Refitter 0.8.2

Refitter

Refitter is a CLI tool for generating a C# REST API Client using the Refit library. Refitter can generate the Refit interface from OpenAPI specifications

Installation:

The tool is packaged as a .NET Tool and is published to nuget.org. You can install the latest version of this tool like this:

dotnet tool install --global Refitter

Usage:

$ refitter --help

USAGE:
    refitter [URL or input file] [OPTIONS]

EXAMPLES:
    refitter ./openapi.json
    refitter https://petstore3.swagger.io/api/v3/openapi.yaml
    refitter ./openapi.json --settings-file ./openapi.refitter --output ./GeneratedCode.cs
    refitter ./openapi.json --namespace "Your.Namespace.Of.Choice.GeneratedCode" --output ./GeneratedCode.cs
    refitter ./openapi.json --namespace "Your.Namespace.Of.Choice.GeneratedCode" --internal
    refitter ./openapi.json --output ./IGeneratedCode.cs --interface-only
    refitter ./openapi.json --use-api-response
    refitter ./openapi.json --cancellation-tokens
    refitter ./openapi.json --no-operation-headers
    refitter ./openapi.json --no-accept-headers
    refitter ./openapi.json --use-iso-date-format
    refitter ./openapi.json --additional-namespace "Your.Additional.Namespace" --additional-namespace "Your.Other.Additional.Namespace"
    refitter ./openapi.json --multiple-interfaces ByEndpoint
    refitter ./openapi.json --tag Pet --tag Store --tag User
    refitter ./openapi.json --match-path '^/pet/.*'
    refitter ./openapi.json --no-deprecated-operations
    refitter ./openapi.json --operation-name-template '{operationName}Async'
    refitter ./openapi.json --optional-nullable-parameters

ARGUMENTS:
    [URL or input file]    URL or file path to OpenAPI Specification file

OPTIONS:
                                          DEFAULT                                                                                                                                                    
    -h, --help                                             Prints help information                                                                                                                   
    -s, --settings-file                                    Path to .refitter settings file. Specifying this will ignore all other settings (except for --output)                                     
    -n, --namespace                       GeneratedCode    Default namespace to use for generated types                                                                                              
    -o, --output                          Output.cs        Path to Output file                                                                                                                       
        --no-auto-generated-header                         Don't add <auto-generated> header to output file                                                                                          
        --no-accept-headers                                Don't add <Accept> header to output file                                                                                                  
        --interface-only                                   Don't generate contract types                                                                                                             
        --use-api-response                                 Return Task<IApiResponse<T>> instead of Task<T>                                                                                           
        --internal                                         Set the accessibility of the generated types to 'internal'                                                                                
        --cancellation-tokens                              Use cancellation tokens                                                                                                                   
        --no-operation-headers                             Don't generate operation headers                                                                                                          
        --no-logging                                       Don't log errors or collect telemetry                                                                                                     
        --additional-namespace                             Add additional namespace to generated types                                                                                               
        --use-iso-date-format                              Explicitly format date query string parameters in ISO 8601 standard date format using delimiters (2023-06-15)                             
        --multiple-interfaces                              Generate a Refit interface for each endpoint. May be one of ByEndpoint, ByTag                                                             
        --match-path                                       Only include Paths that match the provided regular expression. May be set multiple times                                                  
        --tag                                              Only include Endpoints that contain this tag. May be set multiple times and result in OR'ed evaluation                                    
        --skip-validation                                  Skip validation of the OpenAPI specification                                                                                              
        --no-deprecated-operations                         Don't generate deprecated operations                                                                                                      
        --operation-name-template                          Generate operation names using pattern. When using --multiple-interfaces ByEndpoint, this is name of the Execute() method in the interface
        --optional-nullable-parameters                     Generate nullable parameters as optional parameters                                                                                       

