14. Volto View Component: A Default View for a "Talk"#
Get the code: collective/volto-ploneconf
git checkout talkview
More info in The code for the training
In this part we will:
Create a view to display a talk
Register a React view component for content type talk
Write the view component
Topics covered:
View
Displaying data stored in fields of a content type
React Basics
The default visualization for our new content type talk
lists the field values according to the type schema.
Since we want to show the talk data in a nice way, display the speaker portrait and add some components, we write a custom view for type talk.
In the folder frontend
you need to add a new file src/components/Views/Talk.jsx
.
Create the folder Views
first.
As a first step, the file will hold only a placeholder. A view is a React component. So we write a component function that just returns the info about what it will be.
import React from 'react';
const TalkView = props => {
return <div>I am the TalkView component!</div>;
};
export default TalkView;
Also add a convenience import of the new component to src/components/index.js
:
import TalkView from './Views/Talk';
export { TalkView };
This is a common practice and allows us to import the new view component as import { TalkView } from './components';
instead of import { TalkView } from './components/Views/Talk';
.
Now register the new component as the default view for talks
in src/config.js
.
import { TalkView } from './components';
// All your imports required for the config here BEFORE this line
import '@plone/volto/config';
export default function applyConfig(config) {
config.views = {
...config.views,
contentTypesViews: {
...config.views.contentTypesViews,
talk: TalkView,
},
};
return config;
}
This extends the Volto default setting
config.views.contentTypesViews
with the key/value pairtalk: TalkView
.It uses the spread syntax to take the default settings and overrides what needs to be overridden.
When Volto is running (with yarn start
) it picks up these configuration modifications and displays the placeholder in place of the previously used default view.
Now we will improve this view step by step.
First we reuse the component DefaultView.jsx
in our custom view:
import React from 'react';
import { DefaultView } from '@plone/volto/components';
const TalkView = (props) => {
return <DefaultView {...props} />;
};
export default TalkView;
We will now add the content from the field details
after the DefaultView
.
import React from 'react';
import { DefaultView } from '@plone/volto/components';
const TalkView = (props) => {
const { content } = props;
return (
<>
<DefaultView {...props} />
<div dangerouslySetInnerHTML={{ __html: content.details.data }} />
</>
);
};
export default TalkView;
<> </>
is a fragment. The return value of React needs to be one single element.The variable
props
is used to receive data from the parent component. As the TalkView component is registered as a content type view, it receives the content data and some more. We will use the content part. So we introduce a constantcontent
to be more explicit.content.details
is the value of the richtext fielddetails
with mime type, encoding and the data:{ 'content-type': 'text/html', data: '<p>foo bar...</p>', encoding: 'utf8' };
See Serialization.
content.details.data
holds the raw html. To render it properly we usedangerouslySetInnerHTML
(see https://legacy.reactjs.org/docs/dom-elements.html#dangerouslysetinnerhtml).
Please check the 'components' tab of Google developer tools to see the field values of your talk instance.
The result is not really beautiful, because the text sticks to the left border of the page.
You need to wrap it in a Container
to get the same styling as the content of DefaultView
:
import React from 'react';
import { DefaultView } from '@plone/volto/components';
import { Container } from 'semantic-ui-react';
const TalkView = props => {
const { content } = props;
return (
<>
<DefaultView {...props} />
<Container>
<div dangerouslySetInnerHTML={{ __html: content.details.data }} />
</Container>
</>
);
};
export default TalkView;
Container
is a component from Semantic UI React and needs to be imported before it is used.
We now decide to display the type of talk in the title (E.g. "Keynote: The Future of Plone").
This means we cannot use DefaultView
anymore since that displays the title like this: <h1 className="documentFirstHeading">{content.title}</h1>
.
Instead we display the title and description in a custom way.
This has multiple benefits:
All content can now be wrapped in the same
Container
which cleans up the html.We can control where the speaker portrait is displayed. We can now move all information on the speaker into a separate box. The speaker portrait is picked up by the DefaultView because the fields name is
image
, which is the same as the image from the behaviorplone.leadimage
.
