Updated readme with new docs link

Added in some new helper methods for building out new models. More details in the docs. Added another example.

README.md

@@ -47,6 +47,7 @@ See all the documentation at https://pb33f.io/libopenapi/
 - [Using OpenAPI](https://pb33f.io/libopenapi/openapi/)
 - [Using Swagger](https://pb33f.io/libopenapi/swagger/)
 - [The Data Model](https://pb33f.io/libopenapi/model/)
+- [Modifying / Mutating the OpenAPI Model](https://pb33f.io/libopenapi/modifying/)
 - [Using Vendor Extensions](https://pb33f.io/libopenapi/extensions/)
 - [The Index](https://pb33f.io/libopenapi/index/)
 - [The Resolver](https://pb33f.io/libopenapi/resolver/)

datamodel/high/base/schema_proxy.go

@@ -48,6 +48,7 @@ type SchemaProxy struct {
 	schema     *low.NodeReference[*base.SchemaProxy]
 	buildError error
 	rendered   *Schema
+	refStr     string
 }
 
 // NewSchemaProxy creates a new high-level SchemaProxy from a low-level one.
@@ -55,6 +56,18 @@ func NewSchemaProxy(schema *low.NodeReference[*base.SchemaProxy]) *SchemaProxy {
 	return &SchemaProxy{schema: schema}
 }
 
+// CreateSchemaProxy will create a new high-level SchemaProxy from a high-level Schema, this acts the same
+// as if the SchemaProxy is pre-rendered.
+func CreateSchemaProxy(schema *Schema) *SchemaProxy {
+	return &SchemaProxy{rendered: schema}
+}
+
+// CreateSchemaProxyRef will create a new high-level SchemaProxy from a reference string, this is used only when
+// building out new models from scratch that require a reference rather than a schema implementation.
+func CreateSchemaProxyRef(ref string) *SchemaProxy {
+	return &SchemaProxy{refStr: ref}
+}
+
 // Schema will create a new Schema instance using NewSchema from the low-level SchemaProxy backing this high-level one.
 // If there is a problem building the Schema, then this method will return nil. Use GetBuildError to gain access
 // to that building error.
@@ -76,11 +89,20 @@ func (sp *SchemaProxy) Schema() *Schema {
 
 // IsReference returns true if the SchemaProxy is a reference to another Schema.
 func (sp *SchemaProxy) IsReference() bool {
+	if sp.refStr != "" {
+		return true
+	}
+	if sp.schema != nil {
 		return sp.schema.Value.IsSchemaReference()
+	}
+	return false
 }
 
 // GetReference returns the location of the $ref if this SchemaProxy is a reference to another Schema.
 func (sp *SchemaProxy) GetReference() string {
+	if sp.refStr != "" {
+		return sp.refStr
+	}
 	return sp.schema.Value.GetSchemaReference()
 }
 

datamodel/high/base/schema_proxy_test.go

@@ -31,7 +31,7 @@ func TestSchemaProxy_MarshalYAML(t *testing.T) {
         var idxNode yaml.Node
         err := yaml.Unmarshal([]byte(ymlComponents), &idxNode)
         assert.NoError(t, err)
-        return index.NewSpecIndex(&idxNode)
+        return index.NewSpecIndexWithConfig(&idxNode, index.CreateOpenAPIIndexConfig())
     }()
 
     const ref = "#/components/schemas/nice"
@@ -53,3 +53,14 @@ func TestSchemaProxy_MarshalYAML(t *testing.T) {
     assert.Equal(t, "$ref: '#/components/schemas/nice'", strings.TrimSpace(string(rend)))
 
 }
+
+func TestCreateSchemaProxy(t *testing.T) {
+    sp := CreateSchemaProxy(&Schema{Description: "iAmASchema"})
+    assert.Equal(t, "iAmASchema", sp.rendered.Description)
+}
+
+func TestCreateSchemaProxyRef(t *testing.T) {
+    sp := CreateSchemaProxyRef("#/components/schemas/MySchema")
+    assert.Equal(t, "#/components/schemas/MySchema", sp.GetReference())
+}
+

