Churning through v3 models now.

mutations everywhere, for everyone!

datamodel/high/base/schema_proxy.go

@@ -67,6 +67,16 @@ func (sp *SchemaProxy) Schema() *Schema {
 	return sch
 }
 
+// IsReference returns true if the SchemaProxy is a reference to another Schema.
+func (sp *SchemaProxy) IsReference() bool {
+	return sp.schema.Value.IsSchemaReference()
+}
+
+// GetReference returns the location of the $ref if this SchemaProxy is a reference to another Schema.
+func (sp *SchemaProxy) GetReference() string {
+	return sp.schema.Value.GetSchemaReference()
+}
+
 // BuildSchema operates the same way as Schema, except it will return any error along with the *Schema
 func (sp *SchemaProxy) BuildSchema() (*Schema, error) {
 	schema := sp.Schema()
@@ -96,12 +106,23 @@ func (sp *SchemaProxy) MarshalYAML() (interface{}, error) {
 	if sp == nil {
 		return nil, nil
 	}
-	s, err := sp.BuildSchema()
-	if err != nil {
-		return nil, err
+	var s *Schema
+	var err error
+	// if this schema isn't a reference, then build it out.
+	if !sp.IsReference() {
+		s, err = sp.BuildSchema()
+		if err != nil {
+			return nil, err
+		}
+		nb := high.NewNodeBuilder(s, s.low)
+		return nb.Render(), nil
+	} else {
+		// do not build out a reference, just marshal the reference.
+		mp := high.CreateEmptyMapNode()
+		mp.Content = append(mp.Content,
+			high.CreateStringNode("$ref"),
+			high.CreateStringNode(sp.GetReference()))
+		return mp, nil
 	}
-	nb := high.NewNodeBuilder(s, s.low)
-	return nb.Render(), nil
-	
 }
 

datamodel/high/node_builder.go

@@ -211,6 +211,33 @@ func (n *NodeBuilder) AddYAMLNode(parent *yaml.Node, tag, key string, value any)
         valueNode = CreateBoolNode("true")
         break
 
+    case reflect.Int:
+        if value != nil {
+            val := strconv.Itoa(value.(int))
+            valueNode = CreateIntNode(val)
+        } else {
+            return parent
+        }
+        break
+
+    case reflect.Int64:
+        if value != nil {
+            val := strconv.FormatInt(value.(int64), 10)
+            valueNode = CreateIntNode(val)
+        } else {
+            return parent
+        }
+        break
+
+    case reflect.Float64:
+        if value != nil {
+            val := strconv.FormatFloat(value.(float64), 'f', 2, 64)
+            valueNode = CreateFloatNode(val)
+        } else {
+            return parent
+        }
+        break
+
     case reflect.Map:
 
         // the keys will be rendered randomly, if we don't find out the original line
@@ -239,12 +266,22 @@ func (n *NodeBuilder) AddYAMLNode(parent *yaml.Node, tag, key string, value any)
                     if pr, ok := gh.(low.HasValueUnTyped); ok {
                         fg := reflect.ValueOf(pr.GetValueUntyped())
                         for _, ky := range fg.MapKeys() {
-                            er := ky.Interface().(low.HasKeyNode).GetKeyNode().Value
-                            if er == x {
+                            if we, wok := ky.Interface().(low.HasKeyNode); wok {
+                                er := we.GetKeyNode().Value
+                                if er == x {
+                                    orderedCollection = append(orderedCollection, &NodeEntry{
+                                        Tag:   x,
+                                        Key:   x,
+                                        Line:  we.GetKeyNode().Line,
+                                        Value: m.MapIndex(k).Interface(),
+                                    })
+                                }
+                            } else {
+                                // this is a map, without any low level details available
                                 orderedCollection = append(orderedCollection, &NodeEntry{
                                     Tag:   x,
                                     Key:   x,
-                                    Line:  ky.Interface().(low.HasKeyNode).GetKeyNode().Line,
+                                    Line:  9999,
                                     Value: m.MapIndex(k).Interface(),
                                 })
                             }
@@ -296,7 +333,11 @@ func (n *NodeBuilder) AddYAMLNode(parent *yaml.Node, tag, key string, value any)
         for _, cv := range orderedCollection {
             n.AddYAMLNode(p, cv.Tag, cv.Key, cv.Value)
         }
-        valueNode = p
+        if len(p.Content) > 0 {
+            valueNode = p
+        } else {
+            return parent
+        }
 
     case reflect.Slice:
         if vo.IsNil() {
@@ -383,6 +424,24 @@ func CreateBoolNode(str string) *yaml.Node {
     return n
 }
 
