From d5a34561b9fc6aededfaa234d8f0db208884a853 Mon Sep 17 00:00:00 2001
From: Mathew Polzin <matt.polzin@gmail.com>
Date: Fri, 31 Jul 2020 17:50:30 -0700
Subject: [PATCH] instead of failing to parse when an operation callback is
 found, ignore it gracefully (until it is supported by OpenAPIKit in the
 future)

---
 Sources/OpenAPIKit/Operation/Operation.swift  |  8 +-
 .../SwaggerDocSamplesTests.swift              | 76 +++++++++++++++++++
 .../Operation/OperationTests.swift            | 24 ++++++
 3 files changed, 106 insertions(+), 2 deletions(-)

diff --git a/Sources/OpenAPIKit/Operation/Operation.swift b/Sources/OpenAPIKit/Operation/Operation.swift
index 18844ae54..0688d453b 100644
--- a/Sources/OpenAPIKit/Operation/Operation.swift
+++ b/Sources/OpenAPIKit/Operation/Operation.swift
@@ -259,7 +259,7 @@ extension OpenAPI.Operation {
         case parameters
         case requestBody
         case responses
-//      case callbacks
+        case callbacks
         case deprecated
         case security
         case servers
@@ -276,7 +276,7 @@ extension OpenAPI.Operation {
                 .parameters,
                 .requestBody,
                 .responses,
-//                .callbacks,
+                .callbacks,
                 .deprecated,
                 .security,
                 .servers
@@ -305,6 +305,8 @@ extension OpenAPI.Operation {
                 self = .requestBody
             case "responses":
                 self = .responses
+            case "callbacks":
+                self = .callbacks
             case "deprecated":
                 self = .deprecated
             case "security":
@@ -334,6 +336,8 @@ extension OpenAPI.Operation {
                 return "requestBody"
             case .responses:
                 return "responses"
+            case .callbacks:
+                return "callbacks"
             case .deprecated:
                 return "deprecated"
             case .security:
diff --git a/Tests/OpenAPIKitCompatibilitySuite/SwaggerDocSamplesTests.swift b/Tests/OpenAPIKitCompatibilitySuite/SwaggerDocSamplesTests.swift
index e7a7e2a69..bbaca1a5a 100644
--- a/Tests/OpenAPIKitCompatibilitySuite/SwaggerDocSamplesTests.swift
+++ b/Tests/OpenAPIKitCompatibilitySuite/SwaggerDocSamplesTests.swift
@@ -318,6 +318,82 @@ components:
             throw friendlyError
         }
     }
+
+    func test_callbackExample() throws {
+        let docString = commonBaseDocument + """
+paths:
+  /streams:
+    post:
+      description: subscribes a client to receive out-of-band data
+      parameters:
+        - name: callbackUrl
+          in: query
+          required: true
+          description: |
+            the location where data will be sent.  Must be network accessible
+            by the source server
+          schema:
+            type: string
+            format: uri
+            example: https://tonys-server.com
+      responses:
+        '201':
+          description: subscription successfully created
+          content:
+            application/json:
+              schema:
+                description: subscription information
+                required:
+                  - subscriptionId
+                properties:
+                  subscriptionId:
+                    description: this unique identifier allows management of the subscription
+                    type: string
+                    example: 2531329f-fb09-4ef7-887e-84e648214436
+      callbacks:
+        # the name `onData` is a convenience locator
+        onData:
+          # when data is sent, it will be sent to the `callbackUrl` provided
+          # when making the subscription PLUS the suffix `/data`
+          '{$request.query.callbackUrl}/data':
+            post:
+              requestBody:
+                description: subscription payload
+                content:
+                  application/json:
+                    schema:
+                      type: object
+                      properties:
+                        timestamp:
+                          type: string
+                          format: date-time
+                        userData:
+                          type: string
+              responses:
+                '202':
+                  description: |
+                    Your server implementation should return this HTTP status code
+                    if the data was received successfully
+                '204':
+                  description: |
+                    Your server should return this HTTP status code if no longer interested
+                    in further updates
+"""
+
+        // test decoding
+        do {
+            let doc = try YAMLDecoder().decode(OpenAPI.Document.self, from: docString)
+
+            // test validating
+            try doc.validate()
+
+            // test dereferencing and resolving
+            _ = try doc.locallyDereferenced().resolved()
+        } catch let error {
+            let friendlyError = OpenAPI.Error(from: error)
+            throw friendlyError
+        }
+    }
 }
 
 fileprivate let commonBaseDocument = """
diff --git a/Tests/OpenAPIKitTests/Operation/OperationTests.swift b/Tests/OpenAPIKitTests/Operation/OperationTests.swift
index ef4967eb4..d33d8d006 100644
--- a/Tests/OpenAPIKitTests/Operation/OperationTests.swift
+++ b/Tests/OpenAPIKitTests/Operation/OperationTests.swift
@@ -250,6 +250,30 @@ extension OperationTests {
         XCTAssertEqual(operation.responses[200]?.reference, .component(named: "test"))
     }
 
+    func test_doesNotFailDecodingCallbacks() {
+        let operationData =
+"""
+{
+  "responses" : {},
+  "callbacks" : {
+    "callback" : {
+      "{$request.query.queryUrl}" : {
+        "post" : {
+          "responses" : {
+            "200" : {
+              "description" : "callback successfully processed"
+            }
+          }
+        }
+      }
+    }
+  }
+}
+""".data(using: .utf8)!
+
+        XCTAssertNoThrow(try orderUnstableDecode(OpenAPI.Operation.self, from: operationData))
+    }
+
     // Note that JSONEncoder for Linux Foundation does not respect order
     func test_responseOrder_encode() throws {
         let operation = OpenAPI.Operation(