.Refitter File format

The following is an example .refitter file

{
  "openApiPath": "/path/to/your/openAPI", // Required
  "namespace": "Org.System.Service.Api.GeneratedCode", // Optional. Default=GeneratedCode
  "naming": {
    "useOpenApiTitle": false, // Optional. Default=true
    "interfaceName": "MyApiClient" // Optional. Default=ApiClient
  },
  "generateContracts": true, // Optional. Default=true
  "generateXmlDocCodeComments": true, // Optional. Default=true
  "addAutoGeneratedHeader": true, // Optional. Default=true
  "addAcceptHeaders": true, // Optional. Default=true
  "returnIApiResponse": false, // Optional. Default=false
  "generateOperationHeaders": true, // Optional. Default=true
  "typeAccessibility": "Public", // Optional. Values=Public|Internal. Default=Public
  "useCancellationTokens": false, // Optional. Default=false
  "useIsoDateFormat": false, // Optional. Default=false
  "multipleInterfaces": "ByEndpoint", // Optional. May be one of "ByEndpoint" or "ByTag"
  "generateDeprecatedOperations": false, // Optional. Default=true
  "operationNameTemplate": "{operationName}Async", // Optional. Must contain {operationName} when multipleInterfaces != ByEndpoint
  "optionalParameters": false, // Optional. Default=false
  "outputFolder": "../CustomOutput" // Optional. Default=./Generated
  "additionalNamespaces": [ // Optional
    "Namespace1",
    "Namespace2"
  ],
  "includeTags": [ // Optional. OpenAPI Tag to include when generating code
    "Pet",
    "Store",
    "User"
  ],
  "includePathMatches": [ // Optional. Only include Paths that match the provided regular expression
    "^/pet/.*",
    "^/store/.*"
  ],
  "dependencyInjectionSettings": {
    "baseUrl": "https://petstore3.swagger.io/api/v3", // Optional. Leave this blank to set the base address manually
    "httpMessageHandlers": [ // Optional
        "AuthorizationMessageHandler", 
        "TelemetryMessageHandler" 
    ],
    "usePolly": true, // Optional. Set this to true, to configure Polly with a retry policy that uses a jittered backoff. Default=false
    "pollyMaxRetryCount": 3, // Optional. Default=6
    "firstBackoffRetryInSeconds": 0.5 // Optional. Default=1.0
  }
}

• openApiPath - points to the OpenAPI Specifications file. This can be the path to a file stored on disk, relative to the .refitter file. This can also be a URL to a remote file that will be downloaded over HTTP/HTTPS
• namespace - the namespace used in the generated code. If not specified, this defaults to GeneratedCode
• naming.useOpenApiTitle - a boolean indicating whether the OpenApi title should be used. Default is true
• naming.interfaceName - the name of the generated interface. The generated code will automatically prefix this with I so if this set to MyApiClient then the generated interface is called IMyApiClient. Default is ApiClient
• generateContracts - a boolean indicating whether contracts should be generated. A use case for this is several API clients use the same contracts. Default is true
• generateXmlDocCodeComments - a boolean indicating whether XML doc comments should be generated. Default is true
• addAutoGeneratedHeader - a boolean indicating whether XML doc comments should be generated. Default is true
• addAcceptHeaders - a boolean indicating whether to add accept headers [Headers("Accept: application/json")]. Default is true
• returnIApiResponse - a boolean indicating whether to return IApiResponse<T> objects. Default is false
• generateOperationHeaders - a boolean indicating whether to use operation headers in the generated methods. Default is true
• typeAccessibility - the generated type accessibility. Possible values are Public and Internal. Default is Public
• useCancellationTokens - Use cancellation tokens in the generated methods. Default is false
• useIsoDateFormat - Set to true to explicitly format date query string parameters in ISO 8601 standard date format using delimiters (for example: 2023-06-15). Default is false
• multipleInterfaces - Set to ByEndpoint to generate an interface for each endpoint, or ByTag to group Endpoints by their Tag (like SwaggerUI groups them).
• outputFolder - a string describing a relative path to a desired output folder. Default is ./Generated
• additionalNamespaces - A collection of additional namespaces to include in the generated file. A use case for this is when you want to reuse contracts from a different namespace than the generated code. Default is empty
• includeTags - A collection of tags to use a filter for including endpoints that contain this tag.
• includePathMatches - A collection of regular expressions used to filter paths.
• generateDeprecatedOperations - a boolean indicating whether deprecated operations should be generated or skipped. Default is true
• operationNameTemplate - Generate operation names using pattern. This must contain the string {operationName}. An example usage of this could be {operationName}Async to suffix all method names with Async. When using multipleIinterfaces=ByEndpoint, This is name of the Execute() method in the interface
• optionalParameters - Generate non-required parameters as nullable optional parameters
• dependencyInjectionSettings - Setting this will generated extension methods to IServiceCollection for configuring Refit clients
  • baseUrl - Used as the HttpClient base address. Leave this blank to manually set the base URL
  • httpMessageHandlers - A collection of HttpMessageHandler that is added to the HttpClient pipeline
  • usePolly - Set this to true to configure the HttpClient to use Polly using a retry policy with a jittered backoff
  • pollyMaxRetryCount - This is the max retry count used in the Polly retry policy. Default is 6
  • firstBackoffRetryInSeconds - This is the duration of the initial retry backoff. Default is 1 second

