网络爬虫与网页抓取 – 主要区别和优势

在本文中,我们将解释网络爬虫和网络抓取之间的区别,并介绍它们各自的主要优势和使用案例。
1 min read
网络爬虫与网页抓取

在本文中,我们将讨论:

  • 什么是网络爬虫?
  • 什么是网页抓取?
    • 常见的网络抓取使用案例
  • 每种选择的优势
  • 输出差异
  • 挑战
  • 总结

什么是网络爬虫?

网络爬虫,也称为索引,是使用机器人(也称为爬虫)对页面上的信息进行索引。爬虫实际上是搜索引擎所做的工作。它涉及对整个页面进行查看和索引。当机器人爬取一个网站时,它会遍历每个页面和每个链接,直到网站的最后一行,寻找任何信息。

主要搜索引擎如谷歌、必应、雅虎、统计机构和大型在线聚合商都使用网络爬虫。网络爬虫过程通常捕获一般信息,而网页抓取则专注于特定数据集片段。

什么是网页抓取?

网页抓取,也称为网页数据提取,类似于网络爬虫,它识别并定位网页上的目标数据。关键区别在于网络抓取知道确切的数据集标识符,例如需要从中提取数据的网页的HTML元素结构。

网页抓取是一种使用机器人(也称为‘抓取器’)自动提取特定数据集的方法。一旦收集到所需的信息,可以根据业务的需求和目标进行比较、验证和分析。

常见的网络抓取使用案例

以下是企业利用网页抓取实现业务目标的一些最常见方式:

研究: 数据通常是任何研究项目的核心部分,无论其性质是纯学术的还是用于营销、金融或其他业务应用。实时收集用户数据和识别行为模式的能力,例如,在试图阻止全球流行病或识别特定目标受众时,可以至关重要。

零售/电商: 公司,特别是电商领域的公司,需要定期进行市场分析以保持竞争优势。前端和后端零售企业收集的相关数据集包括价格、评论、库存、特价优惠等。

品牌保护: 数据收集正成为保护品牌免受欺诈和品牌稀释以及识别非法利用公司知识产权(名称、标志、物品复制品)获利的恶意行为者的重要部分。数据收集帮助公司监控、识别和对这些网络犯罪分子采取行动。

每种选择的优势是什么?

网页抓取的主要优势

高度准确 – 网络抓取可以帮助你消除操作中的人为错误,确保你收到的信息100%准确。

成本效益高– 网页抓取可能更具成本效益,因为你通常需要的员工更少,而且在许多情况下,你可以获得完全自动化的解决方案,不需要任何基础设施。

精确定位 – 许多网络抓取工具允许你筛选你正在寻找的数据点,这意味着你可以决定在特定工作中收集图像而不是视频,或价格而不是描述。这可以帮助你从长远来看节省时间、带宽和资金。

数据爬取的主要优势

深入挖掘 – 这种方法涉及对每个目标页面的深入索引。这在试图发现和收集万维网深处的信息时非常有用。

实时– 对于希望获取目标数据集实时快照的公司来说,网络爬虫更为优选,因为它们更容易适应当前事件。

质量保证– 爬虫在内容质量评估方面更具优势,这在执行质量检查任务时是一种优势。

输出有何不同?

使用网络爬虫时,主要输出通常是URL列表。可能还有其他字段或信息,但通常链接是主要的副产品。

就网络抓取而言,输出可以是URL,但范围更广,可能包括各种字段,例如:

  • 产品/库存价格
  • 观看/点赞/分享数量(即社交互动)
  • 客户评论
  • 竞争产品的星级评分
  • 从行业广告活动中收集的图像
  • 搜索引擎查询和按时间顺序显示的搜索引擎结果

主要挑战

尽管存在差异,网络爬虫和网页抓取共享一些共同的挑战:

#1: 数据障碍– 许多网站有反抓取/爬虫政策,这使得收集所需的数据点变得具有挑战性。在这种情况下,网页抓取服务有时可能非常有效,特别是如果它们让你访问顶级代理服务,可以帮助你使用真实用户IP收集数据并规避这些类型的阻止。

#2: 劳动密集型– 大规模执行数据爬取/抓取任务可能非常费力且耗时。那些可能起初只需要偶尔数据集的公司,现在需要定期的数据流量,无法再依赖手动收集。

#3: 收集限制– 执行数据抓取/爬虫通常可以轻松完成简单的目标网站,但当你开始遇到更难的目标网站时,有些IP阻止可能难以克服。

总结

‘网络爬虫’是数据索引,而’网页抓取’是数据提取。对于那些希望进行网页抓取的人来说,Bright Data提供了各种尖端解决方案。Web Unlocker使用机器学习算法,持续找到最佳/最快的路径来收集开源目标数据点。不确定哪种解决方案最适合你的需求?今天联系我们吧!

