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c-HTTP Requests and Responses

2 min read

HTTP Request → cURL/browser → URL, path, parameters

HTTP Response → web server → Response code, resource data

HTTP Request

Take a look at the example HTTP request below:

GET /services/login.html HTTP/1.1
MethodGETThe HTTP method or verb, which specifies the type of action to perform.
Path/users/login.htmlThe path to the resource being accessed. This field can also be suffixed with a query string (e.g. ?username=user).
VersionHTTP/1.1The third and final field is used to denote the HTTP version.

HTTP version 1.x sends requests in a clear-text. HTTP version 2.x sends requests as binary data in a dictionary form.

Next set of lines in a request contains information such as HTTP header value pairs, likehost, User-Agent,Cookie and many more. Headers are used to specify various attributes of a request.

HTTP Response

Take a look at the example HTTP Response below:

HTTP/1.1 200 OK

Here, HTTP version is 1.1 and HTTP response code is 200.

After the first line, response lists its headers and response body.

cURL

Using cURL, we can preview both HTTP request and the full HTTP response.

We can use -v verbose flag to view full HTTP request and response.

yoon@yoon-XH695R:~$ curl -v https://jadu101.github.io
* Host jadu101.github.io:443 was resolved.
* IPv6: 2606:50c0:8001::153, 2606:50c0:8003::153, 2606:50c0:8000::153, 2606:50c0:8002::153
* IPv4: 185.199.109.153, 185.199.111.153, 185.199.110.153, 185.199.108.153
*   Trying 185.199.109.153:443...
* Connected to jadu101.github.io (185.199.109.153) port 443
* ALPN: curl offers h2,http/1.1
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
*  CAfile: /etc/ssl/certs/ca-certificates.crt
*  CApath: /etc/ssl/certs

Browser DevTools

Browser devtools were build so that developers can test their web apps.

When we visit a website, browser sends multiple web requests and handles multiple HTTP responses to render the final view we see in the browser window.

Graph View