To generate code from an OpenAPI specifications file, run the following:

$ refitter [path to OpenAPI spec file] --namespace "[Your.Namespace.Of.Choice.GeneratedCode]"

This will generate a file called Output.cs which contains the Refit interface and contract classes generated using NSwag

Using the generated code

Here's an example generated output from the Swagger Petstore example using the default settings

$ refitter ./openapi.json --namespace "Your.Namespace.Of.Choice.GeneratedCode"

using Refit;
using System.Threading.Tasks;
using System.Collections.Generic;

namespace Your.Namespace.Of.Choice.GeneratedCode
{
    public partial interface ISwaggerPetstore
    {
        /// <summary>
        /// Update an existing pet by Id
        /// </summary>
        [Put("/pet")]
        Task<Pet> UpdatePet([Body] Pet body);

        /// <summary>
        /// Add a new pet to the store
        /// </summary>
        [Post("/pet")]
        Task<Pet> AddPet([Body] Pet body);

        /// <summary>
        /// Multiple status values can be provided with comma separated strings
        /// </summary>
        [Get("/pet/findByStatus")]
        Task<ICollection<Pet>> FindPetsByStatus([Query] Status? status);

        /// <summary>
        /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
        /// </summary>
        [Get("/pet/findByTags")]
        Task<ICollection<Pet>> FindPetsByTags([Query(CollectionFormat.Multi)] IEnumerable<string> tags);

        /// <summary>
        /// Returns a single pet
        /// </summary>
        [Get("/pet/{petId}")]
        Task<Pet> GetPetById(long petId);

        [Post("/pet/{petId}")]
        Task UpdatePetWithForm(long petId, [Query] string name, [Query] string status);

        [Delete("/pet/{petId}")]
        Task DeletePet(long petId, [Header("api_key")] string api_key);

        [Post("/pet/{petId}/uploadImage")]
        Task<ApiResponse> UploadFile(long petId, [Query] string additionalMetadata, StreamPart body);

        /// <summary>
        /// Returns a map of status codes to quantities
        /// </summary>
        [Get("/store/inventory")]
        Task<IDictionary<string, int>> GetInventory();

        /// <summary>
        /// Place a new order in the store
        /// </summary>
        [Post("/store/order")]
        Task<Order> PlaceOrder([Body] Order body);

        /// <summary>
        /// For valid response try integer IDs with value <= 5 or > 10. Other values will generated exceptions
        /// </summary>
        [Get("/store/order/{orderId}")]
        Task<Order> GetOrderById(long orderId);

        /// <summary>
        /// For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
        /// </summary>
        [Delete("/store/order/{orderId}")]
        Task DeleteOrder(long orderId);

        /// <summary>
        /// This can only be done by the logged in user.
        /// </summary>
        [Post("/user")]
        Task CreateUser([Body] User body);

        /// <summary>
        /// Creates list of users with given input array
        /// </summary>
        [Post("/user/createWithList")]
        Task<User> CreateUsersWithListInput([Body] IEnumerable<User> body);

        [Get("/user/login")]
        Task<string> LoginUser([Query] string username, [Query] string password);

        [Get("/user/logout")]
        Task LogoutUser();

