fix(apigateway): validation for path parts does not allow creation of…

… resources beginning with dollar sign (#27619)

This PR adjusts the validation rules for path parts in resources created using the APIGateway library to allow the use of dollar mark in pathParts, as requested in #27083. This enables the creation of resources with paths such as $test(from the reproduction steps in the related issue).

An existing resource unit test ('url for a resource') has been updated to ensure that a dollar mark in a pathPart does not throw an error and properly reflects in the output of RestApi.urlForPath. The integration test integ.restapi has also been updated, wherein the appliances resource now has a path of $appliances:all instead of appliances:all.

Closes #27083.

#### All Submissions:
- [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)
#### Adding new Unconventional Dependencies:
- [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-new-unconventional-dependencies)
#### New Features
- [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
  - [x] Did you use yarn integ to deploy the infrastructure and generate the snapshot (i.e. yarn integ without --dry-run)?

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

packages/@aws-cdk-testing/framework-integ/test/aws-apigateway/test/integ.restapi.js.snapshot/test-apigateway-restapi.template.json

@@ -57,7 +57,7 @@
    "UpdateReplacePolicy": "Retain",
    "DeletionPolicy": "Retain"
   },
-  "myapiDeployment92F2CB4993c0f175ba8d5964f5e1cc7bc64fe6e6": {
+  "myapiDeployment92F2CB49069d16df09c59427069eb74581a0403d": {
    "Type": "AWS::ApiGateway::Deployment",
    "Properties": {
     "Description": "beta stage",
@@ -66,8 +66,8 @@
     }
    },
    "DependsOn": [
-    "myapiv1appliancesallGETC4DF552D",
-    "myapiv1appliancesallCF8C6A16",
+    "myapiv1appliancesallGETB8EB1B77",
+    "myapiv1appliancesallD279897B",
     "myapiv1booksGETC6B996D0",
     "myapiv1booksPOST53E2832E",
     "myapiv1books1D4BE6C1",
@@ -86,7 +86,7 @@
     "CacheClusterEnabled": true,
     "CacheClusterSize": "0.5",
     "DeploymentId": {
-     "Ref": "myapiDeployment92F2CB4993c0f175ba8d5964f5e1cc7bc64fe6e6"
+     "Ref": "myapiDeployment92F2CB49069d16df09c59427069eb74581a0403d"
     },
     "Description": "beta stage",
     "MethodSettings": [
@@ -290,19 +290,19 @@
     }
    }
   },
-  "myapiv1appliancesallCF8C6A16": {
+  "myapiv1appliancesallD279897B": {
    "Type": "AWS::ApiGateway::Resource",
    "Properties": {
     "ParentId": {
      "Ref": "myapiv113487378"
     },
-    "PathPart": "appliances:all",
+    "PathPart": "$appliances:all",
     "RestApiId": {
      "Ref": "myapi4C7BF186"
     }
    }
   },
-  "myapiv1appliancesallGETC4DF552D": {
+  "myapiv1appliancesallGETB8EB1B77": {
    "Type": "AWS::ApiGateway::Method",
    "Properties": {
     "AuthorizationType": "NONE",
@@ -311,7 +311,7 @@
      "Type": "MOCK"
     },
     "ResourceId": {
-     "Ref": "myapiv1appliancesallCF8C6A16"
+     "Ref": "myapiv1appliancesallD279897B"
     },
     "RestApiId": {
      "Ref": "myapi4C7BF186"
@@ -682,7 +682,7 @@
     }
    },
    "DependsOn": [
-    "myapiv1appliancesallGETC4DF552D",
+    "myapiv1appliancesallGETB8EB1B77",
     "myapiv1booksGETC6B996D0",
     "myapiv1booksPOST53E2832E",
     "myapiv1toysGET7348114D",

packages/@aws-cdk-testing/framework-integ/test/aws-apigateway/test/integ.restapi.ts

@@ -43,7 +43,7 @@ class Test extends cdk.Stack {
     toys.addMethod('POST');
     toys.addMethod('PUT');
 
-    const appliances = v1.addResource('appliances:all');
+    const appliances = v1.addResource('$appliances:all');
     appliances.addMethod('GET');
 
     const books = v1.addResource('books');

packages/aws-cdk-lib/aws-apigateway/lib/resource.ts

@@ -561,8 +561,8 @@ function validateResourcePathPart(part: string) {
     }
   }
 
-  if (!/^[a-zA-Z0-9:\.\_\-]+$/.test(part)) {
-    throw new Error(`Resource's path part only allow [a-zA-Z0-9:._-], an optional trailing '+'
+  if (!/^[a-zA-Z0-9:\.\_\-\$]+$/.test(part)) {
+    throw new Error(`Resource's path part only allow [a-zA-Z0-9:._-$], an optional trailing '+'
       and curly braces at the beginning and the end: ${part}`);
   }
 }

packages/aws-cdk-lib/aws-apigateway/test/resource.test.ts

@@ -197,6 +197,7 @@ describe('resource', () => {
     const aResource = api.root.addResource('a');
     const cResource = aResource.addResource('b').addResource('c');
     const colonResource = cResource.addResource('d:e');
+    const dollarResource = cResource.addResource('$d');
 
     // THEN
     expect(stack.resolve(api.urlForPath(aResource.path))).toEqual({
@@ -247,6 +248,22 @@ describe('resource', () => {
         ],
       ],
     });
+    expect(stack.resolve(api.urlForPath(dollarResource.path))).toEqual({
+      'Fn::Join': [
+        '',
+        [
+          'https://',
+          { Ref: 'apiC8550315' },
+          '.execute-api.',
+          { Ref: 'AWS::Region' },
+          '.',
+          { Ref: 'AWS::URLSuffix' },
+          '/',
+          { Ref: 'apiDeploymentStageprod896C8101' },
+          '/a/b/c/$d',
+        ],
+      ],
+    });
 
   });