With this changes we do discard the title tag in the HTML head though.
This will change the name occurring in the browser tab or browser head to the current site url.
To use the content title instead, you'll have to import the Helmet
component, which allows to overwrite all meta tags for the HTML head like the page-title.
import React from 'react';
import { Container } from 'semantic-ui-react';
import { Helmet } from '@plone/volto/helpers';
const TalkView = props => {
const { content } = props;
return (
<Container id="view-wrapper talk-view">
<Helmet title={content.title} />
<h1 className="documentFirstHeading">
<span className="type_of_talk">{content.type_of_talk.title}: </span>
{content.title}
</h1>
{content.description && (
<p className="documentDescription">{content.description}</p>
)}
<div dangerouslySetInnerHTML={{ __html: content.details.data }} />
</Container>
);
};
export default TalkView;
content.type_of_talk
is the json representation of the value from the choice fieldtype_of_talk
:{token: "training", title: "Training"}
. We display the title.The
&&
in{content.description && (<p>...</p>)}
makes sure, that this paragraph is only rendered, if the talk actually has a description.
Next we add a segment with info on the speaker:
import React from 'react';
import { Container, Header, Segment } from 'semantic-ui-react';
const TalkView = (props) => {
const { content } = props;
return (
<Container id="view-wrapper talk-view">
<h1 className="documentFirstHeading">
<span className="type_of_talk">{content.type_of_talk.title} </span>
{content.title}
</h1>
{content.description && (
<p className="documentDescription">{content.description}</p>
)}
<div dangerouslySetInnerHTML={{ __html: content.details.data }} />
<Segment clearing>
{content.speaker && <Header dividing>{content.speaker}</Header>}
<p>{content.company || content.website}</p>
{content.email && (
<p>
Email: <a href={`mailto:${content.email}`}>{content.email}</a>
</p>
)}
{content.speaker_biography && (
<div
dangerouslySetInnerHTML={{
__html: content.speaker_biography.data,
}}
/>
)}
</Segment>
</Container>
);
};
export default TalkView;
We use the component Segment for the box.
{`mailto:${content.email}`}
is a template literal
Next we add the image:
import React from 'react';
import { Container, Header, Image, Segment } from 'semantic-ui-react';
import { flattenToAppURL } from '@plone/volto/helpers';
const TalkView = (props) => {
const { content } = props;
return (
<Container id="view-wrapper talk-view">
<h1 className="documentFirstHeading">
<span className="type_of_talk">{content.type_of_talk.title} </span>
{content.title}
</h1>
{content.description && (
<p className="documentDescription">{content.description}</p>
)}
<div dangerouslySetInnerHTML={{ __html: content.details.data }} />
<Segment clearing>
{content.speaker && <Header dividing>{content.speaker}</Header>}
<p>{content.company || content.website}</p>
{content.email && (
<p>
Email: <a href={`mailto:${content.email}`}>{content.email}</a>
</p>
)}
<Image
src={flattenToAppURL(content.image?.scales?.preview?.download)}
size="small"
floated="right"
alt={content.image_caption}
avatar
/>
{content.speaker_biography && (
<div
dangerouslySetInnerHTML={{
__html: content.speaker_biography.data,
}}
/>
)}
</Segment>
</Container>
);
};
export default TalkView;
We use the component Image
We use
flattenToAppURL
to turn the Plone url of the image to the Volto url, e.g. it turns http://localhost:8080/Plone/talks/dexterity-for-the-win/@@images/9fb3d165-82f4-4ffa-804f-2afe1bad8124.jpeg into http://localhost:3000/talks/dexterity-for-the-win/@@images/9fb3d165-82f4-4ffa-804f-2afe1bad8124.jpeg.Open the React Developer Tools in your browser and inspect the property
image
of TalkView and its propertyscale
. If you look at the documentation for the serialization of image-fields you can find out where that information comes from.To deal with talks without speaker image, we check for the existence of the image with
content.image?.scales?.preview?.download
. The expression with question marks returnsundefined
ifcontent
has noimage
key orcontent.image
has noscales
key and so on.?.
is the optional chaining operator.