        [Get("/user/{username}")]
        Task<User> GetUserByName(string username);

        /// <summary>
        /// This can only be done by the logged in user.
        /// </summary>
        [Put("/user/{username}")]
        Task UpdateUser(string username, [Body] User body);

        /// <summary>
        /// This can only be done by the logged in user.
        /// </summary>
        [Delete("/user/{username}")]
        Task DeleteUser(string username);
    }
}

Here's an example generated output from the Swagger Petstore example configured to wrap the return type in IApiResponse<T>

$ refitter ./openapi.json --namespace "Your.Namespace.Of.Choice.GeneratedCode" --use-api-response

using Refit;
using System.Threading.Tasks;
using System.Collections.Generic;

namespace Your.Namespace.Of.Choice.GeneratedCode.WithApiResponse
{
    public partial interface ISwaggerPetstore
    {
        /// <summary>
        /// Update an existing pet by Id
        /// </summary>
        [Put("/pet")]
        Task<IApiResponse<Pet>> UpdatePet([Body] Pet body);

        /// <summary>
        /// Add a new pet to the store
        /// </summary>
        [Post("/pet")]
        Task<IApiResponse<Pet>> AddPet([Body] Pet body);

        /// <summary>
        /// Multiple status values can be provided with comma separated strings
        /// </summary>
        [Get("/pet/findByStatus")]
        Task<IApiResponse<ICollection<Pet>>> FindPetsByStatus([Query] Status? status);

        /// <summary>
        /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
        /// </summary>
        [System.Obsolete]
        [Get("/pet/findByTags")]
        Task<IApiResponse<ICollection<Pet>>> FindPetsByTags([Query(CollectionFormat.Multi)] IEnumerable<string> tags);

        /// <summary>
        /// Returns a single pet
        /// </summary>
        [Get("/pet/{petId}")]
        Task<IApiResponse<Pet>> GetPetById(long petId);

        [Post("/pet/{petId}")]
        Task UpdatePetWithForm(long petId, [Query] string name, [Query] string status);

        [Delete("/pet/{petId}")]
        Task DeletePet(long petId, [Header("api_key")] string api_key);

        [Post("/pet/{petId}/uploadImage")]
        Task<IApiResponse<ApiResponse>> UploadFile(long petId, [Query] string additionalMetadata, StreamPart body);

        /// <summary>
        /// Returns a map of status codes to quantities
        /// </summary>
        [Get("/store/inventory")]
        Task<IApiResponse<IDictionary<string, int>>> GetInventory();

        /// <summary>
        /// Place a new order in the store
        /// </summary>
        [Post("/store/order")]
        Task<IApiResponse<Order>> PlaceOrder([Body] Order body);

        /// <summary>
        /// For valid response try integer IDs with value <= 5 or > 10. Other values will generated exceptions
        /// </summary>
        [Get("/store/order/{orderId}")]
        Task<IApiResponse<Order>> GetOrderById(long orderId);

        /// <summary>
        /// For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
        /// </summary>
        [Delete("/store/order/{orderId}")]
        Task DeleteOrder(long orderId);

        /// <summary>
        /// This can only be done by the logged in user.
        /// </summary>
        [Post("/user")]
        Task CreateUser([Body] User body);

        /// <summary>
        /// Creates list of users with given input array
        /// </summary>
        [Post("/user/createWithList")]
        Task<IApiResponse<User>> CreateUsersWithListInput([Body] IEnumerable<User> body);

        [Get("/user/login")]
        Task<IApiResponse<string>> LoginUser([Query] string username, [Query] string password);

        [Get("/user/logout")]
        Task LogoutUser();

        [Get("/user/{username}")]
        Task<IApiResponse<User>> GetUserByName(string username);

        /// <summary>
        /// This can only be done by the logged in user.
        /// </summary>
        [Put("/user/{username}")]
        Task UpdateUser(string username, [Body] User body);

        /// <summary>
        /// This can only be done by the logged in user.
        /// </summary>
        [Delete("/user/{username}")]
        Task DeleteUser(string username);
    }
}

Here's an example generated output from the Swagger Petstore example configured to generate an interface for each endpoint

