feat(basePath): enable base path for configuration

Sources/OpenAI/OpenAI.swift

@@ -22,17 +22,23 @@ final public class OpenAI: OpenAIProtocol {
 
         /// API host. Set this property if you use some kind of proxy or your own server. Default is api.openai.com
         public let host: String
+
+        /// Optional base path if you set up OpenAI API proxy on a custom path on your own host. Default is ""
+        public let basePath: String
+
         public let port: Int
         public let scheme: String
+
         /// Default request timeout
         public let timeoutInterval: TimeInterval
 
-        public init(token: String, organizationIdentifier: String? = nil, host: String = "api.openai.com", port: Int = 443, scheme: String = "https", timeoutInterval: TimeInterval = 60.0) {
+        public init(token: String, organizationIdentifier: String? = nil, host: String = "api.openai.com", port: Int = 443, scheme: String = "https", basePath: String = "", timeoutInterval: TimeInterval = 60.0) {
             self.token = token
             self.organizationIdentifier = organizationIdentifier
             self.host = host
             self.port = port
             self.scheme = scheme
+            self.basePath = basePath
             self.timeoutInterval = timeoutInterval
         }
     }
@@ -202,8 +208,19 @@ extension OpenAI {
         components.scheme = configuration.scheme
         components.host = configuration.host
         components.port = configuration.port
-        components.path = path
-        return components.url!
+
+        components.path = NSString.path(withComponents: [
+            "/", configuration.basePath, path
+        ])
+
+        if let url = components.url {
+            return url
+        } else {
+            // We're expecting components.url to be not nil
+            // But if it isn't, let's just use some URL api that returns non-nil url
+            // Let all requests fail, but so that we don't crash on explicit unwrapping
+            return URL(fileURLWithPath: "")
+        }
     }
 }
 

Tests/OpenAITests/OpenAITests.swift

@@ -426,12 +426,47 @@ class OpenAITests: XCTestCase {
         XCTAssertEqual(chatsURL, URL(string: "https://api.openai.com:443/v1/chat/completions"))
     }
 
-    func testCustomURLBuilt() {
+    func testCustomURLBuiltWithPredefinedPath() {
         let configuration = OpenAI.Configuration(token: "foo", organizationIdentifier: "bar", host: "my.host.com", timeoutInterval: 14)
         let openAI = OpenAI(configuration: configuration, session: self.urlSession)
         let chatsURL = openAI.buildURL(path: .chats)
         XCTAssertEqual(chatsURL, URL(string: "https://my.host.com:443/v1/chat/completions"))
     }
+
+    func testCustomURLBuiltWithCustomPath() {
+        let configuration = OpenAI.Configuration(
+            token: "foo",
+            organizationIdentifier: "bar",
+            host: "bizbaz.com",
+            timeoutInterval: 14
+        )
+        let openAI = OpenAI(configuration: configuration, session: URLSessionMock())
+        XCTAssertEqual(openAI.buildURL(path: "foo"), URL(string: "https://bizbaz.com:443/foo"))
+    }
+
+    func testCustomURLBuiltWithCustomBasePath() {
+        let configuration = OpenAI.Configuration(
+            token: "foo",
+            organizationIdentifier: "bar",
+            host: "bizbaz.com",
+            basePath: "/openai",
+            timeoutInterval: 14
+        )
+        let openAI = OpenAI(configuration: configuration, session: URLSessionMock())
+        XCTAssertEqual(openAI.buildURL(path: "foo"), URL(string:"https://bizbaz.com:443/openai/foo"))
+    }
+
+    func testCustomURLBuiltWithCustomBasePathWithTrailingSlash() {
+        let configuration = OpenAI.Configuration(
+            token: "foo",
+            organizationIdentifier: "bar",
+            host: "bizbaz.com",
+            basePath: "/openai/",
+            timeoutInterval: 14
+        )
+        let openAI = OpenAI(configuration: configuration, session: URLSessionMock())
+        XCTAssertEqual(openAI.buildURL(path: "/foo"), URL(string: "https://bizbaz.com:443/openai/foo"))
+    }
 }
 
 @available(tvOS 13.0, *)