Merge pull request #38 from thedodd/handle-type-errors

Handle type errors during unmarshalNode routine.

README.md

@@ -359,6 +359,54 @@ func (post Post) JSONAPIRelationshipLinks(relation string) *map[string]interface
 }
 ```
 
+### Errors
+This package also implements support for JSON API compatible `errors` payloads using the following types.
+
+#### `MarshalErrors`
+```go
+MarshalErrors(w io.Writer, errs []*ErrorObject) error
+```
+
+Writes a JSON API response using the given `[]error`.
+
+#### `ErrorsPayload`
+```go
+type ErrorsPayload struct {
+	Errors []*ErrorObject `json:"errors"`
+}
+```
+
+ErrorsPayload is a serializer struct for representing a valid JSON API errors payload.
+
+#### `ErrorObject`
+```go
+type ErrorObject struct { ... }
+
+// Error implements the `Error` interface.
+func (e *ErrorObject) Error() string {
+	return fmt.Sprintf("Error: %s %s\n", e.Title, e.Detail)
+}
+```
+
+ErrorObject is an `Error` implementation as well as an implementation of the JSON API error object.
+
+The main idea behind this struct is that you can use it directly in your code as an error type and pass it directly to `MarshalErrors` to get a valid JSON API errors payload.
+
+##### Errors Example Code
+```go
+// An error has come up in your code, so set an appropriate status, and serialize the error.
+if err := validate(&myStructToValidate); err != nil {
+	context.SetStatusCode(http.StatusBadRequest) // Or however you need to set a status.
+	jsonapi.MarshalErrors(w, []*ErrorObject{{
+		Title: "Validation Error",
+		Detail: "Given request body was invalid.",
+		Status: "400",
+		Meta: map[string]interface{}{"field": "some_field", "error": "bad type", "expected": "string", "received": "float64"},
+	}})
+	return
+}
+```
+
 ## Testing
 
 ### `MarshalOnePayloadEmbedded`

errors.go

@@ -0,0 +1,55 @@
+package jsonapi
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+)
+
+// MarshalErrors writes a JSON API response using the given `[]error`.
+//
+// For more information on JSON API error payloads, see the spec here:
+// http://jsonapi.org/format/#document-top-level
+// and here: http://jsonapi.org/format/#error-objects.
+func MarshalErrors(w io.Writer, errorObjects []*ErrorObject) error {
+	if err := json.NewEncoder(w).Encode(&ErrorsPayload{Errors: errorObjects}); err != nil {
+		return err
+	}
+	return nil
+}
+
+// ErrorsPayload is a serializer struct for representing a valid JSON API errors payload.
+type ErrorsPayload struct {
+	Errors []*ErrorObject `json:"errors"`
+}
+
+// ErrorObject is an `Error` implementation as well as an implementation of the JSON API error object.
+//
+// The main idea behind this struct is that you can use it directly in your code as an error type
+// and pass it directly to `MarshalErrors` to get a valid JSON API errors payload.
+// For more information on Golang errors, see: https://golang.org/pkg/errors/
+// For more information on the JSON API spec's error objects, see: http://jsonapi.org/format/#error-objects
+type ErrorObject struct {
+	// ID is a unique identifier for this particular occurrence of a problem.
+	ID string `json:"id,omitempty"`
+
+	// Title is a short, human-readable summary of the problem that SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.
+	Title string `json:"title,omitempty"`
+
+	// Detail is a human-readable explanation specific to this occurrence of the problem. Like title, this field’s value can be localized.
+	Detail string `json:"detail,omitempty"`
+
+	// Status is the HTTP status code applicable to this problem, expressed as a string value.
+	Status string `json:"status,omitempty"`
+
+	// Code is an application-specific error code, expressed as a string value.
+	Code string `json:"code,omitempty"`
+
+	// Meta is an object containing non-standard meta-information about the error.
+	Meta *map[string]interface{} `json:"meta,omitempty"`
+}
+
+// Error implements the `Error` interface.
+func (e *ErrorObject) Error() string {
+	return fmt.Sprintf("Error: %s %s\n", e.Title, e.Detail)
+}

errors_test.go

@@ -0,0 +1,52 @@
+package jsonapi
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"reflect"
+	"testing"
+)
+
+func TestErrorObjectWritesExpectedErrorMessage(t *testing.T) {
+	err := &ErrorObject{Title: "Title test.", Detail: "Detail test."}
+	var input error = err
+
+	output := input.Error()
+
+	if output != fmt.Sprintf("Error: %s %s\n", err.Title, err.Detail) {
+		t.Fatal("Unexpected output.")
