Introduction
A Go project for handling OpenAPI files. We target the latest OpenAPI version (currently 3), but the project contains support for older OpenAPI versions too.
Licensed under the MIT License.
Contributors and users
The project has received pull requests from many people. Thanks to everyone!
Here's some projects that depend on kin-openapi:
- github.com/Tufin/oasdiff - "A diff tool for OpenAPI Specification 3"
- github.com/danielgtaylor/apisprout - "Lightweight, blazing fast, cross-platform OpenAPI 3 mock server with validation"
- github.com/deepmap/oapi-codegen - "Generate Go client and server boilerplate from OpenAPI 3 specifications"
- github.com/dunglas/vulcain - "Use HTTP/2 Server Push to create fast and idiomatic client-driven REST APIs"
- github.com/danielgtaylor/restish - "...a CLI for interacting with REST-ish HTTP APIs with some nice features built-in"
- github.com/goadesign/goa - "Design-based APIs and microservices in Go"
- github.com/hashicorp/nomad-openapi - "Nomad is an easy-to-use, flexible, and performant workload orchestrator that can deploy a mix of microservice, batch, containerized, and non-containerized applications. Nomad is easy to operate and scale and has native Consul and Vault integrations."
- gitlab.com/jamietanna/httptest-openapi (blog post) - "Go OpenAPI Contract Verification for use with
net/http
" - (Feel free to add your project by creating an issue or a pull request)
Alternatives
- go-swagger stated OpenAPIv3 won't be supported
- swaggo has an open issue on OpenAPIv3
- go-openapi's spec3
Be sure to check OpenAPI Initiative's great tooling list as well as OpenAPI.Tools.
Structure
- openapi2 (godoc)
- Support for OpenAPI 2 files, including serialization, deserialization, and validation.
- openapi2conv (godoc)
- Converts OpenAPI 2 files into OpenAPI 3 files.
- openapi3 (godoc)
- Support for OpenAPI 3 files, including serialization, deserialization, and validation.
- openapi3filter (godoc)
- Validates HTTP requests and responses
- Provides a gorilla/mux router for OpenAPI operations
- openapi3gen (godoc)
- Generates
*openapi3.Schema
values for Go types.
- Generates
Some recipes
Loading OpenAPI document
Use openapi3.Loader
, which resolves all references:
doc, err := openapi3.NewLoader().LoadFromFile("swagger.json")
Getting OpenAPI operation that matches request
loader := openapi3.NewLoader()
doc, _ := loader.LoadFromData([]byte(`...`))
_ := doc.Validate(loader.Context)
router, _ := gorillamux.NewRouter(doc)
route, pathParams, _ := router.FindRoute(httpRequest)
// Do something with route.Operation
Validating HTTP requests/responses
package main
import (
"context"
"fmt"
"net/http"
"github.com/getkin/kin-openapi/openapi3"
"github.com/getkin/kin-openapi/openapi3filter"
"github.com/getkin/kin-openapi/routers/gorillamux"
)
func main() {
ctx := context.Background()
loader := &openapi3.Loader{Context: ctx, IsExternalRefsAllowed: true}
doc, _ := loader.LoadFromFile(".../My-OpenAPIv3-API.yml")
// Validate document
_ := doc.Validate(ctx)
router, _ := gorillamux.NewRouter(doc)
httpReq, _ := http.NewRequest(http.MethodGet, "/items", nil)
// Find route
route, pathParams, _ := router.FindRoute(httpReq)
// Validate request
requestValidationInput := &openapi3filter.RequestValidationInput{
Request: httpReq,
PathParams: pathParams,
Route: route,
}
_ := openapi3filter.ValidateRequest(ctx, requestValidationInput)
// Handle that request
// --> YOUR CODE GOES HERE <--
responseHeaders := http.Header{"Content-Type": []string{"application/json"}}
responseCode := 200
responseBody := []byte(`{}`)
// Validate response
responseValidationInput := &openapi3filter.ResponseValidationInput{
RequestValidationInput: requestValidationInput,
Status: responseCode,
Header: responseHeaders,
}
responseValidationInput.SetBodyBytes(responseBody)
_ := openapi3filter.ValidateResponse(ctx, responseValidationInput)
}
Custom content type for body of HTTP request/response
By default, the library parses a body of HTTP request and response
if it has one of the next content types: "text/plain"
or "application/json"
.
To support other content types you must register decoders for them:
func main() {
// ...