CLI Tool

$ refitter ./openapi.json --namespace "Your.Namespace.Of.Choice.GeneratedCode" --multiple-interfaces ByEndpoint

Output

/// <summary>
/// Update an existing pet
/// </summary>
public partial interface IUpdatePetEndpoint
{
    /// <summary>
    /// Update an existing pet by Id
    /// </summary>
    [Put("/pet")]
    Task<Pet> Execute([Body] Pet body);
}

/// <summary>
/// Add a new pet to the store
/// </summary>
public partial interface IAddPetEndpoint
{
    /// <summary>
    /// Add a new pet to the store
    /// </summary>
    [Post("/pet")]
    Task<Pet> Execute([Body] Pet body);
}

/// <summary>
/// Finds Pets by status
/// </summary>
public partial interface IFindPetsByStatusEndpoint
{
    /// <summary>
    /// Multiple status values can be provided with comma separated strings
    /// </summary>
    [Get("/pet/findByStatus")]
    Task<ICollection<Pet>> Execute([Query] Status? status);
}

/// <summary>
/// Finds Pets by tags
/// </summary>
public partial interface IFindPetsByTagsEndpoint
{
    /// <summary>
    /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
    /// </summary>
    [Get("/pet/findByTags")]
    Task<ICollection<Pet>> Execute([Query(CollectionFormat.Multi)] IEnumerable<string> tags);
}

/// <summary>
/// Find pet by ID
/// </summary>
public partial interface IGetPetByIdEndpoint
{
    /// <summary>
    /// Returns a single pet
    /// </summary>
    [Get("/pet/{petId}")]
    Task<Pet> Execute(long petId);
}

/// <summary>
/// Updates a pet in the store with form data
/// </summary>
public partial interface IUpdatePetWithFormEndpoint
{
    [Post("/pet/{petId}")]
    Task Execute(long petId, [Query] string name, [Query] string status);
}

/// <summary>
/// Deletes a pet
/// </summary>
public partial interface IDeletePetEndpoint
{
    [Delete("/pet/{petId}")]
    Task Execute(long petId, [Header("api_key")] string api_key);
}

/// <summary>
/// uploads an image
/// </summary>
public partial interface IUploadFileEndpoint
{
    [Post("/pet/{petId}/uploadImage")]
    Task<ApiResponse> Execute(long petId, [Query] string additionalMetadata, StreamPart body);
}

/// <summary>
/// Returns pet inventories by status
/// </summary>
public partial interface IGetInventoryEndpoint
{
    /// <summary>
    /// Returns a map of status codes to quantities
    /// </summary>
    [Get("/store/inventory")]
    Task<IDictionary<string, int>> Execute();
}

/// <summary>
/// Place an order for a pet
/// </summary>
public partial interface IPlaceOrderEndpoint
{
    /// <summary>
    /// Place a new order in the store
    /// </summary>
    [Post("/store/order")]
    Task<Order> Execute([Body] Order body);
}

/// <summary>
/// Find purchase order by ID
/// </summary>
public partial interface IGetOrderByIdEndpoint
{
    /// <summary>
    /// For valid response try integer IDs with value <= 5 or > 10. Other values will generated exceptions
    /// </summary>
    [Get("/store/order/{orderId}")]
    Task<Order> Execute(long orderId);
}

/// <summary>
/// Delete purchase order by ID
/// </summary>
public partial interface IDeleteOrderEndpoint
{
    /// <summary>
    /// For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
    /// </summary>
    [Delete("/store/order/{orderId}")]
    Task Execute(long orderId);
}

/// <summary>
/// Create user
/// </summary>
public partial interface ICreateUserEndpoint
{
    /// <summary>
    /// This can only be done by the logged in user.
    /// </summary>
    [Post("/user")]
    Task Execute([Body] User body);
}

/// <summary>
/// Creates list of users with given input array
/// </summary>
public partial interface ICreateUsersWithListInputEndpoint
{
    /// <summary>
    /// Creates list of users with given input array
    /// </summary>
    [Post("/user/createWithList")]
    Task<User> Execute([Body] IEnumerable<User> body);
}

