feat: support customisable basePath in OAS3 (#135)

Author: vwong

.changeset/tasty-days-slide.md

@@ -0,0 +1,5 @@
+---
+"@pactflow/openapi-pact-comparator": minor
+---
+
+Support customisable basePath in OAS3

src/__tests__/fixtures/oas-base-path/oas.yaml

@@ -0,0 +1,12 @@
+openapi: 3.0.0
+info:
+  x-opc-config-base-path: /custom-prefix
+  title: OAS
+  version: 1.0.0
+
+paths:
+  /path:
+    get:
+      responses:
+        "200":
+          description: ok

src/__tests__/fixtures/oas-base-path/opc-results.json

@@ -0,0 +1 @@
+[]

src/__tests__/fixtures/oas-base-path/pact.json

@@ -0,0 +1,16 @@
+{
+  "consumer": { "name": "consumer" },
+  "provider": { "name": "provider" },
+  "interactions": [
+    {
+      "description": "should pass when using prefix",
+      "request": {
+        "method": "GET",
+        "path": "/custom-prefix/path"
+      },
+      "response": {
+        "status": 200
+      }
+    }
+  ]
+}

src/__tests__/fixtures/oas-base-path/smv-results.json

@@ -0,0 +1,29 @@
+[
+  {
+    "code": "request.path-or-method.unknown",
+    "message": "Path or method not defined in spec file: GET /custom-prefix/path",
+    "mockDetails": {
+      "interactionDescription": "should pass when using prefix",
+      "interactionState": "[none]",
+      "location": "[root].interactions[0].request.path",
+      "value": "/custom-prefix/path"
+    },
+    "specDetails": {
+      "location": "[root].paths",
+      "pathMethod": null,
+      "pathName": null,
+      "value": {
+        "/path": {
+          "get": {
+            "responses": {
+              "200": {
+                "description": "ok"
+              }
+            }
+          }
+        }
+      }
+    },
+    "type": "error"
+  }
+]

src/compare/setup.ts

@@ -29,6 +29,10 @@ const SUPPORTED_METHODS = [
   "TRACE",
 ];
 
+interface ExtendedOpenAPIV3InfoObject extends OpenAPIV3.InfoObject {
+  "x-opc-config-base-path"?: string;
+}
+
 export function setupRouter(
   oas: OpenAPIV2.Document | OpenAPIV3.Document,
   config: Config,
@@ -41,8 +45,12 @@ export function setupRouter(
   });
   for (const oasPath in oas.paths) {
     // NB: all path parameters are required in OAS
+    const basePath =
+      (oas.info as ExtendedOpenAPIV3InfoObject)["x-opc-config-base-path"] ||
+      (oas as OpenAPIV2.Document).basePath ||
+      "";
     const path =
-      ((oas as OpenAPIV2.Document).basePath || "") +
+      basePath +
       oasPath
         .replaceAll(/{.*?}/g, cleanPathParameter)
         .replaceAll(/{([.;]?)([^*]+?)\*?}/g, "$1:$2(.+)");