From e039cc439402eb0dbe5f36e5b30e972e0110fb8d Mon Sep 17 00:00:00 2001
From: Sam Woodard <sam.h.woodard@gmail.com>
Date: Sun, 5 Jul 2015 12:12:09 -0700
Subject: [PATCH] handle single relation, and make included unique

---
 jsonapi.go      | 26 ++++++++++++++++++++++++--
 jsonapi_test.go | 12 +++++++++---
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/jsonapi.go b/jsonapi.go
index 243cf6c..ae76f08 100644
--- a/jsonapi.go
+++ b/jsonapi.go
@@ -20,7 +20,7 @@ type JsonApiNode struct {
 
 type JsonApiResponse struct {
 	Data     *JsonApiNode   `json:"data"`
-	Included []*JsonApiNode `json:"included"`
+	Included []*JsonApiNode `json:"included,omitempty"`
 }
 
 func CreateJsonApiResponse(model interface{}) (*JsonApiResponse, error) {
@@ -30,8 +30,19 @@ func CreateJsonApiResponse(model interface{}) (*JsonApiResponse, error) {
 	}
 
 	resp := &JsonApiResponse{Data: rootNode}
+
+	uniqueIncluded := make(map[string]*JsonApiNode)
+
+	for i, n := range included {
+		k := fmt.Sprintf("%s,%s", n.Type, n.Id)
+		if uniqueIncluded[k] == nil {
+			uniqueIncluded[k] = n
+		} else {
+			included = append(included[:i], included[i+1:]...)
+		}
+	}
+
 	resp.Included = included
-	// TODO make Included unique
 
 	return resp, nil
 }
@@ -96,6 +107,17 @@ func visitModelNode(model interface{}) (*JsonApiNode, []*JsonApiNode, error) {
 							err = err
 						}
 					} else {
+						relationship, _, err := visitModelNode(fieldValue.Interface())
+						if err == nil {
+							shallowNode := *relationship
+							shallowNode.Attributes = nil
+
+							included = append(included, relationship)
+
+							node.Relationships[args[1]] = &shallowNode
+						} else {
+							err = err
+						}
 					}
 
 				} else {
diff --git a/jsonapi_test.go b/jsonapi_test.go
index 8428e8c..2469ba6 100644
--- a/jsonapi_test.go
+++ b/jsonapi_test.go
@@ -14,9 +14,10 @@ type Post struct {
 }
 
 type Blog struct {
-	Id    int    `jsonapi:"primary,blogs"`
-	Title string `jsonapi:"attr,title"`
-	Posts []Post `jsonapi:"relation,posts"`
+	Id          int    `jsonapi:"primary,blogs"`
+	Title       string `jsonapi:"attr,title"`
+	Posts       []Post `jsonapi:"relation,posts"`
+	CurrentPost Post   `jsonapi:"relation,current_post"`
 }
 
 func TestHasPrimaryAnnotation(t *testing.T) {
@@ -35,6 +36,11 @@ func TestHasPrimaryAnnotation(t *testing.T) {
 				Body:  "Bas",
 			},
 		},
+		CurrentPost: Post{
+			Id:    1,
+			Title: "Foo",
+			Body:  "Bar",
+		},
 	}
 
 	resp, err := CreateJsonApiResponse(testModel)