Path type parameter error handler: add the parameter index in the input arguments

see previous commit

HISTORY.md

@@ -31,11 +31,15 @@ The codebase for Dependency Injection, Internationalization and localization and
 - **New feature:** add the ability to set custom error handlers on path type parameters errors (existing or custom ones). Example Code:
 
 ```go
-app.Macros().Get("uuid").HandleError(func(ctx iris.Context, err error) {
+app.Macros().Get("uuid").HandleError(func(ctx iris.Context, paramIndex int, err error) {
     ctx.StatusCode(iris.StatusBadRequest)
+
+    param := ctx.Params().GetEntryAt(paramIndex)
     ctx.JSON(iris.Map{
         "error":     err.Error(),
         "message":   "invalid path parameter",
+        "parameter": param.Key,
+        "value":     param.ValueRaw,
     })
 })
 

_examples/routing/dynamic-path/main.go

@@ -153,11 +153,15 @@ func main() {
 	// UUIDv4 (and v1) path parameter validation.
 
 	// Optionally, set custom handler on path parameter type error:
-	app.Macros().Get("uuid").HandleError(func(ctx iris.Context, err error) {
+	app.Macros().Get("uuid").HandleError(func(ctx iris.Context, paramIndex int, err error) {
 		ctx.StatusCode(iris.StatusBadRequest)
+
+		param := ctx.Params().GetEntryAt(paramIndex)
 		ctx.JSON(iris.Map{
 			"error":     err.Error(),
 			"message":   "invalid path parameter",
+			"parameter": param.Key,
+			"value":     param.ValueRaw,
 		})
 	})
 

macro/handler/handler.go

@@ -18,11 +18,11 @@ import (
 // Note that the builtin macros return error too, but they're handled
 // by the `else` literal (error code). To change this behavior
 // and send a custom error response you have to register it:
-//  app.Macros().Get("uuid").HandleError(func(iris.Context, err error)).
+//  app.Macros().Get("uuid").HandleError(func(ctx iris.Context, paramIndex int, err error)).
 // You can also set custom macros by `app.Macros().Register`.
 //
 // See macro.HandleError to set it.
-type ParamErrorHandler = func(*context.Context, error) // alias.
+type ParamErrorHandler = func(*context.Context, int, error) // alias.
 
 // CanMakeHandler reports whether a macro template needs a special macro's evaluator handler to be validated
 // before procceed to the next handler(s).
@@ -112,9 +112,8 @@ func MakeFilter(tmpl macro.Template) context.Filter {
 				if value != nil && p.HandleError != nil {
 					// The "value" is an error here, always (see template.Eval).
 					// This is always a type of ParamErrorHandler at this state (see CanMakeHandler).
-					p.HandleError.(ParamErrorHandler)(ctx, value.(error))
+					p.HandleError.(ParamErrorHandler)(ctx, p.Index, value.(error))
 				}
-
 				return false
 			}
 

macro/macro.go

@@ -315,7 +315,7 @@ func (m *Macro) Trailing() bool {
 
 // HandleError registers a handler which will be executed
 // when a parameter evaluator returns false and a non nil value which is a type of `error`.
-// The "fnHandler" value MUST BE a type of `func(iris.Context, err error)`,
+// The "fnHandler" value MUST BE a type of `func(iris.Context, paramIndex int, err error)`,
 // otherwise the program will receive a panic before server startup.
 // The status code of the ErrCode (`else` literal) is set
 // before the error handler but it can be modified inside the handler itself.

macro/template.go

@@ -34,7 +34,7 @@ type TemplateParam struct {
 	Name    string        `json:"name"`
 	Index   int           `json:"index"`
 	ErrCode int           `json:"errCode"`
-	// Note that, the value MUST BE a type of `func(iris.Context, err error)`.
+	// Note that, the value MUST BE a type of `handler.ParamErrorHandler`.
 	HandleError interface{} `json:"-"` /* It's not an typed value because of import-cycle,
 	// neither a special struct required, see `handler.MakeFilter`. */
 	TypeEvaluator ParamEvaluator  `json:"-"`