Data extraction from web pages is made possible by using specifically programmed web crawlers. Setting up these crawlers require advanced tech skills and high-end resources. Extracting data from the open web is a straightforward process. You create a web crawler to extract the required data points from a public page on the web. When the data you need is behind a login page, the process becomes a bit more complicated. Here is how we scrape data from sites that require a login.
There would be a set of prerequisites to every web crawling job. In the case of extracting data from login based sites, these would be the list of sites, data points to be extracted and cookies or credentials for the login. Since there are login pages present, the setup of the crawler would be a bit more complicated than the regular process.
The crawler setup
Setting up of the crawler is a technically challenging process that requires skilled personnel. The source code of the target website has to be analysed to find the appropriate tags where data points are enclosed. These tags can be used for coding the crawler to extract the same. Since the crawler has to pass a login page, the credentials or cookies for the same has to be set up in the crawler to provide to the site when needed. Once everything is set up, the crawler starts crawling and extracting data from the source sites.
Once the web crawler has extracted and saved the data to a dump file, it has to be processed before it can be usable. Processing includes cleansing and structuring. In cleansing, the unnecessary elements that got scraped along with the required data such as html tags will be removed. Once the data is free of the noise, it can be structured for compatibility with analytics systems or databases. After the processing, data can be plugged into your system to start gaining valuable insights from it.