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- // Package xmlutil provides XML serialization of AWS requests and responses.
- package xmlutil
- import (
- "encoding/base64"
- "encoding/xml"
- "fmt"
- "reflect"
- "sort"
- "strconv"
- "time"
- "github.com/aws/aws-sdk-go/private/protocol"
- )
- // BuildXML will serialize params into an xml.Encoder.
- // Error will be returned if the serialization of any of the params or nested values fails.
- func BuildXML(params interface{}, e *xml.Encoder) error {
- b := xmlBuilder{encoder: e, namespaces: map[string]string{}}
- root := NewXMLElement(xml.Name{})
- if err := b.buildValue(reflect.ValueOf(params), root, ""); err != nil {
- return err
- }
- for _, c := range root.Children {
- for _, v := range c {
- return StructToXML(e, v, false)
- }
- }
- return nil
- }
- // Returns the reflection element of a value, if it is a pointer.
- func elemOf(value reflect.Value) reflect.Value {
- for value.Kind() == reflect.Ptr {
- value = value.Elem()
- }
- return value
- }
- // A xmlBuilder serializes values from Go code to XML
- type xmlBuilder struct {
- encoder *xml.Encoder
- namespaces map[string]string
- }
- // buildValue generic XMLNode builder for any type. Will build value for their specific type
- // struct, list, map, scalar.
- //
- // Also takes a "type" tag value to set what type a value should be converted to XMLNode as. If
- // type is not provided reflect will be used to determine the value's type.
- func (b *xmlBuilder) buildValue(value reflect.Value, current *XMLNode, tag reflect.StructTag) error {
- value = elemOf(value)
- if !value.IsValid() { // no need to handle zero values
- return nil
- } else if tag.Get("location") != "" { // don't handle non-body location values
- return nil
- }
- t := tag.Get("type")
- if t == "" {
- switch value.Kind() {
- case reflect.Struct:
- t = "structure"
- case reflect.Slice:
- t = "list"
- case reflect.Map:
- t = "map"
- }
- }
- switch t {
- case "structure":
- if field, ok := value.Type().FieldByName("_"); ok {
- tag = tag + reflect.StructTag(" ") + field.Tag
- }
- return b.buildStruct(value, current, tag)
- case "list":
- return b.buildList(value, current, tag)
- case "map":
- return b.buildMap(value, current, tag)
- default:
- return b.buildScalar(value, current, tag)
- }
- }
- // buildStruct adds a struct and its fields to the current XMLNode. All fields any any nested
- // types are converted to XMLNodes also.
- func (b *xmlBuilder) buildStruct(value reflect.Value, current *XMLNode, tag reflect.StructTag) error {
- if !value.IsValid() {
- return nil
- }
- fieldAdded := false
- // unwrap payloads
- if payload := tag.Get("payload"); payload != "" {
- field, _ := value.Type().FieldByName(payload)
- tag = field.Tag
- value = elemOf(value.FieldByName(payload))
- if !value.IsValid() {
- return nil
- }
- }
- child := NewXMLElement(xml.Name{Local: tag.Get("locationName")})
- // there is an xmlNamespace associated with this struct
- if prefix, uri := tag.Get("xmlPrefix"), tag.Get("xmlURI"); uri != "" {
- ns := xml.Attr{
- Name: xml.Name{Local: "xmlns"},
- Value: uri,
- }
- if prefix != "" {
- b.namespaces[prefix] = uri // register the namespace
- ns.Name.Local = "xmlns:" + prefix
- }
- child.Attr = append(child.Attr, ns)
- }
- t := value.Type()
- for i := 0; i < value.NumField(); i++ {
- member := elemOf(value.Field(i))
- field := t.Field(i)
- if field.PkgPath != "" {
- continue // ignore unexported fields
- }
- if field.Tag.Get("ignore") != "" {
- continue
- }
- mTag := field.Tag
- if mTag.Get("location") != "" { // skip non-body members
- continue
- }
- if protocol.CanSetIdempotencyToken(value.Field(i), field) {
- token := protocol.GetIdempotencyToken()
- member = reflect.ValueOf(token)
- }
- memberName := mTag.Get("locationName")
- if memberName == "" {
- memberName = field.Name
- mTag = reflect.StructTag(string(mTag) + ` locationName:"` + memberName + `"`)
- }
- if err := b.buildValue(member, child, mTag); err != nil {
- return err
- }
- fieldAdded = true
- }
- if fieldAdded { // only append this child if we have one ore more valid members
- current.AddChild(child)
- }
- return nil
- }
- // buildList adds the value's list items to the current XMLNode as children nodes. All
- // nested values in the list are converted to XMLNodes also.
