bouncer/internal/rule/http/request.go

package http

import (
	"context"
	"fmt"
	"net/url"
	"strconv"
	"strings"
	"time"

	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
	"forge.cadoles.com/cadoles/bouncer/internal/rule"
	"github.com/expr-lang/expr"
	"github.com/pkg/errors"
)

func setRequestHostFunc() expr.Option {
	return expr.Function(
		"set_host",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			host, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			r, ok := ctxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.Host = host

			return true, nil
		},
		new(func(context.Context, string) bool),
	)
}

func setRequestURLFunc() expr.Option {
	return expr.Function(
		"set_url",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			rawURL, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			url, err := url.Parse(rawURL)
			if err != nil {
				return false, errors.WithStack(err)
			}

			r, ok := ctxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.URL = url

			return true, nil
		},
		new(func(context.Context, string) bool),
	)
}

func addRequestHeaderFunc() expr.Option {
	return expr.Function(
		"add_header",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			name, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			value := formatValue(params[2])

			r, ok := ctxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.Header.Add(name, value)

			return true, nil
		},
		new(func(context.Context, string, string) bool),
	)
}

func setRequestHeaderFunc() expr.Option {
	return expr.Function(
		"set_header",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			name, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			value := formatValue(params[2])

			r, ok := ctxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.Header.Set(name, value)

			return true, nil
		},
		new(func(context.Context, string, string) bool),
	)
}

func delRequestHeadersFunc() expr.Option {
	return expr.Function(
		"del_headers",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			pattern, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			r, ok := ctxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			deleted := false

			for key := range r.Header {
				if !wildcard.Match(key, pattern) {
					continue
				}

				r.Header.Del(key)
				deleted = true
			}

			return deleted, nil
		},
		new(func(context.Context, string) bool),
	)
}

func formatValue(v any) string {
	var value string
	switch v := v.(type) {
	case []string:
		value = strings.Join(v, ",")
	case time.Time:
		value = strconv.FormatInt(v.UTC().Unix(), 10)
	case time.Duration:
		value = strconv.FormatInt(int64(v.Seconds()), 10)
	default:
		value = fmt.Sprintf("%v", v)
	}
	return value
}