feat: support read mock response from local file (#788)

* feat: support read mock response from local file

* docs: add more instructors about the mock conditional response

* support response as a random image

---------

Co-authored-by: rick <LinuxSuRen@users.noreply.github.com>

Author: LinuxSuRen

docs/api-testing-mock-schema.json

@@ -60,11 +60,19 @@
                         "type": "object",
                         "properties": {
                             "encoder": {
-                                "type": "string"
+                                "type": "string",
+                                "enum": [
+                                    "base64",
+                                    "url",
+                                    "raw"
+                                ]
                             },
                             "body": {
                                 "type": "string"
                             },
+                            "bodyFromFile": {
+                                "type": "string"
+                            },
                             "header": {
                                 "type": "object",
                                 "description": "HTTP response headers. Common headers include 'Content-Type', 'Cache-Control', 'Set-Cookie', etc.",

docs/site/content/zh/latest/tasks/mock.md

@@ -102,7 +102,11 @@ items:
 curl http://localhost:6060/mock/api/v1/repos/atest/prs -v
 ```
 
-另外，为了满足复杂的场景，还可以对 Response Body 做特定的解码，目前支持：`base64`、`url`：
+#### 编码器
+
+另外，为了满足复杂的场景，还可以对 Response Body 做特定的解码，目前支持：`base64`、`url`、`raw`：
+
+> encoder 为 `raw` 时，表示不进行处理
 
 ```yaml
 #!api-testing-mock
@@ -136,6 +140,63 @@ items:
       encoder: url
 ```
 
+如果你的响应内容比较大，或者保存在一个本地文件中，那么你可以这么写：
+
+```yaml
+#!api-testing-mock
+# yaml-language-server: $schema=https://linuxsuren.github.io/api-testing/api-testing-mock-schema.json
+items:
+  - name: baidu
+    request:
+      path: /api/v1/baidu
+    response:
+      bodyFromFile: /tmp/baidu.html
+```
+
+通过下面的方式也可以生成图片：
+
+```yaml
+items:
+- name: image
+    request:
+      path: /v1/image
+    response:
+      header:
+        Content-Type: image/png
+      body: |
+        {{ randImage 300 300 }}
+```
+
+#### 条件判断
+
+对于查询类的 API，通常会接收参数，并根据参数的不同，返回相应的数据。这时候，可以用到条件判断的表达式：
+
+```yaml
+items:
+  - name: cats
+    request:
+      path: /api/v1/cats/{size}
+    response:
+      header:
+        Content-Type: application/json
+      body: |
+        {{if eq .Param.size "big"}}
+          {
+            "name": "big cat"
+          }
+        {{else if eq .Param.size "middle"}}
+          {
+            "name": "middle cat"
+          }
+        {{else if eq .Param.size "small"}}
+          {
+            "name": "small cat"
+          }
+        {{end}}
+```
+
+## 代理
+
 在实际情况中，往往是向已有系统或平台添加新的 API，此时要 Mock 所有已经存在的 API 就既没必要也需要很多工作量。因此，我们提供了一种简单的方式，即可以增加**代理**的方式把已有的 API 请求转发到实际的地址，只对新增的 API 进行 Mock 处理。如下所示：
 
 ```yaml
@@ -160,7 +221,7 @@ proxies:
     target: http://192.168.123.58:9200
 ```
 
-## TCP 协议代理
+### TCP 协议代理
 
 ```yaml
 proxies:
@@ -170,7 +231,7 @@ proxies:
     target: 192.168.123.58:33060
 ```
 
-## 代理多个服务
+### 代理多个服务
 
 ```shell
 atest mock-compose bin/compose.yaml

pkg/mock/in_memory.go

@@ -24,6 +24,7 @@ import (
 	"io"
 	"net"
 	"net/http"
+	"os"
 	"sort"
 	"strings"
 	"sync"
@@ -450,6 +451,15 @@ func (h *advanceHandler) handle(w http.ResponseWriter, req *http.Request) {
 		w.Header().Set(k, hv)
 	}
 
