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Add support for embedded struct fields #61

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Add support for embedded struct fields #61

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86 changes: 63 additions & 23 deletions decoder.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,15 +17,16 @@ const (
iso8601Z = "20060102T15:04:05Z07:00"
iso8601Hyphen = "2006-01-02T15:04:05"
iso8601HyphenZ = "2006-01-02T15:04:05Z07:00"
tagValue = "value"
)

var (
// CharsetReader is a function to generate reader which converts a non UTF-8
// charset into UTF-8.
CharsetReader func(string, io.Reader) (io.Reader, error)

timeLayouts = []string{iso8601, iso8601Z, iso8601Hyphen, iso8601HyphenZ}
invalidXmlError = errors.New("invalid xml")
timeLayouts = []string{iso8601, iso8601Z, iso8601Hyphen, iso8601HyphenZ}
errInvalidXML = errors.New("invalid xml")
)

type TypeMismatchError string
Expand All @@ -50,7 +51,7 @@ func unmarshal(data []byte, v interface{}) (err error) {
}

if t, ok := tok.(xml.StartElement); ok {
if t.Name.Local == "value" {
if t.Name.Local == tagValue {
val := reflect.ValueOf(v)
if val.Kind() != reflect.Ptr {
return errors.New("non-pointer value passed to unmarshal")
Expand Down Expand Up @@ -91,11 +92,11 @@ func (dec *decoder) decodeValue(val reflect.Value) error {
}

if t, ok := tok.(xml.EndElement); ok {
if t.Name.Local == "value" {
if t.Name.Local == tagValue {
return nil
} else {
return invalidXmlError
}

return errInvalidXML
}

if t, ok := tok.(xml.StartElement); ok {
Expand Down Expand Up @@ -145,14 +146,9 @@ func (dec *decoder) decodeValue(val reflect.Value) error {

for i := 0; i < valType.NumField(); i++ {
field := valType.Field(i)
fieldVal := val.FieldByName(field.Name)

if fieldVal.CanSet() {
if fn := field.Tag.Get("xmlrpc"); fn != "" {
fields[fn] = fieldVal
} else {
fields[field.Name] = fieldVal
}
fErr := handleStructField(fields, field, val.FieldByName(field.Name))
if fErr != nil {
return fErr
}
}
} else {
Expand All @@ -169,15 +165,15 @@ func (dec *decoder) decodeValue(val reflect.Value) error {
switch t := tok.(type) {
case xml.StartElement:
if t.Name.Local != "member" {
return invalidXmlError
return errInvalidXML
}

tagName, fieldName, err := dec.readTag()
if err != nil {
return err
}
if tagName != "name" {
return invalidXmlError
return errInvalidXML
}

var fv reflect.Value
Expand All @@ -194,7 +190,7 @@ func (dec *decoder) decodeValue(val reflect.Value) error {
if tok, err = dec.Token(); err != nil {
return err
}
if t, ok := tok.(xml.StartElement); ok && t.Name.Local == "value" {
if t, ok := tok.(xml.StartElement); ok && t.Name.Local == tagValue {
if err = dec.decodeValue(fv); err != nil {
return err
}
Expand Down Expand Up @@ -240,7 +236,7 @@ func (dec *decoder) decodeValue(val reflect.Value) error {
case xml.StartElement:
var index int
if t.Name.Local != "data" {
return invalidXmlError
return errInvalidXML
}
DataLoop:
for {
Expand All @@ -250,8 +246,8 @@ func (dec *decoder) decodeValue(val reflect.Value) error {

switch tt := tok.(type) {
case xml.StartElement:
if tt.Name.Local != "value" {
return invalidXmlError
if tt.Name.Local != tagValue {
return errInvalidXML
}

if index < slice.Len() {
Expand Down Expand Up @@ -300,7 +296,7 @@ func (dec *decoder) decodeValue(val reflect.Value) error {
case xml.CharData:
data = []byte(t.Copy())
default:
return invalidXmlError
return errInvalidXML
}

switch typeName {
Expand Down Expand Up @@ -440,9 +436,9 @@ func (dec *decoder) readCharData() ([]byte, error) {

if t, ok := tok.(xml.CharData); ok {
return []byte(t.Copy()), nil
} else {
return nil, invalidXmlError
}

return nil, errInvalidXML
}

func checkType(val reflect.Value, kinds ...reflect.Kind) error {
Expand Down Expand Up @@ -470,3 +466,47 @@ func checkType(val reflect.Value, kinds ...reflect.Kind) error {

