Capture and share the backend's message for an invalid API key (google-gemini#120)

Author: paulb777

Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift

@@ -239,7 +239,7 @@ struct ErrorDetailsView: View {
 }
 
 #Preview("Invalid API Key") {
-  ErrorDetailsView(error: GenerateContentError.invalidAPIKey)
+  ErrorDetailsView(error: GenerateContentError.invalidAPIKey(message: "Fix API key placeholder"))
 }
 
 #Preview("Unsupported User Location") {

Sources/GoogleAI/GenerateContentError.swift

@@ -30,7 +30,7 @@ public enum GenerateContentError: Error {
   case responseStoppedEarly(reason: FinishReason, response: GenerateContentResponse)
 
   /// The provided API key is invalid.
-  case invalidAPIKey
+  case invalidAPIKey(message: String)
 
   /// The user's location (region) is not supported by the API.
   ///

Sources/GoogleAI/GenerativeModel.swift

@@ -318,7 +318,7 @@ public final class GenerativeModel {
     if let error = error as? GenerateContentError {
       return error
     } else if let error = error as? RPCError, error.isInvalidAPIKeyError() {
-      return GenerateContentError.invalidAPIKey
+      return GenerateContentError.invalidAPIKey(message: error.message)
     } else if let error = error as? RPCError, error.isUnsupportedUserLocationError() {
       return GenerateContentError.unsupportedUserLocation
     }

Tests/GoogleAITests/GenerativeModelTests.swift

@@ -248,8 +248,8 @@ final class GenerativeModelTests: XCTestCase {
     do {
       _ = try await model.generateContent(testPrompt)
       XCTFail("Should throw GenerateContentError.internalError; no error thrown.")
-    } catch GenerateContentError.invalidAPIKey {
-      // Do nothing, catching a GenerateContentError.invalidAPIKey error is expected.
+    } catch let GenerateContentError.invalidAPIKey(message) {
+      XCTAssertEqual(message, "API key not valid. Please pass a valid API key.")
     } catch {
       XCTFail("Should throw GenerateContentError.invalidAPIKey; error thrown: \(error)")
     }