+func CreateIntNode(str string) *yaml.Node {
+    n := &yaml.Node{
+        Kind:  yaml.ScalarNode,
+        Tag:   "!!int",
+        Value: str,
+    }
+    return n
+}
+
+func CreateFloatNode(str string) *yaml.Node {
+    n := &yaml.Node{
+        Kind:  yaml.ScalarNode,
+        Tag:   "!!float",
+        Value: str,
+    }
+    return n
+}
+
 type Renderable interface {
     MarshalYAML() (interface{}, error)
 }

datamodel/high/v3/document.go

@@ -22,26 +22,26 @@ type Document struct {
 
 	// Version is the version of OpenAPI being used, extracted from the 'openapi: x.x.x' definition.
 	// This is not a standard property of the OpenAPI model, it's a convenience mechanism only.
-	Version string
+	Version string `json:"openapi,omitempty" yaml:"openapi,omitempty"`
 
 	// Info represents a specification Info definitions
 	// Provides metadata about the API. The metadata MAY be used by tooling as required.
 	// - https://spec.openapis.org/oas/v3.1.0#info-object
-	Info *base.Info
+	Info *base.Info `json:"info,omitempty" yaml:"info,omitempty"`
 
 	// Servers is a slice of Server instances which provide connectivity information to a target server. If the servers
 	// property is not provided, or is an empty array, the default value would be a Server Object with a url value of /.
 	// - https://spec.openapis.org/oas/v3.1.0#server-object
-	Servers []*Server
+	Servers []*Server `json:"servers,omitempty" yaml:"servers,omitempty"`
 
 	// Paths contains all the PathItem definitions for the specification.
 	// The available paths and operations for the API, The most important part of ths spec.
 	// - https://spec.openapis.org/oas/v3.1.0#paths-object
-	Paths *Paths
+	Paths *Paths `json:"-" yaml:"-"`
 
 	// Components is an element to hold various schemas for the document.
 	// - https://spec.openapis.org/oas/v3.1.0#components-object
-	Components *Components
+	Components *Components `json:"-" yaml:"-"`
 
 	// Security contains global security requirements/roles for the specification
 	// A declaration of which security mechanisms can be used across the API. The list of values includes alternative
@@ -49,7 +49,7 @@ type Document struct {
 	// to authorize a request. Individual operations can override this definition. To make security optional,
 	// an empty security requirement ({}) can be included in the array.
 	// - https://spec.openapis.org/oas/v3.1.0#security-requirement-object
-	Security []*base.SecurityRequirement
+	Security []*base.SecurityRequirement `json:"security,omitempty" yaml:"security,omitempty"`
 
 	// Tags is a slice of base.Tag instances defined by the specification
 	// A list of tags used by the document with additional metadata. The order of the tags can be used to reflect on
@@ -57,20 +57,20 @@ type Document struct {
 	// The tags that are not declared MAY be organized randomly or based on the tools’ logic.
 	// Each tag name in the list MUST be unique.
 	// - https://spec.openapis.org/oas/v3.1.0#tag-object
-	Tags []*base.Tag
+	Tags []*base.Tag `json:"tags,omitempty" yaml:"tags,omitempty"`
 
 	// ExternalDocs is an instance of base.ExternalDoc for.. well, obvious really, innit.
 	// - https://spec.openapis.org/oas/v3.1.0#external-documentation-object
-	ExternalDocs *base.ExternalDoc
+	ExternalDocs *base.ExternalDoc `json:"externalDocs,omitempty" yaml:"externalDocs,omitempty"`
 
 	// Extensions contains all custom extensions defined for the top-level document.
-	Extensions map[string]any
+	Extensions map[string]any `json:"-" yaml:"-"`
 
