Curlrc Proxy

A reverse proxy is mainly used by administrators and is responsible for balancing workload and high availability. The reverse proxy redirects received requests to one of its web servers. From the outside it is completely invisible and looks as if all required resources are concentrated directly in the proxy.

Click on the three bars located in the upper right corner and click on "Settings". When the settings page appears in front of you, go down to the "System" section and click on "Proxy settings". In the window that appears, click on "Network settings" and then check the box next to "Use a proxy server for local connections". Now all you have to do is enter the IP address and port of the proxy server, and then save your changes.

Scraping a large number of web pages using JavaScript typically involves the use of a headless browser or a scraping library. Puppeteer is a popular headless browser library for Node.js that allows you to automate browser actions, including web scraping.

Here's a basic example using Puppeteer:

Install Puppeteer:

npm install puppeteer

Create a JavaScript script for web scraping:

const puppeteer = require('puppeteer');

async function scrapeWebPages() {
    const browser = await puppeteer.launch();
    const page = await browser.newPage();

    // Array of URLs to scrape
    const urls = ['https://example.com/page1', 'https://example.com/page2', /* add more URLs */];

    for (const url of urls) {
        await page.goto(url, { waitUntil: 'domcontentloaded' });

        // Perform scraping actions here
        const title = await page.title();
        console.log(`Title of ${url}: ${title}`);

        // You can extract other information as needed

        // Add a delay to avoid being blocked (customize the delay based on your needs)
        await page.waitForTimeout(1000);
    }

    await browser.close();
}

scrapeWebPages();

Run the script:

node your-script.js

In this example:

• Puppeteer is used to launch a headless browser and open pages.
• The urls array contains the list of web pages to scrape. You can extend this array with the URLs you need.
• Inside the loop, you can perform scraping actions using Puppeteer functions. For example, extracting data using page.title().

Keep in mind the following:

• Be aware of the legality and terms of service for web scraping on the targeted websites.
• Respect the websites' robots.txt files and use delays between requests to avoid being blocked.
• Customize the scraping logic based on the structure of the web pages you are dealing with.

A Duplex UDP Communicator is a communication system that allows for two-way communication using User Datagram Protocol (UDP). To wait for a response from the other side, you can implement a simple client-server model. Here's a high-level overview of how to achieve this:

1. Server-side:

- Bind a UDP socket to a specific port on the server.
- Start a loop that continuously listens for incoming UDP packets.
- Receive the UDP packet and extract the data.
- Process the received data and prepare a response.
- Send the response back to the client using the client's address and port extracted from the received packet.
- Continue listening for incoming packets.

2. Client-side:

- Bind a UDP socket to a specific port on the client.
- Send a UDP packet to the server's address and port.
- Start a loop that continuously listens for incoming UDP packets.
- Receive the UDP packet and extract the data.
- Process the received data and prepare a response.
- Send the response back to the server using the server's address and port extracted from the received packet.
- Continue listening for incoming packets.

To wait for a response from the other side, you can use a simple time-based approach or a more advanced synchronization mechanism.

3. Time-based approach:

- After sending a packet, wait for a specific amount of time before expecting a response.
- If a response is received within the waiting time, process the response and proceed.
- If the waiting time elapses without receiving a response, handle the timeout and take appropriate action (e.g., retry, abort, or notify the user).

4. Synchronization mechanism:

- Include a unique identifier in each packet sent.
- When the server receives a packet, it sends back a response with the same identifier.
- The client waits for a response with the same identifier before proceeding.
- If a response with the same identifier is received, process the response and proceed.
- If a response with a different identifier is received, discard it and continue waiting for the expected response.
- If no response is received within a specific time, handle the timeout and take appropriate action.

Using a synchronization mechanism is more reliable than a time-based approach, as it ensures that the client only processes responses from the expected server. However, both methods can be effective depending on the specific use case and network conditions.

Google Chrome doesn't have a built-in function to work with a proxy server, although there is such an item in the settings. But when you click on it, you are automatically "redirected" to the standard proxy settings in Windows (or any other operating system).