What Is The Difference Between Web Crawling And Web Scraping?

This article will help you match your use case to the correct data collection methodology as well as understanding the key advantages and challenges of each option.
5 min read
Differences between web scraping and web crawling or indexing

Web crawling, also known as Indexing, is used to index the information on the page using bots also known as crawlers. Crawling is essentially what search engines do. It’s all about viewing a page as a whole and indexing it. When a bot crawls a website, it goes through every page and every link, until the last line of the website, looking for ANY information.

Web crawlers are basically used by major search engines like Google, Bing, Yahoo, statistical agencies, and large online aggregators. The web crawling process usually captures generic information, whereas web scraping hones in on specific data set snippets.

Web scraping, also known as web data extraction, is similar to web crawling in that it identifies and locates the target data from web pages. The key difference is that with web scraping, we know the exact data set identifier e.g. an HTML element structure for web pages that are being fixed, from which data needs to be extracted.

Web scraping is an automated way of extracting specific datasets using bots which are also known as ‘scrapers’. Once the desired information is collected it can be used for comparison, verification, and analysis based on a given business’s needs and goals.

Common web scraping use cases

Here are some of the most popular ways in which businesses leverage web scraping to attain their business goals:

Research: Data is often an integral part of any research project whether it is purely academic in nature or for marketing, financial, or other business applications. The ability to collect user data in real-time and identify behavioral patterns, for example, can be paramount when trying to stop a global pandemic or identify a specific target audience.

Retail / eCommerce: Companies, especially in the eCom space need to regularly perform market analyses in order to maintain a competitive edge. Relevant data sets that both front and backend retail businesses collect include pricing, reviews, inventory, special offers, and the like.

Brand Protection: Data collection is becoming an integral part of protecting against brand fraud, and brand dilution as well as identifying malicious actors who are illegally profiting from corporate intellectual property (names, logos, item reproductions). Data collection helps companies monitor, identify, and take action against such cybercriminals.

What are the advantages of each option?

Key web scraping benefits

Highly accurate – Web scrapers help you eliminate human errors from your operations so that you can be confident that the information you receive is 100% accurate.

Cost-efficient– Web scraping can be more cost-effective as more often than not you will need less staff to operate and in many cases, you will be able to gain access to a completely automated solution that requires zero infrastructure on your end.

Pinpointed – Many web scrapers allow you to filter for exactly the data points you are looking for meaning you can decide that on a specific job they collect images and not videos or pricing and not descriptions. This can help you save time, bandwidth, and money over the long term.

Key data crawling benefits

Deep dive – This method involves an in-depth indexation of every target page. This can be useful when trying to uncover and collect information in the deep underbelly of the World Wide Web.

Real-time– Web crawling is preferable for companies looking for a real-time snapshot of their target data sets as they are more easily adaptable to current events.

Quality assurance– Crawlers are better at content quality assessment meaning it is a tool that provides an advantage when performing QA tasks for example.

How does output differ?

With web crawling, the main output is typically lists of URLs. There can be other fields or information but typically links are the predominant by-product. 

As far as web scraping is concerned, the output can be URLs but the scope is much broader and may include a variety of fields such as:

  • Product/stock price
  • Number of views/likes/shares (i.e. social engagement)
  • Customer reviews
  • Competitor product star ratings
  • Images collected from industry advertising campaigns 
  • Search engine queries, and search engine results as they appear chronologically

Main challenges

Despite their difference web crawling and web scraping share some mutual challenges:

#1: Data blockades– Many websites have anti-scraping/crawling policies, which can make it challenging to collect the data points you need. A web scraping service can sometimes be extremely effective in this instance, especially if they give you access to large proxy networks that can help you collect data using real user IPs and circumvent these types of blocks.

#2: Labor-intensive– Performing data crawling/scraping jobs at scale can be very labor-intensive and time-consuming. Companies who may have started off needing data sets once in a while but now need a regular flow of data, can no longer rely on manual collections.

#3: Collection limitations– Performing data scraping/crawling can usually be easily accomplished for simple target sites but when you start encountering tougher target sites, some IP blocks can be insurmountable.

The bottom line

‘Web crawling’ is data indexing while ‘web scraping’ is data extraction. For those of you looking to perform web scraping, Bright Data offers a variety of cutting-edge solutions. Web Unlocker uses Machine Learning algorithms to consistently find the best/quickest path to collect open source target data points. While Web Scraper IDE is a fully automated, zero-code web scraper that delivers data directly to your inbox.