openapi-generator for C#

Generates simple C# code based on the OpenAPI specification.

OAuth clients can be generated to easily set up calling a secured api.

Constructors will be added to initialize required or non-nullable properties defined in your schema.

If you your schema contains allOf properties and thus supports Inheritance, the classes will correctly inherit from each other and implement the base constructors. Since allOf technically is an array in the swagger document, you may get weird results in the generated code if there's more than one present, as this is not supported in the .NET framework.

Installation

Major and Minor version numbers always dictate the dotnet version being used.

netstandard 2.0 generator installation

dotnet tool install dotnet-openapi-generator -g --version 2.0.0-preview.15

netstandard 2.1 generator installation

dotnet tool install dotnet-openapi-generator -g --version 2.1.0-preview.15

dotnet 5.0 generator installation

dotnet tool install dotnet-openapi-generator -g --version 5.0.0-preview.15

dotnet 6.0 generator installation

dotnet tool install dotnet-openapi-generator -g --version 6.0.0-preview.15

dotnet 7.0 generator installation

dotnet tool install dotnet-openapi-generator -g --version 7.0.0-preview.15

dotnet 8.0 generator installation

dotnet tool install dotnet-openapi-generator -g --version 8.0.0-preview.15

Getting started

C:\Git > dotnet openapi-generator --help
dotnet-openapi-generator 8.0.0-preview.15
Steven Thuriot

  -n, --namespace                    (Default: Project name) The namespace used for the generated files

  -d, --directory                    (Default: Current Directory) The directory to place the files in

  -m, --modifier                     (Default: Public) The modifier for the generated files. Can be Public or Internal

  -c, --clean-directory              (Default: false) Delete folder before generating

  -f, --filter                       (Default: No filter) Only generate Clients that match the supplied regex filter

  --client-modifier                  (Default: -m) The modifier for the generated clients; Useful when generating with interfaces. Can be Public or Internal

  -s, --tree-shake                   (Default: false) Skip generating unused models

  --json-constructor-attribute       (Default: System.Text.Json.Serialization.JsonConstructor) 
                                     Json Constructor Attribute. Constructors are generated when the class contains required properties

  --json-polymorphic-attribute       (Default: System.Text.Json.Serialization.JsonPolymorphic(TypeDiscriminatorPropertyName = "{name}"))
                                     Json Polymorphic Attribute. Marks the generated types as polymorphic using the specified attribute.
                                     {name} is used as a template placeholder

  --json-derived-type-attribute      (Default: System.Text.Json.Serialization.JsonDerivedType(typeof({type}), typeDiscriminator: "{value}")) 
                                     Json Derived Type Attribute. Marks the derived types of the generated types using the specified attribute.
                                     {type} and {value} are used as template placeholders

  --json-property-name-attribute     (Default: System.Text.Json.Serialization.JsonPropertyName("{name}"))
                                     Json Property Name Attribute. Some property names are not valid in C#. This will make sure serialization works out.
                                     {name} is used as a template placeholder


  -j, --json-source-generators       (Default: false) Include dotnet 7.0+ Json Source Generators

  -r, --required-properties          (Default: false) Include C# 11 Required keywords

  --stringbuilder-pool-size          (Default: 50) StringBuilder pool size for building query params. If 0, a simple string concat is used instead

  --oauth-type                       (Default: None) Includes an OAuth Client. Can be ClientCredentials, TokenExchange or CachedTokenExchange

  --oauth-client-credential-style    (Default: PostBody) When including an OAuth Client, we can either pass values in the body or as a basic auth header. Can be PostBody or AuthorizationHeader

  -i, --interfaces                   (Default: false) Generate interfaces for the clients

  -p, --no-project                   (Default: false) Do not generate project

  -o, --no-obsolete                  (Default: false) Do not generate obsolete endpoints

  -a, --additional-document          Location of additional swagger document, used to merge into the main
                                     one. Can be both an http location or a local one and can be used
                                     multiple times

  -v, --verbose                      (Default: false) Verbose logging

  --help                             Display this help screen.

  --version                          Display version information.

  value pos. 0                       Required. Name of the project

  value pos. 1                       Required. Location of the JSON swagger document. Can be both an http location or a local one

Registration

In your Program.cs, add the following or one of its overloads:

ApiRegistration registration = new();
builder.Services.RegisterApiClients(registration);

In case you included --oauth-type during generation, you will have to supply some token information to the ApiRegistration constructor:

TokenOptions options = new(authorityUrl, clientId, clientSecret, scopes);
ApiRegistration registration = new(options);
builder.Services.RegisterApiClients(registration);