spf13--viper/encoding.go

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package viper
import (
"errors"
"strings"
"sync"
"github.com/spf13/viper/internal/encoding/dotenv"
"github.com/spf13/viper/internal/encoding/json"
"github.com/spf13/viper/internal/encoding/toml"
"github.com/spf13/viper/internal/encoding/yaml"
)
// Encoder encodes Viper's internal data structures into a byte representation.
// It's primarily used for encoding a map[string]any into a file format.
type Encoder interface {
Encode(v map[string]any) ([]byte, error)
}
// Decoder decodes the contents of a byte slice into Viper's internal data structures.
// It's primarily used for decoding contents of a file into a map[string]any.
type Decoder interface {
Decode(b []byte, v map[string]any) error
}
// Codec combines [Encoder] and [Decoder] interfaces.
type Codec interface {
Encoder
Decoder
}
// TODO: consider adding specific errors for not found scenarios
// EncoderRegistry returns an [Encoder] for a given format.
//
// Format is case-insensitive.
//
// [EncoderRegistry] returns an error if no [Encoder] is registered for the format.
type EncoderRegistry interface {
Encoder(format string) (Encoder, error)
}
// DecoderRegistry returns an [Decoder] for a given format.
//
// Format is case-insensitive.
//
// [DecoderRegistry] returns an error if no [Decoder] is registered for the format.
type DecoderRegistry interface {
Decoder(format string) (Decoder, error)
}
// [CodecRegistry] combines [EncoderRegistry] and [DecoderRegistry] interfaces.
type CodecRegistry interface {
EncoderRegistry
DecoderRegistry
}
// WithEncoderRegistry sets a custom [EncoderRegistry].
func WithEncoderRegistry(r EncoderRegistry) Option {
return optionFunc(func(v *Viper) {
v.encoderRegistry = r
})
}
// WithDecoderRegistry sets a custom [DecoderRegistry].
func WithDecoderRegistry(r DecoderRegistry) Option {
return optionFunc(func(v *Viper) {
v.decoderRegistry = r
})
}
// WithCodecRegistry sets a custom [EncoderRegistry] and [DecoderRegistry].
func WithCodecRegistry(r CodecRegistry) Option {
return optionFunc(func(v *Viper) {
v.encoderRegistry = r
v.decoderRegistry = r
})
}
// DefaultCodecRegistry is a simple implementation of [CodecRegistry] that allows registering custom [Codec]s.
type DefaultCodecRegistry struct {
codecs map[string]Codec
mu sync.RWMutex
once sync.Once
}
// NewCodecRegistry returns a new [CodecRegistry], ready to accept custom [Codec]s.
func NewCodecRegistry() *DefaultCodecRegistry {
r := &DefaultCodecRegistry{}
r.init()
return r
}
func (r *DefaultCodecRegistry) init() {
r.once.Do(func() {
r.codecs = map[string]Codec{}
})
}
// RegisterCodec registers a custom [Codec].
//
// Format is case-insensitive.
func (r *DefaultCodecRegistry) RegisterCodec(format string, codec Codec) error {
r.init()
r.mu.Lock()
defer r.mu.Unlock()
r.codecs[strings.ToLower(format)] = codec
return nil
}
// Encoder implements the [EncoderRegistry] interface.
//
// Format is case-insensitive.
func (r *DefaultCodecRegistry) Encoder(format string) (Encoder, error) {
encoder, ok := r.codec(format)
if !ok {
return nil, errors.New("encoder not found for this format")
}
return encoder, nil
}
// Decoder implements the [DecoderRegistry] interface.
//
// Format is case-insensitive.
func (r *DefaultCodecRegistry) Decoder(format string) (Decoder, error) {
decoder, ok := r.codec(format)
if !ok {
return nil, errors.New("decoder not found for this format")
}
return decoder, nil
}
func (r *DefaultCodecRegistry) codec(format string) (Codec, bool) {
r.mu.Lock()
defer r.mu.Unlock()
format = strings.ToLower(format)
if r.codecs != nil {
codec, ok := r.codecs[format]
if ok {
return codec, true
}
}
switch format {
case "yaml", "yml":
return yaml.Codec{}, true
case "json":
return json.Codec{}, true
case "toml":
return toml.Codec{}, true
case "dotenv", "env":
return &dotenv.Codec{}, true
}
return nil, false
}