sans-io

To send using any http client, use fhir/r4/sansio to create a Request(Option(Json)) and parse the Response(String).

http clients typically take a Request(String), but fhir sansio keeps request body as JSON to more easily combine multiple requests into a batch.

import fhir/r4/sansio
import gleam/fetch
import gleam/http/request
import gleam/javascript/promise
import gleam/json
import gleam/option.{None, Some}

pub fn main() {
  let assert Ok(client) = sansio.fhirclient_new("https://r4.smarthealthit.org/")
  let pat_req =
    sansio.patient_read_req("87a339d0-8cae-418e-89c7-8651e6aab3c6", client)
  // sansio returns Request(Option(Json)), fetch wants Request(String)
  let pat_req_str =
    pat_req
    |> request.set_body(case pat_req.body {
      Some(body) -> json.to_string(body)
      None -> ""
    })
  promise.try_await(fetch.send(pat_req_str), fn(pat_resp) {
    promise.try_await(fetch.read_text_body(pat_resp), fn(pat_resp_body) {
      let assert Ok(pat) = sansio.patient_resp(pat_resp_body)
      echo pat
      promise.resolve(Ok(pat))
    })
  })
}