feat: stealing the gorilla/schema for us, lol.

cmd/hook/main.go

@@ -2,8 +2,8 @@ package main
 
 import (
 	"vultras.su/core/bond"
-	"vultras.su/core/bond/methods"
+	//"vultras.su/core/bond/methods"
-	"vultras.su/core/bond/contents"
+	"vultras.su/core/bond/statuses"
 	"fmt"
 	"io"
 	"net/url"
@@ -15,67 +15,31 @@ type GetNotesOptions struct {
 }
 
 var root = bond.Root(bond.Path().
-	Def(
+Def(
-		"", bond.Func(func(c *bond.Context) {
-			c.W.Write([]byte("This is the index page"))
-		}),
-	).Def(
-	"hello",
-	bond.Path().Def(
-		"en", bond.Func(func(c *bond.Context) {
-			c.Printf("Hello, World!")
-		}),
-	).Def(
-		"ru",
-		bond.Func(func(c *bond.Context) {
-			c.Printf("Привет, Мир!")
-		}),
-	),
-).Def(
-	"web", bond.Static("./static"),
-).Def(
-	"test", bond.Func(func(c *bond.Context) {
-		c.SetContentType(contents.Plain)
-		c.Printf(
-			"Path: %q\n"+
-				"Content-Type: %q\n",
-			c.Path(), c.ContentType(),
-		)
-		c.Printf("Query:\n")
-		for k, vs := range c.Query() {
-			c.Printf("\t%q:\n", k)
-			for _, v := range vs {
-				c.Printf("\t\t%q\n", v)
-			}
-		}
-	}),
-).Def(
-	"get-notes",
-	bond.Method().Def(
-		methods.Get,
-		bond.Func(func(c *bond.Context) {
-			opts := GetNotesOptions{}
-			c.Scan(&opts)
-			c.Printf("%v", opts)
-		}),
-	),
-).Def(
 	"hook",
 	/*bond.Method().Def(
 		methods.Post,*/
 		bond.Func(func(c *bond.Context){
-			fmt.Printf("content-type: %q", c.ContentType())
+			fmt.Printf("Content-Type: %q\n", c.ContentType())
 			body, err := io.ReadAll(c.R.Body)
 			if err != nil {
 				fmt.Printf("err:%s\n", err)
 				return
 			}
+			fmt.Printf("rawBody: %q\n", body)
+			unesc, err := url.QueryUnescape(string(body))
+			if err != nil {
+				fmt.Printf("err:%s\n", err)
+				return
+			}
+			fmt.Printf("unescapeBody: %q\n", unesc)
 			values, err := url.ParseQuery(string(body))
 			if err != nil {
 				fmt.Printf("err:%s\n", err)
 				return
 			}
-			fmt.Printf("values: %q", values)
+			fmt.Printf("Values: %q\n", values)
+			c.SetStatus(statuses.OK)
 		}),
 	//),
 ))

context.go

@@ -26,6 +26,7 @@ func (c *Context) Method() ReqMethod {
 
 // Set the reply status code.
 func (c *Context) SetStatus(status Status) {
+	c.W.WriteHeader(int(status))
 }
 
 // Set the reply content type.

schema/.editorconfig

@@ -0,0 +1,20 @@
+; https://editorconfig.org/
+
+root = true
+
+[*]
+insert_final_newline = true
+charset = utf-8
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+[{Makefile,go.mod,go.sum,*.go,.gitmodules}]
+indent_style = tab
+indent_size = 4
+
+[*.md]
+indent_size = 4
+trim_trailing_whitespace = false
+
+eclint_indent_style = unset

