The world of IT is chock full of challenging words for straightforward factors. Take HTTP headers, for instance. What are they? How do you use them for scraping?
Table of Contents
The meaning of HTTP headers
Every person with access to the internet has come across HTTP headers. Every browser address bar starts with an https://. HTTP stands for Hypertext Transfer Protocol, a system in use by the World Wide Web since the early 90s.
The Hypertext Transfer Protocol transmits information through browsers to different devices. A simple action such as opening a page on your browser causes a chain reaction whereby tens of HTTP requests and responses are sent and received back.
HTTP headers are a core part of this request and response system that ensures that data is routed between a browser, requested page, and a server.
Components of an HTTP header
If you type any URL in your browser’s address bar, your HTTP request will have lines of text with elements such as:
- Request Line that has some basic information the browser request made
- Status line, which is followed by various HTTP headers
- Content requested
The reason HTTP headers are not so well known is that the source code of a webpage generally displays the HTML portion of the page. The HTTP headers transmitted are not usually available on the browser page source code. Nevertheless, information such as CSS, images, or JavaScript files requested has its HTTP requests meaning that each query sends out many HTTP headers.
If you want to view and analyze your HTTP headers, use apps such as Live HTTP Headers or Firebug. You can also use PHP getallheaders() or headers_list() functions to view them. HTTP headers are very crucial to a safe web scraping process.
HTTP headers-What is web scraping?
Web scraping has become a viral data collection process in the e-commerce boom age. Businesses use it for various applications such as competitive price comparison, brand protection, or digital marketing and SEO analysis. The price comparison apps that people use to make purchase decisions use web scraping to gather and analyze their data.
Web scraping is the process of extracting massive amounts of data from online sources. IT technicians can write programs that automate web scraping. Many businesses, however, block web-scraping bots due to vested interests. If you want to avoid being blocked when web scraping, you can improve your web scraper with proxies.
Furthermore, some websites block the activity to prevent spamming or misuse of website resources. Altering the HTTP header information and the use of rotational proxies and proxy servers can enhance web scraping efficiency. It can also prevent the blocking of your business’s web scraping bots.
Types of HTTP Headers
1. User-agent
This particular HTTP header carries information such as your device’s browser information, operating system, and default language. Websites use the information requested by this header to collect data on your computer network systems. Web servers will first check this data to identify any suspicious requests.
During web scraping, too many identical user-agent HTTP headers can betray bot activity. Web scrapers, therefore, manipulate this header to portray diverse organic user sessions. Alter your user agent data frequently to maintain your anonymity during web scraping.
2. Accept-language
This HTTP header displays your browser default language settings. If your browser settings have multiple languages, the header will redirect a user as per the data posted by this header. The first language displayed is the preferred language.
When web-scraping ensures that the set preferred language does not raise any red flags with the target’s IP location and domain. Too many requests in multiple languages from a single client will portray the bot -like behaviors of poorly designed web scrapers.
3. Accept-Encoding
Most browsers today support GZ files, a compressed archive file type with the GNU sip standard. This compression type is referred to as gzip. The compression can compact the size of data by up to 80%, saving time and bandwidth of users. The accept-encoding HTTP header notifies web servers of the compression mode they should use on a request.
4. Accept
The accept HTTP header notifies web servers on the format of data that should be routed back to the client. When web-scraping, configure your Accept request to display an organic transmission of data between the scraping bot and the server.
5. HTTP headers-Referrer
This HTTP header is not misspelled. It is not referrer, as a dictionary would dictate it to be, but referer. This header has made it to official HTTP specifications with this spelling. HTTP headers always contain the address of the referring URL.
The referer is the previous web page address visited by your browser before navigating to the current page. A common referer header for many search result pages is, therefore http://www.google.com/. When web-scraping, use random websites as referer headers to make your activity less suspicious.
Conclusion
There you have it. It is not rocket science. Configure your HTTP headers while web scraping for efficient and effective data collection online.