 	// JsonSchemaDialect is a 3.1+ property that sets the dialect to use for validating *base.Schema definitions
 	// The default value for the $schema keyword within Schema Objects contained within this OAS document.
 	// This MUST be in the form of a URI.
 	// - https://spec.openapis.org/oas/v3.1.0#schema-object
-	JsonSchemaDialect string
+	JsonSchemaDialect string `json:"$schema,omitempty" yaml:"$schema,omitempty"`
 
 	// Webhooks is a 3.1+ property that is similar to callbacks, except, this defines incoming webhooks.
 	// The incoming webhooks that MAY be received as part of this API and that the API consumer MAY choose to implement.
@@ -78,15 +78,15 @@ type Document struct {
 	// for example by an out-of-band registration. The key name is a unique string to refer to each webhook,
 	// while the (optionally referenced) Path Item Object describes a request that may be initiated by the API provider
 	// and the expected responses. An example is available.
-	Webhooks map[string]*PathItem
+	Webhooks map[string]*PathItem `json:"-" yaml:"-"`
 
 	// Index is a reference to the *index.SpecIndex that was created for the document and used
 	// as a guide when building out the Document. Ideal if further processing is required on the model and
 	// the original details are required to continue the work.
 	//
 	// This property is not a part of the OpenAPI schema, this is custom to libopenapi.
-	Index *index.SpecIndex
-	low   *low.Document
+	Index *index.SpecIndex `json:"-" yaml:"-"`
+	low   *low.Document    `json:"-" yaml:"-"`
 }
 
 // NewDocument will create a new high-level Document from a low-level one.
@@ -154,18 +154,9 @@ func (d *Document) Render() ([]byte, error) {
 
 // MarshalYAML will create a ready to render YAML representation of the Document object.
 func (d *Document) MarshalYAML() (interface{}, error) {
-	n := high.CreateEmptyMapNode()
-	//high.AddYAMLNode(n, low.SchemaDialectLabel, d.JsonSchemaDialect)
-	//high.AddYAMLNode(n, low.OpenAPILabel, d.Version)
-	//high.AddYAMLNode(n, low.InfoLabel, d.Info)
-	//high.AddYAMLNode(n, low.TagsLabel, d.Tags)
-	//high.AddYAMLNode(n, low.ServersLabel, d.Servers)
-	//high.AddYAMLNode(n, low.SecurityLabel, d.Security)
-	//high.AddYAMLNode(n, low.ServersLabel, d.Servers)
-	//high.AddYAMLNode(n, low.ExternalDocsLabel, d.ExternalDocs)
-	//high.AddYAMLNode(n, low.PathsLabel, d.Paths)
-	//high.AddYAMLNode(n, low.ComponentsLabel, d.Components)
-	//high.AddYAMLNode(n, low.WebhooksLabel, d.Webhooks)
-	//high.MarshalExtensions(n, d.Extensions)
-	return n, nil
+	if d == nil {
+		return nil, nil
+	}
+	nb := high.NewNodeBuilder(d, d.low)
+	return nb.Render(), nil
 }

datamodel/high/v3/document_test.go

@@ -485,9 +485,10 @@ func TestDocument_MarshalYAML(t *testing.T) {
 	r, _ := h.Render()
 
 	info, _ := datamodel.ExtractSpecInfo(r)
-	lowDoc, _ = lowv3.CreateDocumentFromConfig(info, datamodel.NewOpenDocumentConfiguration())
-	highDoc := NewDocument(lowDoc)
+	lDoc, e := lowv3.CreateDocumentFromConfig(info, datamodel.NewOpenDocumentConfiguration())
+	assert.Nil(t, e)
 
+	highDoc := NewDocument(lDoc)
 	assert.Equal(t, "3.1.0", highDoc.Version)
 
 	// TODO: COMPLETE THIS

datamodel/high/v3/link.go

@@ -6,6 +6,7 @@ package v3
 import (
 	"github.com/pb33f/libopenapi/datamodel/high"
 	low "github.com/pb33f/libopenapi/datamodel/low/v3"
+	"gopkg.in/yaml.v3"
 )
 
