Generating OpenAPI documentation¶
To use, add the following dependencies:
"com.softwaremill.tapir" %% "tapir-openapi-docs" % "0.8.10"
"com.softwaremill.tapir" %% "tapir-openapi-circe-yaml" % "0.8.10"
Tapir contains a case class-based model of the openapi data structures in the openapi/openapi-model
subproject (the
model is independent from all other tapir modules and can be used stand-alone).
An endpoint can be converted to an instance of the model by importing the tapir.docs.openapi._
package and calling
the provided extension method:
import tapir.openapi.OpenAPI
import tapir.docs.openapi._
val docs: OpenAPI = booksListing.toOpenAPI("My Bookshop", "1.0")
Such a model can then be refined, by adding details which are not auto-generated. Working with a deeply nested case
class structure such as the OpenAPI
one can be made easier by using a lens library, e.g. Quicklens.
Multiple endpoints can be converted to an OpenAPI
instance by calling the extension method on a list of endpoints:
List(addBook, booksListing, booksListingByGenre).toOpenAPI("My Bookshop", "1.0")
The openapi case classes can then be serialised, either to JSON or YAML using Circe:
import tapir.openapi.circe.yaml._
println(docs.toYaml)
Each endpoint corresponds to an operation in the OpenAPI format and should have a unique operation id. By default,
the name
of endpoint is used as the operation id, and if this is not available, the operation id is auto-generated
by concatenating (using camel-case) the request method and path. This can be customised by providing an implicit
instance of OpenAPIDocsOptions
.
Exposing OpenAPI documentation¶
Exposing the OpenAPI documentation can be very application-specific. For example, to expose the docs using the Swagger UI and akka-http:
- add
libraryDependencies += "org.webjars" % "swagger-ui" % "3.22.2"
tobuild.sbt
(or newer) - generate the yaml content to serve as a
String
using tapir:
import tapir.docs.openapi._
import tapir.openapi.circe.yaml._
val docsAsYaml: String = myEndpoints.toOpenAPI("My App", "1.0").toYaml
- add the following routes to your server:
val SwaggerYml = "swagger.yml"
private val redirectToIndex: Route =
redirect(s"/swagger/index.html?url=/swagger/$SwaggerYml", StatusCodes.PermanentRedirect)
// needed only if you use oauth2 authorization
private def redirectToOath2(query: String): Route =
redirect(s"/swagger/oauth2-redirect.html$query", StatusCodes.PermanentRedirect)
private val swaggerVersion = {
val p = new Properties()
val pomProperties = getClass.getResourceAsStream("/META-INF/maven/org.webjars/swagger-ui/pom.properties")
try p.load(pomProperties)
finally pomProperties.close()
p.getProperty("version")
}
val routes: Route =
pathPrefix("swagger") {
pathEndOrSingleSlash {
redirectToIndex
} ~ path(SwaggerYml) {
complete(yml)
} ~ getFromResourceDirectory(s"META-INF/resources/webjars/swagger-ui/$swaggerVersion/")
} ~
// needed only if you use oauth2 authorization
path("oauth2-redirect.html") { request =>
redirectToOath2(request.request.uri.rawQueryString.map(s => '?' + s).getOrElse(""))(request)
}