🔀 Merge branch 'feature/json-body' into develop

errorf.go

@@ -1,6 +1,7 @@
 package errors
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
 )
@@ -14,15 +15,16 @@ import (
 //
 // If you want a different user message, use Msg, such as:
 //
-//	err := errors.Errorf(http.StatusNotFound, "%w", sqlError).Msg("user not found %d", userId)
+//	err := errors.Errorf(http.StatusNotFound, "%w", sqlError).SetMsg("user not found %d", userId)
 func Errorf(status int, format string, parts ...any) SettableError {
+	meta := make(map[string]any)
 	if len(parts) == 0 {
-		return &erf{status, format, ""}
+		return &erf{status, format, "", meta}
 	}
 
 	err := fmt.Errorf(format, parts...)
 	msg := err.Error()
-	er := &erf{status, msg, ""}
+	er := &erf{status, msg, "", meta}
 	if we, ok := err.(wrappedError); ok {
 		return &wrapErr{er, we.Unwrap()}
 	}
@@ -34,14 +36,16 @@ func Errorf(status int, format string, parts ...any) SettableError {
 
 var _ ResponsableError = new(erf)
 var _ SettableError = new(erf)
+var _ json.Marshaler = new(erf)
 
 type erf struct {
 	stat int
 	err  string
 	msg  string
+	meta map[string]any
 }
 
-func (e *erf) GetStatus() int {
+func (e *erf) Status() int {
 	if e.stat < http.StatusContinue || e.stat >= 600 {
 		e.stat = http.StatusInternalServerError
 	}
@@ -52,15 +56,15 @@ func (e *erf) Error() string {
 	return e.err
 }
 
-func (e *erf) GetMsg() string {
+func (e *erf) Msg() string {
 	if e.msg == "" {
 		return e.err
 	}
 	return e.msg
 }
 
-func (e *erf) Status(status int) SettableError {
+func (e *erf) SetStatus(status int) SettableError {
-	// GetStatus already handles invalid values, so we'll just ignore this.
+	// Status already handles invalid values, so we'll just ignore this.
 	if status < http.StatusContinue || status >= 600 {
 		return e
 	}
@@ -68,7 +72,7 @@ func (e *erf) Status(status int) SettableError {
 	return e
 }
 
-func (e *erf) Msg(msg string, parts ...any) SettableError {
+func (e *erf) SetMsg(msg string, parts ...any) SettableError {
 	e.msg = msg
 	if len(parts) > 0 {
 		e.msg = fmt.Sprintf(msg, parts...)
@@ -76,6 +80,21 @@ func (e *erf) Msg(msg string, parts ...any) SettableError {
 	return e
 }
 
+func (e *erf) SetField(field string, value any) SettableError {
+	e.meta[field] = value
+	return e
+}
+
+func (e *erf) JSON() any {
+	m := e.meta
+	m["error"] = e.Msg()
+	return m
+}
+
+func (e *erf) MarshalJSON() ([]byte, error) {
+	return json.Marshal(e.JSON())
+}
+
 var _ UnwrappableError = new(wrapErr)
 
 type wrapErr struct {

errorf_test.go

@@ -2,6 +2,7 @@ package errors
 
 import (
 	"errors"
+	"encoding/json"
 	"net/http"
 	"testing"
 
@@ -28,8 +29,8 @@ func (s *ErrorfTestSuite) TestNoWrap() {
 
 	exp := "42 is more than 13"
 	s.Assert().Equal(exp, err.Error())
-	s.Assert().Equal(exp, err.GetMsg())
+	s.Assert().Equal(exp, err.Msg())
-	s.Assert().Equal(http.StatusTeapot, err.GetStatus())
+	s.Assert().Equal(http.StatusTeapot, err.Status())
 }
 
 func (s *ErrorfTestSuite) TestWrapOne() {
@@ -45,7 +46,7 @@ func (s *ErrorfTestSuite) TestWrapOne() {
 
 	exp := "I'm a little teapot. Here is my handle."
 	s.Assert().Equal(exp, we.Error())
-	s.Assert().Equal(exp, we.GetMsg())
+	s.Assert().Equal(exp, we.Msg())
 	s.Assert().Same(wrapped, we.Unwrap())
 }
 
