.pyimport scrapyimport reclass JobboleSpider(scrapy.Spider):    name = 'jobbole'    allowed_domains = ['blog.jobbole.com']    start_urls = ['http://blog.jobbole.com/110287/']    def parse(self, response):        # 通过Xpath提取字段        title = response.xpath(".//*[@id='post-110287']/div[1]/h1/text()").extract_first()        create_date = response.xpath("//p[@class='entry-meta-hide-on-mobile']/text()").extract_first().strip().replace('·', '').strip()        praise_nums = response.xpath("//span[contains(@class, 'vote-post-up')]/h10/text()").extract_first()        fav_nums = response.xpath("//span[contains(@class, 'bookmark-btn')]/text()").extract_first()        match_re = re.match(r'.*?(\d+).*', fav_nums)        if match_re:            fav_nums = match_re.group(1)        comment_nums = response.xpath("//a[@href='#article-comment']/text()").extract()[0]        match_re = re.match(r'.*?(\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        title = response.css(".entry-header h1::text").extract()        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(r'.*?(\d+).*', fav_nums)        if match_re:            fav_nums = match_re.group(1)        comment_nums = response.css("a[href='#article-comment'] span::text").extract()[0]        match_re = re.match(r'.*?(\d+).*', comment_nums)        if match_re:            comment_nums = match_re.group(1)        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)

 七、利用ItemLoader爬取伯乐在线文章页面元素

# jobbole.pyimport scrapyimport reimport datetimefrom scrapy.http import Requestfrom urllib import parsefrom scrapy.loader import ItemLoaderfrom ArticleSpider.items import JobBoleArticleItem, ArticleItemLoaderfrom ArticleSpider.utils.common import get_md5class JobboleSpider(scrapy.Spider):    name = 'jobbole'    allowed_domains = ['blog.jobbole.com']    start_urls = ['http://blog.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下载后进行解析        post_nodes = response.css("#archive .floated-thumb .post-thumb a")        for post_node in post_nodes:            img_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": img_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()        # 通过Item_Loader加载Item        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', response.meta.get("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

# items.py# -*- coding: utf-8 -*-# Define here the models for your scraped items## See documentation in:# http://doc.scrapy.org/en/latest/topics/items.htmlimport datetimeimport reimport scrapyfrom scrapy.loader import ItemLoaderfrom scrapy.loader.processors import MapCompose, TakeFirst, Joinclass ArticlespiderItem(scrapy.Item):    # define the fields for your item here like:    # name = scrapy.Field()    passdef add_jobbole(value):    return value+'-bobby'def data_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_datedef get_nums(value):    match_re = re.match(r'.*?(\d+).*', value)    if match_re:        nums = match_re.group(1)    else:        nums = 0    return numsdef remove_comment_tags(value):    # 去掉tag中提取的“评论”    if '评论' in value:        return ''    return valuedef return_value(value):    return valueclass ArticleItemLoader(ItemLoader):    # 自定义item_loader    default_output_processor = TakeFirst()class JobBoleArticleItem(scrapy.Item):    title = scrapy.Field(        input_processor=MapCompose(lambda x:x+'-jobbole', add_jobbole)    )    create_date = scrapy.Field(        input_processor=MapCompose(data_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()

# pipeline.py# -*- coding: utf-8 -*-# Define your item pipelines here## Don't forget to add your pipeline to the ITEM_PIPELINES setting# See: http://doc.scrapy.org/en/latest/topics/item-pipeline.htmlimport codecsimport jsonimport MySQLdbimport MySQLdb.cursorsfrom scrapy.pipelines.images import ImagesPipelinefrom scrapy.exporters import JsonItemExporterfrom twisted.enterprise import adbapiclass ArticlespiderPipeline(object):    def process_item(self, item, spider):        return itemclass JsonWithEncodingPipeline:    # 自定义Json文件的导出    def __init__(self):        self.file = codecs.open('article.json', 'w', encoding='utf-8')    def process_item(self, item, spider):        lines = json.dumps(dict(item), ensure_ascii=False) + '\n'        self.file.write(lines)        return item    def spider_closed(self, spider):        self.file.close()class JsonExporterPipeline(object):    # 调用scripy提供的JsonExporter导出Json文件    def __init__(self):        self.file = open('articleExporter.json', 'wb')        self.exporter = JsonItemExporter(self.file, encoding='utf-8', ensure_ascii=False)        self.exporter.start_exporting()    def close_spider(self, spider):        self.exporter.finish_exporting()        self.file.close()    def process_item(self, item, spider):        self.exporter.export_item(item)        return itemclass MysqlPipeline(object):    # 采用同步的机制写入MySQL    def __init__(self):        self.conn = MySQLdb.connect('127.0.0.1', 'root', '123', 'article_spider', charset='utf8', use_unicode=True)        self.cursor = self.conn.cursor()    def process_item(self, item, spider):        insert_sql = """        insert into jobbole_article(url_object_id, title, url, create_date, fav_nums)        Values ("%s", "%s", "%s", "%s", "%s")        """        self.cursor.execute(insert_sql % (item['url_object_id'], item['title'], item['url'], item['create_date'], item['fav_nums']))        self.conn.commit()        return itemclass MysqlTwistedPipeline(object):    def __init__(self, dbpool):        self.dbpool = dbpool    @classmethod    def from_settings(cls, settings):        dbparms = dict(            host=settings['MYSQL_HOST'],            db=settings['MYSQL_DBNAME'],            user=settings['MYSQL_USER'],            passwd=settings['MYSQL_PASSWORD'],            charset='utf8',            cursorclass=MySQLdb.cursors.DictCursor,            use_unicode=True        )        dbpool = adbapi.ConnectionPool('MySQLdb', **dbparms)        return cls(dbpool)    def process_item(self, item, spider):        # 使用Twisted将MySQL插入变成异步执行        query = self.dbpool.runInteraction(self.do_insert, item)        query.addErrback(self.handle_error)        return item    def handle_error(self, failure):        # 处理异步插入的异常        print(failure)    def do_insert(self, cursor, item):        # 执行具体的插入        insert_sql = """                insert into jobbole_article(url_object_id, title, url, create_date, fav_nums)                Values ("%s", "%s", "%s", "%s", "%s")                """        cursor.execute(insert_sql % (item['url_object_id'], item['title'], item['url'], item['create_date'], item['fav_nums']))        cursor.commit()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