Next we add the audience:
import React from 'react';
import { Container, Header, Image, Label, Segment } from 'semantic-ui-react';
import { flattenToAppURL } from '@plone/volto/helpers';
const TalkView = (props) => {
const { content } = props;
const color_mapping = {
beginner: 'green',
advanced: 'yellow',
professional: 'purple',
};
return (
<Container id="view-wrapper talk-view">
<h1 className="documentFirstHeading">
{content.type_of_talk.title || content.type_of_talk.token}:{' '}
{content.title}
</h1>
{content.description && (
<p className="documentDescription">{content.description}</p>
)}
{content.audience?.map((item) => {
let color = color_mapping[item.token] || 'green';
return (
<Label key={item.token} color={color}>
{item.title}
</Label>
);
})}
<div dangerouslySetInnerHTML={{ __html: content.details.data }} />
<Segment clearing>
{content.speaker && <Header dividing>{content.speaker}</Header>}
<p>{content.company || content.website}</p>
{content.email && (
<p>
Email: <a href={`mailto:${content.email}`}>{content.email}</a>
</p>
)}
<Image
src={flattenToAppURL(content.image?.scales?.preview?.download)}
size="small"
floated="right"
alt={content.image_caption}
avatar
/>
{content.speaker_biography && (
<div
dangerouslySetInnerHTML={{
__html: content.speaker_biography.data,
}}
/>
)}
</Segment>
</Container>
);
};
export default TalkView;
With
{content.audience?.map(item => {...})}
we iterate over the individual values of the choice fieldaudience
if that exists.map is used to iterate over the array
audience
using an Arrow-function (=>) in whichitem
is one item in audience.The
item
is anObject
like{'title': 'Advanced', 'token': 'advanced'}
.We map the available field values to colors and use green as a fallback.
As a last step we show the last few fields website
and company
, github
and twitter
:
import React from 'react';
import { flattenToAppURL } from '@plone/volto/helpers';
import { Container, Header, Image, Label, Segment } from 'semantic-ui-react';
const TalkView = (props) => {
const { content } = props;
const color_mapping = {
Beginner: 'green',
Advanced: 'yellow',
Professional: 'purple',
};
return (
<Container id="view-wrapper talk-view">
<h1 className="documentFirstHeading">
{content.type_of_talk.title || content.type_of_talk.token}:{' '}
{content.title}
</h1>
{content.description && (
<p className="documentDescription">{content.description}</p>
)}
{content.audience?.map((item) => {
let audience = item.title || item.token;
let color = color_mapping[audience] || 'green';
return (
<Label key={audience} color={color}>
{audience}
</Label>
);
})}
{content.details && (
<div dangerouslySetInnerHTML={{ __html: content.details.data }} />
)}
<Segment clearing>
{content.speaker && <Header dividing>{content.speaker}</Header>}
{content.website ? (
<p>
<a href={content.website}>
{content.company || content.website}
</a>
</p>
) : (
<p>{content.company}</p>
)}
{content.email && (
<p>
Email: <a href={`mailto:${content.email}`}>{content.email}</a>
</p>
)}
{content.twitter && (
<p>
Twitter:{' '}
<a href={`https://x.com/${content.twitter}`}>
{content.twitter.startsWith('@')
? content.twitter
: '@' + content.twitter}
</a>
</p>
)}
{content.github && (
<p>
Github:{' '}
<a href={`https://github.com/${content.github}`}>
{content.github}
</a>
</p>
)}
{content.image && (
<Image
src={flattenToAppURL(content.image.scales.preview.download)}
size="small"
floated="right"
alt={content.image_caption}
avatar
/>
)}
{content.speaker_biography && (
<div
dangerouslySetInnerHTML={{
__html: content.speaker_biography.data,
}}
/>
)}
</Segment>
</Container>
);
};
export default TalkView;
14.1. Summary#
We created a view for a content type to display its data
We treated the case of missing values