+	}
+}
+
+func TestMarshalErrorsWritesTheExpectedPayload(t *testing.T) {
+	var marshalErrorsTableTasts = []struct {
+		In  []*ErrorObject
+		Out map[string]interface{}
+	}{
+		{ // This tests that given fields are turned into the appropriate JSON representation.
+			In: []*ErrorObject{{ID: "0", Title: "Test title.", Detail: "Test detail", Status: "400", Code: "E1100"}},
+			Out: map[string]interface{}{"errors": []interface{}{
+				map[string]interface{}{"id": "0", "title": "Test title.", "detail": "Test detail", "status": "400", "code": "E1100"},
+			}},
+		},
+		{ // This tests that the `Meta` field is serialized properly.
+			In: []*ErrorObject{{Title: "Test title.", Detail: "Test detail", Meta: &map[string]interface{}{"key": "val"}}},
+			Out: map[string]interface{}{"errors": []interface{}{
+				map[string]interface{}{"title": "Test title.", "detail": "Test detail", "meta": map[string]interface{}{"key": "val"}},
+			}},
+		},
+	}
+	for _, testRow := range marshalErrorsTableTasts {
+		buffer, output := bytes.NewBuffer(nil), map[string]interface{}{}
+		var writer io.Writer = buffer
+
+		_ = MarshalErrors(writer, testRow.In)
+		json.Unmarshal(buffer.Bytes(), &output)
+
+		if !reflect.DeepEqual(output, testRow.Out) {
+			t.Fatalf("Expected: \n%#v \nto equal: \n%#v", output, testRow.Out)
+		}
+	}
+}

request.go

@@ -30,6 +30,8 @@ var (
 	// ErrUnsupportedPtrType is returned when the Struct field was a pointer but
 	// the JSON value was of a different type
 	ErrUnsupportedPtrType = errors.New("Pointer type in struct is not supported")
+	// ErrInvalidType is returned when the given type is incompatible with the expected type.
+	ErrInvalidType = errors.New("Invalid type provided") // I wish we used punctuation.
 )
 
 // UnmarshalPayload converts an io into a struct instance using jsonapi tags on
@@ -294,8 +296,7 @@ func unmarshalNode(data *Node, model reflect.Value, included *map[string]*Node)
 				} else if v.Kind() == reflect.Int {
 					at = v.Int()
 				} else {
-					er = ErrInvalidTime
-					break
+					return ErrInvalidTime
 				}
 
 				t := time.Unix(at, 0)
@@ -346,8 +347,7 @@ func unmarshalNode(data *Node, model reflect.Value, included *map[string]*Node)
 				} else if v.Kind() == reflect.Int {
 					at = v.Int()
 				} else {
-					er = ErrInvalidTime
-					break
+					return ErrInvalidTime
 				}
 
 				v := time.Unix(at, 0)
@@ -408,13 +408,10 @@ func unmarshalNode(data *Node, model reflect.Value, included *map[string]*Node)
 					n := float32(floatValue)
 					numericValue = reflect.ValueOf(&n)
 				case reflect.Float64:
-					n := float64(floatValue)
+					n := floatValue
 					numericValue = reflect.ValueOf(&n)
 				default:
-					// We had a JSON float (numeric), but our field was a non numeric
-					// type
-					er = ErrUnknownFieldNumberType
-					break
+					return ErrUnknownFieldNumberType
 				}
 
 				assign(fieldValue, numericValue)
@@ -437,21 +434,21 @@ func unmarshalNode(data *Node, model reflect.Value, included *map[string]*Node)
 				case uintptr:
 					concreteVal = reflect.ValueOf(&cVal)
 				default:
-					er = ErrUnsupportedPtrType
-					break
+					return ErrUnsupportedPtrType
 				}
 
 				if fieldValue.Type() != concreteVal.Type() {
-					// TODO: use fmt.Errorf so that you can have a more informative
-					// message that reports the attempted type that was not supported.
-					er = ErrUnsupportedPtrType
-					break
+					return ErrUnsupportedPtrType
 				}
 
 				fieldValue.Set(concreteVal)
 				continue
 			}
 
+			// As a final catch-all, ensure types line up to avoid a runtime panic.