@@ -63,7 +64,7 @@ func (s *ErrorfTestSuite) TestWrapTwo() {
 
 	exp := "I'm a little teapot: short and stout. Here is my handle."
 	s.Assert().Equal(exp, we.Error())
-	s.Assert().Equal(exp, we.GetMsg())
+	s.Assert().Equal(exp, we.Msg())
 	unwrapped := we.Unwrap()
 	s.Assert().Len(unwrapped, 2)
 	s.Assert().Same(wrappedOne, unwrapped[0])
@@ -74,31 +75,52 @@ func (s *ErrorfTestSuite) TestSet() {
 	var err SettableError = Errorf(http.StatusTeapot, "Unable to BREW")
 	s.Assert().NotNil(err)
 
-	err.Status(http.StatusTooEarly).Msg("It's only %dAM", 2)
+	err.SetStatus(http.StatusTooEarly).SetMsg("It's only %dAM", 2)
-	s.Assert().Equal(http.StatusTooEarly, err.GetStatus())
+	s.Assert().Equal(http.StatusTooEarly, err.Status())
-	s.Assert().Equal("It's only 2AM", err.GetMsg())
+	s.Assert().Equal("It's only 2AM", err.Msg())
 	s.Assert().Equal("Unable to BREW", err.Error())
 
-	err.Msg("I am so great")
+	err.SetMsg("I am so great")
-	s.Assert().Equal("I am so great", err.GetMsg())
+	s.Assert().Equal("I am so great", err.Msg())
 }
 
 func (s *ErrorfTestSuite) TestGetStatusOutsideRange() {
 	var err ResponsableError = Errorf(5, "Hello")
 	s.Assert().NotNil(err)
-	s.Assert().Equal(http.StatusInternalServerError, err.GetStatus())
+	s.Assert().Equal(http.StatusInternalServerError, err.Status())
 
 	err = Errorf(5, "Hello")
 	s.Assert().NotNil(err)
-	s.Assert().Equal(http.StatusInternalServerError, err.GetStatus())
+	s.Assert().Equal(http.StatusInternalServerError, err.Status())
 }
 
 func (s *ErrorfTestSuite) TestSetStatusOutsideRange() {
 	var err SettableError = Errorf(http.StatusPaymentRequired, "Hello")
 	s.Assert().NotNil(err)
 
-	err.Status(10)
+	err.SetStatus(10)
-	s.Assert().Equal(http.StatusPaymentRequired, err.GetStatus())
+	s.Assert().Equal(http.StatusPaymentRequired, err.Status())
-	err.Status(600)
+	err.SetStatus(600)
-	s.Assert().Equal(http.StatusPaymentRequired, err.GetStatus())
+	s.Assert().Equal(http.StatusPaymentRequired, err.Status())
+}
+
+func (s *ErrorfTestSuite) TestJSON() {
+	var err SettableError = Errorf(http.StatusPaymentRequired, "Hello")
+	s.Assert().NotNil(err)
+
+	m := err.JSON()
+	ma, _ := m.(map[string]any)
+	s.Assert().Equal("Hello", ma["error"])
+	s.Assert().Nil(ma["number"])
+
+	j, _ := json.Marshal(err)
+	s.Assert().Equal(`{"error":"Hello"}`, string(j))
+
+	err.SetField("number",42)
+	m = err.JSON()
+	ma, _ = m.(map[string]any)
+	s.Assert().Equal(42, ma["number"])
+
+	j, _ = json.Marshal(err)
+	s.Assert().Equal(`{"error":"Hello","number":42}`, string(j))
 }

interface.go

@@ -1,27 +1,42 @@
 package errors
 
+import "encoding/json"
+
 // ResponsableError is an error that has information useful in an HTTP response.
 // The string returned by Error should be suitable for logging useful information
 // to assist debugging the error.
-// GetStatus should return an appropriate HTTP status.
+//
-// GetMsg should return a message suitable to display to the end user. If the message
+// Status should return an appropriate HTTP status. It must not return < 100 || >= 600.
+//
+// Msg should return a message suitable to display to the end user. If the message
 // returned by Error is safe for the end user, it may simply call that.
-// GetStatus should not return a value outside of the 100 - 599 range.
+//
+// JSON should return something that can be marshalled to JSON for the response body.
+// It can be something as simple as map[string]string{"error":err.Msg()}.
+// JSON's return value should be used by MarshalJSON()
 type ResponsableError interface {
+	json.Marshaler
 	Error() string
-	GetStatus() int
+	Status() int
-	GetMsg() string
+	Msg() string
+	JSON() any
 }
 
