Minimal User Interface (Rust)

The psibase library can provide a minimal UI to your services. This UI can help get you started developing your own services, but isn't suitable for end users.

example-ui

Run the following to create a project:

cargo new --lib example-ui
cd example-ui
cargo add psibase
cargo add -F derive serde

Replace the content of lib.rs with the following:

#[psibase::service]
#[allow(non_snake_case)]
mod service {
    use psibase::*;

    #[action]
    fn add(a: i32, b: i32) -> i32 {
        a + b
    }

    #[action]
    fn multiply(a: i32, b: i32) -> i32 {
        a * b
    }

    // This action serves HTTP requests
    #[action]
    fn serveSys(request: HttpRequest) -> Option<HttpReply> {
        // serve_simple_ui serves UI files to the browser and
        // provides an RPC interface for preparing transactions.
        // #[psibase::service] automatically generates Wrapper.
        serve_simple_ui::<Wrapper>(&request)
    }
}

Building and Deploying

This will build the service and deploy it to the chain:

cargo psibase deploy -ip example-ui

The -p option will register the service with the http-server service. This allows the service to handle web requests. See the registerServer docs for more details.

Trying the UI

If you're running a test chain locally, then it will typically be at http://psibase.127.0.0.1.sslip.io:8080/ or http://psibase.127.0.0.1.sslip.io:8079/. To try the service, prefix your host with your service name (e.g. http://example.psibase.127.0.0.1.sslip.io:8080/).

How it Works

• psinode forwards most http requests to the http-server service.
• If the URL begins with /common, http-server forwards the request to the common-api service. common-api provides shared resources, such as js library code and an RPC request handler for packing transactions.
• http-server looks at the request domain. If it begins with the name of a registered service, it calls that service's serveSys action to process the request.
• psibase::serve_simple_ui handles the following requests:
  • GET / returns a minimal html file which references the /common/SimpleUI.mjs script. This script generates the UI dynamically.
  • GET /action_templates returns a template json structure (below). This lets the UI know which actions are available and sample values for their arguments. This isn't a schema; it's only suitable for simple cases.
  • GET /schema returns the service's schema.
  • POST /pack_action/add accepts the arguments for the add action as a JSON object, converts it to binary, and returns the result.

For more detail, see Web Services.

/action_templates result

{
  "add": {
    "a": 0,
    "b": 0
  },
  "multiply": {
    "a": 0,
    "b": 0
  },
  "serveSys": { ... }
}