From 2d4210d826d43cf268081646c0822a9785d325d3 Mon Sep 17 00:00:00 2001
From: Vladimir Ignatov <vlad.ignatov@gmail.com>
Date: Tue, 28 May 2024 16:00:13 -0400
Subject: [PATCH] Add fhir_server to sim

---
 backend/index.ts             | 13 +++++++++++--
 backend/lib.ts               | 10 ++++++++++
 backend/routes/fhir/proxy.ts |  5 +++--
 index.d.ts                   |  1 +
 src/isomorphic/codec.ts      | 15 +++++++++++----
 5 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/backend/index.ts b/backend/index.ts
index e3dc012..930e966 100644
--- a/backend/index.ts
+++ b/backend/index.ts
@@ -40,10 +40,19 @@ app.get("/smart-style.json", (_, res) => {
 })
 
 // Auth server
-app.use(["/v/:fhir_release/sim/:sim/auth", "/v/:fhir_release/auth"], authServer)
+app.use([
+    "/v/:fhir_release/sim/:sim/s/:server/auth",
+    "/v/:fhir_release/sim/:sim/auth",
+    "/v/:fhir_release/auth"
+], authServer)
 
 // FHIR servers
-app.use(["/v/:fhir_release/sim/:sim/fhir", "/v/:fhir_release/fhir"], fhirServer)
+app.use([
+    "/v/:fhir_release/sim/:sim/s/:server/fhir",
+    "/v/:fhir_release/sim/:sim/fhir",
+    "/v/:fhir_release/s/:server/fhir",
+    "/v/:fhir_release/fhir"
+], fhirServer)
 
 // The launcher endpoint
 app.get("/launcher", launcher);
diff --git a/backend/lib.ts b/backend/lib.ts
index b28f40f..0e24483 100644
--- a/backend/lib.ts
+++ b/backend/lib.ts
@@ -2,6 +2,7 @@ import jwt from "jsonwebtoken"
 import { NextFunction, Request, Response, RequestHandler } from "express"
 import config from "./config";
 import { HttpError, InvalidRequestError } from "./errors";
+import { decode } from "../src/isomorphic/codec";
 
 
 /**
@@ -45,6 +46,15 @@ export function notSupported(message: string = "", code = 400) {
 }
 
 export function getFhirServerBaseUrl(req: Request) {
+    try {
+        var sim = decode(req.params.sim)
+        if (sim.fhir_server) {
+            return sim.fhir_server
+        }
+    } catch (ex) {
+        console.error("Invalid sim: " + ex)
+    }
+
     const fhirVersion = req.params.fhir_release.toUpperCase();
     let fhirServer = config[`fhirServer${fhirVersion}` as keyof typeof config] as string;
 
diff --git a/backend/routes/fhir/proxy.ts b/backend/routes/fhir/proxy.ts
index 8441f71..513fc6d 100644
--- a/backend/routes/fhir/proxy.ts
+++ b/backend/routes/fhir/proxy.ts
@@ -49,7 +49,8 @@ export default async function proxy(req: Request, res: Response) {
     }
 
     // Proxy ---------------------------------------------------------------
-    const response = await fetch(new URL(fhirServer + req.url).href, fhirRequestOptions);
+    const _url = new URL(fhirServer + req.url).href.replace(/\/\s*\//g, "/")
+    const response = await fetch(_url, fhirRequestOptions);
 
     res.status(response.status);
 
@@ -62,7 +63,7 @@ export default async function proxy(req: Request, res: Response) {
     let body = await response.text()
 
     if (!isBinary) {
-        body = body.replaceAll(fhirServer + "", `${getRequestBaseURL(req)}/v/${fhirVersionLower}/fhir`);
+        body = body.replaceAll(fhirServer + "", `${getRequestBaseURL(req)}${req.baseUrl}`);
     }
 
     res.end(body);
diff --git a/index.d.ts b/index.d.ts
index 72e4fc0..ce9bc95 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -69,6 +69,7 @@ declare namespace SMART {
         jwks?: string
         pkce?: PKCEValidation
         client_type?: SMARTClientType
+        fhir_server?: string
     }
 
     interface AuthorizeParams {
diff --git a/src/isomorphic/codec.ts b/src/isomorphic/codec.ts
index 9e67a4d..d725700 100644
--- a/src/isomorphic/codec.ts
+++ b/src/isomorphic/codec.ts
@@ -64,7 +64,8 @@ export function encode(params: SMART.LaunchParams, ignoreErrors = false): string
             params.jwks_url      || "",
             params.jwks          || "",
             clientTypes.indexOf(params.client_type || "public"),
-            PKCEValidationTypes.indexOf(params.pkce || "auto")
+            PKCEValidationTypes.indexOf(params.pkce || "auto"),
+            params.fhir_server   || ""
         ]))
     }
 
@@ -84,7 +85,8 @@ export function encode(params: SMART.LaunchParams, ignoreErrors = false): string
         params.jwks_url      || "",
         params.jwks          || "",
         clientTypes.indexOf(params.client_type || "public"),
-        PKCEValidationTypes.indexOf(params.pkce || "auto")
+        PKCEValidationTypes.indexOf(params.pkce || "auto"),
+        params.fhir_server   || ""
     ];
 
     return base64UrlEncode(JSON.stringify(arr))
@@ -124,7 +126,8 @@ export function decode(launch: string): SMART.LaunchParams {
         jwks_url     : arr[12] || "",
         jwks         : arr[13] || "",
         client_type  : clientTypes[arr[14]],
-        pkce         : PKCEValidationTypes[arr[15]]
+        pkce         : PKCEValidationTypes[arr[15]],
+        fhir_server  : arr[16] || "",
     }
 }
 
@@ -190,7 +193,8 @@ function decodeLegacy(object: Record<string, string>): SMART.LaunchParams {
         jwks_url     : "",
         jwks         : "",
         client_type  : "public", // "backend-service"
-        pkce         : "auto"
+        pkce         : "auto",
+        fhir_server  : ""
     }
 
     if (object.d && Number.isInteger(+object.d)) { // auth_error
@@ -223,6 +227,9 @@ function decodeLegacy(object: Record<string, string>): SMART.LaunchParams {
     if (object.r) {
         out.jwks = object.r
     }
+    if (object.s) {
+        out.fhir_server = object.s
+    }
     // -------------------------------------------------------------------------
 
     return out as SMART.LaunchParams;