#utils/common.pyimport hashlibdef get_md5(url):    if isinstance(url, str):        url = url.encode('utf-8')    m = hashlib.md5()    m.update(url)    return m.hexdigest()if __name__ == '__main__':    print(get_md5('http://jobbole.com'))

# settings.pyimport os# Scrapy settings for ArticleSpider project## For simplicity, this file contains only settings considered important or# commonly used. You can find more settings consulting the documentation:##     http://doc.scrapy.org/en/latest/topics/settings.html#     http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html#     http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.htmlBOT_NAME = 'ArticleSpider'SPIDER_MODULES = ['ArticleSpider.spiders']NEWSPIDER_MODULE = 'ArticleSpider.spiders'# Crawl responsibly by identifying yourself (and your website) on the user-agent#USER_AGENT = 'ArticleSpider (+http://www.yourdomain.com)'# Obey robots.txt rulesROBOTSTXT_OBEY = False# Configure maximum concurrent requests performed by Scrapy (default: 16)#CONCURRENT_REQUESTS = 32# Configure a delay for requests for the same website (default: 0)# See http://scrapy.readthedocs.org/en/latest/topics/settings.html#download-delay# See also autothrottle settings and docs#DOWNLOAD_DELAY = 3# The download delay setting will honor only one of:#CONCURRENT_REQUESTS_PER_DOMAIN = 16#CONCURRENT_REQUESTS_PER_IP = 16# Disable cookies (enabled by default)#COOKIES_ENABLED = False# Disable Telnet Console (enabled by default)#TELNETCONSOLE_ENABLED = False# Override the default request headers:#DEFAULT_REQUEST_HEADERS = {
    #   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',#   'Accept-Language': 'en',#}# Enable or disable spider middlewares# See http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html#SPIDER_MIDDLEWARES = {
    #    'ArticleSpider.middlewares.ArticlespiderSpiderMiddleware': 543,#}# Enable or disable downloader middlewares# See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html#DOWNLOADER_MIDDLEWARES = {
    #    'ArticleSpider.middlewares.MyCustomDownloaderMiddleware': 543,#}# Enable or disable extensions# See http://scrapy.readthedocs.org/en/latest/topics/extensions.html#EXTENSIONS = {
    #    'scrapy.extensions.telnet.TelnetConsole': None,#}# Configure item pipelines# See http://scrapy.readthedocs.org/en/latest/topics/item-pipeline.htmlITEM_PIPELINES = {    # 'ArticleSpider.pipelines.JsonExporterPipeline': 2,    # 'scrapy.pipelines.images.ImagesPipeline': 1,    'ArticleSpider.pipelines.ArticleImagePipeline': 2,    'ArticleSpider.pipelines.MysqlPipeline': 1,}IMAGES_URLS_FIELD = 'front_image_url'project_dir = os.path.abspath(os.path.dirname(__file__))IMAGES_STORE = os.path.join(project_dir, "images")# IMAGES_MIN_HEIGHT = 100# IMAGES_MIN_WIDTH = 100# Enable and configure the AutoThrottle extension (disabled by default)# See http://doc.scrapy.org/en/latest/topics/autothrottle.html#AUTOTHROTTLE_ENABLED = True# The initial download delay#AUTOTHROTTLE_START_DELAY = 5# The maximum download delay to be set in case of high latencies#AUTOTHROTTLE_MAX_DELAY = 60# The average number of requests Scrapy should be sending in parallel to# each remote server#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0# Enable showing throttling stats for every response received:#AUTOTHROTTLE_DEBUG = False# Enable and configure HTTP caching (disabled by default)# See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings#HTTPCACHE_ENABLED = True#HTTPCACHE_EXPIRATION_SECS = 0#HTTPCACHE_DIR = 'httpcache'#HTTPCACHE_IGNORE_HTTP_CODES = []#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'MYSQL_HOST = '172.0.0.1'MYSQL_DBNAME = 'article_spider'MYSQL_USER = 'root'MYSQL_PASSWORD = '123'