Teach you how to use the Python Portia class library to quickly build a network crawler

Use the Python Portia class library to quickly build a network crawler In this article, you will introduce you to how to use the Python Portia Library to quickly build a network crawler, and explain the complete programming code and related configuration when necessary. Cyber crawler is an automated program that collects data from the Internet.Portia is one of the extensions of the SCRAPY framework, which provides a graphical interface to help create and manage network crawlers.With Portia, you don't need to write any code to build a powerful network crawler. The following is the steps to use Python Portia to build a network crawler: Step 1: Install dependence and environment First, make sure you have installed Python and Scrapy frameworks.You also need to install the Portia class library, you can use the following command to install: pip install portia Step 2: Create a project In the terminal, use the following commands to create a new Portia project: portiacrawl myproject This will create a folder called MyProject in the current directory and contain the required directory and file. Step 3: Configure crawlers Enter the Myproject folder and find a file called `Project.json`.Edit this file to configure your reptile.You can specify the URL you want to crawl, and you can also define fields, structures and extract rules. For example, the following is an example configuration file: json { "start_urls": ["http://example.com"], "spiders": [ { "type": "DefaultSpider", "start_urls": ["http://example.com"] } ], "extractors": [], "feeds": [] } In this configuration file, we specify the initial URL and Spider type to be crawled. Step 4: Create an extractor Next, we need to define the extractor for extracting data.The extractor allows you to specify the fields to be extracted and the corresponding extract rules.You can create the extractor in the following way: In the graphics interface of Portia, select the "My Extrater" tab and click the "Create the Extractor" button.In the open interface, the name and URL of the input extract device are selected by selecting HTML elements and using XPath or CSS selectors to define the extraction rules. Step 5: Run reptile Now, everything is ready, we can run the crawler.In the terminal, use the following command to start the crawler: portiacrawl crawl myproject The reptile will begin to run and extract data based on the rules in the extractor and configuration file. This is the basic step of using the Python Portia class library to quickly build a network crawler.Using Portia, you can easily configure and manage crawlers, and quickly extract data from the website. Please note that the example code and configuration in this article are for reference only, and the actual use may need to be modified appropriately according to your needs.