Sending and Receiving Paekli

Our server can now say hello, but we want it to help us send and receive paekli. Let's stub out a handler for each type of request.

#![allow(unused)]
fn main() {
#[axum::debug_handler]
async fn send_paekli() -> &'static str {
    "\
Thank you for trusting Paekli LLC!
We will deliver your paekli in mint condition.
* throws your paekli directly in the trash *"
}

#[axum::debug_handler]
async fn receive_paekli() -> &'static str {
    "\
There aren't any paekli for you at the moment.
* tries to hide paekli in the trash can *"
}
}

Note the new #[debug_handler] attribute above the handler function. This is what we needed --features macros for when we added the axum dependency. It is a macro that provides better error messages in case there's something wrong with our handler function. I recommend you add it to every new handler you're going to write. I also recommend not making any mistakes in the first place, but... you know.

Picking the right HTTP method

We have already seen the HTTP method GET, which is the default one. It is used to ask a server for some information. There are other methods with specific meanings, the most common ones are:

• GET for reading data
• POST for storing new data
• PUT for modifying existing data
• DELETE for deleting data

These four methods cover all the operations that are commonly performed on data.

POST is the method that most closely matches the operation of sending a paekli, because the server will need to store a new piece of data. DELETE seems appropriate for receiving, since the paekli should be deleted on the server after it has been received.

Recall that the router also needs a path to register a handler, but we won't have to worry about that. We just use the empty or "root" path. The path is conventionally used to specify a resource. Since we only have one resource (paekli), the path doesn't matter. Here's how we can register these new handlers with different HTTP methods:

#![allow(unused)]
fn main() {
let router = axum::Router::new()
    .route("/", post(send_paekli))
    .route("/", delete(receive_paekli));
}

Let's try them out:

> curl --request POST 0.0.0.0:3000
Thank you for trusting Paekli LLC!
We will deliver your paekli in mint condition.
* throws your paekli directly in the trash *

> curl --request DELETE 0.0.0.0:3000
There aren't any paekli for you at the moment.
* tries to hide paekli in the trash can *

Great! We can now execute different functions based on the incoming request.