improve: adds better error handling (#5)

* improve: adds better error handling

* simplify mock

Author: kevinhermawan

Playground/Playground/ViewModels/AppViewModel.swift

@@ -7,6 +7,7 @@
 
 import Foundation
 
+@MainActor
 @Observable
 final class AppViewModel {
     var cohereAPIKey: String

Playground/Playground/Views/ModelListView.swift

@@ -11,8 +11,12 @@ import AIModelRetriever
 struct ModelListView: View {
     private let title: String
     private let provider: AIProvider
+    private let retriever = AIModelRetriever()
 
     @Environment(AppViewModel.self) private var viewModel
+    
+    @State private var isFetching: Bool = false
+    @State private var fetchTask: Task<Void, Never>?
     @State private var models: [AIModel] = []
 
     init(title: String, provider: AIProvider) {
@@ -21,36 +25,55 @@ struct ModelListView: View {
     }
 
     var body: some View {
-        List(models) { model in
-            VStack(alignment: .leading) {
-                Text(model.id)
-                    .font(.footnote)
-                    .foregroundStyle(.secondary)
-                
-                Text(model.name)
+        VStack {
+            if models.isEmpty, isFetching {
+                VStack(spacing: 16) {
+                    ProgressView()
+                    
+                    Button("Cancel") {
+                        fetchTask?.cancel()
+                    }
+                }
+            } else {
+                List(models) { model in
+                    VStack(alignment: .leading) {
+                        Text(model.id)
+                            .font(.footnote)
+                            .foregroundStyle(.secondary)
+                        
+                        Text(model.name)
+                    }
+                }
             }
         }
         .navigationTitle(title)
         .task {
-            let retriever = AIModelRetriever()
+            isFetching = true
 
-            do {
-                switch provider {
-                case .anthropic:
-                    models = retriever.anthropic()
-                case .cohere:
-                    models = try await retriever.cohere(apiKey: viewModel.cohereAPIKey)
-                case .google:
-                    models = retriever.google()
-                case .ollama:
-                    models = try await retriever.ollama()
-                case .openai:
-                    models = try await retriever.openAI(apiKey: viewModel.openaiAPIKey)
-                case .groq:
-                    models = try await retriever.openAI(apiKey: viewModel.groqAPIKey, endpoint: URL(string: "https://api.groq.com/openai/v1/models"))
+            fetchTask = Task {
+                do {
+                    defer {
+                        self.isFetching = false
+                        self.fetchTask = nil
+                    }
+                    
+                    switch provider {
+                    case .anthropic:
+                        models = retriever.anthropic()
+                    case .cohere:
+                        models = try await retriever.cohere(apiKey: viewModel.cohereAPIKey)
+                    case .google:
+                        models = retriever.google()
+                    case .ollama:
+                        models = try await retriever.ollama()
+                    case .openai:
+                        models = try await retriever.openAI(apiKey: viewModel.openaiAPIKey)
+                    case .groq:
+                        models = try await retriever.openAI(apiKey: viewModel.groqAPIKey, endpoint: URL(string: "https://api.groq.com/openai/v1/models"))
+                    }
+                } catch {
+                    print(String(describing: error))
                 }
-            } catch {
-                print(String(describing: error))
             }
         }
     }

