feat(rewriter): add redirect(), get_cookie(), add_cookie() methods to rule engine (#36)

internal/rule/http/request.go

@@ -3,6 +3,7 @@ package http
 import (
 	"context"
 	"fmt"
+	"net/http"
 	"net/url"
 	"strconv"
 	"strings"
@@ -28,7 +29,7 @@ func setRequestHostFunc() expr.Option {
 				return nil, errors.WithStack(err)
 			}
 
-			r, ok := ctxRequest(ctx)
+			r, ok := CtxRequest(ctx)
 			if !ok {
 				return nil, errors.New("could not find http request in context")
 			}
@@ -60,7 +61,7 @@ func setRequestURLFunc() expr.Option {
 				return false, errors.WithStack(err)
 			}
 
-			r, ok := ctxRequest(ctx)
+			r, ok := CtxRequest(ctx)
 			if !ok {
 				return nil, errors.New("could not find http request in context")
 			}
@@ -89,7 +90,7 @@ func addRequestHeaderFunc() expr.Option {
 
 			value := formatValue(params[2])
 
-			r, ok := ctxRequest(ctx)
+			r, ok := CtxRequest(ctx)
 			if !ok {
 				return nil, errors.New("could not find http request in context")
 			}
@@ -118,7 +119,7 @@ func setRequestHeaderFunc() expr.Option {
 
 			value := formatValue(params[2])
 
-			r, ok := ctxRequest(ctx)
+			r, ok := CtxRequest(ctx)
 			if !ok {
 				return nil, errors.New("could not find http request in context")
 			}
@@ -145,7 +146,7 @@ func delRequestHeadersFunc() expr.Option {
 				return nil, errors.WithStack(err)
 			}
 
-			r, ok := ctxRequest(ctx)
+			r, ok := CtxRequest(ctx)
 			if !ok {
 				return nil, errors.New("could not find http request in context")
 			}
@@ -167,6 +168,145 @@ func delRequestHeadersFunc() expr.Option {
 	)
 }
 
+type CookieVar struct {
+	Name     string        `expr:"name"`
+	Value    string        `expr:"value"`
+	Path     string        `expr:"path"`
+	Domain   string        `expr:"domain"`
+	Expires  time.Time     `expr:"expires"`
+	MaxAge   int           `expr:"max_age"`
+	Secure   bool          `expr:"secure"`
+	HttpOnly bool          `expr:"http_only"`
+	SameSite http.SameSite `expr:"same_site"`
+}
+
+func getRequestCookieFunc() expr.Option {
+	return expr.Function(
+		"get_cookie",
+		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)
+			}
+
+			r, ok := CtxRequest(ctx)
+			if !ok {
+				return nil, errors.New("could not find http request in context")
+			}
+
+			cookie, err := r.Cookie(name)
+			if err != nil && !errors.Is(err, http.ErrNoCookie) {
+				return nil, errors.WithStack(err)
+			}
+
+			if cookie == nil {
+				return nil, nil
+			}
+
+			return CookieVar{
+				Name:     cookie.Name,
+				Value:    cookie.Value,
+				Path:     cookie.Path,
+				Domain:   cookie.Domain,
+				Expires:  cookie.Expires,
+				MaxAge:   cookie.MaxAge,
+				Secure:   cookie.Secure,
+				HttpOnly: cookie.HttpOnly,
+				SameSite: cookie.SameSite,
+			}, nil
+		},
+		new(func(context.Context, string) CookieVar),
+	)
+}
+
+func addRequestCookieFunc() expr.Option {
+	return expr.Function(
+		"add_cookie",
+		func(params ...any) (any, error) {
+			ctx, err := rule.Assert[context.Context](params[0])
+			if err != nil {
+				return nil, errors.WithStack(err)
+			}
+
+			values, err := rule.Assert[map[string]any](params[1])
+			if err != nil {
+				return nil, errors.WithStack(err)
+			}
+
+			cookie, err := cookieFrom(values)
+			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.AddCookie(cookie)
+
+			return true, nil
+		},
+		new(func(context.Context, map[string]any) bool),
+	)
+}
+
+func cookieFrom(values map[string]any) (*http.Cookie, error) {
+	cookie := &http.Cookie{}
+
+	if name, ok := values["name"].(string); ok {
+		cookie.Name = name
+	}
+
+	if value, ok := values["value"].(string); ok {
+		cookie.Value = value
+	}
+
+	if domain, ok := values["domain"].(string); ok {
+		cookie.Domain = domain
+	}
+
+	if path, ok := values["path"].(string); ok {
+		cookie.Path = path
+	}
+
+	if httpOnly, ok := values["http_only"].(bool); ok {
+		cookie.HttpOnly = httpOnly
+	}
+
+	if maxAge, ok := values["max_age"].(int); ok {
+		cookie.MaxAge = maxAge
+	}
+
+	if secure, ok := values["secure"].(bool); ok {
+		cookie.Secure = secure
+	}
+
+	if sameSite, ok := values["same_site"].(http.SameSite); ok {
+		cookie.SameSite = sameSite
+	} else if sameSite, ok := values["same_site"].(int); ok {
+		cookie.SameSite = http.SameSite(sameSite)
+	}
+
+	if expires, ok := values["expires"].(time.Time); ok {
+		cookie.Expires = expires
+	} else if rawExpires, ok := values["expires"].(string); ok {
+		expires, err := time.Parse(http.TimeFormat, rawExpires)
+		if err != nil {
+			return nil, errors.WithStack(err)
+		}
+
+		cookie.Expires = expires
+	}
+
+	return cookie, nil
+}
+
 func formatValue(v any) string {
 	var value string
 	switch v := v.(type) {