datamodel/high/node_builder.go

@@ -474,7 +474,7 @@ func (n *NodeBuilder) AddYAMLNode(parent *yaml.Node, entry *NodeEntry) *yaml.Nod
     case reflect.Ptr:
         if r, ok := value.(Renderable); ok {
             if gl, lg := value.(GoesLowUntyped); lg {
-
+                if gl.GoLowUntyped() != nil {
                     ut := reflect.ValueOf(gl.GoLowUntyped())
                     if !ut.IsNil() {
                         if gl.GoLowUntyped().(low.IsReferenced).IsReference() {
@@ -486,6 +486,7 @@ func (n *NodeBuilder) AddYAMLNode(parent *yaml.Node, entry *NodeEntry) *yaml.Nod
                         }
                     }
                 }
+            }
             rawRender, _ := r.MarshalYAML()
             if rawRender != nil {
                 valueNode = rawRender.(*yaml.Node)
@@ -600,6 +601,7 @@ func (n *NodeBuilder) extractLowMapKeys(fg reflect.Value, x string, found bool,
     return found, orderedCollection
 }
 
+// Renderable is an interface that can be implemented by types that provide a custom MarshaYAML method.
 type Renderable interface {
     MarshalYAML() (interface{}, error)
 }

document_examples_test.go

@@ -8,10 +8,12 @@ import (
     "github.com/pb33f/libopenapi/datamodel"
     "io/ioutil"
     "net/url"
+    "os"
     "strings"
     "testing"
 
     "github.com/pb33f/libopenapi/datamodel/high"
+    v3high "github.com/pb33f/libopenapi/datamodel/high/v3"
     low "github.com/pb33f/libopenapi/datamodel/low/base"
     v3 "github.com/pb33f/libopenapi/datamodel/low/v3"
     "github.com/pb33f/libopenapi/resolver"
@@ -599,3 +601,69 @@ components:
     // Output: schemaOne 'x-custom-cakes' (some cakes) has 2 cakes, 'someCake' has 10 candles and blue frosting
     //parameterOne 'x-custom-burgers' (some burgers) has 2 burgers, 'anotherBurger' has mayo sauce and a lamb patty
 }
+
+func ExampleNewDocument_modifyAndReRender() {
+
+    // How to read in an OpenAPI 3 Specification, into a Document,
+    // modify the document and then re-render it back to YAML bytes.
+
+    // load an OpenAPI 3 specification from bytes
+    petstore, _ := os.ReadFile("test_specs/petstorev3.json")
+
+    // create a new document from specification bytes
+    doc, err := NewDocument(petstore)
+
+    // if anything went wrong, an error is thrown
+    if err != nil {
+        panic(fmt.Sprintf("cannot create new document: %e", err))
+    }
+
+    // because we know this is a v3 spec, we can build a ready to go model from it.
+    v3Model, errors := doc.BuildV3Model()
+
+    // if anything went wrong when building the v3 model, a slice of errors will be returned
+    if len(errors) > 0 {
+        for i := range errors {
+            fmt.Printf("error: %e\n", errors[i])
+        }
+        panic(fmt.Sprintf("cannot create v3 model from document: %d errors reported", len(errors)))
+    }
+
+    // create a new path item and operation.
+    newPath := &v3high.PathItem{
+        Description: "this is a new path item",
+        Get: &v3high.Operation{
+            Description: "this is a get operation",
+            OperationId: "getNewThing",
+            RequestBody: &v3high.RequestBody{
+                Description: "this is a new request body",
+            },
+        },
+    }
+
+    // capture original number of paths
+    originalPaths := len(v3Model.Model.Paths.PathItems)
+
+    // add the path to the document
+    v3Model.Model.Paths.PathItems["/new/path"] = newPath
+
+    // render out the new path item to YAML
+    // renderedPathItem, _ := yaml.Marshal(newPath)
+
+    // render the document back to bytes and reload the model.
+    rawBytes, _, newModel, errs := doc.RenderAndReload()
+
+    // if anything went wrong when re-rendering the v3 model, a slice of errors will be returned
+    if len(errors) > 0 {
+        panic(fmt.Sprintf("cannot re-render document: %d errors reported", len(errs)))
+    }
+
+    // capture new number of paths after re-rendering
+    newPaths := len(newModel.Model.Paths.PathItems)
+
+    // print the number of paths and schemas in the document
+    fmt.Printf("There were %d original paths. There are now %d paths in the document\n", originalPaths, newPaths)
+    fmt.Printf("The original spec had %d bytes, the new one has %d\n", len(petstore), len(rawBytes))
+    // Output: There were 13 original paths. There are now 14 paths in the document
+    //The original spec had 31143 bytes, the new one has 27857
+}