return nil
}

// handleStructField will add struct values to the fields map indexed by the "xmlrpc" tag, defaulting to the
// struct field name if no tag is found. This function will recurse into embedded structs. Conflicting
// tag/field names will result in an error.
func handleStructField(fields map[string]reflect.Value, field reflect.StructField, val reflect.Value) error {
if val.Kind() == reflect.Ptr {
if val.IsNil() {
val.Set(reflect.New(val.Type().Elem()))
}

val = val.Elem()
}

if val.Kind() == reflect.Struct {
for i := 0; i < val.NumField(); i++ {
var sField reflect.StructField
if field.Type.Kind() == reflect.Ptr {
sField = field.Type.Elem().Field(i)
} else {
sField = field.Type.Field(i)
}

fErr := handleStructField(fields, sField, val.FieldByName(sField.Name))
if fErr != nil {
return fErr
}
}
}

if val.CanSet() {
fn := field.Tag.Get("xmlrpc")
if fn == "" {
fn = field.Name
}

if _, exists := fields[fn]; exists {
return fmt.Errorf("duplicate field %q in struct", fn)
}

fields[fn] = val
}

return nil
}
79 changes: 79 additions & 0 deletions decoder_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -214,3 +214,82 @@ func decode(charset string, input io.Reader) (io.Reader, error) {

return transform.NewReader(input, charmap.Windows1251.NewDecoder()), nil
}

func Test_decodeEmbeddedStruct(t *testing.T) {
type CityState struct {
City string
State string
}
type CustomerDetails struct {
Name string `xmlrpc:"CustomerName"`
Region CityState
}
type Customer struct {
ID int `xmlrpc:"CustomerId"`
CustomerDetails
}
type Status struct {
Code int `xmlrpc:"Code"`
Msg string `xmlrpc:"Msg"`
Customer
}
type Serial struct {
Serial int
}
type EmbeddedStatus struct {
Name string `xmlrpc:"Name"`
Status
S *Serial
}
type DuplicateEmbeddedFields struct {
City string
Name string `xmlrpc:"CustomerName"`
Status
}

data, err := ioutil.ReadFile("fixtures/embedded.xml")
if err != nil {
t.Fatal(err)
}

// Ensure all values are properly unmarshaled into the embedded struct fields, no matter
// their depth.
es := EmbeddedStatus{}
if err := unmarshal(data, &es); err != nil {
t.Fatal(err)
}

if expected := "Acme"; es.Customer.CustomerDetails.Name != expected {
t.Errorf("expected Customer Name = %q; actual = %q", expected, es.Customer.CustomerDetails.Name)
}
if expected := "Somecity"; es.Customer.CustomerDetails.Region.City != expected {
t.Errorf("expected Customer City = %q; actual = %q", expected, es.Customer.CustomerDetails.Region.City)
}
if expected := "Somestate"; es.Customer.CustomerDetails.Region.State != expected {
t.Errorf("expected Customer State = %q; actual = %q", expected, es.Customer.CustomerDetails.Region.State)
}
if expected := 1234; es.ID != expected {
t.Errorf("expected ID = %d; actual = %d", expected, es.ID)
}
if expected := 1; es.Code != expected {
t.Errorf("expected Code = %d; actual = %d", expected, es.Code)
}
if expected := "Test"; es.Msg != expected {
t.Errorf("expected Msg = %q; actual = %q", expected, es.Msg)
}
if expected := "Blah"; es.Name != expected {
t.Errorf("expected Name = %q; actual = %q", expected, es.Name)
}
if expected := 5678; es.S.Serial != expected {
t.Errorf("expected Serial = %d; actual = %d", expected, es.S.Serial)
}

// Make sure we receive an error if we attempt to decode to a struct with
// conflicting tag/field names.
dupe := DuplicateEmbeddedFields{}
if err := unmarshal(data, &dupe); err == nil {
t.Error("expected an error with conflicting tag/field names")
} else {
t.Log(err)
}
}
41 changes: 41 additions & 0 deletions fixtures/embedded.xml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,41 @@
<?xml version="1.0" encoding="UTF-8" ?>
<methodResponse>
<params>
<value>
<struct>
<member>
<name>Name</name>
<value><string>Blah</string></value>
</member>
<member>
<name>Code</name>
<value><int>1</int></value>
</member>
<member>
<name>Msg</name>
<value><string>Test</string></value>
</member>
<member>
<name>CustomerName</name>
<value><string>Acme</string></value>
</member>
<member>
<name>City</name>
<value><string>Somecity</string></value>
</member>
<member>
<name>State</name>
<value><string>Somestate</string></value>
</member>
<member>
<name>CustomerId</name>
<value><int>1234</int></value>
</member>
<member>
<name>Serial</name>
<value><int>5678</int></value>
</member>
</struct>
</value>
</params>
</methodResponse>