 // Link represents a high-level OpenAPI 3+ Link object that is backed by a low-level one.
@@ -21,13 +22,13 @@ import (
 // in an operation and using them as parameters while invoking the linked operation.
 //  - https://spec.openapis.org/oas/v3.1.0#link-object
 type Link struct {
-	OperationRef string
-	OperationId  string
-	Parameters   map[string]string
-	RequestBody  string
-	Description  string
-	Server       *Server
-	Extensions   map[string]any
+	OperationRef string            `json:"operationRef,omitempty" yaml:"operationRef,omitempty"`
+	OperationId  string            `json:"operationId,omitempty" yaml:"operationId,omitempty"`
+	Parameters   map[string]string `json:"parameters,omitempty" yaml:"parameters,omitempty"`
+	RequestBody  string            `json:"requestBody,omitempty" yaml:"requestBody,omitempty"`
+	Description  string            `json:"description,omitempty" yaml:"description,omitempty"`
+	Server       *Server           `json:"server,omitempty" yaml:"server,omitempty"`
+	Extensions   map[string]any    `json:"-" yaml:"-"`
 	low          *low.Link
 }
 
@@ -55,3 +56,17 @@ func NewLink(link *low.Link) *Link {
 func (l *Link) GoLow() *low.Link {
 	return l.low
 }
+
+// Render will return a YAML representation of the Link object as a byte slice.
+func (l *Link) Render() ([]byte, error) {
+	return yaml.Marshal(l)
+}
+
+// MarshalYAML will create a ready to render YAML representation of the Link object.
+func (l *Link) MarshalYAML() (interface{}, error) {
+	if l == nil {
+		return nil, nil
+	}
+	nb := high.NewNodeBuilder(l, l.low)
+	return nb.Render(), nil
+}

datamodel/high/v3/link_test.go

@@ -0,0 +1,37 @@
+// Copyright 2023 Princess B33f Heavy Industries / Dave Shanley
+// SPDX-License-Identifier: MIT
+
+package v3
+
+import (
+    "github.com/stretchr/testify/assert"
+    "strings"
+    "testing"
+)
+
+func TestLink_MarshalYAML(t *testing.T) {
+    link := Link{
+        OperationRef: "somewhere",
+        OperationId:  "somewhereOutThere",
+        Parameters: map[string]string{
+            "over": "theRainbow",
+        },
+        RequestBody: "hello?",
+        Description: "are you there?",
+        Server: &Server{
+            URL: "https://pb33f.io",
+        },
+    }
+
+    dat, _ := link.Render()
+    desired := `operationRef: somewhere
+operationId: somewhereOutThere
+parameters:
+    over: theRainbow
+requestBody: hello?
+description: are you there?
+server:
+    url: https://pb33f.io`
+
+    assert.Equal(t, desired, strings.TrimSpace(string(dat)))
+}

datamodel/high/v3/media_type.go

@@ -8,6 +8,7 @@ import (
 	"github.com/pb33f/libopenapi/datamodel/high/base"
 	lowmodel "github.com/pb33f/libopenapi/datamodel/low"
 	low "github.com/pb33f/libopenapi/datamodel/low/v3"
+	"gopkg.in/yaml.v3"
 	"sync"
 )
 
@@ -16,11 +17,11 @@ import (
 // Each Media Type Object provides schema and examples for the media type identified by its key.
 //  - https://spec.openapis.org/oas/v3.1.0#media-type-object
 type MediaType struct {
-	Schema     *base.SchemaProxy
-	Example    any
-	Examples   map[string]*base.Example
-	Encoding   map[string]*Encoding
-	Extensions map[string]any
+	Schema     *base.SchemaProxy        `json:"schema,omitempty" yaml:"schema,omitempty"`
+	Example    any                      `json:"example,omitempty" yaml:"example,omitempty"`
+	Examples   map[string]*base.Example `json:"examples,omitempty" yaml:"examples,omitempty"`
+	Encoding   map[string]*Encoding     `json:"encoding,omitempty" yaml:"encoding,omitempty"`
+	Extensions map[string]any           `json:"-" yaml:"-"`
 	low        *low.MediaType
 }
 
