forked from labstack/armor
/
plugin.go
193 lines (175 loc) · 4.1 KB
/
plugin.go
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package plugin
import (
"bytes"
"fmt"
"io"
"strings"
"sync"
"github.com/Knetic/govaluate"
"github.com/labstack/armor"
"github.com/labstack/echo"
"github.com/labstack/gommon/log"
"github.com/mitchellh/mapstructure"
"github.com/valyala/fasttemplate"
)
type (
Plugin interface {
Name() string
Init() error
Process(echo.HandlerFunc) echo.HandlerFunc
Priority() int
}
// Base defines the base struct for plugins.
Base struct {
name string
Skip string `json:"skip"`
Middleware echo.MiddlewareFunc `json:"-"`
Armor *armor.Armor `json:"-"`
Echo *echo.Echo `json:"-"`
Logger *log.Logger `json:"-"`
}
Template struct {
*fasttemplate.Template
}
Expression struct {
*fasttemplate.Template
}
)
var (
bufferPool sync.Pool
)
// Initialize
func init() {
bufferPool = sync.Pool{
New: func() interface{} {
return new(bytes.Buffer)
},
}
}
// lookup returns a plugin by name.
func lookup(base Base) (p Plugin) {
switch base.Name() {
case "body-limit":
p = &BodyLimit{Base: base}
case "logger":
p = &Logger{Base: base}
case "cube":
p = &Cube{Base: base}
case "redirect":
p = &Redirect{Base: base}
case "https-redirect":
p = &HTTPSRedirect{Base: base}
case "https-www-redirect":
p = &HTTPSWWWRedirect{Base: base}
case "https-non-www-redirect":
p = &HTTPSNonWWWRedirect{Base: base}
case "www-redirect":
p = &WWWRedirect{Base: base}
case "non-www-redirect":
p = &NonWWWRedirect{Base: base}
case "add-trailing-slash":
p = &AddTrailingSlash{Base: base}
case "remove-trailing-slash":
p = &RemoveTrailingSlash{Base: base}
case "secure":
p = &Secure{Base: base}
case "cors":
p = &CORS{Base: base}
case "gzip":
p = &Gzip{Base: base}
case "header":
p = &Header{Base: base}
case "proxy":
p = &Proxy{Base: base}
case "static":
p = &Static{Base: base}
case "file":
p = &File{Base: base}
case "nats":
// p = &NATS{Base: base}
}
return
}
// Decode searches the plugin by name, decodes the provided map into plugin and
// calls Plugin#Init().
func Decode(pi armor.Plugin, a *armor.Armor, e *echo.Echo) (p Plugin, err error) {
name := pi["name"].(string)
base := Base{
name: name,
Skip: "false",
Armor: a,
Echo: e,
Logger: a.Logger,
}
if p = lookup(base); p == nil {
return p, fmt.Errorf("plugin=%s not found", name)
}
dec, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
TagName: "json",
Result: p,
})
if err = dec.Decode(pi); err != nil {
return
}
return p, p.Init()
}
func (b *Base) Name() string {
return b.name
}
func NewTemplate(t string) *Template {
return &Template{Template: fasttemplate.New(t, "${", "}")}
}
func (t *Template) Execute(c echo.Context) (string, error) {
buf := bufferPool.Get().(*bytes.Buffer)
buf.Reset()
defer bufferPool.Put(buf)
_, err := t.ExecuteFunc(buf, func(w io.Writer, tag string) (int, error) {
mapTag(buf, c, tag)
return 0, nil
})
return buf.String(), err
}
func NewExpression(t string) *Expression {
return &Expression{fasttemplate.New(t, "${", "}")}
}
func (e *Expression) Evaluate(c echo.Context) (interface{}, error) {
buf := bufferPool.Get().(*bytes.Buffer)
buf.Reset()
defer bufferPool.Put(buf)
if _, err := e.ExecuteFunc(buf, func(w io.Writer, tag string) (int, error) {
buf.WriteString("'")
mapTag(buf, c, tag)
buf.WriteString("'")
return 0, nil
}); err != nil {
return nil, err
}
expr, err := govaluate.NewEvaluableExpression(buf.String())
if err != nil {
return nil, err
}
return expr.Evaluate(nil)
}
func mapTag(b *bytes.Buffer, c echo.Context, t string) {
switch t {
case "scheme":
b.WriteString(c.Scheme())
case "method":
b.WriteString(c.Request().Method)
case "uri":
b.WriteString(c.Request().RequestURI)
case "path":
b.WriteString(c.Request().URL.Path)
default:
switch {
case strings.HasPrefix(t, "header:"):
b.WriteString(c.Request().Header.Get(t[7:]))
case strings.HasPrefix(t, "path:"):
b.WriteString(c.Param(t[5:]))
case strings.HasPrefix(t, "query:"):
b.WriteString(c.QueryParam(t[6:]))
case strings.HasPrefix(t, "form:"):
b.WriteString(c.FormValue(t[5:]))
}
}
}