构建创建页面表单
在上一章节中我们创建了编辑页面功能，本章节我们将添加创建页面功能。以下是我们即将构建内容的预览：
Step 1: Add a Create a new page button
Let’s start by building a button to display the create page form. It’s similar to an Edit button we have built in the part 3:
import { useDispatch } from '@wordpress/data';
import { Button, Modal, TextControl } from '@wordpress/components';
function CreatePageButton() {
const [isOpen, setOpen] = useState( false );
const openModal = () => setOpen( true );
const closeModal = () => setOpen( false );
return (
<>
<Button onClick={ openModal } variant="primary">
Create a new Page
</Button>
{ isOpen && (
<Modal onRequestClose={ closeModal } title="Create a new page">
<CreatePageForm
onCancel={ closeModal }
onSaveFinished={ closeModal }
/>
</Modal>
) }
</>
);
}
function CreatePageForm() {
// Empty for now
return <div/>;
}
Great! Now let’s make MyFirstApp display our shiny new button:
function MyFirstApp() {
// ...
return (
<div>
<div className="list-controls">
<SearchControl onChange={ setSearchTerm } value={ searchTerm }/>
<CreatePageButton/>
</div>
<PagesList hasResolved={ hasResolved } pages={ pages }/>
</div>
);
}
The final result should look as follows:
Step 2: Extract a controlled PageForm
Luckily, the EditPageForm we built in part three already takes us 80% of the way there. The bulk of the user interface is already available, and we will reuse it in the CreatePageForm. Let’s start by extracting the form UI into a separate component:
function EditPageForm( { pageId, onCancel, onSaveFinished } ) {
// ...
return (
<PageForm
title={ page.title }
onChangeTitle={ handleChange }
hasEdits={ hasEdits }
lastError={ lastError }
isSaving={ isSaving }
onCancel={ onCancel }
onSave={ handleSave }
/>
);
}
function PageForm( { title, onChangeTitle, hasEdits, lastError, isSaving, onCancel, onSave } ) {
return (
<div className="my-gutenberg-form">
<TextControl
__next40pxDefaultSize
label="Page title:"
value={ title }
onChange={ onChangeTitle }
/>
{ lastError ? (
<div className="form-error">Error: { lastError.message }</div>
) : (
false
) }
<div className="form-buttons">
<Button
onClick={ onSave }
variant="primary"
disabled={ !hasEdits || isSaving }
>
{ isSaving ? (
<>
<Spinner/>
Saving
</>
) : 'Save' }
</Button>
<Button
onClick={ onCancel }
variant="tertiary"
disabled={ isSaving }
>
Cancel
</Button>
</div>
</div>
);
}
This code quality change should not alter anything about how the application works. Let’s try to edit a page just to be sure:
Great! The edit form is still there, and now we have a building block to power the new CreatePageForm.
步骤 3：构建 CreatePageForm 组件
CreatePageForm 组件只需提供渲染 PageForm 组件所需的以下七个属性：
- title
- onChangeTitle
- hasEdits
- lastError
- isSaving
- onCancel
- onSave
接下来我们看看如何实现：
Title、onChangeTitle、hasEdits
EditPageForm 更新并保存了存在于 Redux 状态中的现有实体记录。因此，我们依赖 editedEntityRecords 选择器。
然而，对于 CreatePageForm 来说，不存在预先存在的实体记录。只有一个空表单。用户输入的任何内容都仅属于该表单本地，这意味着我们可以使用 React 的 useState 钩子来跟踪它：
function CreatePageForm( { onCancel, onSaveFinished } ) {
const [title, setTitle] = useState();
const handleChange = ( title ) => setTitle( title );
return (
<PageForm
title={ title }
onChangeTitle={ setTitle }
hasEdits={ !!title }
{ /* ... */ }
/>
);
}
onSave, onCancel
在 EditPageForm 中，我们调用了 saveEditedEntityRecord('postType', 'page', pageId ) 操作来保存 Redux 状态中的编辑内容。
然而，在 CreatePageForm 中，Redux 状态中没有任何编辑内容，我们也没有 pageId。在这种情况下，我们需要调用的操作名为 saveEntityRecord（名称中没有 Edited 这个词），它接受一个代表新实体记录的对象，而不是 pageId。
传递给 saveEntityRecord 的数据会通过 POST 请求发送到相应的 REST API 端点。例如，调度以下操作：
saveEntityRecord( 'postType', 'page', { title: "Test" } );
会触发一个 POST 请求到 /wp/v2/pages WordPress REST API 端点，请求体中只有一个字段：title=Test。
现在我们对 saveEntityRecord 有了更多了解，让我们在 CreatePageForm 中使用它。
function CreatePageForm( { onSaveFinished, onCancel } ) {
// ...