schema/cache.go

@@ -0,0 +1,305 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package schema
+
+import (
+	"errors"
+	"reflect"
+	"strconv"
+	"strings"
+	"sync"
+)
+
+var errInvalidPath = errors.New("schema: invalid path")
+
+// newCache returns a new cache.
+func newCache() *cache {
+	c := cache{
+		m:       make(map[reflect.Type]*structInfo),
+		regconv: make(map[reflect.Type]Converter),
+		tag:     "schema",
+	}
+	return &c
+}
+
+// cache caches meta-data about a struct.
+type cache struct {
+	l       sync.RWMutex
+	m       map[reflect.Type]*structInfo
+	regconv map[reflect.Type]Converter
+	tag     string
+}
+
+// registerConverter registers a converter function for a custom type.
+func (c *cache) registerConverter(value interface{}, converterFunc Converter) {
+	c.regconv[reflect.TypeOf(value)] = converterFunc
+}
+
+// parsePath parses a path in dotted notation verifying that it is a valid
+// path to a struct field.
+//
+// It returns "path parts" which contain indices to fields to be used by
+// reflect.Value.FieldByString(). Multiple parts are required for slices of
+// structs.
+func (c *cache) parsePath(p string, t reflect.Type) ([]pathPart, error) {
+	var struc *structInfo
+	var field *fieldInfo
+	var index64 int64
+	var err error
+	parts := make([]pathPart, 0)
+	path := make([]string, 0)
+	keys := strings.Split(p, ".")
+	for i := 0; i < len(keys); i++ {
+		if t.Kind() != reflect.Struct {
+			return nil, errInvalidPath
+		}
+		if struc = c.get(t); struc == nil {
+			return nil, errInvalidPath
+		}
+		if field = struc.get(keys[i]); field == nil {
+			return nil, errInvalidPath
+		}
+		// Valid field. Append index.
+		path = append(path, field.name)
+		if field.isSliceOfStructs && (!field.unmarshalerInfo.IsValid || (field.unmarshalerInfo.IsValid && field.unmarshalerInfo.IsSliceElement)) {
+			// Parse a special case: slices of structs.
+			// i+1 must be the slice index.
+			//
+			// Now that struct can implements TextUnmarshaler interface,
+			// we don't need to force the struct's fields to appear in the path.
+			// So checking i+2 is not necessary anymore.
+			i++
+			if i+1 > len(keys) {
+				return nil, errInvalidPath
+			}
+			if index64, err = strconv.ParseInt(keys[i], 10, 0); err != nil {
+				return nil, errInvalidPath
+			}
+			parts = append(parts, pathPart{
+				path:  path,
+				field: field,
+				index: int(index64),
+			})
+			path = make([]string, 0)
+
+			// Get the next struct type, dropping ptrs.
+			if field.typ.Kind() == reflect.Ptr {
+				t = field.typ.Elem()
+			} else {
+				t = field.typ
+			}
+			if t.Kind() == reflect.Slice {
+				t = t.Elem()
+				if t.Kind() == reflect.Ptr {
+					t = t.Elem()
+				}
+			}
+		} else if field.typ.Kind() == reflect.Ptr {
+			t = field.typ.Elem()
+		} else {
+			t = field.typ
+		}
+	}
+	// Add the remaining.
+	parts = append(parts, pathPart{
+		path:  path,
+		field: field,
+		index: -1,
+	})
+	return parts, nil
+}
+
+// get returns a cached structInfo, creating it if necessary.
+func (c *cache) get(t reflect.Type) *structInfo {
+	c.l.RLock()
+	info := c.m[t]
+	c.l.RUnlock()
+	if info == nil {
+		info = c.create(t, "")
+		c.l.Lock()
+		c.m[t] = info
+		c.l.Unlock()
+	}
+	return info
+}
+
+// create creates a structInfo with meta-data about a struct.
+func (c *cache) create(t reflect.Type, parentAlias string) *structInfo {
+	info := &structInfo{}
+	var anonymousInfos []*structInfo
+	for i := 0; i < t.NumField(); i++ {
+		if f := c.createField(t.Field(i), parentAlias); f != nil {
+			info.fields = append(info.fields, f)
+			if ft := indirectType(f.typ); ft.Kind() == reflect.Struct && f.isAnonymous {
+				anonymousInfos = append(anonymousInfos, c.create(ft, f.canonicalAlias))
+			}
+		}
+	}
+	for i, a := range anonymousInfos {
+		others := []*structInfo{info}
+		others = append(others, anonymousInfos[:i]...)
+		others = append(others, anonymousInfos[i+1:]...)
+		for _, f := range a.fields {
+			if !containsAlias(others, f.alias) {
+				info.fields = append(info.fields, f)
+			}
+		}
+	}
+	return info
+}
+
+// createField creates a fieldInfo for the given field.
+func (c *cache) createField(field reflect.StructField, parentAlias string) *fieldInfo {
+	alias, options := fieldAlias(field, c.tag)
+	if alias == "-" {
+		// Ignore this field.
+		return nil
+	}
+	canonicalAlias := alias
+	if parentAlias != "" {
+		canonicalAlias = parentAlias + "." + alias
+	}
+	// Check if the type is supported and don't cache it if not.
+	// First let's get the basic type.
+	isSlice, isStruct := false, false
+	ft := field.Type
+	m := isTextUnmarshaler(reflect.Zero(ft))
+	if ft.Kind() == reflect.Ptr {
+		ft = ft.Elem()
+	}
+	if isSlice = ft.Kind() == reflect.Slice; isSlice {
+		ft = ft.Elem()
+		if ft.Kind() == reflect.Ptr {
+			ft = ft.Elem()
+		}
+	}
+	if ft.Kind() == reflect.Array {
+		ft = ft.Elem()
+		if ft.Kind() == reflect.Ptr {
+			ft = ft.Elem()
+		}
+	}
+	if isStruct = ft.Kind() == reflect.Struct; !isStruct {
+		if c.converter(ft) == nil && builtinConverters[ft.Kind()] == nil {
+			// Type is not supported.
+			return nil
+		}
+	}
+
+	return &fieldInfo{
+		typ:              field.Type,
+		name:             field.Name,
+		alias:            alias,
+		canonicalAlias:   canonicalAlias,
+		unmarshalerInfo:  m,
+		isSliceOfStructs: isSlice && isStruct,
+		isAnonymous:      field.Anonymous,
+		isRequired:       options.Contains("required"),
+	}
+}
+
+// converter returns the converter for a type.
+func (c *cache) converter(t reflect.Type) Converter {
+	return c.regconv[t]
+}
+
+// ----------------------------------------------------------------------------
+
+type structInfo struct {
+	fields []*fieldInfo
+}
+
+func (i *structInfo) get(alias string) *fieldInfo {
+	for _, field := range i.fields {
+		if strings.EqualFold(field.alias, alias) {
+			return field
+		}
+	}
+	return nil
+}
+
+func containsAlias(infos []*structInfo, alias string) bool {
+	for _, info := range infos {
+		if info.get(alias) != nil {
+			return true
+		}
+	}
+	return false
+}
+
+type fieldInfo struct {
+	typ reflect.Type
+	// name is the field name in the struct.
+	name  string
+	alias string
+	// canonicalAlias is almost the same as the alias, but is prefixed with
+	// an embedded struct field alias in dotted notation if this field is
+	// promoted from the struct.
+	// For instance, if the alias is "N" and this field is an embedded field
+	// in a struct "X", canonicalAlias will be "X.N".
+	canonicalAlias string
+	// unmarshalerInfo contains information regarding the
+	// encoding.TextUnmarshaler implementation of the field type.
+	unmarshalerInfo unmarshaler
+	// isSliceOfStructs indicates if the field type is a slice of structs.
+	isSliceOfStructs bool
+	// isAnonymous indicates whether the field is embedded in the struct.
+	isAnonymous bool
+	isRequired  bool
+}
+
+func (f *fieldInfo) paths(prefix string) []string {
+	if f.alias == f.canonicalAlias {
+		return []string{prefix + f.alias}
+	}
+	return []string{prefix + f.alias, prefix + f.canonicalAlias}
+}
+
+type pathPart struct {
+	field *fieldInfo
+	path  []string // path to the field: walks structs using field names.
+	index int      // struct index in slices of structs.
+}
+
+// ----------------------------------------------------------------------------
+
+func indirectType(typ reflect.Type) reflect.Type {
+	if typ.Kind() == reflect.Ptr {
+		return typ.Elem()
+	}
+	return typ
+}
+
+// fieldAlias parses a field tag to get a field alias.
+func fieldAlias(field reflect.StructField, tagName string) (alias string, options tagOptions) {
+	if tag := field.Tag.Get(tagName); tag != "" {
+		alias, options = parseTag(tag)
+	}
+	if alias == "" {
+		alias = field.Name
+	}
+	return alias, options
+}
+
+// tagOptions is the string following a comma in a struct field's tag, or
+// the empty string. It does not include the leading comma.
+type tagOptions []string
+
+// parseTag splits a struct field's url tag into its name and comma-separated
+// options.
+func parseTag(tag string) (string, tagOptions) {
+	s := strings.Split(tag, ",")
+	return s[0], s[1:]
+}
+
+// Contains checks whether the tagOptions contains the specified option.
+func (o tagOptions) Contains(option string) bool {
+	for _, s := range o {
+		if s == option {
+			return true
+		}
+	}
+	return false
+}

schema/converter.go

@@ -0,0 +1,145 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package schema
+
+import (
+	"reflect"
+	"strconv"
+)
+
+type Converter func(string) reflect.Value
+
+var (
+	invalidValue = reflect.Value{}
+	boolType     = reflect.Bool
+	float32Type  = reflect.Float32
+	float64Type  = reflect.Float64
+	intType      = reflect.Int
+	int8Type     = reflect.Int8
+	int16Type    = reflect.Int16
+	int32Type    = reflect.Int32
+	int64Type    = reflect.Int64
+	stringType   = reflect.String
+	uintType     = reflect.Uint
+	uint8Type    = reflect.Uint8
+	uint16Type   = reflect.Uint16
+	uint32Type   = reflect.Uint32
+	uint64Type   = reflect.Uint64
+)
+
+// Default converters for basic types.
+var builtinConverters = map[reflect.Kind]Converter{
+	boolType:    convertBool,
+	float32Type: convertFloat32,
+	float64Type: convertFloat64,
+	intType:     convertInt,
+	int8Type:    convertInt8,
+	int16Type:   convertInt16,
+	int32Type:   convertInt32,
+	int64Type:   convertInt64,
+	stringType:  convertString,
+	uintType:    convertUint,
+	uint8Type:   convertUint8,
+	uint16Type:  convertUint16,
+	uint32Type:  convertUint32,
+	uint64Type:  convertUint64,
+}
+
+func convertBool(value string) reflect.Value {
+	if value == "on" {
+		return reflect.ValueOf(true)
+	} else if v, err := strconv.ParseBool(value); err == nil {
+		return reflect.ValueOf(v)
+	}
+	return invalidValue
+}
+
+func convertFloat32(value string) reflect.Value {
+	if v, err := strconv.ParseFloat(value, 32); err == nil {
+		return reflect.ValueOf(float32(v))
+	}
+	return invalidValue
+}
+
+func convertFloat64(value string) reflect.Value {
+	if v, err := strconv.ParseFloat(value, 64); err == nil {
+		return reflect.ValueOf(v)
+	}
+	return invalidValue
+}
+
+func convertInt(value string) reflect.Value {
+	if v, err := strconv.ParseInt(value, 10, 0); err == nil {
+		return reflect.ValueOf(int(v))
+	}
+	return invalidValue
+}
+
+func convertInt8(value string) reflect.Value {
+	if v, err := strconv.ParseInt(value, 10, 8); err == nil {
+		return reflect.ValueOf(int8(v))
+	}
+	return invalidValue
+}
+
+func convertInt16(value string) reflect.Value {
+	if v, err := strconv.ParseInt(value, 10, 16); err == nil {
+		return reflect.ValueOf(int16(v))
+	}
+	return invalidValue
+}
+
+func convertInt32(value string) reflect.Value {
+	if v, err := strconv.ParseInt(value, 10, 32); err == nil {
+		return reflect.ValueOf(int32(v))
+	}
+	return invalidValue
+}
+
+func convertInt64(value string) reflect.Value {
+	if v, err := strconv.ParseInt(value, 10, 64); err == nil {
+		return reflect.ValueOf(v)
+	}
+	return invalidValue
+}
+
+func convertString(value string) reflect.Value {
+	return reflect.ValueOf(value)
+}
+
+func convertUint(value string) reflect.Value {
+	if v, err := strconv.ParseUint(value, 10, 0); err == nil {
+		return reflect.ValueOf(uint(v))
+	}
+	return invalidValue
+}
+
+func convertUint8(value string) reflect.Value {
+	if v, err := strconv.ParseUint(value, 10, 8); err == nil {
+		return reflect.ValueOf(uint8(v))
+	}
+	return invalidValue
+}
+
+func convertUint16(value string) reflect.Value {
+	if v, err := strconv.ParseUint(value, 10, 16); err == nil {
+		return reflect.ValueOf(uint16(v))
+	}
+	return invalidValue
+}
+
+func convertUint32(value string) reflect.Value {
+	if v, err := strconv.ParseUint(value, 10, 32); err == nil {
+		return reflect.ValueOf(uint32(v))
+	}
+	return invalidValue
+}
+
+func convertUint64(value string) reflect.Value {
+	if v, err := strconv.ParseUint(value, 10, 64); err == nil {
+		return reflect.ValueOf(v)
+	}
+	return invalidValue
+}