README.md

@@ -152,14 +152,39 @@ do {
 }
 ```
 
-## Donations
+### Error Handling
+
+`AIModelRetrieverError` provides structured error handling through the `AIModelRetrieverError` enum. This enum contains three cases that represent different types of errors you might encounter:
+
+```swift
+do {
+    let models = try await modelRetriever.openai(apiKey: "your-api-key")
+} catch let error as LLMChatOpenAIError {
+    switch error {
+    case .serverError(let message):
+        // Handle server-side errors (e.g., invalid API key, rate limits)
+        print("Server Error: \(message)")
+    case .networkError(let error):
+        // Handle network-related errors (e.g., no internet connection)
+        print("Network Error: \(error.localizedDescription)")
+    case .badServerResponse:
+        // Handle invalid server responses
+        print("Invalid response received from server")
+    case .cancelled:
+        // Handle cancelled requests
+        print("Request cancelled")
+    }
+}
+```
+
+## Support
 
 If you find `AIModelRetriever` helpful and would like to support its development, consider making a donation. Your contribution helps maintain the project and develop new features.
 
 - [GitHub Sponsors](https://github.com/sponsors/kevinhermawan)
 - [Buy Me a Coffee](https://buymeacoffee.com/kevinhermawan)
 
-Your support is greatly appreciated!
+Your support is greatly appreciated! ❤️
 
 ## Contributing
 

Sources/AIModelRetriever/AIModelRetriever.swift

@@ -15,18 +15,33 @@ public struct AIModelRetriever: Sendable {
     /// Initializes a new instance of ``AIModelRetriever``.
     public init() {}
 
-    private func performRequest<T: Decodable>(_ request: URLRequest) async throws -> T {
-        let (data, response) = try await URLSession.shared.data(for: request)
-        
-        guard let httpResponse = response as? HTTPURLResponse else {
-            throw AIModelRetrieverError.badServerResponse
-        }
-        
-        guard 200...299 ~= httpResponse.statusCode else {
-            throw AIModelRetrieverError.serverError(statusCode: httpResponse.statusCode, error: String(data: data, encoding: .utf8))
+    private func performRequest<T: Decodable, E: ProviderError>(_ request: URLRequest, errorType: E.Type) async throws -> T {
+        do {
+            let (data, response) = try await URLSession.shared.data(for: request)
+            
+            if let errorResponse = try? JSONDecoder().decode(E.self, from: data) {
+                throw AIModelRetrieverError.serverError(errorResponse.errorMessage)
+            }
+            
+            guard let httpResponse = response as? HTTPURLResponse, 200...299 ~= httpResponse.statusCode else {
+                throw AIModelRetrieverError.badServerResponse
+            }
+            
+            let models = try JSONDecoder().decode(T.self, from: data)
+            
+            return models
+        } catch let error as AIModelRetrieverError {
+            throw error
+        } catch let error as URLError {
+            switch error.code {
+            case .cancelled:
+                throw AIModelRetrieverError.cancelled
+            default:
+                throw AIModelRetrieverError.networkError(error)
+            }
+        } catch {
+            throw AIModelRetrieverError.networkError(error)
         }
-        
-        return try JSONDecoder().decode(T.self, from: data)
     }
 
     private func createRequest(for endpoint: URL, with headers: [String: String]? = nil) -> URLRequest {
@@ -74,7 +89,7 @@ public extension AIModelRetriever {
         let allHeaders = ["Authorization": "Bearer \(apiKey)"]
 
         let request = createRequest(for: defaultEndpoint, with: allHeaders)
-        let response: CohereResponse = try await performRequest(request)
+        let response: CohereResponse = try await performRequest(request, errorType: CohereError.self)
 
         return response.models.map { AIModel(id: $0.name, name: $0.name) }
     }
@@ -86,6 +101,12 @@ public extension AIModelRetriever {
     private struct CohereModel: Decodable {
         let name: String
     }
+    
+    private struct CohereError: ProviderError {
+        let message: String
+        
+        var errorMessage: String { message }
+    }
 }
 
 // MARK: - Google
@@ -122,7 +143,7 @@ public extension AIModelRetriever {
         guard let defaultEndpoint = URL(string: "http://localhost:11434/api/tags") else { return [] }
 
         let request = createRequest(for: endpoint ?? defaultEndpoint, with: headers)
-        let response: OllamaResponse = try await performRequest(request)
+        let response: OllamaResponse = try await performRequest(request, errorType: OllamaError.self)
 