+			if fieldValue.Kind() != v.Kind() {
+				return ErrInvalidType
+			}
 			fieldValue.Set(reflect.ValueOf(val))
 
 		} else if annotation == annotationRelation {
@@ -529,11 +526,7 @@ func unmarshalNode(data *Node, model reflect.Value, included *map[string]*Node)
 		}
 	}
 
-	if er != nil {
-		return er
-	}
-
-	return nil
+	return er
 }
 
 func fullNode(n *Node, included *map[string]*Node) *Node {

request_test.go

@@ -22,6 +22,14 @@ type WithPointer struct {
 	FloatVal *float32 `jsonapi:"attr,float-val"`
 }
 
+type ModelBadTypes struct {
+	ID           string     `jsonapi:"primary,badtypes"`
+	StringField  string     `jsonapi:"attr,string_field"`
+	FloatField   float64    `jsonapi:"attr,float_field"`
+	TimeField    time.Time  `jsonapi:"attr,time_field"`
+	TimePtrField *time.Time `jsonapi:"attr,time_ptr_field"`
+}
+
 func TestUnmarshalToStructWithPointerAttr(t *testing.T) {
 	out := new(WithPointer)
 	in := map[string]interface{}{
@@ -36,7 +44,7 @@ func TestUnmarshalToStructWithPointerAttr(t *testing.T) {
 	if *out.Name != "The name" {
 		t.Fatalf("Error unmarshalling to string ptr")
 	}
-	if *out.IsActive != true {
+	if !*out.IsActive {
 		t.Fatalf("Error unmarshalling to bool ptr")
 	}
 	if *out.IntVal != 8 {
@@ -98,6 +106,23 @@ func TestUnmarshalPayloadWithPointerAttr_AbsentVal(t *testing.T) {
 	}
 }
 
+func TestUnmarshalToStructWithPointerAttr_BadType(t *testing.T) {
+	out := new(WithPointer)
+	in := map[string]interface{}{
+		"name": true, // This is the wrong type.
+	}
+	expectedErrorMessage := ErrUnsupportedPtrType.Error()
+
+	err := UnmarshalPayload(sampleWithPointerPayload(in), out)
+
+	if err == nil {
+		t.Fatalf("Expected error due to invalid type.")
+	}
+	if err.Error() != expectedErrorMessage {
+		t.Fatalf("Unexpected error message: %s", err.Error())
+	}
+}
+
 func TestStringPointerField(t *testing.T) {
 	// Build Book payload
 	description := "Hello World!"
@@ -150,6 +175,35 @@ func TestUnmarshalInvalidJSON(t *testing.T) {
 	}
 }
 
+func TestUnmarshalInvalidJSON_BadType(t *testing.T) {
+	var badTypeTests = []struct {
+		Field    string
+		BadValue interface{}
+		Error    error
+	}{ // The `Field` values here correspond to the `ModelBadTypes` jsonapi fields.
+		{Field: "string_field", BadValue: 0, Error: ErrUnknownFieldNumberType},  // Expected string.
+		{Field: "float_field", BadValue: "A string.", Error: ErrInvalidType},    // Expected float64.
+		{Field: "time_field", BadValue: "A string.", Error: ErrInvalidTime},     // Expected int64.
+		{Field: "time_ptr_field", BadValue: "A string.", Error: ErrInvalidTime}, // Expected *time / int64.
+	}
+	for idx, test := range badTypeTests {
+		println("index:", idx)
+		out := new(ModelBadTypes)
+		in := map[string]interface{}{}
+		in[test.Field] = test.BadValue
+		expectedErrorMessage := test.Error.Error()
+
+		err := UnmarshalPayload(samplePayloadWithBadTypes(in), out)
+
+		if err == nil {
+			t.Fatalf("Expected error due to invalid type.")
+		}
+		if err.Error() != expectedErrorMessage {
+			t.Fatalf("Unexpected error message: %s", err.Error())
+		}
+	}
+}
+
 func TestUnmarshalSetsID(t *testing.T) {
 	in := samplePayloadWithID()
 	out := new(Blog)
@@ -759,6 +813,21 @@ func samplePayloadWithID() io.Reader {
 	return out
 }
 
+func samplePayloadWithBadTypes(m map[string]interface{}) io.Reader {
+	payload := &OnePayload{
+		Data: &Node{
+			ID:         "2",
+			Type:       "badtypes",
+			Attributes: m,
+		},
+	}
+
+	out := bytes.NewBuffer(nil)
+	json.NewEncoder(out).Encode(payload)
+
+	return out
+}
+
 func sampleWithPointerPayload(m map[string]interface{}) io.Reader {
 	payload := &OnePayload{
 		Data: &Node{