在Go中从REST API端点返回JSON对象。

huangapple
go评论108阅读模式
英文:

return json object from REST API endpoint in Go

问题

我正在使用golang构建API。我希望这个端点返回JSON数据，以便我可以在前端中使用它。

  1. http.HandleFunc("/api/orders", createOrder)

目前我的函数没有返回JSON对象，并且jsonMap变量没有将服务器的响应体映射到CreateOrder结构体中。

我的结构体：

  1. type CreateOrder struct {
  2.     Id     string  `json:"id"`
  3.     Status string  `json:"status"`
  4.     Links  []Links `json:"links"`
  5. }

我的createOrder函数（根据评论进行了更新）：

  1. func createOrder(w http.ResponseWriter, r *http.Request) {
  2.     accessToken := generateAccessToken()
  3.     w.Header().Set("Access-Control-Allow-Origin", "*")
  4.     fmt.Println(accessToken)
  6.     body := []byte(`{
  7.         "intent":"CAPTURE",
  8.         "purchase_units":[
  9.            {
  10.               "amount":{
  11.                  "currency_code":"USD",
  12.                  "value":"100.00"
  13.               }
  14.            }
  15.         ]
  16.      }`)
  18.     req, err := http.NewRequest("POST", base+"/v2/checkout/orders", bytes.NewBuffer(body))
  19.     req.Header.Set("Content-Type", "application/json")
  20.     req.Header.Set("Authorization", "Bearer "+accessToken)
  22.     client := &http.Client{}
  23.     resp, err := client.Do(req)
  25.     if err != nil {
  26.         log.Fatalf("An Error Occured %v", err)
  27.     }
  29.     fmt.Println(resp.StatusCode)
  30.     defer resp.Body.Close()
  32.     if err != nil {
  33.         log.Fatal(err)
  34.     }
  36.     var jsonMap CreateOrder
  38.     error := json.NewDecoder(resp.Body).Decode(&jsonMap)
  40.     if error != nil {
  41.         log.Fatal(err)
  42.     }
  44.     w.WriteHeader(resp.StatusCode)
  45.     json.NewEncoder(w).Encode(jsonMap)
  46. }

这是打印出来的内容。它打印出了对象的值，但没有打印出键。

  1. {2MH36251C2958825N CREATED [{something self GET} {soemthing approve GET}]}

应该打印出：

  1. {
  2.   id: '8BW01204PU5017303',
  3.   status: 'CREATED',
  4.   links: [
  5.     {
  6.       href: 'url here',
  7.       rel: 'self',
  8.       method: 'GET'
  9.     },
  10.     ...
  11.   ]
  12. }
英文:

I'm building the API with golang. I want this endpoint to return json data so I can use it in my frontend.

  1. http.HandleFunc("/api/orders", createOrder)

Currently my function is not returning a json object and jsonMap variable is not maping the response body to of the server with the Create struc

My struct

  1. type CreateOrder struct {
  2. 	Id     string  `json:"id"`
  3. 	Status string  `json:"status"`
  4. 	Links  []Links `json:"links"`
  5. }

My CreateOrder function (updated based on comments)

  1. func createOrder(w http.ResponseWriter, r *http.Request) {
  2. 	accessToken := generateAccessToken()
  3. 	w.Header().Set("Access-Control-Allow-Origin", "*")
  4. 	fmt.Println(accessToken)
  6. 	body := []byte(`{
  7. 		"intent":"CAPTURE",
  8. 		"purchase_units":[
  9. 		   {
  10. 			  "amount":{
  11. 				 "currency_code":"USD",
  12. 				 "value":"100.00"
  13. 			  }
  14. 		   }
  15. 		]
  16. 	 }`)
  18. 	req, err := http.NewRequest("POST", base+"/v2/checkout/orders", bytes.NewBuffer(body))
  19. 	req.Header.Set("Content-Type", "application/json")
  20. 	req.Header.Set("Authorization", "Bearer "+accessToken)
  22. 	client := &http.Client{}
  23. 	resp, err := client.Do(req)
  25. 	if err != nil {
  26. 		log.Fatalf("An Error Occured %v", err)
  27. 	}
  29. 	fmt.Println(resp.StatusCode)
  30. 	defer resp.Body.Close()
  32. 	if err != nil {
  33. 		log.Fatal(err)
  34. 	}
  36. 	var jsonMap CreateOrder
  38. 	error := json.NewDecoder(resp.Body).Decode(&jsonMap)
  40. 	if error != nil {
  41. 		log.Fatal(err)
  42. 	}
  44. 	w.WriteHeader(resp.StatusCode)
  45. 	json.NewEncoder(w).Encode(jsonMap)
  47. }