const { saveEntityRecord } = useDispatch( coreDataStore );
const handleSave = async () => {
const savedRecord = await saveEntityRecord(
'postType',
'page',
{ title }
);
if ( savedRecord ) {
onSaveFinished();
}
};
return (
<PageForm
{ /* ... */ }
onSave={ handleSave }
onCancel={ onCancel }
/>
);
}
还有一个细节需要处理：我们新创建的页面尚未被 PagesList 获取。根据 REST API 文档，/wp/v2/pages 端点默认创建（POST 请求）状态为 status=draft 的页面，但返回（GET 请求）状态为 status=publish 的页面。解决方案是显式传递 status 参数：
function CreatePageForm( { onSaveFinished, onCancel } ) {
// ...
const { saveEntityRecord } = useDispatch( coreDataStore );
const handleSave = async () => {
const savedRecord = await saveEntityRecord(
'postType',
'page',
{ title, status: 'publish' }
);
if ( savedRecord ) {
onSaveFinished();
}
};
return (
<PageForm
{ /* ... */ }
onSave={ handleSave }
onCancel={ onCancel }
/>
);
}
请继续将此更改应用到本地的 CreatePageForm 组件中，接下来我们来处理剩下的两个属性。
lastError, isSaving
The EditPageForm retrieved the error and progress information via the getLastEntitySaveError and isSavingEntityRecord selectors. In both cases, it passed the following three arguments: ( 'postType', 'page', pageId ).
In CreatePageForm however, we do not have a pageId. What now? We can skip the pageId argument to retrieve the information about the entity record without any id – this will be the newly created one. The useSelect call is thus very similar to the one from EditPageForm:
function CreatePageForm( { onCancel, onSaveFinished } ) {
// ...
const { lastError, isSaving } = useSelect(
( select ) => ( {
// Notice the missing pageId argument:
lastError: select( coreDataStore )
.getLastEntitySaveError( 'postType', 'page' ),
// Notice the missing pageId argument
isSaving: select( coreDataStore )
.isSavingEntityRecord( 'postType', 'page' ),
} ),
[]
);
// ...
return (
<PageForm
{ /* ... */ }
lastError={ lastError }
isSaving={ isSaving }
/>
);
}
And that’s it! Here's what our new form looks like in action:
Wiring it all together
Here’s everything we built in this chapter in one place:
function CreatePageForm( { onCancel, onSaveFinished } ) {
const [title, setTitle] = useState();
const { lastError, isSaving } = useSelect(
( select ) => ( {
lastError: select( coreDataStore )
.getLastEntitySaveError( 'postType', 'page' ),
isSaving: select( coreDataStore )
.isSavingEntityRecord( 'postType', 'page' ),
} ),
[]
);
const { saveEntityRecord } = useDispatch( coreDataStore );
const handleSave = async () => {
const savedRecord = await saveEntityRecord(
'postType',
'page',
{ title, status: 'publish' }
);
if ( savedRecord ) {
onSaveFinished();
}
};
return (
<PageForm
title={ title }
onChangeTitle={ setTitle }
hasEdits={ !!title }
onSave={ handleSave }
lastError={ lastError }
onCancel={ onCancel }
isSaving={ isSaving }
/>
);
}
function EditPageForm( { pageId, onCancel, onSaveFinished } ) {
const { page, lastError, isSaving, hasEdits } = useSelect(
( select ) => ( {
page: select( coreDataStore ).getEditedEntityRecord( 'postType', 'page', pageId ),
lastError: select( coreDataStore ).getLastEntitySaveError( 'postType', 'page', pageId ),
isSaving: select( coreDataStore ).isSavingEntityRecord( 'postType', 'page', pageId ),
hasEdits: select( coreDataStore ).hasEditsForEntityRecord( 'postType', 'page', pageId ),
} ),
[pageId]
);
const { saveEditedEntityRecord, editEntityRecord } = useDispatch( coreDataStore );
const handleSave = async () => {
const savedRecord = await saveEditedEntityRecord( 'postType', 'page', pageId );
if ( savedRecord ) {
onSaveFinished();
}
};
const handleChange = ( title ) => editEntityRecord( 'postType', 'page', page.id, { title } );
return (
<PageForm
title={ page.title }
onChangeTitle={ handleChange }
hasEdits={ hasEdits }
lastError={ lastError }
isSaving={ isSaving }
onCancel={ onCancel }
onSave={ handleSave }
/>
);
}
function PageForm( { title, onChangeTitle, hasEdits, lastError, isSaving, onCancel, onSave } ) {
return (
<div className="my-gutenberg-form">
<TextControl
__next40pxDefaultSize
label="Page title:"
value={ title }
onChange={ onChangeTitle }
/>
{ lastError ? (
<div className="form-error">Error: { lastError.message }</div>
) : (
false
) }
<div className="form-buttons">
<Button
onClick={ onSave }
variant="primary"
disabled={ !hasEdits || isSaving }
>
{ isSaving ? (
<>
<Spinner/>
Saving
</>
) : 'Save' }
</Button>
<Button
onClick={ onCancel }
variant="tertiary"
disabled={ isSaving }
>
Cancel
</Button>
</div>
</div>
);
}
All that’s left is to refresh the page and enjoy the form:
下一步做什么？
谢谢你的反馈！