package echo import ( "encoding" "encoding/json" "encoding/xml" "errors" "fmt" "net/http" "reflect" "strconv" "strings" ) type ( // Binder is the interface that wraps the Bind method. Binder interface { Bind(i interface{}, c Context) error } // DefaultBinder is the default implementation of the Binder interface. DefaultBinder struct{} // BindUnmarshaler is the interface used to wrap the UnmarshalParam method. // Types that don't implement this, but do implement encoding.TextUnmarshaler // will use that interface instead. BindUnmarshaler interface { // UnmarshalParam decodes and assigns a value from an form or query param. UnmarshalParam(param string) error } ) // BindPathParams binds path params to bindable object func (b *DefaultBinder) BindPathParams(c Context, i interface{}) error { names := c.ParamNames() values := c.ParamValues() params := map[string][]string{} for i, name := range names { params[name] = []string{values[i]} } if err := b.bindData(i, params, "param"); err != nil { return NewHTTPError(http.StatusBadRequest, err.Error()).SetInternal(err) } return nil } // BindQueryParams binds query params to bindable object func (b *DefaultBinder) BindQueryParams(c Context, i interface{}) error { if err := b.bindData(i, c.QueryParams(), "query"); err != nil { return NewHTTPError(http.StatusBadRequest, err.Error()).SetInternal(err) } return nil } // BindBody binds request body contents to bindable object // NB: then binding forms take note that this implementation uses standard library form parsing // which parses form data from BOTH URL and BODY if content type is not MIMEMultipartForm // See non-MIMEMultipartForm: https://golang.org/pkg/net/http/#Request.ParseForm // See MIMEMultipartForm: https://golang.org/pkg/net/http/#Request.ParseMultipartForm func (b *DefaultBinder) BindBody(c Context, i interface{}) (err error) { req := c.Request() if req.ContentLength == 0 { return } ctype := req.Header.Get(HeaderContentType) switch { case strings.HasPrefix(ctype, MIMEApplicationJSON): if err = json.NewDecoder(req.Body).Decode(i); err != nil { if ute, ok := err.(*json.UnmarshalTypeError); ok { return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Unmarshal type error: expected=%v, got=%v, field=%v, offset=%v", ute.Type, ute.Value, ute.Field, ute.Offset)).SetInternal(err) } else if se, ok := err.(*json.SyntaxError); ok { return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Syntax error: offset=%v, error=%v", se.Offset, se.Error())).SetInternal(err) } return NewHTTPError(http.StatusBadRequest, err.Error()).SetInternal(err) } case strings.HasPrefix(ctype, MIMEApplicationXML), strings.HasPrefix(ctype, MIMETextXML): if err = xml.NewDecoder(req.Body).Decode(i); err != nil { if ute, ok := err.(*xml.UnsupportedTypeError); ok { return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Unsupported type error: type=%v, error=%v", ute.Type, ute.Error())).SetInternal(err) } else if se, ok := err.(*xml.SyntaxError); ok { return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Syntax error: line=%v, error=%v", se.Line, se.Error())).SetInternal(err) } return NewHTTPError(http.StatusBadRequest, err.Error()).SetInternal(err) } case strings.HasPrefix(ctype, MIMEApplicationForm), strings.HasPrefix(ctype, MIMEMultipartForm): params, err := c.FormParams() if err != nil { return NewHTTPError(http.StatusBadRequest, err.Error()).SetInternal(err) } if err = b.bindData(i, params, "form"); err != nil { return NewHTTPError(http.StatusBadRequest, err.Error()).SetInternal(err) } default: return ErrUnsupportedMediaType } return nil } // Bind implements the `Binder#Bind` function. // Binding is done in following order: 1) path params; 2) query params; 3) request body. Each step COULD override previous // step binded values. For single source binding use their own methods BindBody, BindQueryParams, BindPathParams. func (b *DefaultBinder) Bind(i interface{}, c Context) (err error) { if err := b.BindPathParams(c, i); err != nil { return err } // Issue #1670 - Query params are binded only for GET/DELETE and NOT for usual request with body (POST/PUT/PATCH) // Reasoning here is that parameters in query and bind destination struct could have UNEXPECTED matches and results due that. // i.e. is `&id=1&lang=en` from URL same as `{"id":100,"lang":"de"}` request body and which one should have priority when binding. // This HTTP method check restores pre v4.1.11 behavior and avoids different problems when query is mixed with body if c.Request().Method == http.MethodGet || c.Request().Method == http.MethodDelete { if err = b.BindQueryParams(c, i); err != nil { return err } } return b.BindBody(c, i) } // bindData will bind data ONLY fields in destination struct that have EXPLICIT tag func (b *DefaultBinder) bindData(destination interface{}, data map[string][]string, tag string) error { if destination == nil || len(data) == 0 { return nil } typ := reflect.TypeOf(destination).Elem() val := reflect.ValueOf(destination).Elem() // Map if typ.Kind() == reflect.Map { for k, v := range data { val.SetMapIndex(reflect.ValueOf(k), reflect.ValueOf(v[0])) } return nil } // !struct if typ.Kind() != reflect.Struct { return errors.New("binding element must be a struct") } for i := 0; i < typ.NumField(); i++ { typeField := typ.Field(i) structField := val.Field(i) if !structField.CanSet() { continue } structFieldKind := structField.Kind() inputFieldName := typeField.Tag.Get(tag) if inputFieldName == "" { // If tag is nil, we inspect if the field is a not BindUnmarshaler struct and try to bind data into it (might contains fields with tags). // structs that implement BindUnmarshaler are binded only when they have explicit tag if _, ok := structField.Addr().Interface().