What is RPC?

• RPC == Remote Procedure Call
• Remote Procedure Call (RPC) is a protocol that one program can use to request a service from a program located in another computer on a network without having to understand the network’s details
• In distributed computing, a remote procedure call is when a computer program causes a procedure to execute in a different address space, which is coded as if it were a normal procedure call, without the programmer explicitly coding the details for the remote interaction
• A procedure call is also sometimes known as a function call or a subroutine call
• Links:
  • https://users.cs.cf.ac.uk/Dave.Marshall/C/node33.html

An RPC is analogous to a function call. Like a function call, when an RPC is made, the calling arguments are passed to the remote procedure and the caller waits for a response to be returned from the remote procedure

RPC Example

RPC call

POST /sayHello HTTP/1.1
HOST: api.example.com
Content-Type: application/json

{"name": "Racey McRacerson"}

In JavaScript, we would do the same by defining a function, and later we’d call it elsewhere:

/* Signature */
function sayHello(name) {
  // ...
}

/* Usage */
sayHello("Racey McRacerson");

The idea is the same. An API is built by defining public methods; then, the methods are called with arguments. RPC is just a bunch of functions, but in the context of an HTTP API, that entails putting the method in the URL and the arguments in the query string or body.

See: https://www.smashingmagazine.com/2016/09/understanding-rest-and-rpc-for-http-apis/