Extract hook and add config and documentation

platform/core/src/utils/dicomLoaderService.js

@@ -4,6 +4,7 @@ import { api } from 'dicomweb-client';
 import DICOMWeb from '../DICOMWeb';
 
 import errorHandler from '../errorHandler';
+import getXHRRetryRequestHook from './xhrRetryRequestHook';
 
 const getImageId = imageObj => {
   if (!imageObj) {
@@ -66,6 +67,7 @@ const wadorsRetriever = (
     url,
     headers,
     errorInterceptor,
+    requestHooks: [getXHRRetryRequestHook()],
   };
   const dicomWeb = new api.DICOMwebClient(config);
 

platform/core/src/utils/index.js

@@ -18,6 +18,7 @@ import isDicomUid from './isDicomUid';
 import resolveObjectPath from './resolveObjectPath';
 import * as hierarchicalListUtils from './hierarchicalListUtils';
 import * as progressTrackingUtils from './progressTrackingUtils';
+import xhrRetryRequestHook from './xhrRetryRequestHook';
 
 const utils = {
   guid,
@@ -40,6 +41,7 @@ const utils = {
   resolveObjectPath,
   hierarchicalListUtils,
   progressTrackingUtils,
+  xhrRetryRequestHook,
 };
 
 export {
@@ -63,6 +65,7 @@ export {
   resolveObjectPath,
   hierarchicalListUtils,
   progressTrackingUtils,
+  xhrRetryRequestHook,
 };
 
 export default utils;

platform/core/src/utils/index.test.js

@@ -23,6 +23,7 @@ describe('Top level exports', () => {
       'resolveObjectPath',
       'hierarchicalListUtils',
       'progressTrackingUtils',
+      'xhrRetryRequestHook',
     ].sort();
 
     const exports = Object.keys(utils.default).sort();

platform/core/src/utils/metadataProvider/fetchOverlayData.js

@@ -4,6 +4,7 @@ import str2ab from '../str2ab';
 import unpackOverlay from './unpackOverlay';
 
 import errorHandler from '../../errorHandler';
+import getXHRRetryRequestHook from '../xhrRetryRequestHook';
 
 export default async function fetchOverlayData(instance, server) {
   const OverlayDataPromises = [];
@@ -69,6 +70,7 @@ async function _getOverlayData(tag, server) {
     url: server.wadoRoot, //BulkDataURI is absolute, so this isn't used
     headers: DICOMWeb.getAuthorizationHeader(server),
     errorInterceptor: errorHandler.getHTTPErrorHandler(),
+    requestHooks: [getXHRRetryRequestHook()],
   };
   const dicomWeb = new api.DICOMwebClient(config);
   const options = {

platform/core/src/utils/metadataProvider/fetchPaletteColorLookupTableData.js

@@ -3,6 +3,7 @@ import DICOMWeb from '../../DICOMWeb';
 import str2ab from '../str2ab';
 
 import errorHandler from '../../errorHandler';
+import getXHRRetryRequestHook from '../xhrRetryRequestHook';
 
 export default async function fetchPaletteColorLookupTableData(
   instance,
@@ -141,6 +142,7 @@ function _getPaletteColor(server, paletteColorLookupTableData, lutDescriptor) {
       url: server.wadoRoot, //BulkDataURI is absolute, so this isn't used
       headers: DICOMWeb.getAuthorizationHeader(server),
       errorInterceptor: errorHandler.getHTTPErrorHandler(),
+      requestHooks: [getXHRRetryRequestHook()],
     };
     const dicomWeb = new api.DICOMwebClient(config);
     const options = {

platform/core/src/utils/xhrRetryRequestHook.js

@@ -0,0 +1,91 @@
+import retry from 'retry';
+
+const defaultRetryOptions = {
+  retries: process.env.DICOMWEB_CLIENT_RETRY_RETRIES || 5,
+  factor: process.env.DICOMWEB_CLIENT_RETRY_FACTOR || 3,
+  minTimeout: process.env.DICOMWEB_CLIENT_RETRY_MIN_TIMEOUT || 1 * 1000,
+  maxTimeout: process.env.DICOMWEB_CLIENT_RETRY_MAX_TIMEOUT || 60 * 1000,
+  randomize: process.env.DICOMWEB_CLIENT_RETRY_RANDOMIZE || true,
+};
+
+let retryOptions = { ...defaultRetryOptions };
+
+/**
+ * Request hook used to add retry functionality to XHR requests.
+ *
+ * @param {XMLHttpRequest} request XHR request instance
+ * @param {object} metadata Metadata about the request
+ * @param {object} metadata.url URL
+ * @param {object} metadata.method HTTP method
+ * @returns {XMLHttpRequest} request instance optionally modified
+ */
+const xhrRetryRequestHook = (request, metadata) => {
+  const { url, method } = metadata;
+
+  function faultTolerantRequestSend(...args) {
+    const operation = retry.operation(retryOptions);
+
+    operation.attempt(function operationAttempt(currentAttempt) {
+      const originalOnReadyStateChange = request.onreadystatechange;
+
+      request.onreadystatechange = function onReadyStateChange() {
+        originalOnReadyStateChange.call(request);
+        if (request.status === 429 || request.status >= 500) {
+          const errorMessage = `Attempt to request ${url} failed.`;
+          const attemptFailedError = new Error(errorMessage);
+          operation.retry(attemptFailedError);
+        }
+      };
+
+      console.warn(`Requesting ${url}... (attempt: ${currentAttempt})`);
+      request.open(method, url, true);
+      originalRequestSend.call(request, ...args);
+    });
+  }
+
+  const originalRequestSend = request.send;
+  request.send = faultTolerantRequestSend;
+
+  return request;
+};
+
+/**
+ * Returns a configured retry request hook function
+ * that can be used to add retry functionality to XHR request.
+ *
+ * Default options:
+ *   retries: 5
+ *   factor: 3
+ *   minTimeout: 1 * 1000
+ *   maxTimeout: 60 * 1000
+ *   randomize: true
+ *
+ * @param {*} options
+ * @param {*} options.retires number of retries
+ * @param {*} options.factor factor
+ * @param {*} options.minTimeout the min timeout
+ * @param {*} options.maxTimeout the max timeout
+ * @param {*} options.randomize randomize
+ * @returns {function} the configured retry request function
+ */
+export const getXHRRetryRequestHook = (options = {}) => {
+  retryOptions = { ...defaultRetryOptions };
+  if ('retries' in options) {
+    retryOptions.retries = options.retries;
+  }
+  if ('factor' in options) {
+    retryOptions.factor = options.factor;
+  }
+  if ('minTimeout' in options) {
+    retryOptions.minTimeout = options.minTimeout;
+  }
+  if ('maxTimeout' in options) {
+    retryOptions.maxTimeout = options.maxTimeout;
+  }
+  if ('randomize' in options) {
+    retryOptions.randomize = options.randomize;
+  }
+  return xhrRetryRequestHook;
+};
+
+export default getXHRRetryRequestHook;