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forgejo/modules/middleware/binding/binding.go
2014-05-08 22:12:05 -04:00

473 lines
15 KiB
Go

// Copyright 2013 The Martini Contrib Authors. All rights reserved.
// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package binding
import (
"encoding/json"
"fmt"
"io"
"net/http"
"reflect"
"regexp"
"strconv"
"strings"
"unicode/utf8"
"github.com/go-martini/martini"
)
/*
To the land of Middle-ware Earth:
One func to rule them all,
One func to find them,
One func to bring them all,
And in this package BIND them.
*/
// Bind accepts a copy of an empty struct and populates it with
// values from the request (if deserialization is successful). It
// wraps up the functionality of the Form and Json middleware
// according to the Content-Type of the request, and it guesses
// if no Content-Type is specified. Bind invokes the ErrorHandler
// middleware to bail out if errors occurred. If you want to perform
// your own error handling, use Form or Json middleware directly.
// An interface pointer can be added as a second argument in order
// to map the struct to a specific interface.
func Bind(obj interface{}, ifacePtr ...interface{}) martini.Handler {
return func(context martini.Context, req *http.Request) {
contentType := req.Header.Get("Content-Type")
if strings.Contains(contentType, "form-urlencoded") {
context.Invoke(Form(obj, ifacePtr...))
} else if strings.Contains(contentType, "multipart/form-data") {
context.Invoke(MultipartForm(obj, ifacePtr...))
} else if strings.Contains(contentType, "json") {
context.Invoke(Json(obj, ifacePtr...))
} else {
context.Invoke(Json(obj, ifacePtr...))
if getErrors(context).Count() > 0 {
context.Invoke(Form(obj, ifacePtr...))
}
}
context.Invoke(ErrorHandler)
}
}
// BindIgnErr will do the exactly same thing as Bind but without any
// error handling, which user has freedom to deal with them.
// This allows user take advantages of validation.
func BindIgnErr(obj interface{}, ifacePtr ...interface{}) martini.Handler {
return func(context martini.Context, req *http.Request) {
contentType := req.Header.Get("Content-Type")
if strings.Contains(contentType, "form-urlencoded") {
context.Invoke(Form(obj, ifacePtr...))
} else if strings.Contains(contentType, "multipart/form-data") {
context.Invoke(MultipartForm(obj, ifacePtr...))
} else if strings.Contains(contentType, "json") {
context.Invoke(Json(obj, ifacePtr...))
} else {
context.Invoke(Json(obj, ifacePtr...))
if getErrors(context).Count() > 0 {
context.Invoke(Form(obj, ifacePtr...))
}
}
}
}
// Form is middleware to deserialize form-urlencoded data from the request.
// It gets data from the form-urlencoded body, if present, or from the
// query string. It uses the http.Request.ParseForm() method
// to perform deserialization, then reflection is used to map each field
// into the struct with the proper type. Structs with primitive slice types
// (bool, float, int, string) can support deserialization of repeated form
// keys, for example: key=val1&key=val2&key=val3
// An interface pointer can be added as a second argument in order
// to map the struct to a specific interface.
func Form(formStruct interface{}, ifacePtr ...interface{}) martini.Handler {
return func(context martini.Context, req *http.Request) {
ensureNotPointer(formStruct)
formStruct := reflect.New(reflect.TypeOf(formStruct))
errors := newErrors()
parseErr := req.ParseForm()
// Format validation of the request body or the URL would add considerable overhead,
// and ParseForm does not complain when URL encoding is off.
// Because an empty request body or url can also mean absence of all needed values,
// it is not in all cases a bad request, so let's return 422.
if parseErr != nil {
errors.Overall[BindingDeserializationError] = parseErr.Error()
}
mapForm(formStruct, req.Form, errors)
validateAndMap(formStruct, context, errors, ifacePtr...)
}
}
func MultipartForm(formStruct interface{}, ifacePtr ...interface{}) martini.Handler {
return func(context martini.Context, req *http.Request) {
ensureNotPointer(formStruct)
formStruct := reflect.New(reflect.TypeOf(formStruct))
errors := newErrors()
// Workaround for multipart forms returning nil instead of an error
// when content is not multipart
// https://code.google.com/p/go/issues/detail?id=6334
multipartReader, err := req.MultipartReader()
if err != nil {
errors.Overall[BindingDeserializationError] = err.Error()
} else {
form, parseErr := multipartReader.ReadForm(MaxMemory)
if parseErr != nil {
errors.Overall[BindingDeserializationError] = parseErr.Error()
}
req.MultipartForm = form
}
mapForm(formStruct, req.MultipartForm.Value, errors)
validateAndMap(formStruct, context, errors, ifacePtr...)