schema/decoder.go

@@ -0,0 +1,521 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package schema
+
+import (
+	"encoding"
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+// NewDecoder returns a new Decoder.
+func NewDecoder() *Decoder {
+	return &Decoder{cache: newCache()}
+}
+
+// Decoder decodes values from a map[string][]string to a struct.
+type Decoder struct {
+	cache             *cache
+	zeroEmpty         bool
+	ignoreUnknownKeys bool
+}
+
+// SetAliasTag changes the tag used to locate custom field aliases.
+// The default tag is "schema".
+func (d *Decoder) SetAliasTag(tag string) {
+	d.cache.tag = tag
+}
+
+// ZeroEmpty controls the behaviour when the decoder encounters empty values
+// in a map.
+// If z is true and a key in the map has the empty string as a value
+// then the corresponding struct field is set to the zero value.
+// If z is false then empty strings are ignored.
+//
+// The default value is false, that is empty values do not change
+// the value of the struct field.
+func (d *Decoder) ZeroEmpty(z bool) {
+	d.zeroEmpty = z
+}
+
+// IgnoreUnknownKeys controls the behaviour when the decoder encounters unknown
+// keys in the map.
+// If i is true and an unknown field is encountered, it is ignored. This is
+// similar to how unknown keys are handled by encoding/json.
+// If i is false then Decode will return an error. Note that any valid keys
+// will still be decoded in to the target struct.
+//
+// To preserve backwards compatibility, the default value is false.
+func (d *Decoder) IgnoreUnknownKeys(i bool) {
+	d.ignoreUnknownKeys = i
+}
+
+// RegisterConverter registers a converter function for a custom type.
+func (d *Decoder) RegisterConverter(value interface{}, converterFunc Converter) {
+	d.cache.registerConverter(value, converterFunc)
+}
+
+// Decode decodes a map[string][]string to a struct.
+//
+// The first parameter must be a pointer to a struct.
+//
+// The second parameter is a map, typically url.Values from an HTTP request.
+// Keys are "paths" in dotted notation to the struct fields and nested structs.
+//
+// See the package documentation for a full explanation of the mechanics.
+func (d *Decoder) Decode(dst interface{}, src map[string][]string) error {
+	v := reflect.ValueOf(dst)
+	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
+		return errors.New("schema: interface must be a pointer to struct")
+	}
+	v = v.Elem()
+	t := v.Type()
+	errors := MultiError{}
+	for path, values := range src {
+		if parts, err := d.cache.parsePath(path, t); err == nil {
+			if err = d.decode(v, path, parts, values); err != nil {
+				errors[path] = err
+			}
+		} else if !d.ignoreUnknownKeys {
+			errors[path] = UnknownKeyError{Key: path}
+		}
+	}
+	errors.merge(d.checkRequired(t, src))
+	if len(errors) > 0 {
+		return errors
+	}
+	return nil
+}
+
+// checkRequired checks whether required fields are empty
+//
+// check type t recursively if t has struct fields.
+//
+// src is the source map for decoding, we use it here to see if those required fields are included in src
+func (d *Decoder) checkRequired(t reflect.Type, src map[string][]string) MultiError {
+	m, errs := d.findRequiredFields(t, "", "")
+	for key, fields := range m {
+		if isEmptyFields(fields, src) {
+			errs[key] = EmptyFieldError{Key: key}
+		}
+	}
+	return errs
+}
+
+// findRequiredFields recursively searches the struct type t for required fields.
+//
+// canonicalPrefix and searchPrefix are used to resolve full paths in dotted notation
+// for nested struct fields. canonicalPrefix is a complete path which never omits
+// any embedded struct fields. searchPrefix is a user-friendly path which may omit
+// some embedded struct fields to point promoted fields.
+func (d *Decoder) findRequiredFields(t reflect.Type, canonicalPrefix, searchPrefix string) (map[string][]fieldWithPrefix, MultiError) {
+	struc := d.cache.get(t)
+	if struc == nil {
+		// unexpect, cache.get never return nil
+		return nil, MultiError{canonicalPrefix + "*": errors.New("cache fail")}
+	}
+
+	m := map[string][]fieldWithPrefix{}
+	errs := MultiError{}
+	for _, f := range struc.fields {
+		if f.typ.Kind() == reflect.Struct {
+			fcprefix := canonicalPrefix + f.canonicalAlias + "."
+			for _, fspath := range f.paths(searchPrefix) {
+				fm, ferrs := d.findRequiredFields(f.typ, fcprefix, fspath+".")
+				for key, fields := range fm {
+					m[key] = append(m[key], fields...)
+				}
+				errs.merge(ferrs)
+			}
+		}
+		if f.isRequired {
+			key := canonicalPrefix + f.canonicalAlias
+			m[key] = append(m[key], fieldWithPrefix{
+				fieldInfo: f,
+				prefix:    searchPrefix,
+			})
+		}
+	}
+	return m, errs
+}
+
+type fieldWithPrefix struct {
+	*fieldInfo
+	prefix string
+}
+
+// isEmptyFields returns true if all of specified fields are empty.
+func isEmptyFields(fields []fieldWithPrefix, src map[string][]string) bool {
+	for _, f := range fields {
+		for _, path := range f.paths(f.prefix) {
+			v, ok := src[path]
+			if ok && !isEmpty(f.typ, v) {
+				return false
+			}
+			for key := range src {
+				if !isEmpty(f.typ, src[key]) && strings.HasPrefix(key, path) {
+					return false
+				}
+			}
+		}
+	}
+	return true
+}
+
+// isEmpty returns true if value is empty for specific type
+func isEmpty(t reflect.Type, value []string) bool {
+	if len(value) == 0 {
+		return true
+	}
+	switch t.Kind() {
+	case boolType, float32Type, float64Type, intType, int8Type, int32Type, int64Type, stringType, uint8Type, uint16Type, uint32Type, uint64Type:
+		return len(value[0]) == 0
+	}
+	return false
+}
+
+// decode fills a struct field using a parsed path.
+func (d *Decoder) decode(v reflect.Value, path string, parts []pathPart, values []string) error {
+	// Get the field walking the struct fields by index.
+	for _, name := range parts[0].path {
+		if v.Type().Kind() == reflect.Ptr {
+			if v.IsNil() {
+				v.Set(reflect.New(v.Type().Elem()))
+			}
+			v = v.Elem()
+		}
+
+		// alloc embedded structs
+		if v.Type().Kind() == reflect.Struct {
+			for i := 0; i < v.NumField(); i++ {
+				field := v.Field(i)
+				if field.Type().Kind() == reflect.Ptr && field.IsNil() && v.Type().Field(i).Anonymous {
+					field.Set(reflect.New(field.Type().Elem()))
+				}
+			}
+		}
+
+		v = v.FieldByName(name)
+	}
+	// Don't even bother for unexported fields.
+	if !v.CanSet() {
+		return nil
+	}
+
+	// Dereference if needed.
+	t := v.Type()
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+		if v.IsNil() {
+			v.Set(reflect.New(t))
+		}
+		v = v.Elem()
+	}
+
+	// Slice of structs. Let's go recursive.
+	if len(parts) > 1 {
+		idx := parts[0].index
+		if v.IsNil() || v.Len() < idx+1 {
+			value := reflect.MakeSlice(t, idx+1, idx+1)
+			if v.Len() < idx+1 {
+				// Resize it.
+				reflect.Copy(value, v)
+			}
+			v.Set(value)
+		}
+		return d.decode(v.Index(idx), path, parts[1:], values)
+	}
+
+	// Get the converter early in case there is one for a slice type.
+	conv := d.cache.converter(t)
+	m := isTextUnmarshaler(v)
+	if conv == nil && t.Kind() == reflect.Slice && m.IsSliceElement {
+		var items []reflect.Value
+		elemT := t.Elem()
+		isPtrElem := elemT.Kind() == reflect.Ptr
+		if isPtrElem {
+			elemT = elemT.Elem()
+		}
+
+		// Try to get a converter for the element type.
+		conv := d.cache.converter(elemT)
+		if conv == nil {
+			conv = builtinConverters[elemT.Kind()]
+			if conv == nil {
+				// As we are not dealing with slice of structs here, we don't need to check if the type
+				// implements TextUnmarshaler interface
+				return fmt.Errorf("schema: converter not found for %v", elemT)
+			}
+		}
+
+		for key, value := range values {
+			if value == "" {
+				if d.zeroEmpty {
+					items = append(items, reflect.Zero(elemT))
+				}
+			} else if m.IsValid {
+				u := reflect.New(elemT)
+				if m.IsSliceElementPtr {
+					u = reflect.New(reflect.PtrTo(elemT).Elem())
+				}
+				if err := u.Interface().(encoding.TextUnmarshaler).UnmarshalText([]byte(value)); err != nil {
+					return ConversionError{
+						Key:   path,
+						Type:  t,
+						Index: key,
+						Err:   err,
+					}
+				}
+				if m.IsSliceElementPtr {
+					items = append(items, u.Elem().Addr())
+				} else if u.Kind() == reflect.Ptr {
+					items = append(items, u.Elem())
+				} else {
+					items = append(items, u)
+				}
+			} else if item := conv(value); item.IsValid() {
+				if isPtrElem {
+					ptr := reflect.New(elemT)
+					ptr.Elem().Set(item)
+					item = ptr
+				}
+				if item.Type() != elemT && !isPtrElem {
+					item = item.Convert(elemT)
+				}
+				items = append(items, item)
+			} else {
+				if strings.Contains(value, ",") {
+					values := strings.Split(value, ",")
+					for _, value := range values {
+						if value == "" {
+							if d.zeroEmpty {
+								items = append(items, reflect.Zero(elemT))
+							}
+						} else if item := conv(value); item.IsValid() {
+							if isPtrElem {
+								ptr := reflect.New(elemT)
+								ptr.Elem().Set(item)
+								item = ptr
+							}
+							if item.Type() != elemT && !isPtrElem {
+								item = item.Convert(elemT)
+							}
+							items = append(items, item)
+						} else {
+							return ConversionError{
+								Key:   path,
+								Type:  elemT,
+								Index: key,
+							}
+						}
+					}
+				} else {
+					return ConversionError{
+						Key:   path,
+						Type:  elemT,
+						Index: key,
+					}
+				}
+			}
+		}
+		value := reflect.Append(reflect.MakeSlice(t, 0, 0), items...)
+		v.Set(value)
+	} else {
+		val := ""
+		// Use the last value provided if any values were provided
+		if len(values) > 0 {
+			val = values[len(values)-1]
+		}
+
+		if conv != nil {
+			if value := conv(val); value.IsValid() {
+				v.Set(value.Convert(t))
+			} else {
+				return ConversionError{
+					Key:   path,
+					Type:  t,
+					Index: -1,
+				}
+			}
+		} else if m.IsValid {
+			if m.IsPtr {
+				u := reflect.New(v.Type())
+				if err := u.Interface().(encoding.TextUnmarshaler).UnmarshalText([]byte(val)); err != nil {
+					return ConversionError{
+						Key:   path,
+						Type:  t,
+						Index: -1,
+						Err:   err,
+					}
+				}
+				v.Set(reflect.Indirect(u))
+			} else {
+				// If the value implements the encoding.TextUnmarshaler interface
+				// apply UnmarshalText as the converter
+				if err := m.Unmarshaler.UnmarshalText([]byte(val)); err != nil {
+					return ConversionError{
+						Key:   path,
+						Type:  t,
+						Index: -1,
+						Err:   err,
+					}
+				}
+			}
+		} else if val == "" {
+			if d.zeroEmpty {
+				v.Set(reflect.Zero(t))
+			}
+		} else if conv := builtinConverters[t.Kind()]; conv != nil {
+			if value := conv(val); value.IsValid() {
+				v.Set(value.Convert(t))
+			} else {
+				return ConversionError{
+					Key:   path,
+					Type:  t,
+					Index: -1,
+				}
+			}
+		} else {
+			return fmt.Errorf("schema: converter not found for %v", t)
+		}
+	}
+	return nil
+}
+
+func isTextUnmarshaler(v reflect.Value) unmarshaler {
+	// Create a new unmarshaller instance
+	m := unmarshaler{}
+	if m.Unmarshaler, m.IsValid = v.Interface().(encoding.TextUnmarshaler); m.IsValid {
+		return m
+	}
+	// As the UnmarshalText function should be applied to the pointer of the
+	// type, we check that type to see if it implements the necessary
+	// method.
+	if m.Unmarshaler, m.IsValid = reflect.New(v.Type()).Interface().(encoding.TextUnmarshaler); m.IsValid {
+		m.IsPtr = true
+		return m
+	}
+
+	// if v is []T or *[]T create new T
+	t := v.Type()
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	if t.Kind() == reflect.Slice {
+		// Check if the slice implements encoding.TextUnmarshaller
+		if m.Unmarshaler, m.IsValid = v.Interface().(encoding.TextUnmarshaler); m.IsValid {
+			return m
+		}
+		// If t is a pointer slice, check if its elements implement
+		// encoding.TextUnmarshaler
+		m.IsSliceElement = true
+		if t = t.Elem(); t.Kind() == reflect.Ptr {
+			t = reflect.PtrTo(t.Elem())
+			v = reflect.Zero(t)
+			m.IsSliceElementPtr = true
+			m.Unmarshaler, m.IsValid = v.Interface().(encoding.TextUnmarshaler)
+			return m
+		}
+	}
+
+	v = reflect.New(t)
+	m.Unmarshaler, m.IsValid = v.Interface().(encoding.TextUnmarshaler)
+	return m
+}
+
+// TextUnmarshaler helpers ----------------------------------------------------
+// unmarshaller contains information about a TextUnmarshaler type
+type unmarshaler struct {
+	Unmarshaler encoding.TextUnmarshaler
+	// IsValid indicates whether the resolved type indicated by the other
+	// flags implements the encoding.TextUnmarshaler interface.
+	IsValid bool
+	// IsPtr indicates that the resolved type is the pointer of the original
+	// type.
+	IsPtr bool
+	// IsSliceElement indicates that the resolved type is a slice element of
+	// the original type.
+	IsSliceElement bool
+	// IsSliceElementPtr indicates that the resolved type is a pointer to a
+	// slice element of the original type.
+	IsSliceElementPtr bool
+}
+
+// Errors ---------------------------------------------------------------------
+
+// ConversionError stores information about a failed conversion.
+type ConversionError struct {
+	Key   string       // key from the source map.
+	Type  reflect.Type // expected type of elem
+	Index int          // index for multi-value fields; -1 for single-value fields.
+	Err   error        // low-level error (when it exists)
+}
+
+func (e ConversionError) Error() string {
+	var output string
+
+	if e.Index < 0 {
+		output = fmt.Sprintf("schema: error converting value for %q", e.Key)
+	} else {
+		output = fmt.Sprintf("schema: error converting value for index %d of %q",
+			e.Index, e.Key)
+	}
+
+	if e.Err != nil {
+		output = fmt.Sprintf("%s. Details: %s", output, e.Err)
+	}
+
+	return output
+}
+
+// UnknownKeyError stores information about an unknown key in the source map.
+type UnknownKeyError struct {
+	Key string // key from the source map.
+}
+
+func (e UnknownKeyError) Error() string {
+	return fmt.Sprintf("schema: invalid path %q", e.Key)
+}
+
+// EmptyFieldError stores information about an empty required field.
+type EmptyFieldError struct {
+	Key string // required key in the source map.
+}
+
+func (e EmptyFieldError) Error() string {
+	return fmt.Sprintf("%v is empty", e.Key)
+}
+
+// MultiError stores multiple decoding errors.
+//
+// Borrowed from the App Engine SDK.
+type MultiError map[string]error
+
+func (e MultiError) Error() string {
+	s := ""
+	for _, err := range e {
+		s = err.Error()
+		break
+	}
+	switch len(e) {
+	case 0:
+		return "(0 errors)"
+	case 1:
+		return s
+	case 2:
+		return s + " (and 1 other error)"
+	}
+	return fmt.Sprintf("%s (and %d other errors)", s, len(e)-1)
+}
+
+func (e MultiError) merge(errors MultiError) {
+	for key, err := range errors {
+		if e[key] == nil {
+			e[key] = err
+		}
+	}
+}

