brotli.go

package caddybrotli

import (
	"fmt"
	"strconv"

	"github.com/andybalholm/brotli"
	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
	"github.com/caddyserver/caddy/v2/modules/caddyhttp/encode"
)

func init() {
	caddy.RegisterModule(Brotli{})
}

// Brotli can create brotli encoders.
type Brotli struct {
	Level int `json:"level,omitempty"`
}

// CaddyModule returns the Caddy module information.
func (Brotli) CaddyModule() caddy.ModuleInfo {
	return caddy.ModuleInfo{
		ID:  "http.encoders.br",
		New: func() caddy.Module { return new(Brotli) },
	}
}

// UnmarshalCaddyfile sets up the encoder from Caddyfile tokens.
func (b *Brotli) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
	b.Level = -1
	for d.Next() {
		if !d.NextArg() {
			continue
		}
		level, err := strconv.Atoi(d.Val())
		if err != nil {
			return err
		}
		b.Level = level
	}
	return nil
}

// Provision provisions b's configuration.
func (b *Brotli) Provision(ctx caddy.Context) error {
	if b.Level == -1 {
		b.Level = defaultBrotliLevel
	}
	return nil
}

// Validate validates b's configuration.
func (b Brotli) Validate() error {
	if b.Level < brotli.BestSpeed {
		return fmt.Errorf("quality too low; must be >= %d", brotli.BestSpeed)
	}
	if b.Level > brotli.BestCompression {
		return fmt.Errorf("quality too high; must be <= %d", brotli.BestCompression)
	}
	return nil
}

// AcceptEncoding returns the name of the encoding as
// used in the Accept-Encoding request headers.
func (Brotli) AcceptEncoding() string { return "br" }

// NewEncoder returns a new brotli writer.
func (b Brotli) NewEncoder() encode.Encoder {
	writer := brotli.NewWriterLevel(nil, b.Level)
	return writer
}

const defaultBrotliLevel = 4

// Interface guards.
var (
	_ encode.Encoding       = (*Brotli)(nil)
	_ caddy.Provisioner     = (*Brotli)(nil)
	_ caddy.Validator       = (*Brotli)(nil)
	_ caddyfile.Unmarshaler = (*Brotli)(nil)
)