Haskell 如何在仆人身上接收职务

下面的代码应该能够发送json正文。 但我总是在以下请求中出错：

curl -X POST -i http://localhost:8080/comtrade --data 'name=nut&age=12'

错误消息是：

数据用户=用户{
年龄：Int，
名称：：字符串
}派生泛型
实例FromJSON用户，其中
parseJSON=withObject“User”parseUser
解析器用户：：对象->解析器用户
parseUser o=do
n获取'[JSON]用户
：生的
myServer：：服务器ComTradeAPI
myServer=getUser
：测试
：serveDirectoryWebApp“站点”
哪里
测试：：处理程序用户
测试=返回（用户12“螺母”）
getUser:：User->Handler Int
getUser usr=return 12
main:：IO（）
main=openBrowser“http://localhost:8080/index.html"
>>运行8080（serve（代理：：Proxy ComTradeAPI）myServer）

---

有谁能告诉我如何让服务服务器接收POST消息吗？

正如Fyodor Soikin在评论中指出的，OP中的cURL示例不发布JSON，而是发布URL编码的数据。如果使用cURL的

-v

（verbose）选项而不是

-i

，则可以看到这一点：

$ curl -v http://localhost:8080/comtrade -d "{ \"name\": \"nut\", \"age\": 12 }"
*   Trying ::1:8080...
* TCP_NODELAY set
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> POST /comtrade HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.67.0
> Accept: */*
> Content-Length: 28
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 28 out of 28 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 405 Method Not Allowed
< Transfer-Encoding: chunked
< Date: Sat, 13 Mar 2021 12:52:59 GMT
< Server: Warp/3.2.28
< Content-Type: text/plain
<
Only GET or HEAD is supported

请注意，cURL仍然将

内容类型默认为
application/x-www-form-urlencoded
。由于API声明为接收JSON，因此必须明确告诉它JSON来了：

$ curl -i http://localhost:8080/comtrade -H "Content-Type: application/json" -d "{ \"name\": \"nut\", \"age\": 12 }"
HTTP/1.1 200 OK
Transfer-Encoding: chunked
Date: Sat, 13 Mar 2021 12:58:09 GMT
Server: Warp/3.2.28
Content-Type: application/json;charset=utf-8

12

据我所知，Haskell代码没有任何问题。这是一个正确使用HTTP协议的问题。
您的服务API将请求内容类型指定为
'[JSON]
，但您的
curl
命令将其指定为URL编码。
$ curl -v http://localhost:8080/comtrade -d "{ \"name\": \"nut\", \"age\": 12 }"
*   Trying ::1:8080...
* TCP_NODELAY set
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> POST /comtrade HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.67.0
> Accept: */*
> Content-Length: 28
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 28 out of 28 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 405 Method Not Allowed
< Transfer-Encoding: chunked
< Date: Sat, 13 Mar 2021 12:52:59 GMT
< Server: Warp/3.2.28
< Content-Type: text/plain
<
Only GET or HEAD is supported

$ curl -v http://localhost:8080/comtrade -d "{ \"name\": \"nut\", \"age\": 12 }"
*   Trying ::1:8080...
* TCP_NODELAY set
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> POST /comtrade HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.67.0
> Accept: */*
> Content-Length: 28
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 28 out of 28 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 405 Method Not Allowed
< Transfer-Encoding: chunked
< Date: Sat, 13 Mar 2021 12:56:42 GMT
< Server: Warp/3.2.28
< Content-Type: text/plain
<
Only GET or HEAD is supported

$ curl -i http://localhost:8080/comtrade -H "Content-Type: application/json" -d "{ \"name\": \"nut\", \"age\": 12 }"
HTTP/1.1 200 OK
Transfer-Encoding: chunked
Date: Sat, 13 Mar 2021 12:58:09 GMT
Server: Warp/3.2.28
Content-Type: application/json;charset=utf-8

12