REMS-260 Prefetch hydration

src/hooks/OrderSignRequest.ts

@@ -3,6 +3,7 @@ import { Url } from 'url';
 import OrderSignRequestPrefetch from './Prefetch/OrderSignRequestPrefetch';
 // https://cds-hooks.hl7.org/1.0/#fhir-resource-access
 interface FhirAuthorization {
+  access_token: string;
   token_type: string;
   expires_in: number;
   scope: string;

src/hooks/Prefetch/OrderSignPrefetch.ts

@@ -1,5 +1,5 @@
 export default interface OrderSignPrefetch {
-  patient?: string;
-  request?: string;
-  practitioner?: string;
+  [key: string]: string;
+  patient: string;
+  practitioner: string;
 }

src/hooks/Prefetch/OrderSignRequestPrefetch.ts

@@ -1,7 +1,6 @@
-import { MedicationRequest, Patient, Practitioner } from 'fhir/r4';
+import { Patient, Practitioner } from 'fhir/r4';
 import RequestPrefetch from './RequestPrefetch';
 export default interface OrderSignRequestPrefetch extends RequestPrefetch {
-  patient: Patient;
-  request: MedicationRequest;
-  practitioner: Practitioner;
+  patient?: Patient;
+  practitioner?: Practitioner;
 }

src/hooks/Prefetch/RequestPrefetch.ts

@@ -1,5 +1,5 @@
 import { Resource } from 'fhir/r4';
 
 export default interface RequestPrefetch {
-  [key: string]: Resource;
+  [key: string]: Resource | undefined;
 }

src/hooks/Prefetch/hydrator/PrefetchHydrator.ts

@@ -0,0 +1,83 @@
+import OrderSignRequest from '../../OrderSignRequest';
+import OrderSignPrefetch from '../OrderSignPrefetch';
+import axios from 'axios';
+function jsonPath(json: any, path: string) {
+  // Use a regular expression to find array accessors in the form of "[i]"
+  const arrayRegex = /\[(\d+)\]/g;
+
+  // Use the regex to find all the array accessors in the path
+  let match;
+  while ((match = arrayRegex.exec(path)) !== null) {
+    // Get the index of the array element to access
+    const index = match[1];
+
+    // Use the index to replace the array accessor in the path with the corresponding property accessor
+    path = path.replace(match[0], `.${index}`);
+  }
+
+  // Split the path into its individual components
+  const pathComponents = path.split('.');
+
+  // Use reduce to iterate over the path components and get the corresponding value from the JSON object
+  return pathComponents.reduce((obj, key) => {
+    // If the key doesn't exist, return undefined
+    if (!obj || !Object.prototype.hasOwnProperty.call(obj, key)) return undefined;
+
+    // Otherwise, return the value at the key
+    return obj[key];
+  }, json);
+}
+function replaceTokens(str: string, json: any): string {
+  // Use a regular expression to find tokens in the form of "{{token}}"
+  const tokenRegex = /{{([\w.]+)}}/g;
+
+  // Use the regex to find all the tokens in the string
+  let match;
+  while ((match = tokenRegex.exec(str)) !== null) {
+    // Get the token from the match
+    const token = match[1];
+
+    // Use the token to get the corresponding value from the JSON object
+    const value = jsonPath(json, token);
+
+    // Replace the token in the original string with the value
+    str = str.replace(match[0], value);
+  }
+
+  // Return the modified string
+  return str;
+}
+function resolveToken(token: string, context: OrderSignRequest) {
+  const fulfilledToken = replaceTokens(token, context);
+  const ehrUrl = `${context.fhirServer}/${fulfilledToken}`;
+  const access_token = context.fhirAuthorization.access_token;
+  const options = {
+    method: 'GET',
+    headers: {
+      Authorization: `Bearer ${access_token}`
+    }
+  };
+  const response = axios(ehrUrl, options);
+  return response.then(e => {
+    return e.data;
+  });
+}
+function hydrate(template: OrderSignPrefetch, request: OrderSignRequest) {
+  let prefetch = request.prefetch;
+  if (!prefetch) {
+    prefetch = {};
+  }
+  // Find unfulfilled prefetch elements and resolve them using
+  // the defined prefetch template
+  const promises = Object.keys(template).map(key => {
+    if (!Object.prototype.hasOwnProperty.call(prefetch, key)) {
+      // prefetch was not fulfilled
+      return resolveToken(template[key], request).then(data => {
+        Object.assign(prefetch, { [key]: data });
+      });
+    }
+  });
+
+  return Promise.all(promises).then(() => prefetch);
+}
+export { hydrate };