This is what gets printed. Prints the value without the keys of the object

  1. {2MH36251C2958825N CREATED [{something self GET} {soemthing approve GET}]}

Should print

  1. {
  2.   id: '8BW01204PU5017303',
  3.   status: 'CREATED',
  4.   links: [
  5.     {
  6.       href: 'url here',
  7.       rel: 'self',
  8.       method: 'GET'
  9.     },
  10.     ...
  11.   ]
  12. }

答案1

得分: 1

  1. func createOrder(w http.ResponseWriter, r *http.Request) {
  2. 	// ...
  4. 	resp, err := http.DefaultClient.Do(req)
  5. 	if err != nil {
  6. 		log.Println("发生错误:", err)
  7. 		return
  8. 	}
  9. 	defer resp.Body.Close()
  10. 	
  11. 	if resp.StatusCode != http.StatusOK /* 或者 http.StatusCreated（取决于你使用的API） */ {
  12. 		log.Println("请求失败，状态为:", http.Status)
  13. 		w.WriteHeader(resp.StatusCode)
  14. 		return
  15. 	}
  17. 	// 解码来自外部服务的响应
  18. 	v := new(CreateOrder)
  19. 	if err := json.NewDecoder(resp.Body).Decode(v); err != nil {
  20. 		log.Println(err)
  21. 		return
  22. 	}
  23. 	
  24. 	// 发送响应到前端
  25. 	w.WriteHeader(resp.StatusCode)
  26. 	if err := json.NewEncoder(w).Encode(v); err != nil {
  27. 		log.Println(err)
  28. 	}
  29. }

或者，如果你想将来自外部服务的数据原样发送到前端，你可以像这样做：

  1. func createOrder(w http.ResponseWriter, r *http.Request) {
  2. 	// ...
  4. 	resp, err := http.DefaultClient.Do(req)
  5. 	if err != nil {
  6. 		log.Println("发生错误:", err)
  7. 		return
  8. 	}
  9. 	defer resp.Body.Close()
  11. 	if resp.StatusCode != http.StatusOK /* 或者 http.StatusCreated（取决于你使用的API） */ {
  12. 		log.Println("请求失败，状态为:", http.Status)
  13. 		w.WriteHeader(resp.StatusCode)
  14. 		return
  15. 	}
  17. 	// 将外部服务的响应复制到前端
  18. 	w.WriteHeader(resp.StatusCode)
  19. 	if _, err := io.Copy(w, resp.Body); err != nil {
  20. 		log.Println(err)
  21. 	}
  22. }
英文: 
  1. func createOrder(w http.ResponseWriter, r *http.Request) {
  2. 	// ...
  4. 	resp, err := http.DefaultClient.Do(req)
  5. 	if err != nil {
  6. 		log.Println("An Error Occured:", err)
  7. 		return
  8. 	}
  9. 	defer resp.Body.Close()
  10. 	
  11. 	if resp.StatusCode != http.StatusOK /* or http.StatusCreated (depends on the API you're using) */ {
  12. 		log.Println("request failed with status:", http.Status)
  13. 		w.WriteHeader(resp.StatusCode)
  14. 		return
  15. 	}
  17. 	// decode response from external service
  18. 	v := new(CreateOrder)
  19. 	if err := json.NewDecoder(resp.Body).Decode(v); err != nil {
  20. 		log.Println(err)
  21. 		return
  22. 	}
  23. 	
  24. 	// send response to frontend
  25. 	w.WriteHeader(resp.StatusCode)
  26. 	if err := json.NewEncoder(w).Encode(v); err != nil {
  27. 		log.Println(err)
  28. 	}
  29. }

Alternatively, if you want to send the data from the external service to the frontend unchanged, you should be able to do something like this:

  1. func createOrder(w http.ResponseWriter, r *http.Request) {
  2. 	// ...
  4. 	resp, err := http.DefaultClient.Do(req)
  5. 	if err != nil {
  6. 		log.Println("An Error Occured:", err)
  7. 		return
  8. 	}
  9. 	defer resp.Body.Close()
  11. 	if resp.StatusCode != http.StatusOK /* or http.StatusCreated (depends on the API you're using) */ {
  12. 		log.Println("request failed with status:", http.Status)
  13. 		w.WriteHeader(resp.StatusCode)
  14. 		return
  15. 	}
  17. 	// copy response from external to frontend
  18. 	w.WriteHeader(resp.StatusCode)
  19. 	if _, err := io.Copy(w, resp.Body); err != nil {
  20. 		log.Println(err)
  21. 	}
  22. }

huangapple
  • 本文由 发表于 2022年12月8日 12:09:12
  • 转载请务必保留本文链接：https://go.coder-hub.com/74725422.html
  • api
  • go
  • json
  • rest
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