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
Method | GET | The HTTP method or verb, which specifies the type of action to perform. |
Path | /users/login.html | The path to the resource being accessed. This field can also be suffixed with a query string (e.g. ?username=user). |
Version | HTTP/1.1 | The 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.