schema/doc.go

@@ -0,0 +1,148 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package gorilla/schema fills a struct with form values.
+
+The basic usage is really simple. Given this struct:
+
+	type Person struct {
+		Name  string
+		Phone string
+	}
+
+...we can fill it passing a map to the Decode() function:
+
+	values := map[string][]string{
+		"Name":  {"John"},
+		"Phone": {"999-999-999"},
+	}
+	person := new(Person)
+	decoder := schema.NewDecoder()
+	decoder.Decode(person, values)
+
+This is just a simple example and it doesn't make a lot of sense to create
+the map manually. Typically it will come from a http.Request object and
+will be of type url.Values, http.Request.Form, or http.Request.MultipartForm:
+
+	func MyHandler(w http.ResponseWriter, r *http.Request) {
+		err := r.ParseForm()
+
+		if err != nil {
+			// Handle error
+		}
+
+		decoder := schema.NewDecoder()
+		// r.PostForm is a map of our POST form values
+		err := decoder.Decode(person, r.PostForm)
+
+		if err != nil {
+			// Handle error
+		}
+
+		// Do something with person.Name or person.Phone
+	}
+
+Note: it is a good idea to set a Decoder instance as a package global,
+because it caches meta-data about structs, and an instance can be shared safely:
+
+	var decoder = schema.NewDecoder()
+
+To define custom names for fields, use a struct tag "schema". To not populate
+certain fields, use a dash for the name and it will be ignored:
+
+	type Person struct {
+		Name  string `schema:"name"`  // custom name
+		Phone string `schema:"phone"` // custom name
+		Admin bool   `schema:"-"`     // this field is never set
+	}
+
+The supported field types in the destination struct are:
+
+	* bool
+	* float variants (float32, float64)
+	* int variants (int, int8, int16, int32, int64)
+	* string
+	* uint variants (uint, uint8, uint16, uint32, uint64)
+	* struct
+	* a pointer to one of the above types
+	* a slice or a pointer to a slice of one of the above types
+
+Non-supported types are simply ignored, however custom types can be registered
+to be converted.
+
+To fill nested structs, keys must use a dotted notation as the "path" for the
+field. So for example, to fill the struct Person below:
+
+	type Phone struct {
+		Label  string
+		Number string
+	}
+
+	type Person struct {
+		Name  string
+		Phone Phone
+	}
+
+...the source map must have the keys "Name", "Phone.Label" and "Phone.Number".
+This means that an HTML form to fill a Person struct must look like this:
+
+	<form>
+		<input type="text" name="Name">
+		<input type="text" name="Phone.Label">
+		<input type="text" name="Phone.Number">
+	</form>
+
+Single values are filled using the first value for a key from the source map.
+Slices are filled using all values for a key from the source map. So to fill
+a Person with multiple Phone values, like:
+
+	type Person struct {
+		Name   string
+		Phones []Phone
+	}
+
+...an HTML form that accepts three Phone values would look like this:
+
+	<form>
+		<input type="text" name="Name">
+		<input type="text" name="Phones.0.Label">
+		<input type="text" name="Phones.0.Number">
+		<input type="text" name="Phones.1.Label">
+		<input type="text" name="Phones.1.Number">
+		<input type="text" name="Phones.2.Label">
+		<input type="text" name="Phones.2.Number">
+	</form>
+
+Notice that only for slices of structs the slice index is required.
+This is needed for disambiguation: if the nested struct also had a slice
+field, we could not translate multiple values to it if we did not use an
+index for the parent struct.
+
+There's also the possibility to create a custom type that implements the
+TextUnmarshaler interface, and in this case there's no need to register
+a converter, like:
+
+	type Person struct {
+	  Emails []Email
+	}
+
+	type Email struct {
+	  *mail.Address
+	}
+
+	func (e *Email) UnmarshalText(text []byte) (err error) {
+		e.Address, err = mail.ParseAddress(string(text))
+		return
+	}
+
+...an HTML form that accepts three Email values would look like this:
+
+	<form>
+		<input type="email" name="Emails.0">
+		<input type="email" name="Emails.1">
+		<input type="email" name="Emails.2">
+	</form>
+*/
+package schema

