Beginner's Guide to Using cURL
What is Server and Why we need to communicate with it?
In simple words a server is a computer on internet that serves.
when we open a website we communicate with a server
when we login to a app we communicate with a server
To get information from the server we must a request to it and it sends us a response back.
cURL allow us to communicate with the server directly removing browser as a dependency.
What is cURL?
cURL is tool which allow us to send message to a server from the terminal.
Browser : talks to the server
cURL: talks to server with commands
With the help of cURL, we can:
Ask server for data
Send data to server
Test APIs
Why Programmers Need cURL?
Why we need cURL
Browser hides many details
App is not fully ready yet
No UI for now
What cURL can do
Test our API’s
Debug server responses
Making Our First Request Using cURL
Example:
curl https://hashnode.com
What happens next
cURL will send a request to hashnode.com
The hashnode server will reply
cURL print the result in our terminal
Understanding Request and Response
Communicating with server is a two step process
Request (us to server)
We can say
“Hey server“
“I want this resource“
Response (Server to us)
The server replies
Status (it worked or not?)
Data (HTML, TXT, JSON etc)
The text we see in the terminal is the response body.
Using cURL to Talk to APIs
When we create our own API, we need to check if they actually work.
Why browser does not work
It can only make GET requests
It hides request and response details
cURL solves this problem.
Making a Request to Our API
We can send request to our API if the our server is running on a specific port in our system.
Example: curl http://localhost:3000
If API is working
Server sends a response
cURL prints it in terminal
This confirms API is reachable.
Common Mistakes Beginners Make with cURL
Trying too many flags too early
Expecting Browser like response
Getting Scared by JSON
Ignoring error message
Thinking cURL is for experts
Closing Statement
cURL is a simple tool which allow us
How client talks to server
How response and request work
How APIs behave