Specify your local folder path and mock mappings in appsettings.json:

💡 You can also organize your mock files using subfolders inside the specified FolderPath.

For example, "Namespace.TypeName.Variant": "subfolder/ExampleResponse.Variant.json" will load the file from Mocks/subfolder/ExampleResponse.Variant.json.

🔧 LocalFolderStoreOptions Configuration

The following configuration property is used by the local folder provider. It should be set under MockOptions:LocalFolderStoreOptions.

📁 The folder should contain JSON files matching your ResponseMappings. You can also organize files into subfolders for variants or grouping.

🚀 Usage: AddLocalFolderStore

Register the middleware in Startup.cs or Program.cs:

Use the middleware:

Place your mock JSON files in the folder specified by FolderPath. Each file is served based on its ResponseMappings key and corresponding HTTP response metadata.

🧪 Troubleshooting

Missing Configurations

⚠️ Missing FolderPath

Error Message

LocalFolderStoreOptions.FolderPath must not be null or empty.

Cause

The FolderPath was not specified under MockOptions:LocalFolderStoreOptions, or it was empty.

Solution

Make sure your appsettings.json (or other configuration source) includes a valid path:

Runtime Errors

⚠️ File not found

Error Message

The mock file 'Mocks/WeatherForecast.json' could not be found.

Cause

The file mapped in ResponseMappings does not exist in the specified folder (or subfolder).

Solution

Verify that the filename and subdirectory (if applicable) exist under the FolderPath. Be sure filenames match exactly (including casing on case-sensitive systems).

💡 Use relative paths like "subfolder/Example.json" for files inside subdirectories.

📘 For additional error handling scenarios, see the Core Troubleshooting Guide.