// MediaType implements the media type definition DSL. A media type definition describes the
// representation of a resource used in a response body.
//
// Media types are defined with a unique identifier as defined by RFC6838. The identifier also
// defines the default value for the Content-Type header of responses. The ContentType DSL allows
// overridding the default as shown in the example below.
//
// The media type definition includes a listing of all the potential attributes that can appear in
// the body. Views specify which of the attributes are actually rendered so that the same media type
// definition may represent multiple rendering of a given resource representation.
//
// All media types must define a view named "default". This view is used to render the media type in
// response bodies when no other view is specified.
//
// A media type definition may also define links to other media types. This is done by first
// defining an attribute for the linked-to media type and then referring to that attribute in the
// Links DSL. Views may then elect to render one or the other or both. Links are rendered using the
// special "link" view. Media types that are linked to must define that view. Here is an example
// showing all the possible media type sub-definitions:
//
// MediaType("application/vnd.goa.example.bottle", func() {
// Description("A bottle of wine")
// TypeName("BottleMedia") // Override default generated name
// ContentType("application/json") // Override default Content-Type header value
// Attributes(func() {
// Attribute("id", Integer, "ID of bottle")
// Attribute("href", String, "API href of bottle")
// Attribute("account", Account, "Owner account")
// Attribute("origin", Origin, "Details on wine origin")
// Links(func() {
// Link("account") // Defines link to Account media type
// Link("origin", "tiny") // Set view used to render link if not "link"
// })
// Required("id", "href")
// })
// View("default", func() {
// Attribute("id")
// Attribute("href")
// Attribute("links") // Renders links
// })
// View("extended", func() {
// Attribute("id")
// Attribute("href")
// Attribute("account") // Renders account inline
// Attribute("origin") // Renders origin inline
// Attribute("links") // Renders links
// })
// })
//
// This function returns the media type definition so it can be referred to throughout the apidsl.
func MediaType(identifier string, apidsl func()) *design.MediaTypeDefinition {
if design.Design.MediaTypes == nil {
design.Design.MediaTypes = make(map[string]*design.MediaTypeDefinition)
}
if !dslengine.IsTopLevelDefinition() {
dslengine.IncompatibleDSL()
return nil
}
// Validate Media Type
identifier, params, err := mime.ParseMediaType(identifier)
if err != nil {
dslengine.ReportError("invalid media type identifier %#v: %s",
identifier, err)
// We don't return so that other errors may be
// captured in this one run.
identifier = "text/plain"
}
canonicalID := design.CanonicalIdentifier(identifier)
// Validate that media type identifier doesn't clash
if _, ok := design.Design.MediaTypes[canonicalID]; ok {
dslengine.ReportError("media type %#v with canonical identifier %#v is defined twice", identifier, canonicalID)
return nil
}
identifier = mime.FormatMediaType(identifier, params)
lastPart := identifier
lastPartIndex := strings.LastIndex(identifier, "/")
if lastPartIndex > -1 {
lastPart = identifier[lastPartIndex+1:]
}
plusIndex := strings.Index(lastPart, "+")
if plusIndex > 0 {
lastPart = lastPart[:plusIndex]
}
lastPart = strings.TrimPrefix(lastPart, "vnd.")
elems := strings.Split(lastPart, ".")
for i, e := range elems {
elems[i] = strings.Title(e)
}
typeName := strings.Join(elems, "")
if typeName == "" {
mediaTypeCount++
typeName = fmt.Sprintf("MediaType%d", mediaTypeCount)
}
// Now save the type in the API media types map
mt := design.NewMediaTypeDefinition(typeName, identifier, apidsl)
design.Design.MediaTypes[canonicalID] = mt
return mt
}
// Resource implements the resource definition dsl. There is one resource definition per resource
// exposed by the API. The resource dsl allows setting the resource default media type. This media
// type is used to render the response body of actions that return the OK response (unless the
// action overrides the default). The default media type also sets the properties of the request
// payload attributes with the same name. See DefaultMedia.
//
// The resource dsl also allows listing the supported resource collection and resource collection
// item actions. Each action corresponds to a specific API endpoint. See Action.
//
// The resource dsl can also specify a parent resource. Parent resources have two effects.
// First, they set the prefix of all resource action paths to the parent resource href. Note that
// actions can override the path using an absolute path (that is a path starting with "//").
