/
form.go
518 lines (478 loc) · 12.2 KB
/
form.go
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// Copyright 2017 The Mellium Contributors.
// Use of this source code is governed by the BSD 2-clause
// license that can be found in the LICENSE file.
package form
import (
"encoding/xml"
"errors"
"fmt"
"io"
"strconv"
"strings"
"mellium.im/xmlstream"
"mellium.im/xmpp/jid"
)
var spaceReplacer = strings.NewReplacer(
"\r\n", " ",
"\n\r", " ",
"\n", " ",
"\r", " ",
)
// Type is a form type. For more information see the constants defined in this
// package.
type Type string
const (
// TypeForm indicates that the form-processing entity is asking the
// form-submitting entity to complete a form.
TypeForm Type = "form"
// TypeSubmit indicates that the form-submitting entity is submitting data to
// the form-processing entity.
TypeSubmit Type = "submit"
// TypeCancel indicates that the form-submitting entity has cancelled
// submission of data to the form-processing entity.
TypeCancel Type = "cancel"
// TypeResult indicates that the form-processing entity is returning data
// (e.g., search results) to the form-submitting entity, or the data is a
// generic data set.
TypeResult Type = "result"
)
// NS is the data forms namespace.
const NS = "jabber:x:data"
// Data represents a data form.
type Data struct {
title string
instructions string
typ Type
fields []field
values map[string]interface{}
}
// Title returns the title of the form.
func (d *Data) Title() string {
return d.title
}
// Instructions returns the instructions set on the form.
func (d *Data) Instructions() string {
return d.instructions
}
// ForFields iterates over the fields of the form and calls a function for each
// one, passing it information about the field.
func (d *Data) ForFields(f func(FieldData)) {
for _, field := range d.fields {
f(FieldData{
Type: field.typ,
Var: field.varName,
Label: field.label,
Desc: field.desc,
Required: field.required,
Raw: field.value,
})
}
}
// UnmarshalXML satisfies the xml.Unmarshaler interface for *Data.
func (d *Data) UnmarshalXML(decoder *xml.Decoder, start xml.StartElement) error {
for _, attr := range start.Attr {
if attr.Name.Local == "type" {
d.typ = Type(attr.Value)
break
}
}
d.values = make(map[string]interface{})
for {
tok, err := decoder.Token()
if err != nil && err != io.EOF {
return err
}
if tok == nil && err == io.EOF {
return nil
}
switch t := tok.(type) {
case xml.StartElement:
start = t
case xml.EndElement:
return nil
case xml.CharData:
// Realistically we should never hit this in XMPP, but for the sake of
// being able to parse forms from examples and the like skip over
// chardata.
continue
default:
// We shouldn't ever hit this, but just in case we do return an error.
return errors.New("unexpected token type")
}
switch start.Name.Local {
case "title":
s := struct {
XMLName xml.Name `xml:"title"`
Inner string `xml:",chardata"`
}{}
err = decoder.DecodeElement(&s, &start)
if err != nil {
return err
}
d.title = s.Inner
case "instructions":
s := struct {
XMLName xml.Name `xml:"instructions"`
Inner string `xml:",chardata"`
}{}
err = decoder.DecodeElement(&s, &start)
if err != nil {
return err
}
if d.instructions == "" {
d.instructions = s.Inner
} else {
d.instructions += "\n" + s.Inner
}
case "field":
f := field{}
err = decoder.DecodeElement(&f, &start)
if err != nil {
return err
}
if f.typ == "" {
f.typ = TypeText
}
d.fields = append(d.fields, f)
default:
return fmt.Errorf("unexpected element %v", start.Name)
}
if err == io.EOF {
break
}
}
return decoder.Skip()
}
// Len returns the number of fields on the form.
func (d *Data) Len() int {
if d == nil {
return 0
}
return len(d.fields)
}
// Raw looks up the value parsed for a form field as it appeared in the XML.
func (d *Data) Raw(id string) (v []string, ok bool) {
if d == nil {
return nil, false
}
for _, field := range d.fields {
if field.varName == id {
return field.value, true
}
}
return nil, false
}
// Get looks up the value submitted for a form field.