}
}
// Json is middleware to deserialize a JSON payload from the request
// into the struct that is passed in. The resulting struct is then
// validated, but no error handling is actually performed here.
// An interface pointer can be added as a second argument in order
// to map the struct to a specific interface.
func Json(jsonStruct interface{}, ifacePtr ...interface{}) martini.Handler {
return func(context martini.Context, req *http.Request) {
ensureNotPointer(jsonStruct)
jsonStruct := reflect.New(reflect.TypeOf(jsonStruct))
errors := newErrors()
if req.Body != nil {
defer req.Body.Close()
}
if err := json.NewDecoder(req.Body).Decode(jsonStruct.Interface()); err != nil && err != io.EOF {
errors.Overall[BindingDeserializationError] = err.Error()
}
validateAndMap(jsonStruct, context, errors, ifacePtr...)
}
}
// Validate is middleware to enforce required fields. If the struct
// passed in is a 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 them and maps them.
func Validate(obj interface{}) martini.Handler {
return func(context martini.Context, req *http.Request) {
errors := newErrors()
validateStruct(errors, obj)
if validator, ok := obj.(Validator); ok {
validator.Validate(errors, req, context)
}
context.Map(*errors)
}
}
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\-\@?^=%&/~\+#])?`)
)
func validateStruct(errors *Errors, obj interface{}) {
typ := reflect.TypeOf(obj)
val := reflect.ValueOf(obj)
if typ.Kind() == reflect.Ptr {
typ = typ.Elem()
val = val.Elem()
}
for i := 0; i < typ.NumField(); i++ {
field := typ.Field(i)
// Allow ignored fields in the struct
if field.Tag.Get("form") == "-" {
continue
}
fieldValue := val.Field(i).Interface()
if field.Type.Kind() == reflect.Struct {
validateStruct(errors, fieldValue)
continue
}
zero := reflect.Zero(field.Type).Interface()
// Match rules.
for _, rule := range strings.Split(field.Tag.Get("binding"), ";") {
if len(rule) == 0 {
continue
}
switch {
case rule == "Required":
if reflect.DeepEqual(zero, fieldValue) {
errors.Fields[field.Name] = BindingRequireError
break
}
case rule == "AlphaDash":
if alphaDashPattern.MatchString(fmt.Sprintf("%v", fieldValue)) {
errors.Fields[field.Name] = BindingAlphaDashError
break
}
case rule == "AlphaDashDot":
if alphaDashDotPattern.MatchString(fmt.Sprintf("%v", fieldValue)) {
errors.Fields[field.Name] = BindingAlphaDashDotError
break
}
case strings.HasPrefix(rule, "MinSize("):
min, err := strconv.Atoi(rule[8 : len(rule)-1])
if err != nil {
errors.Overall["MinSize"] = err.Error()
break
}
if str, ok := fieldValue.(string); ok && utf8.RuneCountInString(str) < min {
errors.Fields[field.Name] = BindingMinSizeError
break
}
v := reflect.ValueOf(fieldValue)
if v.Kind() == reflect.Slice && v.Len() < min {
errors.Fields[field.Name] = BindingMinSizeError
break
}
case strings.HasPrefix(rule, "MaxSize("):
max, err := strconv.Atoi(rule[8 : len(rule)-1])
if err != nil {
errors.Overall["MaxSize"] = err.Error()
break
}
if str, ok := fieldValue.(string); ok && utf8.RuneCountInString(str) > max {
errors.Fields[field.Name] = BindingMaxSizeError
break
}
v := reflect.ValueOf(fieldValue)
if v.Kind() == reflect.Slice && v.Len() > max {
errors.Fields[field.Name] = BindingMinSizeError
break
}
case rule == "Email":
if !emailPattern.MatchString(fmt.Sprintf("%v", fieldValue)) {
errors.Fields[field.Name] = BindingEmailError
break
}
case rule == "Url":
str := fmt.Sprintf("%v", fieldValue)
if len(str) == 0 {
continue
} else if !urlPattern.MatchString(str) {
errors.Fields[field.Name] = BindingUrlError
break
}
}
}
}
}
func mapForm(formStruct reflect.Value, form map[string][]string, errors *Errors) {
typ := formStruct.Elem().Type()
for i := 0; i < typ.NumField(); i++ {
typeField := typ.Field(i)
if inputFieldName := typeField.Tag.Get("form"); inputFieldName != "" {
structField := formStruct.Elem().Field(i)
if !structField.CanSet() {
continue
}
inputValue, exists := form[inputFieldName]
if !exists {
continue
}
numElems := len(inputValue)
if structField.Kind() == reflect.Slice && numElems > 0 {
sliceOf := structField.Type().Elem().Kind()
slice := reflect.MakeSlice(structField.Type(), numElems, numElems)
for i := 0; i < numElems; i++ {
setWithProperType(sliceOf, inputValue[i], slice.Index(i), inputFieldName, errors)
}
formStruct.Elem().Field(i).Set(slice)
} else {
setWithProperType(typeField.Type.Kind(), inputValue[0], structField, inputFieldName, errors)
}
}
}
}
// ErrorHandler simply counts the number of errors in the
// context and, if more than 0, writes a 400 Bad Request
// response and a JSON payload describing the errors with
// the "Content-Type" set to "application/json".