// Second, goa uses the parent resource href coupled with the resource BasePath if any to build
// hrefs to the resource collection or resource collection items. By default goa uses the show
// action if present to compute a resource href (basically concatenating the parent resource href
// with the base path and show action path). The resource definition may specify a canonical action
// via CanonicalActionName to override that default. Here is an example of a resource definition:
//
// Resource("bottle", func() {
// Description("A wine bottle") // Resource description
// DefaultMedia(BottleMedia) // Resource default media type
// BasePath("/bottles") // Common resource action path prefix if not ""
// Parent("account") // Name of parent resource if any
// CanonicalActionName("get") // Name of action that returns canonical representation if not "show"
// UseTrait("Authenticated") // Included trait if any, can appear more than once
//
// Origin("http://swagger.goa.design", func() { // Define CORS policy, may be prefixed with "*" wildcard
// Headers("X-Shared-Secret") // One or more authorized headers, use "*" to authorize all
// Methods("GET", "POST") // One or more authorized HTTP methods
// Expose("X-Time") // One or more headers exposed to clients
// MaxAge(600) // How long to cache a preflight request response
// Credentials() // Sets Access-Control-Allow-Credentials header
// })
//
// Response(Unauthorized, ErrorMedia) // Common responses to all actions
// Response(BadRequest, ErrorMedia)
//
// Action("show", func() { // Action definition, can appear more than once
// // ... Action dsl
// })
// })
func Resource(name string, dsl func()) *design.ResourceDefinition {
if design.Design.Resources == nil {
design.Design.Resources = make(map[string]*design.ResourceDefinition)
}
if !dslengine.IsTopLevelDefinition() {
dslengine.IncompatibleDSL()
return nil
}
if _, ok := design.Design.Resources[name]; ok {
dslengine.ReportError("resource %#v is defined twice", name)
return nil
}
resource := design.NewResourceDefinition(name, dsl)
design.Design.Resources[name] = resource
return resource
}
// API implements the top level API DSL. It defines the API name, default description and other
// default global property values. Here is an example showing all the possible API sub-definitions:
//
// API("API name", func() {
// Title("title") // API title used in documentation
// Description("description") // API description used in documentation
// Version("2.0") // API version being described
// TermsOfService("terms")
// Contact(func() { // API Contact information
// Name("contact name")
// Email("contact email")
// URL("contact URL")
// })
// License(func() { // API Licensing information
// Name("license name")
// URL("license URL")
// })
// Docs(func() {
// Description("doc description")
// URL("doc URL")
// })
// Host("goa.design") // API hostname
// Scheme("http")
// BasePath("/base/:param") // Common base path to all API actions
// Params(func() { // Common parameters to all API actions
// Param("param")
// })
// Security("JWT")
// Origin("http://swagger.goa.design", func() { // Define CORS policy, may be prefixed with "*" wildcard
// Headers("X-Shared-Secret") // One or more authorized headers, use "*" to authorize all
// Methods("GET", "POST") // One or more authorized HTTP methods
// Expose("X-Time") // One or more headers exposed to clients
// MaxAge(600) // How long to cache a preflight request response
// Credentials() // Sets Access-Control-Allow-Credentials header
// })
// Consumes("application/xml") // Built-in encoders and decoders
// Consumes("application/json")
// Produces("application/gob")
// Produces("application/json", func() { // Custom encoder
// Package("github.com/goadesign/goa/encoding/json")
// })
// ResponseTemplate("static", func() { // Response template for use by actions
// Description("description")
// Status(404)
// MediaType("application/json")
// })
// ResponseTemplate("dynamic", func(arg1, arg2 string) {
// Description(arg1)
// Status(200)
// MediaType(arg2)
// })
// NoExample() // Prevent automatic generation of examples
// Trait("Authenticated", func() { // Traits define DSL that can be run anywhere
// Headers(func() {
// Header("header")
// Required("header")
// })
// })
// }
//
func API(name string, dsl func()) *design.APIDefinition {
if design.Design.Name != "" {
dslengine.ReportError("multiple API definitions, only one is allowed")
return nil
}
if !dslengine.IsTopLevelDefinition() {
dslengine.IncompatibleDSL()
return nil
}
if name == "" {
dslengine.ReportError("API name cannot be empty")
}
design.Design.Name = name
design.Design.DSLFunc = dsl
return design.Design
}
// Type implements the type definition dsl. A type definition describes a data structure consisting
// of attributes. Each attribute has a type which can also refer to a type definition (or use a
// primitive type or nested attibutes). The dsl syntax for define a type definition is the
// Attribute dsl, see Attribute.
