chore(binding): Optimize error format

Change-Id: Iafcf66fb5d2882cfe747b31e00d0fae68b2ce191

Author: andeya

binding/bind.go

@@ -1,7 +1,6 @@
 package binding
 
 import (
-	"errors"
 	"net/http"
 	"reflect"
 	_ "unsafe"
@@ -123,7 +122,7 @@ func (b *Binding) getObjOrPrepare(value reflect.Value) (*receiver, error) {
 			return false
 		}
 
-		p := recv.getOrAddParam(fh)
+		p := recv.getOrAddParam(fh, b.bindErrFactory)
 		in := auto
 		name := fh.FieldSelector().Name()
 
@@ -176,17 +175,14 @@ func (b *Binding) getObjOrPrepare(value reflect.Value) (*receiver, error) {
 		}
 		p.in = in
 		p.name = name
-		p.requiredError = errors.New("missing required parameter: " + name)
-		p.typeError = errors.New("parameter type does not match binding data: " + name)
-		p.cannotError = errors.New("parameter cannot be bound: " + name)
 		return true
 	})
 
 	if errMsg != "" {
 		return nil, b.bindErrFactory(errExprSelector.String(), errMsg)
 	}
 
-	recv.combNamePath()
+	recv.initParams()
 
 	b.recvs.Store(runtimeTypeID, recv)
 	return recv, nil

binding/param_info.go

@@ -20,7 +20,9 @@ type paramInfo struct {
 	name          string
 	required      bool
 
-	requiredError, typeError, cannotError error
+	bindErrFactory func(failField, msg string) error
+
+	requiredError, typeError, cannotError, contentTypeError error
 }
 
 func (p *paramInfo) getField(expr *tagexpr.TagExpr) (reflect.Value, error) {
@@ -106,7 +108,7 @@ func (p *paramInfo) bindBody(expr *tagexpr.TagExpr, bodyCodec uint8, postForm ur
 	case jsonBody:
 		return p.bindJSON(expr, bodyBytes)
 	}
-	return false, nil
+	return false, p.contentTypeError
 }
 
 func (p *paramInfo) bindJSON(expr *tagexpr.TagExpr, bodyBytes []byte) (bool, error) {
@@ -236,7 +238,3 @@ func (p *paramInfo) setStringSlice(v reflect.Value, a []string) error {
 
 	return p.typeError
 }
-
-// func (p *paramInfo) newError(errStr string) error {
-// 	return errors.New("field type does not match binding data: " + p.fieldSelector)
-// }

binding/receiver.go

@@ -39,7 +39,7 @@ func (r *receiver) getParam(fieldSelector string) *paramInfo {
 	return nil
 }
 
-func (r *receiver) getOrAddParam(fh *tagexpr.FieldHandler) *paramInfo {
+func (r *receiver) getOrAddParam(fh *tagexpr.FieldHandler, bindErrFactory func(failField, msg string) error) *paramInfo {
 	fieldSelector := fh.StringSelector()
 	p := r.getParam(fieldSelector)
 	if p != nil {
@@ -48,6 +48,7 @@ func (r *receiver) getOrAddParam(fh *tagexpr.FieldHandler) *paramInfo {
 	p = new(paramInfo)
 	p.fieldSelector = fieldSelector
 	p.structField = fh.StructField()
+	p.bindErrFactory = bindErrFactory
 	r.params = append(r.params, p)
 	return p
 }
@@ -103,15 +104,7 @@ func (r *receiver) getCookies(req *http.Request) []*http.Cookie {
 	return nil
 }
 
-// func (a *receiver) getPath(req *http.Request) *url.Values {
-// 	v := new(url.Values)
-// 	if a.hasQuery {
-// 		(*v) = req.URL.Query()
-// 	}
-// 	return v
-// }
-
-func (r *receiver) combNamePath() {
+func (r *receiver) initParams() {
 	if !r.hasBody {
 		return
 	}
@@ -136,5 +129,9 @@ func (r *receiver) combNamePath() {
 			}
 		}
 		p.namePath = namePath + p.name
+		p.requiredError = p.bindErrFactory(p.namePath, "missing required parameter")
+		p.typeError = p.bindErrFactory(p.namePath, "parameter type does not match binding data")
+		p.cannotError = p.bindErrFactory(p.namePath, "parameter cannot be bound")
+		p.contentTypeError = p.bindErrFactory(p.namePath, "does not support binding to the content type body")
 	}
 }