schema/encoder.go

@@ -0,0 +1,214 @@
+package schema
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"reflect"
+	"strconv"
+)
+
+type encoderFunc func(reflect.Value) string
+
+// Encoder encodes values from a struct into url.Values.
+type Encoder struct {
+	cache  *cache
+	regenc map[reflect.Type]encoderFunc
+}
+
+// NewEncoder returns a new Encoder with defaults.
+func NewEncoder() *Encoder {
+	return &Encoder{cache: newCache(), regenc: make(map[reflect.Type]encoderFunc)}
+}
+
+// Encode encodes a struct into map[string][]string.
+//
+// Intended for use with url.Values.
+func (e *Encoder) Encode(src interface{}, dst map[string][]string) error {
+	v := reflect.ValueOf(src)
+
+	return e.encode(v, dst)
+}
+
+// RegisterEncoder registers a converter for encoding a custom type.
+func (e *Encoder) RegisterEncoder(value interface{}, encoder func(reflect.Value) string) {
+	e.regenc[reflect.TypeOf(value)] = encoder
+}
+
+// SetAliasTag changes the tag used to locate custom field aliases.
+// The default tag is "schema".
+func (e *Encoder) SetAliasTag(tag string) {
+	e.cache.tag = tag
+}
+
+// isValidStructPointer test if input value is a valid struct pointer.
+func isValidStructPointer(v reflect.Value) bool {
+	return v.Type().Kind() == reflect.Ptr && v.Elem().IsValid() && v.Elem().Type().Kind() == reflect.Struct
+}
+
+func isZero(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Func:
+	case reflect.Map, reflect.Slice:
+		return v.IsNil() || v.Len() == 0
+	case reflect.Array:
+		z := true
+		for i := 0; i < v.Len(); i++ {
+			z = z && isZero(v.Index(i))
+		}
+		return z
+	case reflect.Struct:
+		type zero interface {
+			IsZero() bool
+		}
+		if v.Type().Implements(reflect.TypeOf((*zero)(nil)).Elem()) {
+			iz := v.MethodByName("IsZero").Call([]reflect.Value{})[0]
+			return iz.Interface().(bool)
+		}
+		z := true
+		for i := 0; i < v.NumField(); i++ {
+			z = z && isZero(v.Field(i))
+		}
+		return z
+	}
+	// Compare other types directly:
+	z := reflect.Zero(v.Type())
+	return v.Interface() == z.Interface()
+}
+
+func (e *Encoder) encode(v reflect.Value, dst map[string][]string) error {
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+	if v.Kind() != reflect.Struct {
+		return errors.New("schema: interface must be a struct")
+	}
+	t := v.Type()
+
+	errors := MultiError{}
+
+	for i := 0; i < v.NumField(); i++ {
+		name, opts := fieldAlias(t.Field(i), e.cache.tag)
+		if name == "-" {
+			continue
+		}
+
+		// Encode struct pointer types if the field is a valid pointer and a struct.
+		if isValidStructPointer(v.Field(i)) && !e.hasCustomEncoder(v.Field(i).Type()) {
+			err := e.encode(v.Field(i).Elem(), dst)
+			if err != nil {
+				log.Fatal(err)
+			}
+			continue
+		}
+
+		encFunc := typeEncoder(v.Field(i).Type(), e.regenc)
+
+		// Encode non-slice types and custom implementations immediately.
+		if encFunc != nil {
+			value := encFunc(v.Field(i))
+			if opts.Contains("omitempty") && isZero(v.Field(i)) {
+				continue
+			}
+
+			dst[name] = append(dst[name], value)
+			continue
+		}
+
+		if v.Field(i).Type().Kind() == reflect.Struct {
+			err := e.encode(v.Field(i), dst)
+			if err != nil {
+				log.Fatal(err)
+			}
+			continue
+		}
+
+		if v.Field(i).Type().Kind() == reflect.Slice {
+			encFunc = typeEncoder(v.Field(i).Type().Elem(), e.regenc)
+		}
+
+		if encFunc == nil {
+			errors[v.Field(i).Type().String()] = fmt.Errorf("schema: encoder not found for %v", v.Field(i))
+			continue
+		}
+
+		// Encode a slice.
+		if v.Field(i).Len() == 0 && opts.Contains("omitempty") {
+			continue
+		}
+
+		dst[name] = []string{}
+		for j := 0; j < v.Field(i).Len(); j++ {
+			dst[name] = append(dst[name], encFunc(v.Field(i).Index(j)))
+		}
+	}
+
+	if len(errors) > 0 {
+		return errors
+	}
+	return nil
+}
+
+func (e *Encoder) hasCustomEncoder(t reflect.Type) bool {
+	_, exists := e.regenc[t]
+	return exists
+}
+
+func typeEncoder(t reflect.Type, reg map[reflect.Type]encoderFunc) encoderFunc {
+	if f, ok := reg[t]; ok {
+		return f
+	}
+
+	switch t.Kind() {
+	case reflect.Bool:
+		return encodeBool
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return encodeInt
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return encodeUint
+	case reflect.Float32:
+		return encodeFloat32
+	case reflect.Float64:
+		return encodeFloat64
+	case reflect.Ptr:
+		f := typeEncoder(t.Elem(), reg)
+		return func(v reflect.Value) string {
+			if v.IsNil() {
+				return "null"
+			}
+			return f(v.Elem())
+		}
+	case reflect.String:
+		return encodeString
+	default:
+		return nil
+	}
+}
+
+func encodeBool(v reflect.Value) string {
+	return strconv.FormatBool(v.Bool())
+}
+
+func encodeInt(v reflect.Value) string {
+	return strconv.FormatInt(int64(v.Int()), 10)
+}
+
+func encodeUint(v reflect.Value) string {
+	return strconv.FormatUint(uint64(v.Uint()), 10)
+}
+
+func encodeFloat(v reflect.Value, bits int) string {
+	return strconv.FormatFloat(v.Float(), 'f', 6, bits)
+}
+
+func encodeFloat32(v reflect.Value) string {
+	return encodeFloat(v, 32)
+}
+
+func encodeFloat64(v reflect.Value) string {
+	return encodeFloat(v, 64)
+}
+
+func encodeString(v reflect.Value) string {
+	return v.String()
+}

