Add MTLS support.

src/__tests__/getMtlsFetch.test.js

@@ -0,0 +1,59 @@
+/*
+Copyright 2025 Adobe. All rights reserved.
+This file is licensed to you under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License. You may obtain a copy
+of the License at http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software distributed under
+the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+OF ANY KIND, either express or implied. See the License for the specific language
+governing permissions and limitations under the License.
+*/
+
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import getMtlsFetch from '../getMtlsFetch.js';
+import { MTLS_BINDING } from '../constants.js';
+
+describe('getMtlsFetch', () => {
+  let mockEnv;
+  let mockFetch;
+
+  beforeEach(() => {
+    mockFetch = vi.fn();
+    mockEnv = {};
+  });
+
+  it('should return the MTLS fetch function when the binding exists', () => {
+    // Arrange
+    mockEnv[MTLS_BINDING] = { fetch: mockFetch };
+
+    // Act
+    const result = getMtlsFetch(mockEnv);
+
+    // Assert
+    expect(result).toBe(mockFetch);
+  });
+
+  it('should return a function that throws an error when the binding does not exist', () => {
+    // Arrange
+    mockEnv = {}; // Empty env without MTLS binding
+
+    // Act
+    const result = getMtlsFetch(mockEnv);
+
+    // Assert
+    expect(() => result()).toThrowError(
+      'MTLS certificate not found on the worker'
+    );
+  });
+
+  it('should handle undefined env gracefully', () => {
+    // Act
+    const result = getMtlsFetch(undefined);
+
+    // Assert
+    expect(result).toBeInstanceOf(Function);
+    expect(() => result()).toThrowError(
+      'MTLS certificate not found on the worker'
+    );
+  });
+});

src/__tests__/index.test.js

@@ -33,13 +33,16 @@ describe('index', () => {
       request: { header: {}, body: { xdm: {}, data: {} } }
     };
 
-    const execute = index.initialize(containerInitFunction, {
-      fetch: globalFetch
-    });
+    const execute = index.initialize(containerInitFunction);
 
-    return execute(callData, {
-      headersForSubrequests: {}
-    }).then((result) => {
+    return execute(
+      callData,
+      {},
+      {
+        headersForSubrequests: {},
+        fetch: globalFetch
+      }
+    ).then((result) => {
       expect(result).toStrictEqual([
         {
           ruleId: 'RLbb1d94c79fee4733a510564a86ba3c59',

src/constants.js

@@ -11,3 +11,4 @@ governing permissions and limitations under the License.
 
 export const CORE = 'core';
 export const PROMISE_TIMEOUT = 30000;
+export const MTLS_BINDING = 'ADOBE_MTLS_CERTIFICATE';

src/executeRules.js

@@ -17,14 +17,14 @@ import logRuleStarting from './rules/logRuleStarting.js';
 import logRuleEnding from './rules/logRuleEnding.js';
 import returnRuleResult from './rules/returnRuleResult.js';
 import createPromiseChain from './rules/createPromiseChain.js';
+import getMtlsFetch from './getMtlsFetch.js';
 
 export default (
   moduleProvider,
   container,
-  globalFetch,
   requestData,
   env,
-  { headersForSubrequests } = {}
+  { headersForSubrequests, fetch: globalFetch } = {}
 ) => {
   const rulePromises = [];
 
@@ -53,11 +53,19 @@ export default (
       logger
     );
 
+    const mtlsFetch = getRuleFetchFn(
+      getMtlsFetch(env),
+      getHeaderOverrides(env),
+      headersForSubrequests,
+      logger
+    );
+
     const utils = {
       getRule: () => ({ id, name }),
       getBuildInfo: () => buildInfo,
       logger,
-      fetch
+      fetch,
+      mtlsFetch
     };
 
     const initialContext = {

src/getMtlsFetch.js

@@ -0,0 +1,22 @@
+/*
+Copyright 2025 Adobe. All rights reserved.
+This file is licensed to you under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License. You may obtain a copy
+of the License at http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software distributed under
+the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+OF ANY KIND, either express or implied. See the License for the specific language
+governing permissions and limitations under the License.
+*/
+
+import { MTLS_BINDING } from './constants.js';
+
+export default (env) => {
+  if (env && env[MTLS_BINDING]) {
+    return env[MTLS_BINDING].fetch;
+  }
+
+  return () => {
+    throw new Error('MTLS certificate not found on the worker');
+  };
+};

src/getRuleFetchFn.js

@@ -12,12 +12,7 @@ governing permissions and limitations under the License.
 const byteArrayToString = (buf) =>
   new TextDecoder('utf-8').decode(new Uint8Array(buf));
 
-export default (
-  globalFetch,
-  headerOverrides,
-  headersForSubrequests,
-  logger
-) => {
+export default (fetch, headerOverrides, headersForSubrequests, logger) => {
   return (resource, init = {}) => {
     // If resource is not a string then it must be a Request object and we
     // need to read it's headers. Otherwise the Request headers will be
@@ -50,7 +45,7 @@ export default (
       }
     });
 
-    return globalFetch(resource, init).then(
+    return fetch(resource, init).then(
       (r) => {
         // Below we will read the body of the response. The body can be read only once.
         // We are cloning the response and sending it down to the actions so in case

src/index.js

@@ -29,14 +29,14 @@ const getDataElementValue = createGetDataElementValue(
 
 const getDataElementValues = createGetDataElementValues(getDataElementValue);
 
-const initialize = (containerInitFunction, { fetch }) => {
+const initialize = (containerInitFunction) => {
   const container = containerInitFunction(getDataElementValues);
   if (container.dataElements) {
     dataElements = container.dataElements;
   }
 
   moduleProvider.registerModules(container.modules, container.extensions);
-  return executeRules.bind(null, moduleProvider, container, fetch);
+  return executeRules.bind(null, moduleProvider, container);
 };
 
 export default {