- func (b *xmlBuilder) buildList(value reflect.Value, current *XMLNode, tag reflect.StructTag) error {
- if value.IsNil() { // don't build omitted lists
- return nil
- }
- // check for unflattened list member
- flattened := tag.Get("flattened") != ""
- xname := xml.Name{Local: tag.Get("locationName")}
- if flattened {
- for i := 0; i < value.Len(); i++ {
- child := NewXMLElement(xname)
- current.AddChild(child)
- if err := b.buildValue(value.Index(i), child, ""); err != nil {
- return err
- }
- }
- } else {
- list := NewXMLElement(xname)
- current.AddChild(list)
- for i := 0; i < value.Len(); i++ {
- iname := tag.Get("locationNameList")
- if iname == "" {
- iname = "member"
- }
- child := NewXMLElement(xml.Name{Local: iname})
- list.AddChild(child)
- if err := b.buildValue(value.Index(i), child, ""); err != nil {
- return err
- }
- }
- }
- return nil
- }
- // buildMap adds the value's key/value pairs to the current XMLNode as children nodes. All
- // nested values in the map are converted to XMLNodes also.
- //
- // Error will be returned if it is unable to build the map's values into XMLNodes
- func (b *xmlBuilder) buildMap(value reflect.Value, current *XMLNode, tag reflect.StructTag) error {
- if value.IsNil() { // don't build omitted maps
- return nil
- }
- maproot := NewXMLElement(xml.Name{Local: tag.Get("locationName")})
- current.AddChild(maproot)
- current = maproot
- kname, vname := "key", "value"
- if n := tag.Get("locationNameKey"); n != "" {
- kname = n
- }
- if n := tag.Get("locationNameValue"); n != "" {
- vname = n
- }
- // sorting is not required for compliance, but it makes testing easier
- keys := make([]string, value.Len())
- for i, k := range value.MapKeys() {
- keys[i] = k.String()
- }
- sort.Strings(keys)
- for _, k := range keys {
- v := value.MapIndex(reflect.ValueOf(k))
- mapcur := current
- if tag.Get("flattened") == "" { // add "entry" tag to non-flat maps
- child := NewXMLElement(xml.Name{Local: "entry"})
- mapcur.AddChild(child)
- mapcur = child
- }
- kchild := NewXMLElement(xml.Name{Local: kname})
- kchild.Text = k
- vchild := NewXMLElement(xml.Name{Local: vname})
- mapcur.AddChild(kchild)
- mapcur.AddChild(vchild)
- if err := b.buildValue(v, vchild, ""); err != nil {
- return err
- }
- }
- return nil
- }
- // buildScalar will convert the value into a string and append it as a attribute or child
- // of the current XMLNode.
- //
- // The value will be added as an attribute if tag contains a "xmlAttribute" attribute value.
- //
- // Error will be returned if the value type is unsupported.
- func (b *xmlBuilder) buildScalar(value reflect.Value, current *XMLNode, tag reflect.StructTag) error {
- var str string
- switch converted := value.Interface().(type) {
- case string:
- str = converted
- case []byte:
- if !value.IsNil() {
- str = base64.StdEncoding.EncodeToString(converted)
- }
- case bool:
- str = strconv.FormatBool(converted)
- case int64:
- str = strconv.FormatInt(converted, 10)
- case int:
- str = strconv.Itoa(converted)
- case float64:
- str = strconv.FormatFloat(converted, 'f', -1, 64)
- case float32:
- str = strconv.FormatFloat(float64(converted), 'f', -1, 32)
- case time.Time:
- const ISO8601UTC = "2006-01-02T15:04:05Z"
- str = converted.UTC().Format(ISO8601UTC)
- default:
- return fmt.Errorf("unsupported value for param %s: %v (%s)",
- tag.Get("locationName"), value.Interface(), value.Type().Name())
- }
- xname := xml.Name{Local: tag.Get("locationName")}
- if tag.Get("xmlAttribute") != "" { // put into current node's attribute list
- attr := xml.Attr{Name: xname, Value: str}
- current.Attr = append(current.Attr, attr)
- } else { // regular text node
- current.AddChild(&XMLNode{Name: xname, Text: str})
- }
- return nil
- }
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