Web scraping is a method of extracting vast volumes of data from websites and saving it to a local file on your device or to a database in spreadsheet form.
Many websites’ data can only be accessed by a web browser. They don’t allow you to keep a copy of this information for personal use. The only other choice is to manually copy and paste the results, which is a time-consuming task that can take hours or even days to complete.
Web scraping is a method of automating this operation so that, instead of manually downloading data from websites, the web scraping program can do so in a fraction of the time.
Based on your requirements, web scraping software can automatically load and retrieve data from various website pages. You can conveniently copy the data available on the website to a file on your computer with a single click of a mouse.
· So what’s the point?
· How do web scrapers collect data from the Internet?
∘ Making an HTTP request to the server
∘ Extracting and parsing the code
∘ Saving locally
· How Web Scrapers, Well, Scrape
∘ Pick your content
∘ Inspect the webpage
∘ Figure out what you want to extract
∘ Write the code and run It
∘ Store the data
· Automation May Compliment You
So what’s the point?
The Internet is the world’s largest information and data archive in human history. Humans have the most to benefit from this data, but it’s simply too much information for us to gather and process without dying of old age. As a result, site scraping is becoming increasingly important. We need computers to read the data for us so that we can use it in several industries, where a few use cases for web scraping are:
- price monitoring
- competitor analysis
- social media insights
- news tracking
- real estate decision making
Neglecting the value of web scraping is denying the power that the internet holds.
How do web scrapers collect data from the Internet?
So now we know what site scraping is and why it is used by various organizations. But how does it all work? Although the exact process varies depending on the program or methods used, all web scraping bots go through these motions:
Making an HTTP request to the server
When you use your computer to access a website, you submit what’s known as an HTTP request to the website’s host. If the request is accepted, they’ll send a HTTP response with the content on the particular page you want to visit. In a sense, that content is already stored on your computer, cutting the Internet won’t make the page disappear (unless you reload it).
Web scrapers go through this step as well. The difference is that once they receive their response, instead of just viewing it, they plan on making a copy.
Extracting and parsing the code
This step can change a lot depending on what you want the scraper to do. Once the bot has access to the HTML data, it’s ready to extract everything. Of course, maybe you don’t want that. For example, a page might be very large and you only want a small portion of its data.
In that case, you should add some conditions on what the scraper to grab. The easiest example of this is grabbing headers by selecting only text inside <h> tags. Of course, there are plenty of other identifiers that you can use.
A word of advice, though: if you expect to use the content on a page more than once, it’s easier to just extract all the code, store it locally and look up whatever specific information you need. This way, you’re doing fewer requests, so it’s more economical for you and less straining on the website.
Saving locally
After we’ve got the data in order, it will be stored in a local file. Information is frequently saved in a structured format, such as csv or xls. Alternatively, formats such as JSON or XML are useful if you’re planning on having other programs process the data.
While web scraping may seem easy at first glance, it has its quirks, especially once you have to throw proxies or Javascript rendering into the mix. Still, it beats manually gathering data all day, every day.
How Web Scrapers, Well, Scrape
If you decide to make your own web scraper, the data extraction process will involve a few steps. Note that pre-built products may take care of a few of these steps without your input, but the general procedure goes like this:
Pick your content
As a first step, it’s critical to define the specific problem you’re trying to tackle via web scraping. For instance, you want to buy a vintage Citroen DS, and you don’t want to burn a hole through your wallet. Use web scraping and you can:
- Browse websites about vintage cars, getting info on what details to look for, where to buy and even if there are preferable times of year for the transaction;
- Check multiple sources easily, finding the best prices and car conditions;
- Set a notification in case the price drops in online stores.
Now that you have a good idea of what you want to do and how you want to solve it, you’ll need to locate the data source, which is the website where your data is stored.
Find a reputable source with all the specific information you require and scrape ahead! Actually, find several, just to make sure that the info you get is genuine.
Inspect the webpage
To get an idea about how the bot sees a webpage, you should take a look at it’s HTML code. To do that, you just have to right-click somewhere on the page and select Inspect Element. Since you might be interested in a specific bit of information, this step is crucial in understanding how data is nested on the page, what tags and classes you need to look for.
Right-click anywhere on the page and select Inspect Element or View Page Source to inspect it. To see where a particular object on a page is, such as text or a pic, right-click it and select Inspect Element.
Figure out what you want to extract
If you’re looking for car reviews, you’ll need to figure out where they’re stored in the front-end code. While hovering over a piece of code, the browser will automatically highlight the corresponding data in the regular user interface. So, if you’re not sure what a bit of code does, that highlight can help you figure it out.
Find the content you want to scrape in the interface, then find the corresponding code. The data we’re looking for is nested within the highlighted <div> tag. When you open the <div> tag, plenty of new tags appear on the screen. Each tag has a “class.”
Each website has its own architecture and style. To a lesser degree, this is true for different pages on the same website. So, this step is 100% necessary for new websites, but it may be needed for different pages on the same site as well.
Write the code and run It
After you’ve discovered the correct tags, you’ll need to specify them in your code. This tells the bot where to look for information and what to extract.
After you’ve written the code, it’s quite self-explanatory, you’ll need to run it. It shouldn’t take more than a couple of seconds.
Store the data
The final step involves downloading and saving the data. The most common format for human viewing is CSV. It can also be sent further on the software pipeline to other programs for processing. In this case, you may want to use JSON format, if the destination doesn’t support CSV format.
Anyway, the scraper did its job and you are free to store the data on your machine, on the cloud or immediately work on it, resulting in something new.
That is all there is to it. This is how web scraping unfolds.
Automation May Compliment You
All you have to do now is start looking into web scraping software if you don’t have the time or interest to work on your own scraper.
To begin with, there are some tools that you can use. More powerful scraping tools may be found if you want to scrape in bulk, so the list above is ideal for choosing a neat API.
