feat(rules): add post-request rules system with response manipulation (#160)

* Add comprehensive post-request rules support for response phase
* Enable response body, status, and header manipulation via set commands
* Refactor command handlers to support both request and response phases
* Implement response modifier system for post-request template execution
* Support response-based rule matching with status and header checks
* Add comprehensive benchmarks for matcher performance
* Refactor authentication and proxying commands for unified error handling
* Support negated conditions with !
* Enhance error handling, error formatting and validation
* Routes: add `rule_file` field with rule preset support
* Environment variable substitution: now supports variables without `GODOXY_` prefix

* new conditions:
  * `on resp_header <key> [<value>]`
  * `on status <status>`
* new commands:
  * `require_auth`
  * `set resp_header <key> <template>`
  * `set resp_body <template>`
  * `set status <code>`
  * `log <level> <path> <template>`
  * `notify <level> <provider> <title_template> <body_template>`

internal/route/rules/command.go

@@ -3,19 +3,21 @@ package rules
 import "net/http"
 
 type (
+	handlerFunc func(w http.ResponseWriter, r *http.Request) error
+
 	CommandHandler interface {
 		// CommandHandler can read and modify the values
 		// then handle the request
 		// finally proceed to next command (or return) base on situation
-		Handle(cached Cache, w http.ResponseWriter, r *http.Request) (proceed bool)
+		Handle(w http.ResponseWriter, r *http.Request) error
+		IsResponseHandler() bool
 	}
 	// NonTerminatingCommand will run then proceed to next command or reverse proxy.
-	NonTerminatingCommand http.HandlerFunc
+	NonTerminatingCommand handlerFunc
 	// TerminatingCommand will run then return immediately.
-	TerminatingCommand http.HandlerFunc
-	// DynamicCommand will return base on the request
-	// and can read or modify the values.
-	DynamicCommand func(cached Cache, w http.ResponseWriter, r *http.Request) (proceed bool)
+	TerminatingCommand handlerFunc
+	// OnResponseCommand will run then return based on the response.
+	OnResponseCommand handlerFunc
 	// BypassCommand will skip all the following commands
 	// and directly return to reverse proxy.
 	BypassCommand struct{}
@@ -23,29 +25,55 @@ type (
 	Commands []CommandHandler
 )
 
-func (c NonTerminatingCommand) Handle(cached Cache, w http.ResponseWriter, r *http.Request) (proceed bool) {
-	c(w, r)
-	return true
+func (c NonTerminatingCommand) Handle(w http.ResponseWriter, r *http.Request) error {
+	return c(w, r)
 }
 
-func (c TerminatingCommand) Handle(cached Cache, w http.ResponseWriter, r *http.Request) (proceed bool) {
-	c(w, r)
+func (c NonTerminatingCommand) IsResponseHandler() bool {
 	return false
 }
 
-func (c DynamicCommand) Handle(cached Cache, w http.ResponseWriter, r *http.Request) (proceed bool) {
-	return c(cached, w, r)
+func (c TerminatingCommand) Handle(w http.ResponseWriter, r *http.Request) error {
+	if err := c(w, r); err != nil {
+		return err
+	}
+	return errTerminated
 }
 
-func (c BypassCommand) Handle(cached Cache, w http.ResponseWriter, r *http.Request) (proceed bool) {
+func (c TerminatingCommand) IsResponseHandler() bool {
+	return false
+}
+
+func (c OnResponseCommand) Handle(w http.ResponseWriter, r *http.Request) error {
+	return c(w, r)
+}
+
+func (c OnResponseCommand) IsResponseHandler() bool {
 	return true
 }
 
-func (c Commands) Handle(cached Cache, w http.ResponseWriter, r *http.Request) (proceed bool) {
+func (c BypassCommand) Handle(w http.ResponseWriter, r *http.Request) error {
+	return errTerminated
+}
+
+func (c BypassCommand) IsResponseHandler() bool {
+	return false
+}
+
+func (c Commands) Handle(w http.ResponseWriter, r *http.Request) error {
 	for _, cmd := range c {
-		if !cmd.Handle(cached, w, r) {
-			return false
+		if err := cmd.Handle(w, r); err != nil {
+			return err
 		}
 	}
-	return true
+	return nil
+}
+
+func (c Commands) IsResponseHandler() bool {
+	for _, cmd := range c {
+		if cmd.IsResponseHandler() {
+			return true
+		}
+	}
+	return false
 }