feat: adding authorizer decorator

davidecavaliere · Sep 28, 2018 · a2b138c · a2b138c
1 parent 89ad199
commit a2b138c
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diff --git a/src/index.ts b/src/index.ts
@@ -1,3 +1,4 @@
 export * from './lib/endpoint/endpoint.decorator';
 export * from './lib/lambda/lambda.decorator';
+export * from './lib/lambda/authorizer.decorator';
 export * from './lib/index';
diff --git a/src/lib/lambda/authorizer.decorator.spec.ts b/src/lib/lambda/authorizer.decorator.spec.ts
@@ -0,0 +1,79 @@
+// tslint:disable:no-expression-statement no-object-mutation
+import test from 'ava';
+import { Lambda, LambdaOptions } from './lambda.decorator';
+import { Endpoint } from '../../';
+import { boostrap } from '../index';
+import { Authorizer, getAuthorizerMetadata } from './authorizer.decorator';
+
+const option1: LambdaOptions = {
+  method: 'get',
+  name: 'lambda-name-1',
+  path: '/'
+};
+
+const option2: LambdaOptions = {
+  method: 'get',
+  name: 'lambda-name-2',
+  path: ':id'
+};
+
+@Endpoint({
+  name: 'endpoint'
+})
+class TestClass {
+  public readonly toTestAccessToInstance: string = 'base';
+
+  @Lambda(option1)
+  public findAll(arg1, arg2, arg3) {
+    // console.log('running original findAll()');
+    return this.toTestAccessToInstance + arg1 + arg2 + arg3;
+  }
+
+  @Lambda(option2)
+  public findOne() {
+    return 1;
+  }
+
+  @Authorizer()
+  public async authorize(token, resource): Promise<boolean> {
+    console.log('token', token);
+    console.log('resource', resource);
+    return token.scope.some(value => value === resource);
+  }
+}
+
+let instance: TestClass;
+
+test.beforeEach(() => {
+  instance = boostrap(TestClass, 'express');
+});
+
+test('authorize function', (t) => {
+  t.plan(1);
+
+  return instance.authorize.apply(instance, [{
+    authorizationToken: {
+      scope: ['some-method-arn']
+    },
+    methodArn: 'some-method-arn'
+  }]).then((value) => {
+    t.deepEqual(value, {
+
+      principalId: {
+        scope: ['some-method-arn']
+      },
+      policyDocument: {
+        Version: '2012-10-17',
+        Statement: [
+          {
+            Action: 'execute-api:Invoke',
+            Effect: 'Allow',
+            Resource: 'some-method-arn',
+          },
+        ],
+      }
+    });
+  });
+});
+
+
diff --git a/src/lib/lambda/authorizer.decorator.ts b/src/lib/lambda/authorizer.decorator.ts
@@ -0,0 +1,80 @@
+// tslint:disable:only-arrow-functions readonly-array prefer- no-if-statement no-object-mutation no-this no-object-literal-type-assertion
+
+import debug from 'debug';
+import 'reflect-metadata';
+import { getSingleton } from '../index';
+import { CustomAuthorizerEvent, CustomAuthorizerResult } from 'aws-lambda';
+
+const d = debug('microgamma:apigator:authorizer');
+
+export const AuthorizerMetadata = Symbol('Authorizer');
+
+export interface AuthorizerOptions {
+  name: string;
+}
+
+export function Authorizer(options?: AuthorizerOptions) {
+  d('constructing a class decorator', options);
+  return (target: any, key: string, descriptor) => {
+    d('decorating method');
+    d('target', target);
+    d('function name', key);
+    d('descriptor', descriptor);
+
+    Reflect.defineMetadata(AuthorizerMetadata, {
+      name: options ? options.name : key
+    }, target);
+
+    const instance = getSingleton(target.constructor.name);
+    d('current instance is:', instance);
+
+    const originalFunction = descriptor.value;
+    d('original function is', originalFunction);
+
+    descriptor.value = async (...args: any[]) => {
+      try {
+
+        const authContext: CustomAuthorizerEvent = args[0];
+        d('authContext is', authContext);
+        const newArgs = [authContext.authorizationToken, authContext.methodArn];
+
+        const retValue = await originalFunction.apply(instance, newArgs);
+
+        d('retValue', retValue);
+
+        return {
+          principalId: authContext.authorizationToken,
+          policyDocument: {
+            Version: '2012-10-17',
+            Statement: [
+              {
+                Action: 'execute-api:Invoke',
+                Effect: retValue ? 'Allow' : 'Deny',
+                Resource: authContext.methodArn,
+              },
+            ],
+          }
+        } as CustomAuthorizerResult;
+
+      } catch (e) {
+
+        d('something is going on', e);
+
+        if (e.message.match(/^\[[0-9]{3,}\](.)+/)) {
+          throw Error(e);
+        }
+
+        throw Error(`[500] ${e}`);
+      }
+    };
+
+    return descriptor;
+  };
+}
+
+export function getAuthorizerMetadata(instance): AuthorizerOptions {
+  d('metadata keys', Reflect.getMetadataKeys(instance));
+  const metadata = Reflect.getMetadata(AuthorizerMetadata, instance);
+  d('metadata', metadata);
+  return metadata;
+}