//
// On top of specifying any attribute type, type definitions can also be used to describe the data
// structure of a request payload. They can also be used by media type definitions as reference, see
// Reference. Here is an example:
//
// Type("createPayload", func() {
// Description("Type of create and upload action payloads")
// Attribute("name", String, "name of bottle")
// Attribute("origin", Origin, "Details on wine origin") // See Origin definition below
// Required("name")
// })
//
// var Origin = Type("origin", func() {
// Description("Origin of bottle")
// Attribute("Country")
// })
//
// This function returns the newly defined type so the value can be used throughout the dsl.
func Type(name string, dsl func()) *design.UserTypeDefinition {
if design.Design.Types == nil {
design.Design.Types = make(map[string]*design.UserTypeDefinition)
} else if _, ok := design.Design.Types[name]; ok {
dslengine.ReportError("type %#v defined twice", name)
return nil
}
if !dslengine.IsTopLevelDefinition() {
dslengine.IncompatibleDSL()
return nil
}
t := &design.UserTypeDefinition{
TypeName: name,
AttributeDefinition: &design.AttributeDefinition{DSLFunc: dsl},
}
if dsl == nil {
t.Type = design.String
}
design.Design.Types[name] = t
return t
}
// MediaType implements the media type definition apidsl. A media type definition describes the
// representation of a resource used in a response body. This includes listing all the *potential*
// resource attributes that can appear in the body. Views specify which of the attributes are
// actually rendered so that the same media type definition may represent multiple rendering of a
// given resource representation.
//
// All media types must define a view named "default". This view is used to render the media type in
// response bodies when no other view is specified.
//
// A media type definition may also define links to other media types. This is done by first
// defining an attribute for the linked-to media type and then referring to that attribute in the
// Links apidsl. Views may then elect to render one or the other or both. Links are rendered using the
// special "link" view. Media types that are linked to must define that view. Here is an example
// showing all the possible media type sub-definitions:
//
// MediaType("application/vnd.goa.example.bottle", func() {
// Description("A bottle of wine")
// TypeName("BottleMedia") // Optionally override the default generated name
// Attributes(func() {
// Attribute("id", Integer, "ID of bottle")
// Attribute("href", String, "API href of bottle")
// Attribute("account", Account, "Owner account")
// Attribute("origin", Origin, "Details on wine origin")
// Links(func() {
// Link("account") // Defines a link to the Account media type
// Link("origin", "tiny") // Overrides the default view used to render links
// })
// Required("id", "href")
// })
// View("default", func() {
// Attribute("id")
// Attribute("href")
// Attribute("links") // Default view renders links
// })
// View("extended", func() {
// Attribute("id")
// Attribute("href")
// Attribute("account") // Extended view renders account inline
// Attribute("origin") // Extended view renders origin inline
// Attribute("links") // Extended view also renders links
// })
// })
//
// This function returns the media type definition so it can be referred to throughout the apidsl.
func MediaType(identifier string, apidsl func()) *design.MediaTypeDefinition {
if design.Design.MediaTypes == nil {
design.Design.MediaTypes = make(map[string]*design.MediaTypeDefinition)
}
if !dslengine.IsTopLevelDefinition() {
dslengine.IncompatibleDSL()
return nil
}
// Validate Media Type
identifier, params, err := mime.ParseMediaType(identifier)
if err != nil {
dslengine.ReportError("invalid media type identifier %#v: %s",
identifier, err)
// We don't return so that other errors may be
// captured in this one run.
identifier = "text/plain"
}
canonicalID := design.CanonicalIdentifier(identifier)
// Validate that media type identifier doesn't clash
if _, ok := design.Design.MediaTypes[canonicalID]; ok {
dslengine.ReportError("media type %#v is defined twice", identifier)
return nil
}
parts := strings.Split(identifier, "+")
// Make sure it has the `+json` suffix (TBD update when goa supports other encodings)
if len(parts) > 1 {
parts = parts[1:]
found := false
for _, part := range parts {
if part == "json" {
found = true
break
}
}
if !found {
identifier += "+json"
}
}
identifier = mime.FormatMediaType(identifier, params)
// Concoct a Go type name from the identifier, should it be possible to set it in the apidsl?
// pros: control the type name generated, cons: not needed in apidsl, adds one more thing to worry about
lastPart := identifier
lastPartIndex := strings.LastIndex(identifier, "/")
if lastPartIndex > -1 {
lastPart = identifier[lastPartIndex+1:]
}
plusIndex := strings.Index(lastPart, "+")
if plusIndex > 0 {
lastPart = lastPart[:plusIndex]
}
lastPart = strings.TrimPrefix(lastPart, "vnd.")
elems := strings.Split(lastPart, ".")
for i, e := range elems {
elems[i] = strings.Title(e)
}
typeName := strings.Join(elems, "")
if typeName == "" {
mediaTypeCount++
typeName = fmt.Sprintf("MediaType%d", mediaTypeCount)
}
// Now save the type in the API media types map
mt := design.NewMediaTypeDefinition(typeName, identifier, apidsl)
design.Design.MediaTypes[canonicalID] = mt
return mt
}