src/hooks/rems.hook.test.ts

@@ -5,7 +5,6 @@ describe('hook: test rems', () => {
   test('should have definition and handler', () => {
     const prefetch = {
       patient: 'Patient/{{context.patientId}}',
-      request: 'MedicationRequest?_id={{context.draftOrders.MedicationRequest.id}}',
       practitioner: 'Practitioner/{{context.userId}}'
     };
     const expectedDefinition = new OrderSign(

src/hooks/rems.hook.ts

@@ -5,6 +5,7 @@ import OrderSignPrefetch from './Prefetch/OrderSignPrefetch';
 import { Coding } from 'fhir/r4';
 import { Link } from '../cards/Card';
 import config from '../config';
+import { hydrate } from './Prefetch/hydrator/PrefetchHydrator';
 
 const CARD_DETAILS = 'Documentation Required, please complete form via Smart App link.';
 // TODO: this codemap should be replaced with a system similar to original CRD's questionnaire package operation
@@ -135,17 +136,16 @@ interface TypedRequestBody extends Express.Request {
   body: OrderSignRequest;
 }
 
-const prefetch: OrderSignPrefetch = {
+const hookPrefetch: OrderSignPrefetch = {
   patient: 'Patient/{{context.patientId}}',
-  request: 'MedicationRequest?_id={{context.draftOrders.MedicationRequest.id}}',
   practitioner: 'Practitioner/{{context.userId}}'
 };
 const definition = new OrderSign(
   'rems-order-sign',
   'order-sign',
   'REMS Requirement Lookup',
   'REMS Requirement Lookup',
-  prefetch
+  hookPrefetch
 );
 const source = {
   label: 'MCODE REMS Administrator Prototype',
@@ -162,80 +162,79 @@ function buildErrorCard(reason: string) {
 const handler = (req: TypedRequestBody, res: any) => {
   console.log('REMS order-sign hook');
   try {
-    const context = req.body.context;
-    const contextRequest = context.draftOrders?.entry?.[0].resource;
-    const prefetch = req.body.prefetch;
-    const patient = prefetch?.patient;
-    const prefetchRequest = prefetch?.request;
-    const practitioner = prefetch?.practitioner;
-    const npi = practitioner?.identifier;
+    hydrate(hookPrefetch, req.body).then(hydratedPrefetch => {
+      const context = req.body.context;
+      const contextRequest = context.draftOrders?.entry?.[0].resource;
+      const patient = hydratedPrefetch?.patient;
+      const prefetchRequest = hydratedPrefetch?.request;
+      const practitioner = hydratedPrefetch?.practitioner;
+      const npi = practitioner?.identifier;
+      console.log('    Practitioner: ' + practitioner?.id + ' NPI: ' + npi);
+      console.log('    Patient: ' + patient?.id);
 
-    console.log('    MedicationRequest: ' + prefetchRequest?.id);
-    console.log('    Practitioner: ' + practitioner?.id + ' NPI: ' + npi);
-    console.log('    Patient: ' + patient?.id);
-
-    // verify a MedicationRequest was sent
-    if (contextRequest && contextRequest.resourceType !== 'MedicationRequest') {
-      res.json(buildErrorCard('DraftOrders does not contain a MedicationRequest'));
-      return;
-    }
+      // verify a MedicationRequest was sent
+      if (contextRequest && contextRequest.resourceType !== 'MedicationRequest') {
+        res.json(buildErrorCard('DraftOrders does not contain a MedicationRequest'));
+        return;
+      }
 
