This project consists of a web crawler that scrapes .gov websites and stores the results in a Postgres database.This web crawler was made for an assignment for the class in information retrieval and extraction. You can read more about the assignment on the following link. The project has two main components:

1. Database Setup directory ('DatabaseSetup'): This directory contains a docker-compose file for setting up the Postgres database.
2. Web Crawler script ('WebCrawlerService.py'): This Python script is responsible for the web crawling process.

• Concurrent scraping using multithreading
• Support for handling robot.txt and sitemap.xml files
• Storage of data in a PostgreSQL database
• Duplicate page detection and handling
• SQLite database for managing crawl frontier and crawl delays

• chromedriver
• Docker (if on Windows, install docker desktop)
• Docker Compose
• Postman
• IDE (PyCharm/VsCode)
• Python (3 and up)

• pgAdmin
• DB Browser for SQLite

In the DatabaseSetup directory, open a terminal (e.g., PowerShell on Windows) and run the following command:

docker compose up -d

This command will create the PostgreSQL database using the schema provided in the init-schema file.

1. Open the project in your preferred IDE (e.g., PyCharm or VSCode).
2. Install the required dependencies by running pip install -r requirements.txt.
3. In the WebCrawlerService.py script, you can set the number of threads you want to run in the main function by adjusting the max_workers parameter (e.g., max_workers=10).
4. Run the program using the IDE's run button or use the command flask --app sample --debug run.
5. To startthe web crawler, send a POST request to the /scrape endpoint using Postman with the following JSON format: Example:

    {
  "messages": [
            "https://www.gov.si/",
            "https://evem.gov.si/",
            "https://e-uprava.gov.si/",
            "https://www.e-prostor.gov.si/"
  ]
}

This will initiate the web scraping process for the specified websites, and the results will be stored in the PostgreSQL database.