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| API and MCP server, Rust identity service, registration, site redesign | 1 | //! Plumbing shared by g1t services that run on Workers. |
| 2 | //! | |
| 3 | //! Services talk to each other over service bindings with a small JSON | |
| 4 | //! protocol: `POST /rpc/<method>` with the method's arguments as the body, | |
| 5 | //! answered with the method's return value. | |
| 6 | ||
| 7 | use serde::Serialize; | |
| 8 | use serde::de::DeserializeOwned; | |
| 9 | use worker::{Date, Fetcher, Headers, Method, Request, RequestInit, Response, Result}; | |
| 10 | ||
| 11 | /// The current time in milliseconds since the epoch. | |
| 12 | pub fn now_ms() -> u64 { | |
| 13 | Date::now().as_millis() | |
| 14 | } | |
| 15 | ||
| 16 | /// The method name of an RPC request, or `None` if it is not one. | |
| 17 | pub fn rpc_method(request: &Request) -> Option<String> { | |
| 18 | if request.method() != Method::Post { | |
| 19 | return None; | |
| 20 | } | |
| 21 | request | |
| 22 | .path() | |
| 23 | .strip_prefix("/rpc/") | |
| 24 | .map(|method| method.to_owned()) | |
| 25 | } | |
| 26 | ||
| 27 | /// Deserializes a method's arguments. | |
| 28 | pub fn args<A: DeserializeOwned>(body: serde_json::Value) -> Result<A> { | |
| 29 | serde_json::from_value(body) | |
| 30 | .map_err(|error| worker::Error::RustError(format!("bad arguments: {error}"))) | |
| 31 | } | |
| 32 | ||
| 33 | /// Serializes a method's return value as the response body. | |
| 34 | pub fn reply<R: Serialize>(value: &R) -> Result<Response> { | |
| 35 | Response::from_json(value) | |
| 36 | } | |
| 37 | ||
| 38 | /// Calls `method` on another service through its binding. | |
| 39 | pub async fn call<A: Serialize, R: DeserializeOwned>( | |
| 40 | service: &Fetcher, | |
| 41 | method: &str, | |
| 42 | arguments: &A, | |
| 43 | ) -> Result<R> { | |
| 44 | let headers = Headers::new(); | |
| 45 | headers.set("content-type", "application/json")?; | |
| 46 | let mut init = RequestInit::new(); | |
| 47 | init.with_method(Method::Post) | |
| 48 | .with_headers(headers) | |
| 49 | .with_body(Some(serde_json::to_string(arguments)?.into())); | |
| 50 | // The hostname is ignored; a service binding always reaches its service. | |
| 51 | let request = Request::new_with_init(&format!("https://service/rpc/{method}"), &init)?; | |
| 52 | let mut response = service.fetch_request(request).await?; | |
| 53 | if response.status_code() != 200 { | |
| 54 | return Err(worker::Error::RustError(format!( | |
| 55 | "{method} failed with status {}: {}", | |
| 56 | response.status_code(), | |
| 57 | response.text().await.unwrap_or_default() | |
| 58 | ))); | |
| 59 | } | |
| 60 | response.json().await | |
| 61 | } |