当测试HTTP请求时出现Go空指针解引用错误。

huangapple
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英文:

Go Nil Dereference Error When Testing HTTP Request

问题

我正在尝试在我的Go库中测试一个HTTP请求。调用该请求的对象通过依赖注入接受一个HTTP客户端对象，所以在我的测试中，我像这样模拟了HTTP客户端：

  1. func TestMyObject(t *testing.T) {
  2.     server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  3.         w.WriteHeader(200)
  4.         w.Header().Set("Content-Type", "application/json")
  5.         fmt.Fprintln(w, mockJSONResponse)
  6.     }))
  7.     defer server.Close()
  9.     // 创建一个传输对象，将所有流量重定向到示例服务器
  10.     transport := &http.Transport{
  11.         Proxy: func(req *http.Request) (*url.URL, error) {
  12.             return url.Parse(server.URL)
  13.         },
  14.     }
  16.     // 创建一个带有传输对象的http.Client
  17.     httpClient := &http.Client{Transport: transport}
  19.     // 将httpClient传递给我的对象
  20. }

这是在我的对象中进行HTTP请求的方式：

  1. // Make - 发送一个准备好的HTTP请求
  2. func (ir *MyObject) Make() *http.Response {
  3.     if ir.Err != nil {
  4.         return nil
  5.     }
  7.     ir.resp, ir.Err = ir.Client.Do(ir.req)
  9.     runtime.SetFinalizer(ir, func(ir *MyObject) {
  10.         ir.resp.Body.Close()
  11.     })
  13.     ir.logReqRes()
  14.     ir.checkErrorResponse()
  16.     return ir.resp
  17. }

然而，我得到了空指针解引用错误：

  1. panic: runtime error: invalid memory address or nil pointer dereference [recovered]
  2. panic: runtime error: invalid memory address or nil pointer dereference

在这个函数中（我试图记录响应）：

  1. // 记录请求和响应
  2. func (ir *MyObject) logReqRes() {
  3.     log.Print("AAAAAAA")
  4.     log.Print(ir.resp)
  5.     log.Print("AAAAAAA")
  6.     if reqInfo, err := httputil.DumpRequest(ir.req, true); err == nil {
  7.         log.Print("Logging request:")
  8.         log.Print(string(reqInfo))
  9.     }
  10.     if respInfo, err := httputil.DumpResponse(ir.resp, true); err == nil {
  11.         log.Print("Logging response:")
  12.         log.Print(string(respInfo))
  13.     }
  14. }

如你所见，ir.resp 为 nil，原因不明。有什么想法吗？

英文:

I am trying to test a HTTP request in my Go library. Object which makes the call accepts a HTTP client object via dependency injection so in my test I am mocking the HTTP client like this:

  1. func TestMyObject(t *testing.T) {
  2. 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  3. 		w.WriteHeader(200)
  4. 		w.Header().Set("Content-Type", "application/json")
  5. 		fmt.Fprintln(w, mockJSONResponse)
  6. 	}))
  7. 	defer server.Close()
  9. 	// Make a transport that reroutes all traffic to the example server
  10. 	transport := &http.Transport{
  11. 		Proxy: func(req *http.Request) (*url.URL, error) {
  12. 			return url.Parse(server.URL)
  13. 		},
  14. 	}
  16. 	// Make a http.Client with the transport
  17. 	httpClient := &http.Client{Transport: transport}
  19.     // I am passing the httpClient to my object
  20. }

Here is how the HTTP request is made within my object:

  1. // Make - makes a prepared HTTP request
  2. func (ir *MyObject) Make() *http.Response {
  3. 	if ir.Err != nil {
  4. 		return nil
  5. 	}
  7. 	ir.resp, ir.Err = ir.Client.Do(ir.req)
  9. 	runtime.SetFinalizer(ir, func(ir *MyObject) {
  10. 		ir.resp.Body.Close()
  11. 	})
  13. 	ir.logReqRes()
  14. 	ir.checkErrorResponse()
  16. 	return ir.resp
  17. }

I am getting nil pointer dereference error though:

  1. panic: runtime error: invalid memory address or nil pointer dereference [recovered]
  2. panic: runtime error: invalid memory address or nil pointer dereference

In this function (I am trying to log the response):

  1. // Logs request and response
  2. func (ir *MyObject) logReqRes() {
  3. 	log.Print("AAAAAAA")
  4. 	log.Print(ir.resp)
  5. 	log.Print("AAAAAAA")
  6. 	if reqInfo, err := httputil.DumpRequest(ir.req, true); err == nil {
  7. 		log.Print("Logging request:")
  8. 		log.Print(string(reqInfo))
  9. 	}
  10. 	if respInfo, err := httputil.DumpResponse(ir.resp, true); err == nil {
  11. 		log.Print("Logging response:")
  12. 		log.Print(string(respInfo))
  13. 	}
  14. }

As you can see, ir.resp is nil for some reason. Any ideas?

答案1

得分: 0

好的，以下是翻译好的内容：

好的，我发现了一个问题。更好的错误日志显示实际上表明我的错误非常简单。

我将这个作为URL传递给了模拟的HTTP客户端：

  1. host/api/v1/tokens/

这导致了以下错误：

  1. Post host/api/v1/tokens/: 不支持的协议方案

显然，即使你正在使用一个测试服务器，URL也必须包含一个正确的HTTP协议方案（http://）。

英文:

Ok. I found an issue. Better logging of errors actually showed that my mistake was very simple.

I was passing this as a URL to mocked HTTP client:

  1. host/api/v1/tokens/

Which was resulting in this error:

  1. Post host/api/v1/tokens/: unsupported protocol scheme

Apparently the URL must include a proper HTTP scheme (http://) even when you are using a test server.

huangapple
  • 本文由 发表于 2015年4月20日 17:05:51
  • 转载请务必保留本文链接：https://go.coder-hub.com/29743508.html
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