Incoming Requests
In incoming requests, you must know about HTTP verb / method, queries, params, headers, body and flows.
For HTTP verb / method, there's are many but i only introduce most common one. All of the method have their own usage like
- GET - For client GET data from server-side
- POST - For client POST data at body to server-side for creation or other requests that used post body.
- PUT - For client replace specific data with body given.
- PATCH - For client update partial data with body given.
- DELETE - For client delete specific data from server-side.
For queries, params, headers and body, they like a message that from client. 4 of them will receive on different places.
- Queries - Can found at behind of the URL. Look like ?value=abc.
- Params - Defined by backend developer when routing. Look like 'sampleurl.com/:id' when pass 'sampleurl.com/123', id would be 123.
- Headers - Using postman you will see some default headers like Content-Type, X-Response-Time and Content-Length. Most of the backend would implement these headers and for authorized usage also.
- Body - When method POST used most of the backend developer would pass data using post body. For now many of the framework have default used JSON as parser.
As incoming requests to processing requests, they would pass into middleware of the backend framework. Most of the time they will checking body is it JSON and authorized access. Once all the condition pass only will start processing requests. After processing data, it will response to client that i called it outgoing response.
Outgoing Response
In outgoing response, you must know headers, response and status. Response most of the time is same structure, cause only need to reply to client is it success or not, fail due to what and success with payload that client needs. Headers would be quite same with incoming requests, what different is on framework, some of the framework would add customized on it. Status would be a verb like HTTP method, it is a number that can defined many means.
- 200+ - Success
- 300+ - Redirection
- 400+ - Client error
- 500+ - Server error
In a short saying on these would be like that for more information you can look into https://developer.mozilla.org/en-US/docs/Web/HTTP/Status.
Processing Requests
There was a complete flow from incoming until outgoing. And another you need to know is type for processing requests, it can be sequential or parallel.
- Sequential - mean only process one requests whatever how many requests has send to the server
- Parallel - mean process multiple requests at the same time
We will stop here, Next time will talk about framework features and how they work.