// Register a body's decoder for content type "application/xml".
openapi3filter.RegisterBodyDecoder("application/xml", xmlBodyDecoder)
// Now you can validate HTTP request that contains a body with content type "application/xml".
requestValidationInput := &openapi3filter.RequestValidationInput{
Request: httpReq,
PathParams: pathParams,
Route: route,
}
if err := openapi3filter.ValidateRequest(ctx, requestValidationInput); err != nil {
panic(err)
}
// ...
// And you can validate HTTP response that contains a body with content type "application/xml".
if err := openapi3filter.ValidateResponse(ctx, responseValidationInput); err != nil {
panic(err)
}
}
func xmlBodyDecoder(body io.Reader, h http.Header, schema *openapi3.SchemaRef, encFn openapi3filter.EncodingFn) (decoded interface{}, err error) {
// Decode body to a primitive, []inteface{}, or map[string]interface{}.
}
Custom function to check uniqueness of array items
By defaut, the library check unique items by below predefined function
func isSliceOfUniqueItems(xs []interface{}) bool {
s := len(xs)
m := make(map[string]struct{}, s)
for _, x := range xs {
key, _ := json.Marshal(&x)
m[string(key)] = struct{}{}
}
return s == len(m)
}
In the predefined function using json.Marshal
to generate a string can
be used as a map key which is to support check the uniqueness of an array
when the array items are objects or arrays. You can register
you own function according to your input data to get better performance:
func main() {
// ...
// Register a customized function used to check uniqueness of array.
openapi3.RegisterArrayUniqueItemsChecker(arrayUniqueItemsChecker)
// ... other validate codes
}
func arrayUniqueItemsChecker(items []interface{}) bool {
// Check the uniqueness of the input slice
}
Sub-v0 breaking API changes
v0.84.0
- The prototype of
openapi3gen.NewSchemaRefForValue
changed:- It no longer returns a map but that is still accessible under the field
(*Generator).SchemaRefs
. - It now takes in an additional argument (basically
doc.Components.Schemas
) which gets written to so$ref
cycles can be properly handled.
- It no longer returns a map but that is still accessible under the field
v0.61.0
- Renamed
openapi2.Swagger
toopenapi2.T
. - Renamed
openapi2conv.FromV3Swagger
toopenapi2conv.FromV3
. - Renamed
openapi2conv.ToV3Swagger
toopenapi2conv.ToV3
. - Renamed
openapi3.LoadSwaggerFromData
toopenapi3.LoadFromData
. - Renamed
openapi3.LoadSwaggerFromDataWithPath
toopenapi3.LoadFromDataWithPath
. - Renamed
openapi3.LoadSwaggerFromFile
toopenapi3.LoadFromFile
. - Renamed
openapi3.LoadSwaggerFromURI
toopenapi3.LoadFromURI
. - Renamed
openapi3.NewSwaggerLoader
toopenapi3.NewLoader
. - Renamed
openapi3.Swagger
toopenapi3.T
. - Renamed
openapi3.SwaggerLoader
toopenapi3.Loader
. - Renamed
openapi3filter.ValidationHandler.SwaggerFile
toopenapi3filter.ValidationHandler.File
. - Renamed
routers.Route.Swagger
torouters.Route.Spec
.
v0.51.0
- Type
openapi3filter.Route
moved torouters
(andRoute.Handler
was dropped. See getkin#329) - Type
openapi3filter.RouteError
moved torouters
(so didErrPathNotFound
andErrMethodNotAllowed
which are nowRouteError
s) - Routers'
FindRoute(...)
method now takes only one argument:*http.Request
getkin/kin-openapi/openapi3filter.Router
moved togetkin/kin-openapi/routers/legacy
openapi3filter.NewRouter()
and its relatedWithSwaggerFromFile(string)
,WithSwagger(*openapi3.Swagger)
,AddSwaggerFromFile(string)
andAddSwagger(*openapi3.Swagger)
are all replaced with a single<router package>.NewRouter(*openapi3.Swagger)
- NOTE: the
NewRouter(doc)
call now requires that the user ensuresdoc
is valid (doc.Validate() != nil
). This used to be asserted.
- NOTE: the
v0.47.0
Field (*openapi3.SwaggerLoader).LoadSwaggerFromURIFunc
of type func(*openapi3.SwaggerLoader, *url.URL) (*openapi3.Swagger, error)
was removed after the addition of the field (*openapi3.SwaggerLoader).ReadFromURIFunc
of type func(*openapi3.SwaggerLoader, *url.URL) ([]byte, error)
.