PING-PONG

Explore the simplicity of coding with Vara through a minimal program that demonstrates a Ping-Pong service.

tip

The project code is developed using the Sails framework.

Implementation details

The Ping-Pong program is found in the app/src/lib.rs file and responds with a "Pong!" message every time it receives a ping request. Additionally, it keeps a count of the pings received, allowing users to track their interactions with the service.

The code below defines a basic PingPongService using the sails framework:

app/src/lib.rs

#[sails_rs::service]
impl PingPongService {
    fn init() -> Self {
        unsafe {
            PING_COUNTER = Some(U256::zero());
        }
        Self(())
    }
    // Service's method (command)
    pub fn ping(&mut self) -> String {
        let ping_counter = self.get_mut();
        *ping_counter += U256::one();
        "Pong!".to_string()
    }

    // Service's query
    pub fn get_ping_count(&self) -> U256 {
        *self.get()
    }    
}

This code outlines the PingPongService with the sails_rs::service macro and includes the following core functions:

• init(): This initializes the PingPongService by setting a global PING_COUNTER to zero, preparing it for tracking future pings.
• ping(&mut self) -> String: This command method increments the ping counter on each call and returns the response "Pong!".
• get_ping_count(&self) -> U256: This query method provides the current count of pings without altering the state, allowing external users to view the interaction count.

Source code

The source code of this example of Ping-Pong program and the example of an implementation of its testing is available on gear-foundation/dapp/contracts/ping-pong.

See also an example of the smart contract testing implementation based on gtest: gear-foundation/dapps/vara-man/tests.

For more details about testing programs written on Gear, refer to the Program Testing article.