initial commit

vendor/github.com/go-chi/render/render.go

@@ -0,0 +1,143 @@
+package render
+
+import (
+	"net/http"
+	"reflect"
+)
+
+// Renderer interface for managing response payloads.
+type Renderer interface {
+	Render(w http.ResponseWriter, r *http.Request) error
+}
+
+// Binder interface for managing request payloads.
+type Binder interface {
+	Bind(r *http.Request) error
+}
+
+// Bind decodes a request body and executes the Binder method of the
+// payload structure.
+func Bind(r *http.Request, v Binder) error {
+	if err := Decode(r, v); err != nil {
+		return err
+	}
+	return binder(r, v)
+}
+
+// Render renders a single payload and respond to the client request.
+func Render(w http.ResponseWriter, r *http.Request, v Renderer) error {
+	if err := renderer(w, r, v); err != nil {
+		return err
+	}
+	Respond(w, r, v)
+	return nil
+}
+
+// RenderList renders a slice of payloads and responds to the client request.
+func RenderList(w http.ResponseWriter, r *http.Request, l []Renderer) error {
+	for _, v := range l {
+		if err := renderer(w, r, v); err != nil {
+			return err
+		}
+	}
+	Respond(w, r, l)
+	return nil
+}
+
+func isNil(f reflect.Value) bool {
+	switch f.Kind() {
+	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
+		return f.IsNil()
+	default:
+		return false
+	}
+}
+
+// Executed top-down
+func renderer(w http.ResponseWriter, r *http.Request, v Renderer) error {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Ptr {
+		rv = rv.Elem()
+	}
+
+	// We call it top-down.
+	if err := v.Render(w, r); err != nil {
+		return err
+	}
+
+	// We're done if the Renderer isn't a struct object
+	if rv.Kind() != reflect.Struct {
+		return nil
+	}
+
+	// For structs, we call Render on each field that implements Renderer
+	for i := 0; i < rv.NumField(); i++ {
+		f := rv.Field(i)
+		if f.Type().Implements(rendererType) {
+
+			if isNil(f) {
+				continue
+			}
+
+			fv := f.Interface().(Renderer)
+			if err := renderer(w, r, fv); err != nil {
+				return err
+			}
+
+		}
+	}
+
+	return nil
+}
+
+// Executed bottom-up
+func binder(r *http.Request, v Binder) error {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Ptr {
+		rv = rv.Elem()
+	}
+
+	// Call Binder on non-struct types right away
+	if rv.Kind() != reflect.Struct {
+		return v.Bind(r)
+	}
+
+	// For structs, we call Bind on each field that implements Binder
+	for i := 0; i < rv.NumField(); i++ {
+		f := rv.Field(i)
+		if f.Type().Implements(binderType) {
+
+			if isNil(f) {
+				continue
+			}
+
+			fv := f.Interface().(Binder)
+			if err := binder(r, fv); err != nil {
+				return err
+			}
+		}
+	}
+
+	// We call it bottom-up
+	if err := v.Bind(r); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+var (
+	rendererType = reflect.TypeOf(new(Renderer)).Elem()
+	binderType   = reflect.TypeOf(new(Binder)).Elem()
+)
+
+// contextKey is a value for use with context.WithValue. It's used as
+// a pointer so it fits in an interface{} without allocation. This technique
+// for defining context keys was copied from Go 1.7's new use of context in net/http.
+type contextKey struct {
+	name string
+}
+
+func (k *contextKey) String() string {
+	return "chi render context value " + k.name
+}