StormCrawler is an open-source web crawler framework that allows developers to build customized web crawlers and extract information from websites. It is built on top of the Apache Storm distributed real-time computation system and integrates with other open-source tools such as Apache Nutch, Elasticsearch, and Apache Tika.
StormCrawler provides a scalable architecture for crawling large datasets by parallelizing the crawling process across a cluster of machines. It also offers a modular and extensible design, allowing developers to add custom functionality to the crawler and integrate it with their existing data processing pipelines.
Some of the features of StormCrawler include support for HTTP and HTTPS protocols, URL filtering, parsing and extraction of content using Tika, metadata extraction, integration with Elasticsearch for indexing and searching, and support for distributed crawling using Apache Storm. StormCrawler is widely used in industries such as media, e-commerce, and research for web crawling and data extraction purposes.
Learning and using StormCrawler may require some familiarity with distributed systems and the Apache Storm ecosystem, but the framework provides extensive documentation and examples to help developers get started.
For developers who are new to Storm or distributed systems, there may be a learning curve in understanding the underlying concepts and configuring the system. However, the community around StormCrawler is active and supportive, with forums and Slack channels available for developers to ask questions and get help.
In addition, StormCrawler offers a number of tools and features that simplify the process of building and deploying web crawlers, such as a web-based administration interface, pre-built plugins for common use cases, and integration with popular search and storage technologies.
Overall, while there may be some initial effort required to learn and configure the system, StormCrawler can provide a powerful and flexible solution for building customized web crawlers and extracting information from websites.
To start building a project with StormCrawler, you will need some knowledge of Java and the Apache Storm framework. Specifically, you will need to know how to write Java code and use Maven, a Java-based build tool, to manage dependencies and build your project.
You may also need to be familiar with other related technologies such as Apache Nutch, Elasticsearch, and Apache Tika, depending on your specific use case.
StormCrawler itself is written in Java and provides a Java-based API for developing custom crawlers and processing pipelines. While it is possible to use other programming languages, such as Python or Scala, with StormCrawler, the core functionality is designed to be used with Java.
StormCrawler supports using proxy servers to crawl the web.
To use a proxy server, you can configure the HttpProtocol plugin with the appropriate proxy settings. This can be done either through a configuration file or programmatically in your Java code.
By default, StormCrawler will use the system's default proxy settings, but you can override these settings by specifying them in your configuration file or programmatically.
StormCrawler can be configured to use rotating proxies, which can help to avoid IP blocking and increase the success rate of web crawling.
There are several ways to implement rotating proxies with StormCrawler, depending on your specific use case and requirements. Here are a few options:
- Using a proxy pool service: There are several third-party services that provide rotating proxy pools, such as ScraperAPI and ProxyCrawl. You can configure StormCrawler to use these services as your proxy provider.
- Building a custom proxy pool: You can build your own proxy pool using open-source tools like Squid or HAProxy, and configure StormCrawler to use this pool as your proxy provider.
- Implementing proxy rotation in your code: You can implement your own proxy rotation logic in your Java code, by periodically switching between a list of proxies or using a proxy selection algorithm. You can then configure the HttpProtocol plugin to use the selected proxy.
Regardless of the approach you choose, StormCrawler provides the flexibility to integrate with different proxy providers and implement custom proxy rotation logic to meet your needs.