/// <summary>
/// Logs user into the system
/// </summary>
public partial interface ILoginUserEndpoint
{
    [Get("/user/login")]
    Task<string> Execute([Query] string username, [Query] string password);
}

/// <summary>
/// Logs out current logged in user session
/// </summary>
public partial interface ILogoutUserEndpoint
{
    [Get("/user/logout")]
    Task Execute();
}

/// <summary>
/// Get user by user name
/// </summary>
public partial interface IGetUserByNameEndpoint
{
    [Get("/user/{username}")]
    Task<User> Execute(string username);
}

/// <summary>
/// Update user
/// </summary>
public partial interface IUpdateUserEndpoint
{
    /// <summary>
    /// This can only be done by the logged in user.
    /// </summary>
    [Put("/user/{username}")]
    Task Execute(string username, [Body] User body);
}

/// <summary>
/// Delete user
/// </summary>
public partial interface IDeleteUserEndpoint
{
    /// <summary>
    /// This can only be done by the logged in user.
    /// </summary>
    [Delete("/user/{username}")]
    Task Execute(string username);
}

RestService

Here's an example usage of the generated code above

using Refit;
using System;
using System.Threading.Tasks;

namespace Your.Namespace.Of.Choice.GeneratedCode;

internal class Program
{
    private static async Task Main(string[] args)
    {
        var client = RestService.For<ISwaggerPetstore>("https://petstore3.swagger.io/api/v3");
        var pet = await client.GetPetById(1);

        Console.WriteLine("## Using Task<T> as return type ##");
        Console.WriteLine($"Name: {pet.Name}");
        Console.WriteLine($"Category: {pet.Category.Name}");
        Console.WriteLine($"Status: {pet.Status}");
        Console.WriteLine();

        var client2 = RestService.For<WithApiResponse.ISwaggerPetstore>("https://petstore3.swagger.io/api/v3");
        var response = await client2.GetPetById(2);

        Console.WriteLine("## Using Task<IApiResponse<T>> as return type ##");
        Console.WriteLine($"HTTP Status Code: {response.StatusCode}");
        Console.WriteLine($"Name: {response.Content.Name}");
        Console.WriteLine($"Category: {response.Content.Category.Name}");
        Console.WriteLine($"Status: {response.Content.Status}");
    }
}

The RestService class generates an implementation of ISwaggerPetstore that uses HttpClient to make its calls.

The code above when run will output something like this:

## Using Task<T> as return type ##
Name: Gatitotototo
Category: Chaucito
Status: Sold

## Using Task<IApiResponse<T>> as return type ##
HTTP Status Code: OK
Name: Gatitotototo
Category: Chaucito
Status: Sold

ASP.NET Core and HttpClientFactory

Here's an example Minimal API with the Refit.HttpClientFactory library:

using Refit;
using Your.Namespace.Of.Choice.GeneratedCode;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services
    .AddRefitClient<ISwaggerPetstore>()
    .ConfigureHttpClient(c => c.BaseAddress = new Uri("https://petstore3.swagger.io/api/v3"));

var app = builder.Build();
app.MapGet(
        "/pet/{id:long}",
        async (ISwaggerPetstore petstore, long id) =>
        {
            try
            {
                return Results.Ok(await petstore.GetPetById(id));
            }
            catch (Refit.ApiException e)
            {
                return Results.StatusCode((int)e.StatusCode);
            }
        })
    .WithName("GetPetById")
    .WithOpenApi();

app.UseHttpsRedirection();
app.UseSwaggerUI();
app.UseSwagger();
app.Run();

.NET Core supports registering the generated ISwaggerPetstore interface via HttpClientFactory

The following request to the API above

$ curl -X 'GET' 'https://localhost:5001/pet/1' -H 'accept: application/json'

Returns a response that looks something like this:

{
  "id": 1,
  "name": "Special_char_owner_!@#$^&()`.testing",
  "photoUrls": [
    "https://petstore3.swagger.io/resources/photos/623389095.jpg"
  ],
  "tags": [],
  "status": "Sold"
}

System requirements

.NET 6.0 (LTS)

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