// If the value has not been set yet and no default value exists, ok will be
// false.
func (d *Data) Get(id string) (v interface{}, ok bool) {
v, ok = d.values[id]
if ok {
return v, ok
}
fieldIDX := -1
for i, field := range d.fields {
if field.varName == id {
fieldIDX = i
break
}
}
// No field with the given name found, so no default.
if fieldIDX == -1 {
return nil, false
}
// We found a field, so use its default.
field := d.fields[fieldIDX]
switch field.typ {
case TypeFixed:
// A submission of type fixed has no value.
return "", false
case TypeBoolean:
for _, vv := range field.value {
if vv == "false" || vv == "0" {
return false, true
}
if vv == "true" || vv == "1" {
return true, true
}
}
return false, false
case TypeText, TypeTextPrivate, TypeHidden, TypeList, "":
if len(field.value) == 0 {
return "", false
}
return field.value[0], true
case TypeJID:
for _, vv := range field.value {
if j, err := jid.Parse(vv); err == nil {
return j, true
}
}
return jid.JID{}, false
case TypeJIDMulti:
var jids []jid.JID
for _, vv := range field.value {
if j, err := jid.Parse(vv); err == nil {
jids = append(jids, j)
}
}
return jids, len(jids) > 0
case TypeTextMulti:
b := &strings.Builder{}
for i, vv := range field.value {
if i > 0 {
b.WriteString("\n")
}
b.WriteString(vv)
}
return b.String(), len(field.value) > 0
case TypeListMulti:
var items []string
items = append(items, field.value...)
return items, len(items) > 0
}
return nil, false
}
// GetJID is like Get except that it asserts that the form submission is a JID.
// If the form submission was not a JID or is not set, ok will be false.
func (d *Data) GetJID(id string) (j jid.JID, ok bool) {
v, ok := d.Get(id)
if !ok {
return j, ok
}
j, ok = v.(jid.JID)
return j, ok
}
// GetString is like Get except that it asserts that the form submission is a
// string (regardless of whether it was a single line or multi-line submission).
// If the form submission was not a string or is not set, ok will be false.
func (d *Data) GetString(id string) (s string, ok bool) {
v, ok := d.Get(id)
if !ok {
return s, ok
}
s, ok = v.(string)
return s, ok
}
// GetStrings is like Get except that it asserts that the form submission is a
// slice of strings.
// If the form submission was not a string slice or is not set, ok will be
// false.
func (d *Data) GetStrings(id string) (s []string, ok bool) {
v, ok := d.Get(id)
if !ok {
return s, ok
}
s, ok = v.([]string)
return s, ok
}
// GetBool is like Get except that it asserts that the form submission is a
// bool.
// If the form submission was not a bool or is not set, ok will be false.
func (d *Data) GetBool(id string) (b, ok bool) {
v, ok := d.Get(id)
if !ok {
return b, ok
}
b, ok = v.(bool)
return b, ok
}
// GetJIDs is like Get except that it asserts that the form submission is a
// slice of JIDs.
// If the form submission was not a JID slice or is not set, ok will be false.
func (d *Data) GetJIDs(id string) (j []jid.JID, ok bool) {
v, ok := d.Get(id)
if !ok {
return j, ok
}
j, ok = v.([]jid.JID)
return j, ok
}
// Set sets the form field to the provided value.
// If the value is of the incorrect type for the form field an error is
// returned.
// If no form field with the given name exists, ok will be false.
// It is permitted to send back fields that did not exist in the original form
// so this is not an error, but most implementations will ignore them.
func (d *Data) Set(id string, v interface{}) (ok bool, err error) {
var typ FieldType
for _, field := range d.fields {
if field.varName == id {
typ = field.typ
ok = true
break
}
}
switch typ {
case TypeFixed:
return false, fmt.Errorf("cannot set fixed field")
case TypeBoolean:
vv, isTyp := v.(bool)
if !isTyp {
return false, fmt.Errorf("expected %T, got %T", vv, v)
}
case TypeText, TypeTextPrivate, TypeHidden, TypeList, TypeTextMulti:
vv, isTyp := v.(string)
if !isTyp {
return false, fmt.Errorf("expected %T, got %T", vv, v)
}
case TypeJID:
vv, isTyp := v.(jid.JID)
if !isTyp {
return false, fmt.Errorf("expected %T, got %T", vv, v)
}
case TypeJIDMulti:
vv, isTyp := v.([]jid.JID)
if !isTyp {
return false, fmt.Errorf("expected %T, got %T", vv, v)
}
case TypeListMulti:
vv, isTyp := v.([]string)
if !isTyp {
return false, fmt.Errorf("expected %T, got %T", vv, v)
}
}
d.values[id] = v
return ok, err
}
// Submit returns a form that can be used to submit the original data.
