Take a moment to look at the address bar of your browser. Do you see that “HTTPS://” before the actual website address starts? The Internet, as we know it, is built around HTTP, and the HTTP header referer plays a vital role in it. It’s everywhere on the web and part of every client-to-server and server-to-server communication. You should know that HTTPheader referer is only one type of HTTP headers. Today we are going to take a closer look at HTTP headers, see what they are used for, and how they can improve web scraping. Let’s start with a simple definition so you can quickly jump the train.
There are four types of HTTP headers: General-header – the fields in the general-header section have general applicability for response and request messages.
Client request-header – these fields only apply to request messages. Server response-header – the fields in this section definite response messages.
Entity-header – these fields contain information about the resource identified by the request. The HTTP header most relevant for web scraping is the client request-header. The client request header has the following five main types.
The user-agent HTTP header communicates to the server what browser and operating system you are using. It also contains information about the software version and tells the server which HTML layout to send to you (PC, mobile, or tablet).
The Accept-Language header tells the server which language you understand, indicating your preferred language so that a web server can send you relevant content.
When the web server handles a request, they can use a compression algorithm. It request header simply tells a server whether to use the compression and, if yes, which compression algorithm to apply.
Accept header requests are simple. It tells the web server what type of data you can handle so that the server knows what type of data to send you.
HTTP header referrer contains the information about the last web page address you’ve visited before sending an HTTP request. What are They Used for? HTTP headers, including the HTTP header referer, are used by the client and web server. They use them to pass valuable information with an HTTP request and response. Most often, web browsers and web servers insert HTTP header messages automatically. However, sometimes you might want to manually add headers to achieve your goals. For instance, you can add HTTP headers to imitate organic traffic, format headers according to a specific web server format requirements, or enable or disable compression algorithms.
You are probably aware that using proxies such as residential proxy and the rotating proxy can help you run an ongoing web scraping operation while avoiding blocks. While proxies play an important role in any web scraping operation, you can further optimize it to avoid blocks via HTTP headers. Optimizing each type of the HTTP request header can help you bypass anti-scraping measures and complete every web scraping session without any hiccups. Optimizing User-Agent is vital for the success of any web scraping operation.
If a scaring bot sends multiple requests with identical User-Agent, it will raise red flags, so using different User-Agent messages will help you bots appear as human agents. Setting the Accept-Language so that it’s relevant to the IP location where the requests originate will also appear organic to web servers. If you don’t do it, web servers can suspect bot-like activity and block the scraping process. Optimizing the Accept-Encoding request header can speed up the scraping process because the server will be able to send compressed data, thus reducing the load of traffic. Properly configuring HTTP header referer is also important. You can set a random website before launching a scraping operation so that your bots appear as average human users. You should configure the HTTP header referrer before every such operation to avoid getting blocked or banned.
As you can see, HTTP headers are the bread and butter of communication between clients and servers. Using and optimizing each type of header will benefit your web scraping operation. Do it consistently, and you’ll be able to slip under the anti-scraping mechanisms most web servers have in place.
I am a web developer and this information reminds me of my college days. Thanks for sharing this basic yet useful information.