 // SettableError is a ResponsableError which can be modified after initial creation.
-// The Status method can set the status, while the Msg method can set user message.
+//
+// The SetStatus method can set the status, while the SetMsg method can set user message.
 // If any values are passed after the message, it should be passed to fmt.Sprintf for formatting.
+//
 // Methods are chainable.
+//
 // SetStatus should not use a value outside of 100-599. It may either ignore such values, or panic.
+//
+// SetField should add some metadata to the error, which will be included in the data returned by JSON()
 type SettableError interface {
 	ResponsableError
-	Status(int) SettableError
+	SetStatus(int) SettableError
-	Msg(string, ...any) SettableError
+	SetMsg(string, ...any) SettableError
+	SetField(string, any) SettableError
 }
 
 // UnwrappableError allows a ResponsableError to wrap another error.

new.go

@@ -24,5 +24,5 @@ func NewBadRequest(format string, parts ...any) SettableError {
 func NewInternalError(format string, parts ...any) SettableError {
 	status := http.StatusInternalServerError
 	msg := "Unknown Error"
-	return Errorf(status, format, parts...).Msg(msg)
+	return Errorf(status, format, parts...).SetMsg(msg)
 }

new_test.go

@@ -19,8 +19,8 @@ func (s *NewTestSuite) TestNotFound() {
 	msg := "I can't see you"
 	var err ResponsableError = NewNotFound(msg)
 	s.Assert().NotNil(err)
-	s.Assert().Equal(http.StatusNotFound, err.GetStatus())
+	s.Assert().Equal(http.StatusNotFound, err.Status())
-	s.Assert().Equal(msg, err.GetMsg())
+	s.Assert().Equal(msg, err.Msg())
 	s.Assert().Equal(msg, err.Error())
 }
 
@@ -28,7 +28,7 @@ func (s *NewTestSuite) TestNotFoundDefaultMsg() {
 	msg := "Not Found"
 	var err ResponsableError = NewNotFound("")
 	s.Assert().NotNil(err)
-	s.Assert().Equal(msg, err.GetMsg())
+	s.Assert().Equal(msg, err.Msg())
 	s.Assert().Equal(msg, err.Error())
 }
 
@@ -36,8 +36,8 @@ func (s *NewTestSuite) TestBadRequest() {
 	msg := "I can't see you"
 	var err ResponsableError = NewBadRequest(msg)
 	s.Assert().NotNil(err)
-	s.Assert().Equal(http.StatusBadRequest, err.GetStatus())
+	s.Assert().Equal(http.StatusBadRequest, err.Status())
-	s.Assert().Equal(msg, err.GetMsg())
+	s.Assert().Equal(msg, err.Msg())
 	s.Assert().Equal(msg, err.Error())
 }
 
@@ -45,7 +45,7 @@ func (s *NewTestSuite) TestBadRequestDefaultMsg() {
 	msg := "Bad Request"
 	var err ResponsableError = NewBadRequest("")
 	s.Assert().NotNil(err)
-	s.Assert().Equal(msg, err.GetMsg())
+	s.Assert().Equal(msg, err.Msg())
 	s.Assert().Equal(msg, err.Error())
 }
 
@@ -53,5 +53,5 @@ func (s *NewTestSuite) TestInternal() {
 	var err ResponsableError = NewInternalError("%d > %d", 42, 13)
 	s.Assert().NotNil(err)
 	s.Assert().Equal("42 > 13", err.Error())
-	s.Assert().Equal("Unknown Error", err.GetMsg())
+	s.Assert().Equal("Unknown Error", err.Msg())
 }