schema/encoder_test.go

@@ -0,0 +1,525 @@
+package schema
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+)
+
+type E1 struct {
+	F01 int     `schema:"f01"`
+	F02 int     `schema:"-"`
+	F03 string  `schema:"f03"`
+	F04 string  `schema:"f04,omitempty"`
+	F05 bool    `schema:"f05"`
+	F06 bool    `schema:"f06"`
+	F07 *string `schema:"f07"`
+	F08 *int8   `schema:"f08"`
+	F09 float64 `schema:"f09"`
+	F10 func()  `schema:"f10"`
+	F11 inner
+}
+type inner struct {
+	F12 int
+}
+
+func TestFilled(t *testing.T) {
+	f07 := "seven"
+	var f08 int8 = 8
+	s := &E1{
+		F01: 1,
+		F02: 2,
+		F03: "three",
+		F04: "four",
+		F05: true,
+		F06: false,
+		F07: &f07,
+		F08: &f08,
+		F09: 1.618,
+		F10: func() {},
+		F11: inner{12},
+	}
+
+	vals := make(map[string][]string)
+	errs := NewEncoder().Encode(s, vals)
+
+	valExists(t, "f01", "1", vals)
+	valNotExists(t, "f02", vals)
+	valExists(t, "f03", "three", vals)
+	valExists(t, "f05", "true", vals)
+	valExists(t, "f06", "false", vals)
+	valExists(t, "f07", "seven", vals)
+	valExists(t, "f08", "8", vals)
+	valExists(t, "f09", "1.618000", vals)
+	valExists(t, "F12", "12", vals)
+
+	emptyErr := MultiError{}
+	if errs.Error() == emptyErr.Error() {
+		t.Errorf("Expected error got %v", errs)
+	}
+}
+
+type Aa int
+
+type E3 struct {
+	F01 bool    `schema:"f01"`
+	F02 float32 `schema:"f02"`
+	F03 float64 `schema:"f03"`
+	F04 int     `schema:"f04"`
+	F05 int8    `schema:"f05"`
+	F06 int16   `schema:"f06"`
+	F07 int32   `schema:"f07"`
+	F08 int64   `schema:"f08"`
+	F09 string  `schema:"f09"`
+	F10 uint    `schema:"f10"`
+	F11 uint8   `schema:"f11"`
+	F12 uint16  `schema:"f12"`
+	F13 uint32  `schema:"f13"`
+	F14 uint64  `schema:"f14"`
+	F15 Aa      `schema:"f15"`
+}
+
+// Test compatibility with default decoder types.
+func TestCompat(t *testing.T) {
+	src := &E3{
+		F01: true,
+		F02: 4.2,
+		F03: 4.3,
+		F04: -42,
+		F05: -43,
+		F06: -44,
+		F07: -45,
+		F08: -46,
+		F09: "foo",
+		F10: 42,
+		F11: 43,
+		F12: 44,
+		F13: 45,
+		F14: 46,
+		F15: 1,
+	}
+	dst := &E3{}
+
+	vals := make(map[string][]string)
+	encoder := NewEncoder()
+	decoder := NewDecoder()
+
+	encoder.RegisterEncoder(src.F15, func(reflect.Value) string { return "1" })
+	decoder.RegisterConverter(src.F15, func(string) reflect.Value { return reflect.ValueOf(1) })
+
+	err := encoder.Encode(src, vals)
+	if err != nil {
+		t.Errorf("Encoder has non-nil error: %v", err)
+	}
+	err = decoder.Decode(dst, vals)
+	if err != nil {
+		t.Errorf("Decoder has non-nil error: %v", err)
+	}
+
+	if *src != *dst {
+		t.Errorf("Decoder-Encoder compatibility: expected %v, got %v\n", src, dst)
+	}
+}
+
+func TestEmpty(t *testing.T) {
+	s := &E1{
+		F01: 1,
+		F02: 2,
+		F03: "three",
+	}
+
+	estr := "schema: encoder not found for <nil>"
+	vals := make(map[string][]string)
+	err := NewEncoder().Encode(s, vals)
+	if err.Error() != estr {
+		t.Errorf("Expected: %s, got %v", estr, err)
+	}
+
+	valExists(t, "f03", "three", vals)
+	valNotExists(t, "f04", vals)
+}
+
+func TestStruct(t *testing.T) {
+	estr := "schema: interface must be a struct"
+	vals := make(map[string][]string)
+	err := NewEncoder().Encode("hello world", vals)
+
+	if err.Error() != estr {
+		t.Errorf("Expected: %s, got %v", estr, err)
+	}
+}
+
+func TestSlices(t *testing.T) {
+	type oneAsWord int
+	ones := []oneAsWord{1, 2}
+	s1 := &struct {
+		ones     []oneAsWord `schema:"ones"`
+		ints     []int       `schema:"ints"`
+		nonempty []int       `schema:"nonempty"`
+		empty    []int       `schema:"empty,omitempty"`
+	}{ones, []int{1, 1}, []int{}, []int{}}
+	vals := make(map[string][]string)
+
+	encoder := NewEncoder()
+	encoder.RegisterEncoder(ones[0], func(v reflect.Value) string { return "one" })
+	err := encoder.Encode(s1, vals)
+	if err != nil {
+		t.Errorf("Encoder has non-nil error: %v", err)
+	}
+
+	valsExist(t, "ones", []string{"one", "one"}, vals)
+	valsExist(t, "ints", []string{"1", "1"}, vals)
+	valsExist(t, "nonempty", []string{}, vals)
+	valNotExists(t, "empty", vals)
+}
+
+func TestCompatSlices(t *testing.T) {
+	type oneAsWord int
+	type s1 struct {
+		Ones []oneAsWord `schema:"ones"`
+		Ints []int       `schema:"ints"`
+	}
+	ones := []oneAsWord{1, 1}
+	src := &s1{ones, []int{1, 1}}
+	vals := make(map[string][]string)
+	dst := &s1{}
+
+	encoder := NewEncoder()
+	encoder.RegisterEncoder(ones[0], func(v reflect.Value) string { return "one" })
+
+	decoder := NewDecoder()
+	decoder.RegisterConverter(ones[0], func(s string) reflect.Value {
+		if s == "one" {
+			return reflect.ValueOf(1)
+		}
+		return reflect.ValueOf(2)
+	})
+
+	err := encoder.Encode(src, vals)
+	if err != nil {
+		t.Errorf("Encoder has non-nil error: %v", err)
+	}
+	err = decoder.Decode(dst, vals)
+	if err != nil {
+		t.Errorf("Dncoder has non-nil error: %v", err)
+	}
+
+	if len(src.Ints) != len(dst.Ints) || len(src.Ones) != len(dst.Ones) {
+		t.Fatalf("Expected %v, got %v", src, dst)
+	}
+
+	for i, v := range src.Ones {
+		if dst.Ones[i] != v {
+			t.Fatalf("Expected %v, got %v", v, dst.Ones[i])
+		}
+	}
+
+	for i, v := range src.Ints {
+		if dst.Ints[i] != v {
+			t.Fatalf("Expected %v, got %v", v, dst.Ints[i])
+		}
+	}
+}
+
+func TestRegisterEncoder(t *testing.T) {
+	type oneAsWord int
+	type twoAsWord int
+	type oneSliceAsWord []int
+
+	s1 := &struct {
+		oneAsWord
+		twoAsWord
+		oneSliceAsWord
+	}{1, 2, []int{1, 1}}
+	v1 := make(map[string][]string)
+
+	encoder := NewEncoder()
+	encoder.RegisterEncoder(s1.oneAsWord, func(v reflect.Value) string { return "one" })
+	encoder.RegisterEncoder(s1.twoAsWord, func(v reflect.Value) string { return "two" })
+	encoder.RegisterEncoder(s1.oneSliceAsWord, func(v reflect.Value) string { return "one" })
+
+	err := encoder.Encode(s1, v1)
+	if err != nil {
+		t.Errorf("Encoder has non-nil error: %v", err)
+	}
+
+	valExists(t, "oneAsWord", "one", v1)
+	valExists(t, "twoAsWord", "two", v1)
+	valExists(t, "oneSliceAsWord", "one", v1)
+}
+
+func TestEncoderOrder(t *testing.T) {
+	type builtinEncoderSimple int
+	type builtinEncoderSimpleOverridden int
+	type builtinEncoderSlice []int
+	type builtinEncoderSliceOverridden []int
+	type builtinEncoderStruct struct{ nr int }
+	type builtinEncoderStructOverridden struct{ nr int }
+
+	s1 := &struct {
+		builtinEncoderSimple           `schema:"simple"`