         return response.models.map { AIModel(id: $0.model, name: $0.name) }
     }
@@ -135,6 +156,16 @@ public extension AIModelRetriever {
         let name: String
         let model: String
     }
+    
+    private struct OllamaError: ProviderError {
+        let error: Error
+        
+        struct Error: Decodable {
+            let message: String
+        }
+        
+        var errorMessage: String { error.message }
+    }
 }
 
 // MARK: - OpenAI
@@ -156,7 +187,7 @@ public extension AIModelRetriever {
         allHeaders["Authorization"] = "Bearer \(apiKey)"
 
         let request = createRequest(for: endpoint ?? defaultEndpoint, with: allHeaders)
-        let response: OpenAIResponse = try await performRequest(request)
+        let response: OpenAIResponse = try await performRequest(request, errorType: OpenAIError.self)
 
         return response.data.map { AIModel(id: $0.id, name: $0.id) }
     }
@@ -168,4 +199,21 @@ public extension AIModelRetriever {
     private struct OpenAIModel: Decodable {
         let id: String
     }
+    
+    private struct OpenAIError: ProviderError {
+        let error: Error
+        
+        struct Error: Decodable {
+            let message: String
+        }
+        
+        var errorMessage: String { error.message }
+    }
+}
+
+// MARK: - Supporting Types
+private extension AIModelRetriever {
+    protocol ProviderError: Decodable {
+        var errorMessage: String { get }
+    }
 }

Sources/AIModelRetriever/AIModelRetrieverError.swift

@@ -9,13 +9,33 @@ import Foundation
 
 /// An enum that represents errors that can occur during AI model retrieval.
 public enum AIModelRetrieverError: Error, Sendable {
-    /// Indicates that the server response was not in the expected format.
-    case badServerResponse
+    /// A case that represents a server-side error response.
+    ///
+    /// - Parameter message: The error message from the server.
+    case serverError(String)
 
-    /// Indicates that the server returned an error.
+    /// A case that represents a network-related error.
     ///
-    /// - Parameters:
-    ///   - statusCode: The HTTP status code returned by the server.
-    ///   - error: An optional string that contains additional error information provided by the server.
-    case serverError(statusCode: Int, error: String?)
+    /// - Parameter error: The underlying network error.
+    case networkError(Error)
+    
+    /// A case that represents an invalid server response.
+    case badServerResponse
+    
+    /// A case that represents a request has been canceled.
+    case cancelled
+        
+    /// A localized message that describes the error.
+    public var errorDescription: String? {
+        switch self {
+        case .serverError(let error):
+            return error
+        case .networkError(let error):
+            return error.localizedDescription
+        case .badServerResponse:
+            return "Invalid response received from server"
+        case .cancelled:
+            return "Request was cancelled"
+        }
+    }
 }

Sources/AIModelRetriever/Documentation.docc/Documentation.md

@@ -103,22 +103,25 @@ do {
 
 ### Error Handling
 
-The package uses ``AIModelRetrieverError`` to represent specific errors that may occur. You can catch and handle these errors as follows:
+``AIModelRetrieverError`` provides structured error handling through the ``AIModelRetrieverError`` enum. This enum contains three cases that represent different types of errors you might encounter:
 
 ```swift
-let apiKey = "your-openai-api-key"
-
 do {
-    let models = try await modelRetriever.openai(apiKey: apiKey)
-    // Process models
-} catch let error as AIModelRetrieverError {
+    let models = try await modelRetriever.openai(apiKey: "your-api-key")
+} catch let error as LLMChatOpenAIError {
     switch error {
+    case .serverError(let message):
+        // Handle server-side errors (e.g., invalid API key, rate limits)
+        print("Server Error: \(message)")
+    case .networkError(let error):
+        // Handle network-related errors (e.g., no internet connection)
+        print("Network Error: \(error.localizedDescription)")
     case .badServerResponse:
-        print("Received an invalid response from the server")
-    case .serverError(let statusCode, let errorMessage):
-        print("Server error (status \(statusCode)): \(errorMessage ?? "No error message provided")")
+        // Handle invalid server responses
+        print("Invalid response received from server")
+    case .cancelled:
+        // Handle cancelled requests
+        print("Request cancelled")
     }
-} catch {
-    print("An unexpected error occurred: \(error)")
 }
 ```