@@ -43,6 +44,20 @@ func (m *MediaType) GoLow() *low.MediaType {
 	return m.low
 }
 
+// Render will return a YAML representation of the MediaType object as a byte slice.
+func (m *MediaType) Render() ([]byte, error) {
+	return yaml.Marshal(m)
+}
+
+// MarshalYAML will create a ready to render YAML representation of the MediaType object.
+func (m *MediaType) MarshalYAML() (interface{}, error) {
+	if m == nil {
+		return nil, nil
+	}
+	nb := high.NewNodeBuilder(m, m.low)
+	return nb.Render(), nil
+}
+
 // ExtractContent takes in a complex and hard to navigate low-level content map, and converts it in to a much simpler
 // and easier to navigate high-level one.
 func ExtractContent(elements map[lowmodel.KeyReference[string]]lowmodel.ValueReference[*low.MediaType]) map[string]*MediaType {

datamodel/high/v3/media_type_test.go

@@ -0,0 +1,49 @@
+// Copyright 2023 Princess B33f Heavy Industries / Dave Shanley
+// SPDX-License-Identifier: MIT
+
+package v3
+
+import (
+    "github.com/pb33f/libopenapi/datamodel"
+    "github.com/pb33f/libopenapi/datamodel/low/v3"
+    "github.com/stretchr/testify/assert"
+    "io/ioutil"
+    "strings"
+    "testing"
+)
+
+func TestMediaType_MarshalYAML(t *testing.T) {
+    // load the petstore spec
+    data, _ := ioutil.ReadFile("../../../test_specs/petstorev3.json")
+    info, _ := datamodel.ExtractSpecInfo(data)
+    var err []error
+    lowDoc, err = v3.CreateDocumentFromConfig(info, &datamodel.DocumentConfiguration{})
+    if err != nil {
+        panic("broken something")
+    }
+
+    // create a new document and extract a media type object from it.
+    d := NewDocument(lowDoc)
+    mt := d.Paths.PathItems["/pet"].Put.RequestBody.Content["application/json"]
+
+    // render out the media type
+    yml, _ := mt.Render()
+
+    // the rendered output should be a ref to the media type.
+    op := `schema:
+    $ref: '#/components/schemas/Pet'`
+
+    assert.Equal(t, op, strings.TrimSpace(string(yml)))
+
+    // modify the media type to have an example
+    mt.Example = "testing a nice mutation"
+
+    op = `example: testing a nice mutation
+schema:
+    $ref: '#/components/schemas/Pet'`
+
+    yml, _ = mt.Render()
+
+    assert.Equal(t, op, strings.TrimSpace(string(yml)))
+
+}

datamodel/high/v3/oauth_flow.go

@@ -6,16 +6,17 @@ package v3
 import (
 	"github.com/pb33f/libopenapi/datamodel/high"
 	low "github.com/pb33f/libopenapi/datamodel/low/v3"
+	"gopkg.in/yaml.v3"
 )
 
 // OAuthFlow represents a high-level OpenAPI 3+ OAuthFlow object that is backed by a low-level one.
 //  - https://spec.openapis.org/oas/v3.1.0#oauth-flow-object
 type OAuthFlow struct {
-	AuthorizationUrl string
-	TokenUrl         string
-	RefreshUrl       string
-	Scopes           map[string]string
-	Extensions       map[string]any
+	AuthorizationUrl string            `json:"authorizationUrl,omitempty" yaml:"authorizationUrl,omitempty"`
+	TokenUrl         string            `json:"tokenUrl,omitempty" yaml:"tokenUrl,omitempty"`
+	RefreshUrl       string            `json:"refreshUrl,omitempty" yaml:"refreshUrl,omitempty"`
+	Scopes           map[string]string `json:"scopes,omitempty" yaml:"scopes,omitempty"`
+	Extensions       map[string]any    `json:"-" yaml:"-"`
 	low              *low.OAuthFlow
 }
 