+	if h.item.Response.BodyFromFile != "" {
+		// read from file
+		if data, readErr := os.ReadFile(h.item.Response.BodyFromFile); readErr != nil {
+			memLogger.Error(readErr, "failed to read file", "file", h.item.Response.BodyFromFile)
+		} else {
+			h.item.Response.Body = string(data)
+		}
+	}
+
 	var err error
 	if h.item.Response.Encoder == "base64" {
 		h.item.Response.BodyData, err = base64.StdEncoding.DecodeString(h.item.Response.Body)
@@ -458,9 +468,21 @@ func (h *advanceHandler) handle(w http.ResponseWriter, req *http.Request) {
 		if resp, err = http.Get(h.item.Response.Body); err == nil {
 			h.item.Response.BodyData, err = io.ReadAll(resp.Body)
 		}
+	} else if h.item.Response.Encoder == "raw" {
+		h.item.Response.BodyData = []byte(h.item.Response.Body)
 	} else {
 		if h.item.Response.BodyData, err = render.RenderAsBytes("start-item", h.item.Response.Body, h.item); err != nil {
-			fmt.Printf("failed to render body: %v", err)
+			memLogger.Error(err, "failed to render body")
+		}
+	}
+
+	if strings.HasPrefix(h.item.Response.Header[util.ContentType], "image/") {
+		if strings.HasPrefix(string(h.item.Response.BodyData), util.ImageBase64Prefix) {
+			// decode base64 image data
+			imgData := strings.TrimPrefix(string(h.item.Response.BodyData), util.ImageBase64Prefix)
+			if h.item.Response.BodyData, err = base64.StdEncoding.DecodeString(imgData); err != nil {
+				memLogger.Error(err, "failed to decode base64 image data")
+			}
 		}
 	}
 

pkg/mock/in_memory_test.go

@@ -24,10 +24,14 @@ import (
 	"strings"
 	"testing"
 
+	_ "embed"
 	"github.com/linuxsuren/api-testing/pkg/util"
 	"github.com/stretchr/testify/assert"
 )
 
+//go:embed testdata/api.yaml
+var mockFile []byte
+
 func TestInMemoryServer(t *testing.T) {
 	server := NewInMemoryServer(context.Background(), 0)
 	server.EnableMetrics()
@@ -167,6 +171,13 @@ func TestInMemoryServer(t *testing.T) {
 		assert.Equal(t, "hello", string(data))
 	})
 
+	t.Run("read response from file", func(t *testing.T) {
+		resp, err = http.Get(api + "/v1/readResponseFromFile")
+		assert.NoError(t, err)
+		data, _ := io.ReadAll(resp.Body)
+		assert.Equal(t, mockFile, data)
+	})
+
 	t.Run("not found config file", func(t *testing.T) {
 		server := NewInMemoryServer(context.Background(), 0)
 		err := server.Start(NewLocalFileReader("fake"), "/")

pkg/mock/server.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2024 API Testing Authors.
+Copyright 2024-2025 API Testing Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/mock/testdata/api.yaml

@@ -30,6 +30,12 @@ items:
     response:
       body: aGVsbG8=
       encoder: base64
+  - name: readResponseFromFile
+    request:
+      path: /v1/readResponseFromFile
+    response:
+      encoder: raw
+      bodyFromFile: testdata/api.yaml
   - name: prList
     request:
       path: /v1/repos/{repo}/prs
@@ -50,6 +56,14 @@ items:
             "status": "success"
           }]
         }
+  - name: image
+    request:
+      path: /v1/image
+    response:
+      header:
+        Content-Type: image/png
+      body: |
+        {{ randImage 300 300 }}
 proxies:
   - path: /v1/myProjects
     target: http://localhost:{{.GetPort}}

pkg/mock/types.go

@@ -44,11 +44,12 @@ type RequestWithAuth struct {
 }
 
 type Response struct {
-	Encoder    string            `yaml:"encoder" json:"encoder"`
-	Body       string            `yaml:"body" json:"body"`
-	Header     map[string]string `yaml:"header" json:"header"`
-	StatusCode int               `yaml:"statusCode" json:"statusCode"`
-	BodyData   []byte
+	Encoder      string            `yaml:"encoder" json:"encoder"`
+	Body         string            `yaml:"body" json:"body"`
+	BodyFromFile string            `yaml:"bodyFromFile" json:"bodyFromFile"`
+	Header       map[string]string `yaml:"header" json:"header"`
+	StatusCode   int               `yaml:"statusCode" json:"statusCode"`
+	BodyData     []byte
 }
 
 type Webhook struct {

pkg/server/remote_server.go

@@ -1405,7 +1405,9 @@ func (s *mockServerController) Reload(ctx context.Context, in *MockConfig) (repl
 		}
 
 		server := mock.NewInMemoryServer(ctx, int(in.GetPort())).WithTLS(dServer.GetTLS())
-		server.Start(s.mockWriter, in.Prefix)
+		if err = server.Start(s.mockWriter, in.Prefix); err != nil {
+			return
+		}
 		server.WithLogWriter(s)
 		s.loader = server
 	}