// 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, resp http.ResponseWriter) {
if errs.Count() > 0 {
resp.Header().Set("Content-Type", "application/json; charset=utf-8")
if _, ok := errs.Overall[BindingDeserializationError]; ok {
resp.WriteHeader(http.StatusBadRequest)
} else {
resp.WriteHeader(422)
}
errOutput, _ := json.Marshal(errs)
resp.Write(errOutput)
return
}
}
// 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.Fields[nameInTag] = BindingIntegerTypeError
} 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.Fields[nameInTag] = BindingIntegerTypeError
} else {
structField.SetUint(uintVal)
}
case reflect.Bool:
structField.SetBool(val == "on")
case reflect.Float32:
if val == "" {
val = "0.0"
}
floatVal, err := strconv.ParseFloat(val, 32)
if err != nil {
errors.Fields[nameInTag] = BindingFloatTypeError
} else {
structField.SetFloat(floatVal)
}
case reflect.Float64:
if val == "" {
val = "0.0"
}
floatVal, err := strconv.ParseFloat(val, 64)
if err != nil {
errors.Fields[nameInTag] = BindingFloatTypeError
} else {
structField.SetFloat(floatVal)
}
case reflect.String:
structField.SetString(val)
}
}
// Don't pass in pointers to bind to. Can lead to bugs. See:
// https://github.com/codegangsta/martini-contrib/issues/40
// https://github.com/codegangsta/martini-contrib/pull/34#issuecomment-29683659
func ensureNotPointer(obj interface{}) {
if reflect.TypeOf(obj).Kind() == reflect.Ptr {
panic("Pointers are not accepted as binding models")
}
}
// Performs validation and combines errors from validation
// with errors from deserialization, then maps both the
// resulting struct and the errors to the context.
func validateAndMap(obj reflect.Value, context martini.Context, errors *Errors, ifacePtr ...interface{}) {
context.Invoke(Validate(obj.Interface()))
errors.Combine(getErrors(context))
context.Map(*errors)
context.Map(obj.Elem().Interface())
if len(ifacePtr) > 0 {
context.MapTo(obj.Elem().Interface(), ifacePtr[0])
}
}
func newErrors() *Errors {
return &Errors{make(map[string]string), make(map[string]string)}
}
func getErrors(context martini.Context) Errors {
return context.Get(reflect.TypeOf(Errors{})).Interface().(Errors)
}
type (
// Implement the Validator interface to define your own input
// validation before the request even gets to your application.
// The Validate method will be executed during the validation phase.
Validator interface {
Validate(*Errors, *http.Request, martini.Context)
}
)
var (
// Maximum amount of memory to use when parsing a multipart form.
// Set this to whatever value you prefer; default is 10 MB.
MaxMemory = int64(1024 * 1024 * 10)
)
// Errors represents the contract of the response body when the
// binding step fails before getting to the application.
type Errors struct {
Overall map[string]string `json:"overall"`
Fields map[string]string `json:"fields"`
}
// Total errors is the sum of errors with the request overall
// and errors on individual fields.
func (err Errors) Count() int {
return len(err.Overall) + len(err.Fields)
}
func (this *Errors) Combine(other Errors) {
for key, val := range other.Fields {
if _, exists := this.Fields[key]; !exists {
this.Fields[key] = val
}
}
for key, val := range other.Overall {
if _, exists := this.Overall[key]; !exists {
this.Overall[key] = val
}
}
}
const (
BindingRequireError string = "Required"
BindingAlphaDashError string = "AlphaDash"
BindingAlphaDashDotError string = "AlphaDashDot"
BindingMinSizeError string = "MinSize"
BindingMaxSizeError string = "MaxSize"
BindingEmailError string = "Email"
BindingUrlError string = "Url"
BindingDeserializationError string = "DeserializationError"
BindingIntegerTypeError string = "IntegerTypeError"
BindingBooleanTypeError string = "BooleanTypeError"
BindingFloatTypeError string = "FloatTypeError"
)