+		builtinEncoderSimpleOverridden `schema:"simple_overridden"`
+		builtinEncoderSlice            `schema:"slice"`
+		builtinEncoderSliceOverridden  `schema:"slice_overridden"`
+		builtinEncoderStruct           `schema:"struct"`
+		builtinEncoderStructOverridden `schema:"struct_overridden"`
+	}{
+		1,
+		1,
+		[]int{2},
+		[]int{2},
+		builtinEncoderStruct{3},
+		builtinEncoderStructOverridden{3},
+	}
+	v1 := make(map[string][]string)
+
+	encoder := NewEncoder()
+	encoder.RegisterEncoder(s1.builtinEncoderSimpleOverridden, func(v reflect.Value) string { return "one" })
+	encoder.RegisterEncoder(s1.builtinEncoderSliceOverridden, func(v reflect.Value) string { return "two" })
+	encoder.RegisterEncoder(s1.builtinEncoderStructOverridden, func(v reflect.Value) string { return "three" })
+
+	err := encoder.Encode(s1, v1)
+	if err != nil {
+		t.Errorf("Encoder has non-nil error: %v", err)
+	}
+
+	valExists(t, "simple", "1", v1)
+	valExists(t, "simple_overridden", "one", v1)
+	valExists(t, "slice", "2", v1)
+	valExists(t, "slice_overridden", "two", v1)
+	valExists(t, "nr", "3", v1)
+	valExists(t, "struct_overridden", "three", v1)
+}
+
+func valExists(t *testing.T, key string, expect string, result map[string][]string) {
+	valsExist(t, key, []string{expect}, result)
+}
+
+func valsExist(t *testing.T, key string, expect []string, result map[string][]string) {
+	vals, ok := result[key]
+	if !ok {
+		t.Fatalf("Key not found. Expected: %s", key)
+	}
+
+	if len(expect) != len(vals) {
+		t.Fatalf("Expected: %v, got: %v", expect, vals)
+	}
+
+	for i, v := range expect {
+		if vals[i] != v {
+			t.Fatalf("Unexpected value. Expected: %v, got %v", v, vals[i])
+		}
+	}
+}
+
+func valNotExists(t *testing.T, key string, result map[string][]string) {
+	if val, ok := result[key]; ok {
+		t.Error("Key not omitted. Expected: empty; got: " + val[0] + ".")
+	}
+}
+
+func valsLength(t *testing.T, expectedLength int, result map[string][]string) {
+	length := len(result)
+	if length != expectedLength {
+		t.Errorf("Expected length of %v, but got %v", expectedLength, length)
+	}
+}
+
+func noError(t *testing.T, err error) {
+	if err != nil {
+		t.Errorf("Unexpected error. Got %v", err)
+	}
+}
+
+type E4 struct {
+	ID string `json:"id"`
+}
+
+func TestEncoderSetAliasTag(t *testing.T) {
+	data := map[string][]string{}
+
+	s := E4{
+		ID: "foo",
+	}
+	encoder := NewEncoder()
+	encoder.SetAliasTag("json")
+	err := encoder.Encode(&s, data)
+	if err != nil {
+		t.Fatalf("Failed to encode: %v", err)
+	}
+	valExists(t, "id", "foo", data)
+}
+
+type E5 struct {
+	F01 int      `schema:"f01,omitempty"`
+	F02 string   `schema:"f02,omitempty"`
+	F03 *string  `schema:"f03,omitempty"`
+	F04 *int8    `schema:"f04,omitempty"`
+	F05 float64  `schema:"f05,omitempty"`
+	F06 E5F06    `schema:"f06,omitempty"`
+	F07 E5F06    `schema:"f07,omitempty"`
+	F08 []string `schema:"f08,omitempty"`
+	F09 []string `schema:"f09,omitempty"`
+}
+
+type E5F06 struct {
+	F0601 string `schema:"f0601,omitempty"`
+}
+
+func TestEncoderWithOmitempty(t *testing.T) {
+	vals := map[string][]string{}
+
+	s := E5{
+		F02: "test",
+		F07: E5F06{
+			F0601: "test",
+		},
+		F09: []string{"test"},
+	}
+
+	encoder := NewEncoder()
+	err := encoder.Encode(&s, vals)
+	if err != nil {
+		t.Fatalf("Failed to encode: %v", err)
+	}
+
+	valNotExists(t, "f01", vals)
+	valExists(t, "f02", "test", vals)
+	valNotExists(t, "f03", vals)
+	valNotExists(t, "f04", vals)
+	valNotExists(t, "f05", vals)
+	valNotExists(t, "f06", vals)
+	valExists(t, "f0601", "test", vals)
+	valNotExists(t, "f08", vals)
+	valsExist(t, "f09", []string{"test"}, vals)
+}
+
+type E6 struct {
+	F01 *inner
+	F02 *inner
+	F03 *inner `schema:",omitempty"`
+}
+
+func TestStructPointer(t *testing.T) {
+	vals := map[string][]string{}
+	s := E6{
+		F01: &inner{2},
+	}
+
+	encoder := NewEncoder()
+	err := encoder.Encode(&s, vals)
+	if err != nil {
+		t.Fatalf("Failed to encode: %v", err)
+	}
+	valExists(t, "F12", "2", vals)
+	valExists(t, "F02", "null", vals)
+	valNotExists(t, "F03", vals)
+}
+
+func TestRegisterEncoderCustomArrayType(t *testing.T) {
+	type CustomInt []int
+	type S1 struct {
+		SomeInts CustomInt `schema:",omitempty"`
+	}
+
+	ss := []S1{
+		{},
+		{CustomInt{}},
+		{CustomInt{1, 2, 3}},
+	}
+
+	for s := range ss {
+		vals := map[string][]string{}
+
+		encoder := NewEncoder()
+		encoder.RegisterEncoder(CustomInt{}, func(value reflect.Value) string {
+			return fmt.Sprint(value.Interface())
+		})
+
+		err := encoder.Encode(ss[s], vals)
+		if err != nil {
+			t.Fatalf("Failed to encode: %v", err)
+		}
+	}
+}
+
+func TestRegisterEncoderStructIsZero(t *testing.T) {
+	type S1 struct {
+		SomeTime1 time.Time `schema:"tim1,omitempty"`
+		SomeTime2 time.Time `schema:"tim2,omitempty"`
+	}
+
+	ss := []*S1{
+		{
+			SomeTime1: time.Date(2020, 8, 4, 13, 30, 1, 0, time.UTC),
+		},
+	}
+
+	for s := range ss {
+		vals := map[string][]string{}
+
+		encoder := NewEncoder()
+		encoder.RegisterEncoder(time.Time{}, func(value reflect.Value) string {
+			return value.Interface().(time.Time).Format(time.RFC3339Nano)
+		})
+
+		err := encoder.Encode(ss[s], vals)
+		if err != nil {
+			t.Errorf("Encoder has non-nil error: %v", err)
+		}
+
+		ta, ok := vals["tim1"]
+		if !ok {
+			t.Error("expected tim1 to be present")
+		}
+
+		if len(ta) != 1 {
+			t.Error("expected tim1 to be present")
+		}
+
+		if ta[0] != "2020-08-04T13:30:01Z" {
+			t.Error("expected correct tim1 time")
+		}
+
+		_, ok = vals["tim2"]
+		if ok {
+			t.Error("expected tim1 not to be present")
+		}
+	}
+}
+
+func TestRegisterEncoderWithPtrType(t *testing.T) {
+	type CustomTime struct {
+		time time.Time
+	}
+
+	type S1 struct {
+		DateStart *CustomTime
+		DateEnd   *CustomTime
+		Empty     *CustomTime `schema:"empty,omitempty"`
+	}
+
+	ss := S1{
+		DateStart: &CustomTime{time: time.Now()},
+		DateEnd:   nil,
+	}
+
+	encoder := NewEncoder()
+	encoder.RegisterEncoder(&CustomTime{}, func(value reflect.Value) string {
+		if value.IsNil() {
+			return ""
+		}
+
+		custom := value.Interface().(*CustomTime)
+		return custom.time.String()
+	})
+
+	vals := map[string][]string{}
+	err := encoder.Encode(ss, vals)
+
+	noError(t, err)
+	valsLength(t, 2, vals)
+	valExists(t, "DateStart", ss.DateStart.time.String(), vals)
+	valExists(t, "DateEnd", "", vals)
+}

