英文:
go-json-rest: JSON payload is empty
问题
我正在尝试使用go-json-rest创建RESTful API。
我有以下模型结构：
type Todo struct {
id int
name string
}
我试图发送一个POST请求来创建一个Todo类型的对象：
func CreateTodo(w rest.ResponseWriter, r *rest.Request) {
body, _ := ioutil.ReadAll(r.Body)
log.Println("body content is: ", string(body)) // 这里我可以看到 { "name": "test1" }
var todo Todo = Todo{}
err := r.DecodeJsonPayload(&todo) // 这里的错误显示JSON负载为空
defer r.Body.Close()
if err != nil {
log.Println("error in parsing json")
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if todo.name == "" {
rest.Error(w, "todo name is required", 400)
return
}
lock.Lock()
var nextId int = len(todos)
// todos[nextId] = todo
todo.id = nextId // 设置其id
todos = append(todos, todo)
log.Println("num of todos: ", len(todos))
lock.Unlock()
w.WriteJson(&todo)
}
然而，在POSTMAN客户端的控制台中，错误显示为：
{
"Error": "JSON payload is empty"
}
我想知道可能出了什么问题。谢谢。
编辑：
这个问题不应该被视为重复问题，因为我甚至没有尝试使用json包来进行JSON对象的编组/解组。相反，我正在使用rest.Request对象（内置于go-json-rest中）来解码从客户端发送的JSON参数。
经过深入挖掘和搜索，我发现下面的答案解决了我的问题：
body, _ := ioutil.ReadAll(r.Body)会消耗请求体中的所有内容。因此，删除这行代码后，JSON解析就可以正常工作！
英文:
I'm trying to use go-json-rest to create RESTful APIs
I have this model struct:
type Todo struct {
id int
name string
}
And I am trying to do a POST request to create an object of Todo type:
func CreateTodo(w rest.ResponseWriter, r *rest.Request) {
body, _ := ioutil.ReadAll(r.Body)
log.Println("body content is: ", string(body)) // here I can see {"name": "test1"}
var todo Todo = Todo{}
err := r.DecodeJsonPayload(&todo) // here the error shows JSON payload is empty
defer r.Body.Close()
if err != nil {
log.Println("error in parsing json")
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if todo.name == "" {
rest.Error(w, "todo name is required", 400)
return
}
lock.Lock()
var nextId int = len(todos)
// todos[nextId] = todo
todo.id = nextId // set its id
todos = append(todos, todo)
log.Println("num of todos: ", len(todos))
lock.Unlock()
w.WriteJson(&todo)
}
However, in the console of the POSTMAN client, the error shows:
{
"Error": "JSON payload is empty"
}
I was wondering where might go wrong. Thanks
Edit:
This should not be considered a duplicate question, because I am not even trying to use the json package to do marshalling/unmarshalling of JSON object. Instead I am using the rest.Request object (built in go-json-rest) to decode the json parameters as posted from client.
After much digging and search on this problem I found this answer below resolved my issue:
> body, _ := ioutil.ReadAll(r.Body) will consume everything from the
> request body. So after removing this line, the json parsing works!
答案1
得分: 0
我之前只是在不真正理解ioutil.ReadAll()对请求体的操作时，做了一个愚蠢的事情，即在解码JSON参数之前执行了body, _ := ioutil.ReadAll(r.Body)。
正如我在编辑后的帖子中引用的那样，ioutil.ReadAll()会消耗请求体中的所有内容，不会留下任何内容供JSON解码器解析。在删除body, _ := ioutil.ReadAll(r.Body)这一行之后，JSON解析按预期工作。
英文:
I was just being silly doing body, _ := ioutil.ReadAll(r.Body) before decoding the JSON parameters without really understanding what ioutil.ReadAll() does to the request body.
As I quoted above in the edited post, ioutil.ReadAll() consumes everything in the request body, leaving nothing for the json decoder to parse. After removing the line body, _ := ioutil.ReadAll(r.Body), the json parsing works as expected.
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论