From fed40ff8bd7e0f5f034a171777892b629fae7f70 Mon Sep 17 00:00:00 2001
From: Piotr Mankowski <pmanko@uw.edu>
Date: Wed, 31 Jan 2024 14:23:04 +0000
Subject: [PATCH] Fix passthrough

---
 src/lib/helpers.ts | 49 +++++++++++++++++++++++++++++-----------------
 src/routes/fhir.ts | 26 ++++++++++++------------
 2 files changed, 45 insertions(+), 30 deletions(-)

diff --git a/src/lib/helpers.ts b/src/lib/helpers.ts
index bfcd1f6..bf8b055 100644
--- a/src/lib/helpers.ts
+++ b/src/lib/helpers.ts
@@ -1,9 +1,8 @@
 'use strict'
-import config from "../lib/config"
-import { Request, Response } from "express"
-import got from "got"
-import logger from "../lib/winston"
-
+import config from '../lib/config'
+import { Request, Response } from 'express'
+import got from 'got'
+import logger from '../lib/winston'
 
 export function invalidBundle(resource: any): boolean {
   return (
@@ -29,21 +28,35 @@ export function invalidBundleMessage(): any {
     },
   }
 }
+
+export async function hapiPassthrough(targetUri: any, res: Response): Promise<any> {
+  logger.info(`Getting ${targetUri}`)
+
+  const options = {
+    username: config.get('fhirServer:username'),
+    password: config.get('fhirServer:password'),
+  }
+
+  try {
+    const result = await got.get(targetUri, options).json()
+    return res.status(200).json(result)
+  } catch (error) {
+    return res.status(500).json(error)
+  }
+}
+
+export function getHapiPassthrough(): any {
+  return async (req: Request, res: Response) => {
+    const targetUri = config.get('fhirServer:baseURL') + req.url
+
+    return hapiPassthrough(targetUri, res)
+  }
+}
+
 export function getMetadata(): any {
   return async (req: Request, res: Response) => {
     const targetUri = config.get('fhirServer:baseURL') + '/metadata'
-    logger.info(`Getting ${targetUri}`)
-
-    const options = {
-      username: config.get('fhirServer:username'),
-      password: config.get('fhirServer:password'),
-    }
-
-    try {
-      const result = await got.get(targetUri, options).json()
-      res.status(200).json(result)
-    } catch (error) {
-      return res.status(500).json(error)
-    }
+
+    return hapiPassthrough(targetUri, res)
   }
 }
diff --git a/src/routes/fhir.ts b/src/routes/fhir.ts
index 388bc61..04da619 100644
--- a/src/routes/fhir.ts
+++ b/src/routes/fhir.ts
@@ -3,7 +3,7 @@ import express, { Request, Response } from 'express'
 import got from 'got'
 import URI from 'urijs'
 import config from '../lib/config'
-import { invalidBundle, invalidBundleMessage } from '../lib/helpers'
+import { getHapiPassthrough, invalidBundle, invalidBundleMessage } from '../lib/helpers'
 import logger from '../lib/winston'
 import { generateSimpleIpsBundle } from '../workflows/ipsWorkflows'
 import { getResourceTypeEnum, isValidResourceType } from '../lib/validate'
@@ -22,7 +22,7 @@ router.get('/:resource/:id?/:operation?', async (req: Request, res: Response) =>
   try {
     let uri = URI(config.get('fhirServer:baseURL'))
 
-    if(isValidResourceType(req.params.resource)) {
+    if (isValidResourceType(req.params.resource)) {
       uri = uri.segment(getResourceTypeEnum(req.params.resource).toString())
     } else {
       return res.status(400).json({ message: `Invalid resource type ${req.params.resource}` })
@@ -31,15 +31,19 @@ router.get('/:resource/:id?/:operation?', async (req: Request, res: Response) =>
     if (req.params.id && /^[a-zA-Z0-9\-_]+$/.test(req.params.id)) {
       uri = uri.segment(encodeURIComponent(req.params.id))
     } else {
-      return res.status(400).json({ message: `Invalid resource id ${req.params.id}` })
+      logger.info(`Invalid id ${req.params.id} - falling back on pass-through to HAPI FHIR server`)
+      return getHapiPassthrough()(req, res)
     }
 
     for (const param in req.query) {
       const value = req.query[param]
-      if(value && /^[a-zA-Z0-9\-_]+$/.test(value.toString())) {
+      if (value && /^[a-zA-Z0-9\-_]+$/.test(value.toString())) {
         uri.addQuery(param, encodeURIComponent(value.toString()))
       } else {
-        return res.status(400).json({ message: `Invalid query parameter ${param}=${value}` })
+        logger.info(
+          `Invalid query parameter ${param}=${value} - falling back on pass-through to HAPI FHIR server`,
+        )
+        return getHapiPassthrough()(req, res)
       }
     }
 
@@ -98,13 +102,11 @@ router.post('/', async (req, res) => {
       return res.status(400).json(invalidBundleMessage())
     }
 
-    const uri = URI(config.get("fhirServer:baseURL"));
-
+    const uri = URI(config.get('fhirServer:baseURL'))
 
     const ret = await got.post(uri.toString(), { json: resource })
 
     res.status(ret.statusCode).json(ret.body)
-
   } catch (error) {
     return res.status(500).json(error)
   }
@@ -132,12 +134,12 @@ async function saveResource(req: any, res: any) {
 
   logger.info('Received a request to add resource type ' + resourceType + ' with id ' + id)
 
-  const ret = await got.post(config.get('fhirServer:baseURL') + '/' + getResourceTypeEnum(resourceType).toString, { json: resource })
+  const ret = await got.post(
+    config.get('fhirServer:baseURL') + '/' + getResourceTypeEnum(resourceType).toString,
+    { json: resource },
+  )
 
   res.status(ret.statusCode).json(ret.body)
 }
 
-
-
-
 export default router