From cbcc3ecf43c3d3cdd3c2c932885ca3132f93cfd3 Mon Sep 17 00:00:00 2001
From: rinfx <yucheng.lxr@alibaba-inc.com>
Date: Wed, 28 Jan 2026 10:52:45 +0800
Subject: [PATCH] bugfix for model-mapper & model-router (#3370)

---
 plugins/wasm-go/extensions/model-mapper/main.go | 11 +++++++----
 plugins/wasm-go/extensions/model-router/main.go | 12 ++++++------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/plugins/wasm-go/extensions/model-mapper/main.go b/plugins/wasm-go/extensions/model-mapper/main.go
index 2278b8e11..abf3c202f 100644
--- a/plugins/wasm-go/extensions/model-mapper/main.go
+++ b/plugins/wasm-go/extensions/model-mapper/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"errors"
 	"sort"
 	"strings"
@@ -136,11 +137,8 @@ func onHttpRequestHeaders(ctx wrapper.HttpContext, config Config) types.Action {
 			break
 		}
 	}
-	if !matched {
-		return types.ActionContinue
-	}
 
-	if !ctx.HasRequestBody() {
+	if !matched || !ctx.HasRequestBody() {
 		ctx.DontReadRequestBody()
 		return types.ActionContinue
 	}
@@ -158,6 +156,11 @@ func onHttpRequestBody(ctx wrapper.HttpContext, config Config, body []byte) type
 		return types.ActionContinue
 	}
 
+	if !json.Valid(body) {
+		log.Error("invalid json body")
+		return types.ActionContinue
+	}
+
 	oldModel := gjson.GetBytes(body, config.modelKey).String()
 
 	newModel := config.defaultModel
diff --git a/plugins/wasm-go/extensions/model-router/main.go b/plugins/wasm-go/extensions/model-router/main.go
index d67b21956..7ed24ba8e 100644
--- a/plugins/wasm-go/extensions/model-router/main.go
+++ b/plugins/wasm-go/extensions/model-router/main.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/json"
 	"io"
 	"mime"
 	"mime/multipart"
@@ -91,15 +92,11 @@ func onHttpRequestHeaders(ctx wrapper.HttpContext, config ModelRouterConfig) typ
 		}
 	}
 
-	if !enable {
+	if !enable || !ctx.HasRequestBody() {
 		ctx.DontReadRequestBody()
 		return types.ActionContinue
 	}
 
-	if !ctx.HasRequestBody() {
-		return types.ActionContinue
-	}
-
 	// Prepare for body processing
 	proxywasm.RemoveHttpRequestHeader("content-length")
 	// 100MB buffer limit
@@ -124,7 +121,10 @@ func onHttpRequestBody(ctx wrapper.HttpContext, config ModelRouterConfig, body [
 }
 
 func handleJsonBody(ctx wrapper.HttpContext, config ModelRouterConfig, body []byte) types.Action {
-
+	if !json.Valid(body) {
+		log.Error("invalid json body")
+		return types.ActionContinue
+	}
 	modelValue := gjson.GetBytes(body, config.modelKey).String()
 	if modelValue == "" {
 		return types.ActionContinue