(BindUnmarshaler); !ok && structFieldKind == reflect.Struct { if err := b.bindData(structField.Addr().Interface(), data, tag); err != nil { return err } } // does not have explicit tag and is not an ordinary struct - so move to next field continue } inputValue, exists := data[inputFieldName] if !exists { // Go json.Unmarshal supports case insensitive binding. However the // url params are bound case sensitive which is inconsistent. To // fix this we must check all of the map values in a // case-insensitive search. for k, v := range data { if strings.EqualFold(k, inputFieldName) { inputValue = v exists = true break } } } if !exists { continue } // Call this first, in case we're dealing with an alias to an array type if ok, err := unmarshalField(typeField.Type.Kind(), inputValue[0], structField); ok { if err != nil { return err } continue } numElems := len(inputValue) if structFieldKind == reflect.Slice && numElems > 0 { sliceOf := structField.Type().Elem().Kind() slice := reflect.MakeSlice(structField.Type(), numElems, numElems) for j := 0; j < numElems; j++ { if err := setWithProperType(sliceOf, inputValue[j], slice.Index(j)); err != nil { return err } } val.Field(i).Set(slice) } else if err := setWithProperType(typeField.Type.Kind(), inputValue[0], structField); err != nil { return err } } return nil } func setWithProperType(valueKind reflect.Kind, val string, structField reflect.Value) error { // But also call it here, in case we're dealing with an array of BindUnmarshalers if ok, err := unmarshalField(valueKind, val, structField); ok { return err } switch valueKind { case reflect.Ptr: return setWithProperType(structField.Elem().Kind(), val, structField.Elem()) case reflect.Int: return setIntField(val, 0, structField) case reflect.Int8: return setIntField(val, 8, structField) case reflect.Int16: return setIntField(val, 16, structField) case reflect.Int32: return setIntField(val, 32, structField) case reflect.Int64: return setIntField(val, 64, structField) case reflect.Uint: return setUintField(val, 0, structField) case reflect.Uint8: return setUintField(val, 8, structField) case reflect.Uint16: return setUintField(val, 16, structField) case reflect.Uint32: return setUintField(val, 32, structField) case reflect.Uint64: return setUintField(val, 64, structField) case reflect.Bool: return setBoolField(val, structField) case reflect.Float32: return setFloatField(val, 32, structField) case reflect.Float64: return setFloatField(val, 64, structField) case reflect.String: structField.SetString(val) default: return errors.New("unknown type") } return nil } func unmarshalField(valueKind reflect.Kind, val string, field reflect.Value) (bool, error) { switch valueKind { case reflect.Ptr: return unmarshalFieldPtr(val, field) default: return unmarshalFieldNonPtr(val, field) } } func unmarshalFieldNonPtr(value string, field reflect.Value) (bool, error) { fieldIValue := field.Addr().Interface() if unmarshaler, ok := fieldIValue.(BindUnmarshaler); ok { return true, unmarshaler.UnmarshalParam(value) } if unmarshaler, ok := fieldIValue.(encoding.TextUnmarshaler); ok { return true, unmarshaler.UnmarshalText([]byte(value)) } return false, nil } func unmarshalFieldPtr(value string, field reflect.Value) (bool, error) { if field.IsNil() { // Initialize the pointer to a nil value field.Set(reflect.New(field.Type().Elem())) } return unmarshalFieldNonPtr(value, field.Elem()) } func setIntField(value string, bitSize int, field reflect.Value) error { if value == "" { value = "0" } intVal, err := strconv.ParseInt(value, 10, bitSize) if err == nil { field.SetInt(intVal) } return err } func setUintField(value string, bitSize int, field reflect.Value) error { if value == "" { value = "0" } uintVal, err := strconv.ParseUint(value, 10, bitSize) if err == nil { field.SetUint(uintVal) } return err } func setBoolField(value string, field reflect.Value) error { if value == "" { value = "false" } boolVal, err := strconv.ParseBool(value) if err == nil { field.SetBool(boolVal) } return err } func setFloatField(value string, bitSize int, field reflect.Value) error { if value == "" { value = "0.0" } floatVal, err := strconv.ParseFloat(value, bitSize) if err == nil { field.SetFloat(floatVal) } return err }