Classification of web crawler

In the actual complete crawler work, there are usually several types of crawlers. According to the implementation technology and structure, crawlers can be divided into general web crawlers, focused web crawlers, incremental web crawlers, deep web crawlers and other types.

General web crawlers: can be called full-network crawlers. The target resources crawled by this type of crawler are in the entire Internet. And the target data of their crawling range is huge. It is precisely because the data they crawl is massive data, so for this type of crawler, the performance requirements of its crawling are very high. This type of web crawler is mainly used in large search engines and has very high application value.

When crawling, general web crawlers must adopt certain crawling strategies. In addition to controlling the frequency, the reasonable use of crawler IP proxy is also particularly important. After all, such frequent operations will put pressure on the website. Changing IP can hide the identity when visiting the website and greatly reduce the risk of account closure.

Focused web crawler: also called topic web crawler, focused web crawler is a kind of crawler that selectively crawls web pages according to pre-defined topics. Unlike general web crawlers, focused web crawlers do not locate target resources in the entire Internet, but locate the target web pages to be crawled in pages related to the topic. At this time, the bandwidth resources and server resources required for crawling can be greatly saved. Focused web crawlers are mainly used in crawling specific information, mainly providing services for a certain type of specific people.

Incremental web crawler: refers to updating only the changed parts when updating, and not updating the unchanged parts. Therefore, when crawling web pages, incremental web crawlers only crawl web pages with changed content or newly generated web pages, and will not crawl web pages with unchanged content. Incremental web crawlers can ensure that the crawled pages are new pages as much as possible to a certain extent.

Deep web crawler: Web pages on the Internet can be classified into surface pages and deep pages according to their existence. The so-called surface page refers to a static page that can be reached using a static link without submitting a form; the deep page is hidden behind the form and cannot be directly obtained through a static link. It is a page that can only be obtained after submitting certain keywords.

On the Internet, the number of deep pages is often much larger than the number of surface pages. Therefore, we need to find a way to crawl deep pages. To crawl deep pages, we need to find a way to automatically fill in the corresponding form. Therefore, the most important part of the deep web crawler is the form filling part.

98IP proxy is the best assistant for all kinds of crawlers to change IP. It has high anonymity and low latency, helping users to complete crawler tasks quickly and smoothly.