Fix the transformer plugin issue: file information is lost when processing body with files that the body type is multipart/form-data

plugins/wasm-go/extensions/transformer/utils.go

@@ -16,10 +16,13 @@ package main
 
 import (
 	"bytes"
+	"encoding/base64"
 	"encoding/json"
+	"fmt"
 	"io"
 	"mime"
 	"mime/multipart"
+	"net/textproto"
 	"net/url"
 	"sort"
 	"strconv"
@@ -136,14 +139,27 @@ func parseBody(contentType string, body []byte) (interface{}, error) {
 			}
 			formName := p.FormName()
 			fileName := p.FileName()
-			if formName == "" || fileName != "" {
+			contentType := p.Header.Get("Content-Type") // 获取文件的 MIME 类型
+
+			if formName == "" {
 				continue
 			}
 			formValue, err := io.ReadAll(p)
 			if err != nil {
 				return nil, err
 			}
-			ret[formName] = append(ret[formName], string(formValue))
+
+			if fileName == "" {
+				ret[formName] = append(ret[formName], string(formValue))
+			} else {
+				// 文件字段：记录文件名和 base64 内容
+				ret[formName+".filename"] = append(ret[formName+".filename"], fileName)
+				ret[formName+".content-type"] = append(ret[formName+".content-type"], contentType) // 保存 MIME 类型
+				encoded := base64.StdEncoding.EncodeToString(formValue)
+				ret[formName+".content"] = append(ret[formName+".content"], encoded)
+				ret[formName] = append(ret[formName], "")
+			}
+
 		}
 		return ret, nil
 
@@ -188,10 +204,56 @@ func constructBody(contentType string, body interface{}) ([]byte, error) {
 		if err = w.SetBoundary(params["boundary"]); err != nil {
 			return nil, err
 		}
+
+		// 先处理文件字段（因为需要 .filename 和 .content）
+		processed := make(map[string]bool) // 避免重复处理
+
 		for k, vs := range bd {
-			for _, v := range vs {
-				if err = w.WriteField(k, v); err != nil {
-					return nil, err
+			if strings.HasSuffix(k, ".filename") || strings.HasSuffix(k, ".content") || strings.HasSuffix(k, ".content-type") {
+				continue
+			}
+
+			// 判断是否是文件字段
+			filenames, hasFilename := bd[k+".filename"]
+			contents, hasContent := bd[k+".content"]
+
+			if hasFilename && hasContent {
+				// 是文件字段
+				processed[k] = true
+				for i := 0; i < len(filenames) && i < len(contents); i++ {
+					filename := filenames[i]
+					content64 := contents[i]
+					// 获取对应的 MIME 类型
+					var contentType string
+					if contentTypes, exists := bd[k+".content-type"]; exists && i < len(contentTypes) {
+						contentType = contentTypes[i]
+					} else {
+						contentType = "application/octet-stream" // 默认值
+					}
+					content, err := base64.StdEncoding.DecodeString(content64)
+					if err != nil {
+						return nil, errors.Wrap(err, "decode base64 content failed")
+					}
+
+					// 创建带 Content-Type 的表单文件
+					h := make(textproto.MIMEHeader)
+					h.Set("Content-Disposition", fmt.Sprintf(`form-data; name="%s"; filename="%s"`, k, filename))
+					h.Set("Content-Type", contentType)
+
+					fw, err := w.CreatePart(h)
+					if err != nil {
+						return nil, err
+					}
+					_, err = fw.Write(content)
+					if err != nil {
+						return nil, err
+					}
+				}
+			} else {
+				for _, v := range vs {
+					if err = w.WriteField(k, v); err != nil {
+						return nil, err
+					}
 				}
 			}
 		}

test/e2e/conformance/tests/go-wasm-transformer.go

@@ -663,6 +663,66 @@ var WasmPluginsTransformer = suite.ConformanceTest{
 					},
 				},
 			},
+			{
+				Meta: http.AssertionMeta{
+					TestCaseName:    "case 19: request multipart/form-data body with file",
+					TargetBackend:   "infra-backend-v1",
+					TargetNamespace: "higress-conformance-infra",
+				},
+				Request: http.AssertionRequest{
+					ActualRequest: http.Request{
+						Host:        "foo19.com",
+						Path:        "/post",
+						Method:      "POST",
+						ContentType: "multipart/form-data; boundary=--------------------------180978275079165582161528",
+						Body: []byte(`
+						----------------------------180978275079165582161528
+						Content-Disposition: form-data; name="file1"; filename="test.txt"
+						Content-Type: text/plain
+
+						这是一个txt文件
+						----------------------------180978275079165582161528
+						Content-Disposition: form-data; name="file2"; filename="test.txt"
+						Content-Type: text/plain
+
+						这是一个txt文件
+						----------------------------180978275079165582161528--
+
+						`),
+					},
+					ExpectedRequest: &http.ExpectedRequest{
+						Request: http.Request{
+							Host:        "foo19.com",
+							Path:        "/post",
+							Method:      "POST",
+							ContentType: "multipart/form-data; boundary=--------------------------180978275079165582161528",
+							Body: []byte(`
+							----------------------------180978275079165582161528
+							Content-Disposition: form-data; name="file2"; filename="test.txt"
+							Content-Type: text/plain
+
+							这是一个txt文件
+							----------------------------180978275079165582161528
+							Content-Disposition: form-data; name="file1"; filename="test.txt"
+							Content-Type: text/plain
+
+							这是一个txt文件
+							----------------------------180978275079165582161528
+							Content-Disposition: form-data; name="x-process"
+
+							wasm
+							----------------------------180978275079165582161528--
+
+						`),
+						},
+					},
+				},
+				Response: http.AssertionResponse{
+					ExpectedResponse: http.Response{
+						StatusCode: 200,
+					},
+				},
+			},
 		}
 		t.Run("WasmPlugin transformer", func(t *testing.T) {
 			for _, testcase := range testcases {

test/e2e/conformance/tests/go-wasm-transformer.yaml

@@ -420,6 +420,26 @@ spec:
                 port:
                   number: 8080
 ---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  annotations:
+  name: wasmplugin-transform-request-body-multipart-formdata-file
+  namespace: higress-conformance-infra
+spec:
+  ingressClassName: higress
+  rules:
+    - host: "foo19.com"
+      http:
+        paths:
+          - pathType: Prefix
+            path: "/"
+            backend:
+              service:
+                name: infra-backend-v1
+                port:
+                  number: 8080
+---
 apiVersion: extensions.higress.io/v1alpha1
 kind: WasmPlugin
 metadata:
@@ -891,4 +911,15 @@ spec:
                 strategy: SPLIT_AND_RETAIN_FIRST
               - key: X-split-dedupe-last
                 strategy: SPLIT_AND_RETAIN_LAST
+
+    - ingress:
+        - wasmplugin-transform-request-body-multipart-formdata-file
+      configDisable: false
+      config:
+        reqRules:
+          - operate: add
+            body:
+              - key: X-process
+                value: wasm
+
   url: file:///opt/plugins/wasm-go/extensions/transformer/plugin.wasm