5. Block editing with a form

We'll add schema-based editing of the block settings. In Volto the convention is to use the schema generated from a function, so that the resulting object can be freely mutated, as it comes from a closure.

The most basic schema would look something like this:

export const TableSchema = ({formData, intl}) => ({
  title: 'Table',
  fieldsets: [
    {
      id: 'default',
      title: 'Default',
      fields: ['description'],
    },
  ],
  properties: {
    description: {
        title: 'Description',
        widget: 'textarea'
    }
  },
  required: ['title'],
});

This schema is based on the one used by plone.restapi to edit the server-side Dexterity content. We're appropriating it. It lives on the client side right now, so we have some freedom in extending it with new logic and capabilities. The only requirement is that Volto's form implementation understands it. But even here we have a lot of freedom, as the form passes all the field props to the widgets.

To understand how to structure the schema, you need to read Volto's Field.jsx code. In it, we see the following logic:

const Widget =
  getWidgetByFieldId(props.id) ||
  getWidgetByName(props.widget) ||
  getWidgetByChoices(props) ||
  getWidgetByVocabulary(props.vocabulary) ||
  getWidgetByVocabularyFromHint(props) ||
  getWidgetByFactory(props.factory) ||
  getWidgetByType(props.type) ||
  getWidgetDefault();

The precedence order of the algorithm is pretty self-explanatory.

You can specify a widget for a particular field with:

config.widgets.id.some_fieldname = MyWidget`;

Or you can set the widget property in a schema:

//...
properties: {
  headline: {
    title: "Headline",'
    widget: "headline_widget",
  }
}
//...

See Volto's widget documentation for more details, including how to designate a widget for a particular Dexterity field.

Now we add a basic schema to control the table styling. Create the src/DataTable/schema.js file:

import { defineMessages } from 'react-intl';

export const TableSchema = ({ intl }) => ({
  title: 'Table',

  fieldsets: [
    {
      id: 'default',
      title: intl.formatMessage(messages.defaultFieldset),
      fields: ['file_path'],
    },
    {
      id: 'style',
      title: intl.formatMessage(messages.styling),
      fields: ['fixed', 'celled', 'striped', 'compact', 'basic', 'inverted'],
    },
  ],

  properties: {
    file_path: {
      title: intl.formatMessage(messages.dataFile),
      widget: 'object_browser',
      mode: 'link',
    },
    fixed: {
      type: 'boolean',
      title: intl.formatMessage(messages.fixed),
    },
    compact: {
      type: 'boolean',
      title: intl.formatMessage(messages.compact),
    },
    basic: {
      type: 'boolean',
      title: intl.formatMessage(messages.basic),
    },
    celled: {
      type: 'boolean',
      title: intl.formatMessage(messages.celled),
    },
    inverted: {
      type: 'boolean',
      title: intl.formatMessage(messages.inverted),
    },
    striped: {
      type: 'boolean',
      title: intl.formatMessage(messages.striped),
    },
  },

  required: ['file_path'],
});

const messages = defineMessages({
  fixed: {
    id: 'Fixed width table cells',
    defaultMessage: 'Fixed width table cells',
  },
  compact: {
    id: 'Make the table compact',
    defaultMessage: 'Make the table compact',
  },
  basic: {
    id: 'Reduce complexity',
    defaultMessage: 'Reduce complexity',
  },
  celled: {
    id: 'Divide each row into separate cells',
    defaultMessage: 'Divide each row into separate cells',
  },
  inverted: {
    id: 'Table color inverted',
    defaultMessage: 'Table color inverted',
  },
  striped: {
    id: 'Stripe alternate rows with color',
    defaultMessage: 'Stripe alternate rows with color',
  },
  styling: {
    id: 'Styling',
    defaultMessage: 'Styling',
  },
  defaultFieldset: {
    id: 'Default',
    defaultMessage: 'Default',
  },
  dataFile: {
    id: 'Data file',
    defaultMessage: 'Data file',
  },
});

Notice that our schema is actually a function that returns a JavaScript object, not least because we need to have access to the intl utility to provide internationalization.