@@ -39,3 +40,17 @@ func NewOAuthFlow(flow *low.OAuthFlow) *OAuthFlow {
 func (o *OAuthFlow) GoLow() *low.OAuthFlow {
 	return o.low
 }
+
+// Render will return a YAML representation of the OAuthFlow object as a byte slice.
+func (o *OAuthFlow) Render() ([]byte, error) {
+	return yaml.Marshal(o)
+}
+
+// MarshalYAML will create a ready to render YAML representation of the OAuthFlow object.
+func (o *OAuthFlow) MarshalYAML() (interface{}, error) {
+	if o == nil {
+		return nil, nil
+	}
+	nb := high.NewNodeBuilder(o, o.low)
+	return nb.Render(), nil
+}

datamodel/high/v3/oauth_flow_test.go

@@ -0,0 +1,44 @@
+// Copyright 2023 Princess B33f Heavy Industries / Dave Shanley
+// SPDX-License-Identifier: MIT
+
+package v3
+
+import (
+    "github.com/stretchr/testify/assert"
+    "strings"
+    "testing"
+)
+
+func TestOAuthFlow_MarshalYAML(t *testing.T) {
+
+    oflow := &OAuthFlow{
+        AuthorizationUrl: "https://pb33f.io",
+        TokenUrl:         "https://pb33f.io/token",
+        RefreshUrl:       "https://pb33f.io/refresh",
+        Scopes:           map[string]string{"chicken": "nuggets", "beefy": "soup"},
+    }
+
+    rend, _ := oflow.Render()
+
+    desired := `authorizationUrl: https://pb33f.io
+tokenUrl: https://pb33f.io/token
+refreshUrl: https://pb33f.io/refresh
+scopes:
+    chicken: nuggets
+    beefy: soup`
+
+    assert.Equal(t, desired, strings.TrimSpace(string(rend)))
+
+    // mutate
+    oflow.Scopes = nil
+    oflow.Extensions = map[string]interface{}{"x-burgers": "why not?"}
+
+    desired = `authorizationUrl: https://pb33f.io
+tokenUrl: https://pb33f.io/token
+refreshUrl: https://pb33f.io/refresh
+x-burgers: why not?`
+
+    rend, _ = oflow.Render()
+    assert.Equal(t, desired, strings.TrimSpace(string(rend)))
+
+}

datamodel/high/v3/server.go

@@ -6,15 +6,16 @@ package v3
 import (
 	"github.com/pb33f/libopenapi/datamodel/high"
 	low "github.com/pb33f/libopenapi/datamodel/low/v3"
+	"gopkg.in/yaml.v3"
 )
 
 // Server represents a high-level OpenAPI 3+ Server object, that is backed by a low level one.
 //  - https://spec.openapis.org/oas/v3.1.0#server-object
 type Server struct {
-	URL         string
-	Description string
-	Variables   map[string]*ServerVariable
-	Extensions  map[string]any
+	URL         string                     `json:"url,omitempty" yaml:"url,omitempty"`
+	Description string                     `json:"description,omitempty" yaml:"description,omitempty"`
+	Variables   map[string]*ServerVariable `json:"variables,omitempty" yaml:"variables,omitempty"`
+	Extensions  map[string]any             `json:"-" yaml:"-"`
 	low         *low.Server
 }
 
@@ -37,3 +38,17 @@ func NewServer(server *low.Server) *Server {
 func (s *Server) GoLow() *low.Server {
 	return s.low
 }
+
+// Render will return a YAML representation of the Server object as a byte slice.
+func (s *Server) Render() ([]byte, error) {
+	return yaml.Marshal(s)
+}
+
+// MarshalYAML will create a ready to render YAML representation of the Server object.
+func (s *Server) MarshalYAML() (interface{}, error) {
+	if s == nil {
+		return nil, nil
+	}
+	nb := high.NewNodeBuilder(s, s.low)
+	return nb.Render(), nil
+}

