Oapi-codegen

External

• https://github.com/deepmap/oapi-codegen

Internal

• Go OpenAPI
• A Simple CRUD REST Application with OpenAPI

Installation

Get the latest version from https://github.com/deepmap/oapi-codegen/tags

Then:

go install github.com/deepmap/oapi-codegen/v2/cmd/oapi-codegen@v2.1.0

The installation will place the package under $GOPATH/pkg/mod/cache/download/github.com/deepmap and $GOPATH/pkg/mod/github.com/deepmap, will compile the binary and place it under ~/go/bin.

Generate Code

Generate client and server code:

oapi-codegen -package petstore ./petstore-expanded.yaml > ./internal/petstore/petstore.gen.go
go mod tidy

make Support

.PHONY: generate_oapi_artifacts

generate_oapi_artifacts: internal/petstore/spec.gen.go internal/petstore/types.gen.go internal/petstore/server.gen.go internal/petstore/client.gen.go

internal/petstore/spec.gen.go: ./petstore.yaml
	oapi-codegen -generate spec -package petstore $< > $@

internal/petstore/types.gen.go: ./petstore.yaml
	oapi-codegen -generate types -package petstore $< > $@

internal/petstore/server.gen.go: ./petstore.yaml
	oapi-codegen -generate server -package petstore $< > $@

internal/petstore/client.gen.go: ./petstore.yaml
	oapi-codegen -generate client -package petstore $< > $@

Type Generation

See:

OpenAPI Specification Schemas

Code Generation for OpenAPI Specification Path/Operation Combinations

OpenAPI Specification Path | Server Code Generation for Path/Operation Combinations

Implement the handlers and register them with echo:

echo | Registering Handlers Generated by oapi-codegen from an OpenAPI Specification

Options

-package

The package name for the generated code.

-generate

Comma-separated list of code to generate; valid options: "types", "client", "chi-server", "server", "gin", "gorilla", "spec", "skip-fmt", "skip-prune", "fiber", "iris". The default is "types,client,server,spec".

types

Generate the types declared in the /components/schemas section of the OpenAPI specification.

oapi-codegen -generate types -package petstore ./petstore-expanded.yaml > ./internal/petstore/types.gen.go

spec

Generates this:

var swaggerSpec = []string{...}

func decodeSpec() ([]byte, error) {...}

var rawSpec = decodeSpecCached()

func decodeSpecCached() func() ([]byte, error) {...}

func PathToRawSpec(pathToFile string) map[string]func() ([]byte, error) {...}

func GetSwagger() (swagger *openapi3.T, err error) {...}

server

Default, generates server code for the echo HTTP server.

chi-server

Generates server code for the chi HTTP server. The code is compatible with net/http server:

oapi-codegen -generate chi-server -package petstore ./petstore.yaml > ./internal/petstore/server.gen.go

package petstore

[...]

// ServerInterface represents all server handlers.
type ServerInterface interface {
	// (GET /pets)
	GetPets(w http.ResponseWriter, r *http.Request, params GetPetsParams)
	// (POST /pets)
	CreatePet(w http.ResponseWriter, r *http.Request)
}