schema/license.txt

@@ -0,0 +1,27 @@
+Copyright (c) 2023 The Gorilla Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+	 * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+	 * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+	 * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

schema/readme.md

@@ -0,0 +1,94 @@
+# gorilla/schema
+
+![testing](https://github.com/gorilla/schema/actions/workflows/test.yml/badge.svg)
+[![codecov](https://codecov.io/github/gorilla/schema/branch/main/graph/badge.svg)](https://codecov.io/github/gorilla/schema)
+[![godoc](https://godoc.org/github.com/gorilla/schema?status.svg)](https://godoc.org/github.com/gorilla/schema)
+[![sourcegraph](https://sourcegraph.com/github.com/gorilla/schema/-/badge.svg)](https://sourcegraph.com/github.com/gorilla/schema?badge)
+
+
+![Gorilla Logo](https://github.com/gorilla/.github/assets/53367916/d92caabf-98e0-473e-bfbf-ab554ba435e5)
+
+Package gorilla/schema converts structs to and from form values.
+
+## Example
+
+Here's a quick example: we parse POST form values and then decode them into a struct:
+
+```go
+// Set a Decoder instance as a package global, because it caches
+// meta-data about structs, and an instance can be shared safely.
+var decoder = schema.NewDecoder()
+
+type Person struct {
+    Name  string
+    Phone string
+}
+
+func MyHandler(w http.ResponseWriter, r *http.Request) {
+    err := r.ParseForm()
+    if err != nil {
+        // Handle error
+    }
+
+    var person Person
+
+    // r.PostForm is a map of our POST form values
+    err = decoder.Decode(&person, r.PostForm)
+    if err != nil {
+        // Handle error
+    }
+
+    // Do something with person.Name or person.Phone
+}
+```
+
+Conversely, contents of a struct can be encoded into form values. Here's a variant of the previous example using the Encoder:
+
+```go
+var encoder = schema.NewEncoder()
+
+func MyHttpRequest() {
+    person := Person{"Jane Doe", "555-5555"}
+    form := url.Values{}
+
+    err := encoder.Encode(person, form)
+
+    if err != nil {
+        // Handle error
+    }
+
+    // Use form values, for example, with an http client
+    client := new(http.Client)
+    res, err := client.PostForm("http://my-api.test", form)
+}
+
+```
+
+To define custom names for fields, use a struct tag "schema". To not populate certain fields, use a dash for the name and it will be ignored:
+
+```go
+type Person struct {
+    Name  string `schema:"name,required"`  // custom name, must be supplied
+    Phone string `schema:"phone"`          // custom name
+    Admin bool   `schema:"-"`              // this field is never set
+}
+```
+
+The supported field types in the struct are:
+
+* bool
+* float variants (float32, float64)
+* int variants (int, int8, int16, int32, int64)
+* string
+* uint variants (uint, uint8, uint16, uint32, uint64)
+* struct
+* a pointer to one of the above types
+* a slice or a pointer to a slice of one of the above types
+
+Unsupported types are simply ignored, however custom types can be registered to be converted.
+
+More examples are available on the Gorilla website: https://www.gorillatoolkit.org/pkg/schema
+
+## License
+
+BSD licensed. See the LICENSE file for details.

short.go

@@ -6,3 +6,4 @@ func Redirect(u string, status Status) Handler {
 		c.Redirect(u, status)
 	})
 }
+