http-server

Composable HTTP Server

Expose Wasm Components and messaging channels as HTTP endpoints.

The HTTP server maps incoming HTTP requests to component function invocations or to messages published to a channel based on TOML route configuration. It runs as a runtime Service, starting automatically when [server.*] definitions with type = "http" are present.

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Configuration

Server routes are defined under [server.<name>] in TOML config files.

Component routes

Invoke a component function, mapping path parameters and an optional request body to function arguments:

[server.api]
type = "http"
port = 8080

[server.api.route.get-user]
path = "/users/{id}"
component = "user-service"
function = "get-user"

[server.api.route.create-user]
path = "/users"
component = "user-service"
function = "create"
body = "user"

Channel routes

Publish the raw request body to a messaging channel:

[server.api.route.events]
path = "/events"
channel = "incoming-events"

Route properties

Property	Required	Description
path	yes	URL path with optional {param} segments
component	yes*	Component to invoke
function	yes*	Function name on the component
body	no	Names a function parameter to populate from the request body
channel	yes*	Channel to publish to (mutually exclusive with component/function)
method	no	HTTP method (see defaults below)

* Either component + function or channel is required, never both.

Method defaults

If method is not specified, it is inferred:

• Component routes with body default to POST
• Component routes without body default to GET
• Channel routes default to POST (the only valid option)

Content types

Component routes currently support two content types for the request body:

• application/json (default): parsed as JSON
• text/plain: wrapped as a JSON string value

Other content types are rejected with 415 Unsupported Media Type.

Channel routes forward the raw request body and content-type header to the channel. The activator handles content-type interpretation when the message is consumed.

All component route responses are JSON-serialized with content-type: application/json.

Validation

The config handler rejects:

• Duplicate routes (same method and path structure)
• body param name that collides with a path param name
• body with method GET
• body on channel routes (since it's the payload, not a named param)
• GET with channel routes

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Standalone binary

composable-http-server config.toml [additional-configs...]

Multiple config files are merged, allowing separation of concerns (e.g. domain components, infrastructure capabilities, server routes in separate files). The default log level is info, overridable via the RUST_LOG environment variable.

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Library usage

Register the HTTP service with a RuntimeBuilder:

use composable_runtime::Runtime;
use composable_http_server::HttpService;

let runtime = Runtime::builder()
    .from_paths(&config_paths)
    .with_service::<HttpService>()
    .build()
    .await?;

runtime.run().await

The service claims [server.*] definitions where type = "http", so other server types can coexist under the same [server.*] category using different type selectors.