Binding middleware for tango
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// Copyright 2014 martini-contrib/binding Authors
// Copyright 2014 Unknwon
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.
// Package binding is a middleware that provides request data binding and validation for Macaron.
package binding
import (
"encoding/json"
"fmt"
"net/http"
"reflect"
"regexp"
"strconv"
"strings"
"gitea.com/lunny/tango"
)
// NOTE: last sync 1928ed2 on Aug 26, 2014.
const _VERSION = "0.0.4"
func Version() string {
return _VERSION
}
type Options struct {
}
// Validate is middleware to enforce required fields. If the struct
// passed in implements Validator, then the user-defined Validate method
// is executed, and its errors are mapped to the context. This middleware
// performs no error handling: it merely detects errors and maps them.
func Bind(options ...Options) tango.HandlerFunc {
return func(ctx *tango.Context) {
if action := ctx.Action(); action != nil {
if v, ok := action.(Bindinger); ok {
v.SetBinder(ctx.Req())
}
}
ctx.Next()
}
}
type Bindinger interface {
SetBinder(*http.Request)
}
type Binder struct {
req *http.Request
}
func (vd *Binder) SetBinder(req *http.Request) {
vd.req = req
}
func (vd Binder) Bind(obj interface{}) Errors {
contentType := vd.req.Header.Get("Content-Type")
if vd.req.Method == "POST" || vd.req.Method == "PUT" || len(contentType) > 0 {
switch {
case strings.Contains(contentType, "form-urlencoded"):
return vd.MapForm(obj)
case strings.Contains(contentType, "multipart/form-data"):
return vd.MultipartForm(obj)
case strings.Contains(contentType, "json"):
return vd.Json(obj)
default:
var errors Errors
if contentType == "" {
errors.Add([]string{}, ERR_CONTENT_TYPE, "Empty Content-Type")
} else {
errors.Add([]string{}, ERR_CONTENT_TYPE, "Unsupported Content-Type")
}
return errors
}
} else {
return vd.MapForm(obj)
}
}
const (
_JSON_CONTENT_TYPE = "application/json; charset=utf-8"
STATUS_UNPROCESSABLE_ENTITY = 422
)
// errorHandler simply counts the number of errors in the
// context and, if more than 0, writes a response with an
// error code and a JSON payload describing the errors.
// The response will have a JSON content-type.
// Middleware remaining on the stack will not even see the request
// if, by this point, there are any errors.
// This is a "default" handler, of sorts, and you are
// welcome to use your own instead. The Bind middleware
// invokes this automatically for convenience.
func errorHandler(errs Errors, rw http.ResponseWriter) {
if len(errs) > 0 {
rw.Header().Set("Content-Type", _JSON_CONTENT_TYPE)
if errs.Has(ERR_DESERIALIZATION) {
rw.WriteHeader(http.StatusBadRequest)
} else if errs.Has(ERR_CONTENT_TYPE) {
rw.WriteHeader(http.StatusUnsupportedMediaType)
} else {
rw.WriteHeader(STATUS_UNPROCESSABLE_ENTITY)
}
errOutput, _ := json.Marshal(errs)
rw.Write(errOutput)
return
}
}
var (
alphaDashPattern = regexp.MustCompile("[^\\d\\w-_]")
alphaDashDotPattern = regexp.MustCompile("[^\\d\\w-_\\.]")
emailPattern = regexp.MustCompile("[\\w!#$%&'*+/=?^_`{|}~-]+(?:\\.[\\w!#$%&'*+/=?^_`{|}~-]+)*@(?:[\\w](?:[\\w-]*[\\w])?\\.)+[a-zA-Z0-9](?:[\\w-]*[\\w])?")
urlPattern = regexp.MustCompile(`(http|https):\/\/[\w\-_]+(\.[\w\-_]+)+([\w\-\.,@?^=%&:/~\+#]*[\w\-\@?^=%&/~\+#])?`)
)
type (
// Rule represents a validation rule.