datamodel/high/v3/server_test.go

@@ -0,0 +1,43 @@
+// Copyright 2023 Princess B33f Heavy Industries / Dave Shanley
+// SPDX-License-Identifier: MIT
+
+package v3
+
+import (
+    "github.com/stretchr/testify/assert"
+    "strings"
+    "testing"
+)
+
+func TestServer_MarshalYAML(t *testing.T) {
+
+    server := &Server{
+        URL:         "https://pb33f.io",
+        Description: "the b33f",
+    }
+
+    desired := `url: https://pb33f.io
+description: the b33f`
+
+    rend, _ := server.Render()
+    assert.Equal(t, desired, strings.TrimSpace(string(rend)))
+
+    // mutate
+    server.Variables = map[string]*ServerVariable{
+        "rainbow": {
+            Enum: []string{"one", "two", "three"},
+        },
+    }
+
+    desired = `url: https://pb33f.io
+description: the b33f
+variables:
+    rainbow:
+        enum:
+            - one
+            - two
+            - three`
+
+    rend, _ = server.Render()
+    assert.Equal(t, desired, strings.TrimSpace(string(rend)))
+}

datamodel/high/v3/server_variable.go

@@ -3,16 +3,20 @@
 
 package v3
 
-import low "github.com/pb33f/libopenapi/datamodel/low/v3"
+import (
+	"github.com/pb33f/libopenapi/datamodel/high"
+	low "github.com/pb33f/libopenapi/datamodel/low/v3"
+	"gopkg.in/yaml.v3"
+)
 
 // ServerVariable represents a high-level OpenAPI 3+ ServerVariable object, that is backed by a low-level one.
 //
 // ServerVariable is an object representing a Server Variable for server URL template substitution.
 // - https://spec.openapis.org/oas/v3.1.0#server-variable-object
 type ServerVariable struct {
-	Enum        []string
-	Default     string
-	Description string
+	Enum        []string `json:"enum,omitempty" yaml:"enum,omitempty"`
+	Default     string   `json:"default,omitempty" yaml:"default,omitempty"`
+	Description string   `json:"description,omitempty" yaml:"description,omitempty"`
 	low         *low.ServerVariable
 }
 
@@ -32,7 +36,21 @@ func NewServerVariable(variable *low.ServerVariable) *ServerVariable {
 	return v
 }
 
-// GoLow returns the low-level ServerVariable used to to create the high\-level one.
+// GoLow returns the low-level ServerVariable used to create the high\-level one.
 func (s *ServerVariable) GoLow() *low.ServerVariable {
 	return s.low
 }
+
+// Render will return a YAML representation of the ServerVariable object as a byte slice.
+func (s *ServerVariable) Render() ([]byte, error) {
+	return yaml.Marshal(s)
+}
+
+// MarshalYAML will create a ready to render YAML representation of the ServerVariable object.
+func (s *ServerVariable) MarshalYAML() (interface{}, error) {
+	if s == nil {
+		return nil, nil
+	}
+	nb := high.NewNodeBuilder(s, s.low)
+	return nb.Render(), nil
+}

datamodel/high/v3/server_variable_test.go

@@ -0,0 +1,43 @@
+// Copyright 2023 Princess B33f Heavy Industries / Dave Shanley
+// SPDX-License-Identifier: MIT
+
+package v3
+
+import (
+    "github.com/stretchr/testify/assert"
+    "strings"
+    "testing"
+)
+
+func TestServerVariable_MarshalYAML(t *testing.T) {
+
+    svar := &ServerVariable{
+        Enum:        []string{"one", "two", "three"},
+        Description: "money day",
+    }
+
+    desired := `enum:
+    - one
+    - two
+    - three
+description: money day`
+
+    svarRend, _ := svar.Render()
+
+    assert.Equal(t, desired, strings.TrimSpace(string(svarRend)))
+
+    // mutate
+
+    svar.Default = "is moments away"
+
+    desired = `enum:
+    - one
+    - two
+    - three
+default: is moments away
+description: money day`
+
+    svarRend, _ = svar.Render()
+
+    assert.Equal(t, desired, strings.TrimSpace(string(svarRend)))
+}

index/spec_index.go

@@ -424,8 +424,6 @@ func (index *SpecIndex) checkPolymorphicNode(name string) (bool, string) {
 	return false, ""
 }
 
-
-
 // GetPathCount will return the number of paths found in the spec
 func (index *SpecIndex) GetPathCount() int {
 	if index.root == nil {