Question about Idiomatic Rust.

[10thfloor]

Hello, as someone new to Rust, I have a query about borrowing and method calling syntax for a function that takes a string.

Should the calling syntax of SDK methods that take strings be simplified from, for example:

check_availability(&"grpc://access.devnet.nodes.onflow.org:9000".to_string()).await?;

to

check_availability(&"grpc://access.devnet.nodes.onflow.org:9000").await?;

If the function definition is modified as such (change the network_address parameter from &String to &str and use to_owned method instead of clone):

pub async fn check_availability(network_address: &str) -> Result<(), Box<dyn error::Error>> {
    let mut client = AccessApiClient::connect(network_address.to_owned()).await?;

    let request = tonic::Request::new(PingRequest {});

    client.ping(request).await?;

    Ok(())
}

Thought about posting on SO, but thought I would come here first, because it's easier to ask when there is some code for context.

[10thfloor]

Haven't read too much Rust code in life, so apologies if this is redundant.

[MarshallBelles]

@10thfloor

In Rust, when you specify a string as "hello world" what you are doing is creating a static non-mutable str (utf8 bytes) which has some limitations. The String class is heap-allocated to allow for mutability.

I chose to have a mutable String reference so that you only have to define your network_address once, and can make adjustments if needed. (This also makes the reference thread safe).

[10thfloor]

Great. Thanks for the explanation.

[fee1-dead]

You could make adjustments with a String and convert that to &str relatively cheaply. &str is not limited to just literals.