-    // verify ids
-    if (
-      patient?.id &&
-      patient.id.replace('Patient/', '') !== context.patientId.replace('Patient/', '')
-    ) {
-      res.json(buildErrorCard('Context patientId does not match prefetch Patient ID'));
-      return;
-    }
-    if (
-      practitioner?.id &&
-      practitioner.id.replace('Practitioner/', '') !== context.userId.replace('Practitioner/', '')
-    ) {
-      res.json(buildErrorCard('Context userId does not match prefetch Practitioner ID'));
-      return;
-    }
-    if (
-      prefetchRequest?.id &&
-      contextRequest &&
-      contextRequest.id &&
-      prefetchRequest.id.replace('MedicationRequest/', '') !==
-        contextRequest.id.replace('MedicationRequest/', '')
-    ) {
-      res.json(buildErrorCard('Context draftOrder does not match prefetch MedicationRequest ID'));
-      return;
-    }
+      // verify ids
+      if (
+        patient?.id &&
+        patient.id.replace('Patient/', '') !== context.patientId.replace('Patient/', '')
+      ) {
+        res.json(buildErrorCard('Context patientId does not match prefetch Patient ID'));
+        return;
+      }
+      if (
+        practitioner?.id &&
+        practitioner.id.replace('Practitioner/', '') !== context.userId.replace('Practitioner/', '')
+      ) {
+        res.json(buildErrorCard('Context userId does not match prefetch Practitioner ID'));
+        return;
+      }
+      if (
+        prefetchRequest?.id &&
+        contextRequest &&
+        contextRequest.id &&
+        prefetchRequest.id.replace('MedicationRequest/', '') !==
+          contextRequest.id.replace('MedicationRequest/', '')
+      ) {
+        res.json(buildErrorCard('Context draftOrder does not match prefetch MedicationRequest ID'));
+        return;
+      }
 
-    const medicationCode = contextRequest?.medicationCodeableConcept?.coding?.[0];
-    if (medicationCode && medicationCode.code) {
-      const returnCard = validCodes.some(e => {
-        return e.code === medicationCode.code && e.system === medicationCode.system;
-      });
-      if (returnCard) {
-        const card = new Card(medicationCode.display || 'Rems', CARD_DETAILS, source, 'info');
-        const links = codeMap[medicationCode.code];
-        links.forEach(e => {
-          if (e.type == 'absolute') {
-            // no construction needed
-            card.addLink(e);
-          } else {
-            // link is SMART
-            // TODO: smart links should be built with discovered questionnaires, not hard coded ones
-            e.appContext = `${e.appContext}&order=${JSON.stringify(contextRequest)}&coverage=${
-              contextRequest.insurance?.[0].reference
-            }`;
-            card.addLink(e);
-          }
-        });
-        res.json({
-          cards: [card]
+      const medicationCode = contextRequest?.medicationCodeableConcept?.coding?.[0];
+      if (medicationCode && medicationCode.code) {
+        const returnCard = validCodes.some(e => {
+          return e.code === medicationCode.code && e.system === medicationCode.system;
         });
+        if (returnCard) {
+          const card = new Card(medicationCode.display || 'Rems', CARD_DETAILS, source, 'info');
+          const links = codeMap[medicationCode.code];
+          links.forEach(e => {
+            if (e.type == 'absolute') {
+              // no construction needed
+              card.addLink(e);
+            } else {
+              // link is SMART
+              // TODO: smart links should be built with discovered questionnaires, not hard coded ones
+              e.appContext = `${e.appContext}&order=${JSON.stringify(contextRequest)}&coverage=${
+                contextRequest.insurance?.[0].reference
+              }`;
+              card.addLink(e);
+            }
+          });
+          res.json({
+            cards: [card]
+          });
+        } else {
+          res.json(buildErrorCard('Unsupported code'));
+        }
       } else {
-        res.json(buildErrorCard('Unsupported code'));
+        res.json(buildErrorCard('MedicationRequest does not contain a code'));
       }
-    } else {
-      res.json(buildErrorCard('MedicationRequest does not contain a code'));
-    }
+    });
   } catch (error) {
     console.log(error);
     res.json(buildErrorCard('Unknown Error'));