getting error message along with result in go api

I have one route in API where I can get users with roles. In this route, if I put the name of the user then I will get all the roles assigned to him/her. But the problem is that it returns only the first result. If that role is present in another object then it is not getting displayed. So I comment on the return line and everything works fine but along with the result, I am getting the error message:"user not found" Can you guys please tell me what mistake I am doing?
Thank you.
Route -

GET("/users/:username", controllers.GetUserByRole)

Controller -

func GetUserByRole(c *gin.Context) {
	paramId := c.Param("username")
	.............
    .............
    .............
	var newUsers []models.User
	iter := client.Collection("users").Documents(ctx)

	for {
		doc, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			log.Fatalf("Failed to iterate: %v", err)
		}

		var tempUsers models.User
		if err := doc.DataTo(&tempUsers); err != nil {
			break
		}
		newUsers = append(newUsers, tempUsers)
	}

	for _, a := range newUsers {
		for _, element := range a.Roles{
				if element == paramId {
            c.IndentedJSON(http.StatusOK, a)
            return     //if I comment this line line then I geting message `"user not found"` along with results
        }
    }
    }
    c.IndentedJSON(http.StatusNotFound, gin.H{"message": "user not found"})
}

URL: http://localhost:3000/users/Analyst
Response Should be:

  {
     "id": 1,
     "name": "Leanne Graham",
     "username": "Bret",
     "roles": ["Developer", "Analyst"],
  },
  {
    "id": 3,
    "name": "Clementine Bauch",
    "username": "Samantha",
    "roles": ["Manger", "Analyst"],
  }

but I am getting like this (only the first matching one):

  {
     "id": 1,
     "name": "Leanne Graham",
     "username": "Bret",
     "roles": ["Developer", "Analyst"],
  }

If I comment the return line then response is (desired result + error message):

  {
     "id": 1,
     "name": "Leanne Graham",
     "username": "Bret",
     "roles": ["Developer", "Analyst"],
  },
  {
    "id": 3,
    "name": "Clementine Bauch",
    "username": "Samantha",
    "roles": ["Manger", "Analyst"],
  }{
    "message": "album not found"
}

Complete API response -

[
  {
     "id": 1,
     "name": "Leanne Graham",
     "username": "Bret",
     "roles": ["Developer", "Analyst"],
  },
  {
    "id": 2,
    "name": "Ervin Howell",
    "username": "Antonette",
    "roles": ["Assistant"],,
  },
  {
    "id": 3,
    "name": "Clementine Bauch",
    "username": "Samantha",
    "roles": ["Manger", "Analyst"],
  }
]


</details>


# 答案1
**得分**: 2

你可以这样做：

```go
var userList []models.User
for _, a := range newUsers {
    for _, element := range a.AssignedTo {
        if element == paramId {
            userList = append(userList, a)
        }
    }
}
if len(userList) == 0 {
    c.IndentedJSON(http.StatusNotFound, gin.H{"message": "用户未找到"})
    return
}

c.IndentedJSON(http.StatusOK, userList)

这段代码的作用是根据指定的参数ID筛选出符合条件的用户，并将结果以JSON格式返回。如果未找到符合条件的用户，将返回一个包含错误信息的JSON响应。

var userList []models.User
for _, a := range newUsers {
	for _, element := range a.AssignedTo {
		if element == paramId {
			userList = append(userList, a)
		}
	}
}
if len(userList) == 0 {
	 c.IndentedJSON(http.StatusNotFound, gin.H{"message": "user not found"})
     return
}

c.IndentedJSON(http.StatusOK, userList)

答案2

得分: 0

看起来你的return语句在for循环内部，所以它找到第一个值后立即返回。当你将其注释掉时，函数没有返回，所以它成功完成然后打印错误消息。将return语句移到两个for循环之外，问题就会解决。此外，通过添加一个errorflag来发送错误消息也是一种解决方法。也建议采用Manjeet Thakur的替代解决方案。

func GetUserByRole(c *gin.Context) {
    paramId := c.Param("username")
    .............
    .............
    .............
    var newUsers []models.User
    iter := client.Collection("users").Documents(ctx)

    for {
        doc, err := iter.Next()
        if err == iterator.Done {
            break
        }
        if err != nil {
            log.Fatalf("Failed to iterate: %v", err)
        }

        var tempUsers models.User
        if err := doc.DataTo(&tempUsers); err != nil {
            break
        }
        newUsers = append(newUsers, tempUsers)
    }
    var errorflag := 1
    for _, a := range newUsers {
        for _, element := range a.AssignedTo {
            if element == paramId {
                c.IndentedJSON(http.StatusOK, a)
                errorflag := 0
                //如果我注释掉这一行，我会得到`"user not found"`的消息以及结果
            }
        }
    }
    if errorflag {
        c.IndentedJSON(http.StatusNotFound, gin.H{"message": "user not found"})
    }
    return
}

func GetUserByRole(c *gin.Context) {
    paramId := c.Param("username")
    .............
    .............
    .............
    var newUsers []models.User
    iter := client.Collection("users").Documents(ctx)
 
    for {
        doc, err := iter.Next()
        if err == iterator.Done {
            break
        }
        if err != nil {
            log.Fatalf("Failed to iterate: %v", err)
        }
 
        var tempUsers models.User
        if err := doc.DataTo(&tempUsers); err != nil {
            break
        }
        newUsers = append(newUsers, tempUsers)
    }
    var errorflag := 1
    for _, a := range newUsers {
        for _, element := range a.AssignedTo {
                if element == paramId {
            c.IndentedJSON(http.StatusOK, a)
            errorflag := 0
                 //if I comment this line line then I geting message `"user not found"` along with results
        }
    }
    }
    if errorflag{
    c.IndentedJSON(http.StatusNotFound, gin.H{"message": "user not found"})
    }
    return
}