HTTP Headers Explained: What You Need to Know

HTTP headers can be found everywhere on the internet. Whether you know programming or not, you’ve probably seen it. One of the most common places you’ll locate an HTTP header is in your browser’s address bar. All the websites you visit will start with the “https://” line. If you’re an upcoming programmer, your first Hello World script also sent HTTP headers without you even realizing it.

In this article, we’re going to explore what HTTP headers are all about. We’re going to provide all the information you need to know about HTTP headers.

HTTP Headers — What are They?

HTTP is an acronym; it stands for Hypertext Transfer Protocol. All of the World Wide Web uses this protocol to function. Everything that you see and do in your browser is quickly transmitted over the HTTP protocol. An example is when you visited this article page. Your browser has sent over 40 HTTP requests and received responses for them in less than a second.

Now you know what an HTTP is, what exactly are HTTP headers? HTTP headers are very important in these HTTP request and response exchanges. They are responsible for carrying all the relevant information being sent. This includes information about your (the client) browser, the page requested, servers, etc. HTTP headers are essentially used to convey any additional information between the host server and the client.

HTTP headers are optional, however, they make up the majority of HTTP requests and are present most of the time. Whenever you request any webpage via a web browser, the HTTP headers will be automatically inserted by your browser without you seeing them. Similarly, all HTTP response headers are also inserted while not letting the user see. There are browser extensions available that let you view HTTP headers. You can find a few for Google Chrome and Mozilla Firefox.

In short, HTTP headers are crucial when it comes to web scraping for enormous amounts of data. With proper use of HTTP, you’ll be more efficient and accurate when it comes to your web scraping.

HTTP Header Groups

HTTP Headers can be neatly grouped based on their functions. Let’s look at a few most common HTTP headers and some very useful ones for web scraping.

General HTTP Headers

General Headers applies to both HTTP requests and responses. However, they have no relation to the data that is being transmitted in the body.

Request HTTP Headers

Request HTTP headers will contain all the information about the data being fetched, or about the client requesting the data.

Response Headers

Response HTTP headers will hold extra information about the response whenever you request a web page. This information includes details about the server, its location, etc.

Entity HTTP Headers

Finally, we have Entity HTTP Headers. These headers have information about the overall body of the data/resource you’re trying to request. The Entity HTTP Header will show you the MIME type, or the content’s length.

Best HTTP Headers for Web Scraping

Now let’s look at some of the best HTTP headers to use when it comes to web scraping. These will let you scrape a lot more data effectively.

User-Agent HTTP Header

First is the User-Agent HTTP Header. This header is responsible for passing any information related to the user. This information includes the operating system, application type, software, software, version, and more. The User-Agent HTTP Header also allows the data target to choose which type of HTML layout to use in its response; whether PC, mobile, or tablet. You should use the most common user agents for efficient web scraping.

Accept-Encoding HTTP Header

The Accept-Encoding HTTP Header is a request header. Its job is to notify the webserver on what compression algorithm to utilize when a request is being handled. Simply put, it states whether or not the required information can be compressed. It only does this if the server can handle compressing the information. If optimized properly, it can save plenty of traffic volume. This is both a win for the client and the webserver.

Accept-Language HTTP Header

The Accept-Language HTTP is a request header. It is responsible for passing information that tells the web server which appropriate language to use. This ensures that the client will understand the language used. This header is often used when the web servers can’t identify the preferred language used; such as via URL.

Accept HTTP Header

The Accept HTTP Header is also a request header. It falls into the content negotiation category. The Accept HTTP Header notifies the webserver on what type of data format is needed to return to the client. One of the most common mistakes in web scraping is forgetting to configure your request header to the target server’s accepted format.

Referer HTTP Header

Finally, we have the Referer HTTP Header. This request header’s role is to provide the web page’s addresses before the request is sent to the web server.

Conclusion

Now you know the different HTTP headers relevant to the web scraping process. HTTP headers are crucial for an efficient web scraping process. For example, using the most common user agents helps you avoid being blocked. You should consider configuring HTTP headers to improve your data extraction process.