echo/middleware/middleware.go

package middleware

import (
	"net/http"
	"net/url"
	"regexp"
	"strconv"
	"strings"

	"github.com/labstack/echo/v4"
)

type (
	// Skipper defines a function to skip middleware. Returning true skips processing
	// the middleware.
	Skipper func(echo.Context) bool

	// BeforeFunc defines a function which is executed just before the middleware.
	BeforeFunc func(echo.Context)
)

func captureTokens(pattern *regexp.Regexp, input string) *strings.Replacer {
	groups := pattern.FindAllStringSubmatch(input, -1)
	if groups == nil {
		return nil
	}
	values := groups[0][1:]
	replace := make([]string, 2*len(values))
	for i, v := range values {
		j := 2 * i
		replace[j] = "$" + strconv.Itoa(i+1)
		replace[j+1] = v
	}
	return strings.NewReplacer(replace...)
}

//rewritePath sets request url path and raw path
func rewritePath(replacer *strings.Replacer, target string, req *http.Request) error {
	replacerRawPath := replacer.Replace(target)
	replacerPath, err := url.PathUnescape(replacerRawPath)
	if err != nil {
		return err
	}
	req.URL.Path, req.URL.RawPath = replacerPath, replacerRawPath
	return nil
}

// DefaultSkipper returns false which processes the middleware.
func DefaultSkipper(echo.Context) bool {
	return false
}