Snap Framework:自定义snaplet处理程序将不会呈现模板 [英] Snap Framework: Custom snaplet handler won't render template

问题描述

我刚开始编写自定义的snaplet并遇到了障碍.我有以下基本的snaplet，在"snaplets/admin-pg/snaplets/heist/templates"中有一个角色"模板.有人可以告诉我为什么handleUsers函数不呈现角色"模板吗?我收到未接受处理程序'/pgadmin/users'"错误.我确定我缺少一些非常基本的东西.谢谢.

I'm just getting started with writing custom snaplets and hit a road block. I have the following basic snaplet which has a "roles" template located in the "snaplets/admin-pg/snaplets/heist/templates". Can someone tell me why the handleUsers function does not render the "roles" template? I get a "No handler accepted '/pgadmin/users' " error. I'm sure I'm missing something very basic. Thanks.

我的主应用程序定义如下.它是HasHeist的一个实例

My main app is defined as follows. It is an instance of HasHeist

data App = App
    { _heist :: Snaplet (Heist App)
    , _pgadmin :: Snaplet (Admin App)
    }

我在主应用程序("Site.hs")中对快照的初始化代码为:

My initializtion code for the snaplet in the main App ("Site.hs") is:

h <- nestSnaplet "" heist $ heistInit "templates"
z <- nestSnaplet "pgadmin" pgadmin $ adminPGInit h

自定义snaplet代码...

Custom snaplet code...

data Admin b = Admin { name :: String}

adminPGInit :: HasHeist a => Snaplet (Heist a) -> SnapletInit a (Admin a)
adminPGInit h = makeSnaplet "admin-pg" description datadir $ do
  config <- getSnapletUserConfig
  fp <- getSnapletFilePath  
  addTemplatesAt h "" fp
  addRoutes [ ("/users", handleUsers) 
            , ("/foo", handleFoo)]

  return $ Admin "Admin Snaplet"
    where
      description = "PostgreSQL Admin"
      datadir = Just $ liftM (++"/resources") getDataDir



handleUsers :: HasHeist b => Handler b (Admin b) ()    
handleUsers = do
  render "roles"

handleFoo :: HasHeist b => Handler b (Admin b) () 
handleFoo = writeBS "foo from admin"

推荐答案

使用addTemplates代替addTemplatesAt.您可以从源代码中看到它与您在这里的内容略有不同.

Use addTemplates instead of addTemplatesAt. You can see from the source code that it's slightly different from what you have here.

此外，一个不相关的细节，您不需要Admin数据类型上的类型参数.由于它不使用b，因此不需要它作为类型参数.

Also, an irrelevant detail, you don't need a type parameter on the Admin data type. Since it does not use b, you don't need it as a type parameter.

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