feat(UserSession): multiple requests to getToken for similar URLs now…

… return the same Promise

When called many times in quick succession getToken would make multiple requests to
token
endpoints. Now only 1 request is made and the existing Promise is returned.

AFFECTS PACKAGES:
@esri/arcgis-rest-auth

packages/arcgis-rest-auth/src/UserSession.ts

@@ -176,6 +176,9 @@ export class UserSession implements IAuthenticationManager {
   private _tokenExpires: Date;
   private _refreshToken: string;
   private _refreshTokenExpires: Date;
+  private _pendingTokenRequests: {
+    [key: string]: Promise<string>;
+  };
 
   /**
    * Internal list of trusted 3rd party servers (federated servers) that have
@@ -229,6 +232,7 @@ export class UserSession implements IAuthenticationManager {
     this.redirectUri = options.redirectUri;
     this.refreshTokenDuration = options.refreshTokenDuration || 20160;
     this.trustedServers = {};
+    this._pendingTokenRequests = {};
   }
 
   /**
@@ -504,7 +508,11 @@ export class UserSession implements IAuthenticationManager {
       return Promise.resolve(existingToken.token);
     }
 
-    return request(`${root}/rest/info`)
+    if (this._pendingTokenRequests[root]) {
+      return this._pendingTokenRequests[root];
+    }
+
+    this._pendingTokenRequests[root] = request(`${root}/rest/info`)
       .then((response: any) => {
         return response.owningSystemUrl;
       })
@@ -538,6 +546,8 @@ export class UserSession implements IAuthenticationManager {
         };
         return response.token;
       });
+
+    return this._pendingTokenRequests[root];
   }
 
   /**
@@ -552,7 +562,16 @@ export class UserSession implements IAuthenticationManager {
       return Promise.resolve(this.token);
     }
 
-    return this.refreshSession().then(session => session.token);
+    if (!this._pendingTokenRequests[this.portal]) {
+      this._pendingTokenRequests[
+        this.portal
+      ] = this.refreshSession().then(session => {
+        this._pendingTokenRequests[this.portal] = null;
+        return session.token;
+      });
+    }
+
+    return this._pendingTokenRequests[this.portal];
   }
 
   /**

packages/arcgis-rest-auth/test/UserSession.test.ts

@@ -4,6 +4,8 @@ import * as fetchMock from "fetch-mock";
 import { YESTERDAY, TOMORROW } from "./utils";
 
 describe("UserSession", () => {
+  afterEach(fetchMock.restore);
+
   it("should serialze to and from JSON", () => {
     const session = new UserSession({
       clientId: "clientId",
@@ -155,6 +157,67 @@ describe("UserSession", () => {
         });
     });
 
+    it("should only make 1 token request to an untrusted portal for similar URLs", done => {
+      const session = new UserSession({
+        clientId: "id",
+        token: "token",
+        refreshToken: "refresh",
+        tokenExpires: TOMORROW,
+        portal: "https://gis.city.gov/sharing/rest"
+      });
+
+      fetchMock.mock(
+        "https://gisservices.city.gov/public/rest/info",
+        {
+          currentVersion: 10.51,
+          fullVersion: "10.5.1.120",
+          owningSystemUrl: "https://gis.city.gov",
+          authInfo: {
+            isTokenBasedSecurity: true,
+            tokenServicesUrl: "https://gis.city.gov/sharing/generateToken"
+          }
+        },
+        { times: 1, method: "POST" }
+      );
+
+      fetchMock.mock(
+        "https://gis.city.gov/sharing/rest/info",
+        {
+          owningSystemUrl: "http://gis.city.gov",
+          authInfo: {
+            tokenServicesUrl: "https://gis.city.gov/sharing/generateToken",
+            isTokenBasedSecurity: true
+          }
+        },
+        { times: 1, method: "POST" }
+      );
+
+      fetchMock.mock(
+        "https://gis.city.gov/sharing/generateToken",
+        {
+          token: "serverToken",
+          expires: TOMORROW
+        },
+        { times: 1, method: "POST" }
+      );
+
+      Promise.all([
+        session.getToken(
+          "https://gisservices.city.gov/public/rest/services/trees/FeatureServer/0/query"
+        ),
+        session.getToken(
+          "https://gisservices.city.gov/public/rest/services/trees/FeatureServer/0/query"
+        )
+      ]).then(([token1, token2]) => {
+        expect(token1).toBe("serverToken");
+        expect(token2).toBe("serverToken");
+        expect(
+          fetchMock.calls("https://gis.city.gov/sharing/generateToken").length
+        ).toBe(1);
+        done();
+      });
+    });
+
     it("should throw an ArcGISAuthError when the owning system doesn't match", done => {
       const session = new UserSession({
         clientId: "id",
@@ -291,6 +354,42 @@ describe("UserSession", () => {
         done();
       });
     });
+
+    it("should only make 1 token request to the portal for similar URLs", done => {
+      const session = new UserSession({
+        clientId: "id",
+        token: "token",
+        refreshToken: "refresh",
+        tokenExpires: YESTERDAY
+      });
+
+      fetchMock.mock(
+        "https://www.arcgis.com/sharing/rest/oauth2/token",
+        {
+          access_token: "new",
+          expires_in: 1800,
+          username: "casey"
+        },
+        { times: 1, method: "POST" }
+      );
+
+      Promise.all([
+        session.getToken("https://www.arcgis.com/sharing/rest/portals/self"),
+        session.getToken("https://www.arcgis.com/sharing/rest/portals/self")
+      ])
+        .then(([token1, token2]) => {
+          expect(token1).toBe("new");
+          expect(token2).toBe("new");
+          expect(
+            fetchMock.calls("https://www.arcgis.com/sharing/rest/oauth2/token")
+              .length
+          ).toBe(1);
+          done();
+        })
+        .catch(e => {
+          fail(e);
+        });
+    });
   });
 
   describe(".beginOAuth2()", () => {