如何验证创建多条记录的表单

Question

语境

我有一个带有由控制器动态生成的任意数量输入的表单的视图。提交表单时，每个输入都应创建自己的记录，因此，如果有 60 个输入，则应创建 60 条记录。

问题

应如何验证每个输入/字段？在 IHP 文档的示例中，单个表单仅创建 1 条记录，因此我不确定执行此操作的最佳或惯用方法是什么。

也许我可以将如下所示的函数映射到每个提交的输入，但是 Left 情况将由第一个验证失败而不是所有验证失败触发，因此我需要在重定向到前一个之前将每个失败保存在列表中（？）表单视图。

 action CreatePostAction = do
    let post = newRecord @Post
    post
        |> fill @'["title", "body"]
        |> validateField #title nonEmpty
        |> validateField #body nonEmpty
        |> ifValid \case
            Left post -> render NewView { post }
            Right post -> do
                post <- post |> createRecord
                setSuccessMessage "Post created"
                redirectTo PostsAction

Answer 1

尝试这样的事情：

    action CreatePostAction = do
        let titles :: [Text] = paramList "title"
        let bodys :: [Text] = paramList "body"

        let posts = zip titles bodys
                |> map (\(title, body) -> newRecord @Post
                        |> set #title title
                        |> set #body body
                        |> validateField #title nonEmpty
                        |> validateField #body nonEmpty
                    )

        validatedPosts :: [Either Post Post] <- forM posts (ifValid (\post -> pure post))

        case Either.partitionEithers validatedPosts of
            ([], posts) -> do
                createMany posts
                setSuccessMessage "Post created"
                redirectTo PostsAction

            (invalidPosts, validPosts) -> render NewView { posts }

为此，您需要这样的视图：

    action CreatePostAction = do
        let titles :: [Text] = paramList "title"
        let bodys :: [Text] = paramList "body"

        let posts = zip titles bodys
                |> map (\(title, body) -> newRecord @Post
                        |> set #title title
                        |> set #body body
                        |> validateField #title nonEmpty
                        |> validateField #body nonEmpty
                    )

        validatedPosts :: [Either Post Post] <- forM posts (ifValid (\post -> pure post))

        case Either.partitionEithers validatedPosts of
            ([], posts) -> do
                createMany posts
                setSuccessMessage "Post created"
                redirectTo PostsAction

            (invalidPosts, validPosts) -> render NewView { posts }

我的NewPostAction看起来像这样：

module Web.View.Posts.New where
import Web.View.Prelude
import qualified Text.Blaze.Html5 as H
import qualified Text.Blaze.Html5.Attributes as A

data NewView = NewView { posts :: [Post] }

instance View NewView where
    html NewView { .. } = [hsx|
        <nav>
            <ol class="breadcrumb">
                <li class="breadcrumb-item"><a href={PostsAction}>Posts</a></li>
                <li class="breadcrumb-item active">New Post</li>
            </ol>
        </nav>
        <h1>New Post</h1>

        <form id="main-form" method="POST" action={CreatePostAction}>
            <input type="submit" class="btn btn-primary"/>
            {forEach posts renderForm}
        </form>
    |]

renderForm :: Post -> Html
renderForm post = [hsx|
    <div class="form-group">
        <label>
            Title
        </label>
        <input type="text" name="title" value={get #title post} class={classes ["form-control", ("is-invalid", isInvalidTitle)]}/>
        {titleFeedback}
    </div>

    <div class="form-group">
        <label>
            Body
        </label>
        <input type="text" name="body" value={get #body post} class={classes ["form-control", ("is-invalid", isInvalidBody)]}/>
        {bodyFeedback}
    </div>
|]
    where
        isInvalidTitle = isJust (getValidationFailure #title post)
        isInvalidBody = isJust (getValidationFailure #body post)

        titleFeedback = case getValidationFailure #title post of
            Just result -> [hsx|<div class="invalid-feedback">{result}</div>|]
            Nothing -> mempty

        bodyFeedback = case getValidationFailure #body post of
            Just result -> [hsx|<div class="invalid-feedback">{result}</div>|]
            Nothing -> mempty