Rule struct {
// IsMatch checks if rule matches.
IsMatch func(string) bool
// IsValid applies validation rule to condition.
IsValid func(Errors, string, interface{}) bool
}
// RuleMapper represents a validation rule mapper,
// it allwos users to add custom validation rules.
RuleMapper []*Rule
)
var ruleMapper RuleMapper
// AddRule adds new validation rule.
func AddRule(r *Rule) {
ruleMapper = append(ruleMapper, r)
}
func in(fieldValue interface{}, arr string) bool {
val := fmt.Sprintf("%v", fieldValue)
vals := strings.Split(arr, ",")
isIn := false
for _, v := range vals {
if v == val {
isIn = true
break
}
}
return isIn
}
func parseFormName(raw, actual string) string {
if len(actual) > 0 {
return actual
}
return nameMapper(raw)
}
// NameMapper represents a form/json tag name mapper.
type NameMapper func(string) string
var (
nameMapper = func(field string) string {
newstr := make([]rune, 0, 10)
for i, chr := range field {
if isUpper := 'A' <= chr && chr <= 'Z'; isUpper {
if i > 0 {
newstr = append(newstr, '_')
}
chr -= ('A' - 'a')
}
newstr = append(newstr, chr)
}
return string(newstr)
}
)
// SetNameMapper sets name mapper.
func SetNameMapper(nm NameMapper) {
nameMapper = nm
}
// This sets the value in a struct of an indeterminate type to the
// matching value from the request (via Form middleware) in the
// same type, so that not all deserialized values have to be strings.
// Supported types are string, int, float, and bool.
func setWithProperType(valueKind reflect.Kind, val string, structField reflect.Value, nameInTag string, errors Errors) {
switch valueKind {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if val == "" {
val = "0"
}
intVal, err := strconv.ParseInt(val, 10, 64)
if err != nil {
errors.Add([]string{nameInTag}, ERR_INTERGER_TYPE, "Value could not be parsed as integer")
} else {
structField.SetInt(intVal)
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if val == "" {
val = "0"
}
uintVal, err := strconv.ParseUint(val, 10, 64)
if err != nil {
errors.Add([]string{nameInTag}, ERR_INTERGER_TYPE, "Value could not be parsed as unsigned integer")
} else {
structField.SetUint(uintVal)
}
case reflect.Bool:
if val == "on" {
structField.SetBool(true)
return
}
if val == "" {
val = "false"
}
boolVal, err := strconv.ParseBool(val)
if err != nil {
errors.Add([]string{nameInTag}, ERR_BOOLEAN_TYPE, "Value could not be parsed as boolean")
} else if boolVal {
structField.SetBool(true)
}
case reflect.Float32:
if val == "" {
val = "0.0"
}
floatVal, err := strconv.ParseFloat(val, 32)
if err != nil {
errors.Add([]string{nameInTag}, ERR_FLOAT_TYPE, "Value could not be parsed as 32-bit float")
} else {
structField.SetFloat(floatVal)
}
case reflect.Float64:
if val == "" {
val = "0.0"
}
floatVal, err := strconv.ParseFloat(val, 64)
if err != nil {
errors.Add([]string{nameInTag}, ERR_FLOAT_TYPE, "Value could not be parsed as 64-bit float")
} else {
structField.SetFloat(floatVal)
}
case reflect.String:
structField.SetString(val)
}
}
// Don't pass in pointers to bind to. Can lead to bugs.
func ensureNotPointer(obj interface{}) {
if reflect.TypeOf(obj).Kind() == reflect.Ptr {
panic("Pointers are not accepted as binding models")
}
}
// Don't pass in pointers to bind to. Can lead to bugs.
func ensurePointer(obj interface{}) {
if reflect.TypeOf(obj).Kind() != reflect.Ptr {
panic("Pointers are only accepted as binding models")
}
}