// If a value has not been set for all required fields ok will be false.
func (d *Data) Submit() (submission xml.TokenReader, ok bool) {
if d == nil {
d = &Data{}
}
ok = true
submissionData := New()
submissionData.values = d.values
submissionData.fields = d.fields
submissionData.typ = TypeSubmit
for _, f := range submissionData.fields {
if f.required {
_, isSet := submissionData.Get(f.varName)
if !isSet {
ok = false
}
}
}
return submissionData.TokenReader(), ok
}
// TokenReader implements xmlstream.Marshaler for Data.
func (d *Data) TokenReader() xml.TokenReader {
var child []xml.TokenReader
// Unwrap title (which cannot contain newlines)
if d.title != "" {
child = append(child, xmlstream.Wrap(
xmlstream.Token(xml.CharData(spaceReplacer.Replace(d.title))),
xml.StartElement{Name: xml.Name{Local: "title"}},
))
}
// Split instructions elements up one per line since the instructions element
// cannot contain new lines (but there can be multiple of them).
instructions := d.instructions
for {
idx := strings.IndexAny(instructions, "\r\n")
line := instructions
if idx != -1 {
line = instructions[:idx]
instructions = instructions[idx+1:]
if line == "" {
continue
}
}
if line != "" {
child = append(child, xmlstream.Wrap(
xmlstream.Token(xml.CharData(line)),
xml.StartElement{Name: xml.Name{Local: "instructions"}},
))
}
if idx == -1 {
break
}
}
for _, f := range d.fields {
// If we're type submit, skip unset fields and use the value from Get
// instead of the raw field value (get returns defaults even if the field is
// unset and may normalize some values).
// Otherwise just append all fields exactly as they appear.
if d.typ == TypeSubmit {
if f.typ == TypeFixed {
continue
}
vv, isSet := d.Get(f.varName)
if !f.required && !isSet {
continue
}
switch typed := vv.(type) {
case []string:
f.value = typed
case string:
if f.typ == TypeTextMulti {
var lines []string
for {
idx := strings.IndexAny(typed, "\n\r")
if idx == -1 {
if len(typed) > 0 {
lines = append(lines, typed)
break
}
}
lines = append(lines, typed[:idx])
typed = typed[idx+1:]
}
f.value = lines
} else {
f.value = []string{typed}
}
case jid.JID:
f.value = []string{typed.String()}
case []jid.JID:
f.value = make([]string, 0, len(typed))
for _, j := range typed {
f.value = append(f.value, j.String())
}
case bool:
f.value = []string{strconv.FormatBool(typed)}
}
}
child = append(child, f.TokenReader())
}
return xmlstream.Wrap(
xmlstream.MultiReader(child...),
xml.StartElement{
Name: xml.Name{Space: NS, Local: "x"},
Attr: []xml.Attr{{
Name: xml.Name{Local: "type"},
Value: string(d.typ),
}},
},
)
}
// WriteXML implements xmlstream.WriterTo for Data.
func (d *Data) WriteXML(w xmlstream.TokenWriter) (int, error) {
return xmlstream.Copy(w, d.TokenReader())
}
// MarshalXML satisfies the xml.Marshaler interface for *Data.
func (d *Data) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
_, err := d.WriteXML(e)
if err != nil {
return err
}
return e.Flush()
}
// New builds a new data form from the provided options.
func New(f ...Field) *Data {
d := &Data{
typ: TypeForm,
values: make(map[string]interface{}),
}
for _, field := range f {
field(d)
}
return d
}
// Cancel returns a data form that can be used to cancel an interaction.
func Cancel(title, instructions string) *Data {
d := New(Title(title), Instructions(instructions))
d.typ = TypeCancel
return d
}