To use the schema, we need to change the block edit component from src/DataTable/DataTableEdit.jsx:

// ...
import { InlineForm } from '@plone/volto/components';
import { TableSchema } from './schema';
// ...

const DataTableEdit = (props) => {
  const { selected, onChangeBlock, block, data } = props;
  const schema = TableSchema(props);

  return (
    <div className="dataTable-edit">
      <SidebarPortal selected={selected}>
        {!data.file_path?.length ? (
          <Segment.Group raised>
            <header className="header pulled">
              <h2>Data table</h2>
            </header>
            <Segment className="sidebar-metadata-container" secondary>
              No file selected
              <Icon name={tableSVG} size="100px" color="#b8c6c8" />
            </Segment>
          </Segment.Group>
        ) : (
          ''
        )}
        {data.file_path ? (
          <InlineForm
            schema={schema}
            title={schema.title}
            onChangeField={(id, value) => {
              onChangeBlock(block, {
                ...data,
                [id]: value,
              });
            }}
            formData={data}
          />
        ) : (
          ''
        )}
      </SidebarPortal>
      {data.file_path?.length ? (
        <DataTableView {...props} />
      ) : (
        <div className="no-value">
          <Form>
            <Icon name={tableSVG} size="100px" color="#b8c6c8" />
            <Field
              id="file_path"
              widget="object_browser"
              mode="link"
              title="Pick a file"
              value={data.file_path || []}
              onChange={(id, value) => {
                onChangeBlock(block, {
                  ...data,
                  [id]: value,
                });
              }}
            />
          </Form>
        </div>
      )}
    </div>
  );
};

export default DataTableEdit;

We're using the InlineForm, a component provided by Volto that renders an "embeddable" form. This form requires, as parameters, the schema, and the form values. We'll render this form in the sidebar.

Now the view module from src/DataTable/DataTable.jsx can become:

import React from 'react';
import { Table } from 'semantic-ui-react';
import { withFileData } from '@plone-collective/volto-datatable-tutorial/hocs';

const format = (data) => {
  return {
    fixed: data.fixed,
    compact: data.compact,
    basic: data.basic ? 'very' : undefined,
    celled: data.celled,
    inverted: data.inverted,
    striped: data.striped
  };
};

const DataTableView = ({ file_data, data }) => {
  const fields = file_data?.meta?.fields || [];

  return file_data ? (
    <Table { ...format(data) }>
      <Table.Header>
        <Table.Row>
          {fields.map((f) => (
            <Table.Cell key={f}>{f}</Table.Cell>
          ))}
        </Table.Row>
      </Table.Header>
      <Table.Body>
        {file_data.data.map((o, i) => (
          <Table.Row key={i}>
            {fields.map((f) => (
              <Table.Cell>{o[f]}</Table.Cell>
            ))}
          </Table.Row>
        ))}
      </Table.Body>
    </Table>
  ) : (
    <div>No data</div>
  );
};

export default withFileData(({ data: { file_path } }) => file_path?.[0])(
  DataTableView
);

Here's how your block would look like:

../_images/basic-table-edit.png

5.1. Initial block data as a reusable pattern

For the view component, we've created a HOC mechanism that grants automatic data injection. Can we do the same and simplify the Edit component? Let's make the "new block needs to point to a file", a mechanism that we can reuse. Perhaps later we'll write a chart block that uses the CSV file, so we'll be able to reuse code by composing.

Add the src/hocs/withBlockDataSource.js HOC file:

import React from 'react';
import { Segment, Form } from 'semantic-ui-react';
import { SidebarPortal, Field, Icon } from '@plone/volto/components';

const withBlockDataSource = (opts) => (WrappedComponent) => {
  const { icon, title, getFilePath } = opts;

  return (props) => {
    const { data, selected, onChangeBlock, block } = props;
    const file_path = getFilePath(props);

    return (
      <div className={`${data['@type']}-edit`}>
        {!file_path ? (
          <>
            <div className="no-value">
              <Form>
                <Icon name={icon} size="100px" color="#b8c6c8" />
                <Field
                  id="file_path"
                  widget="object_browser"
                  mode="link"
                  title="Pick a file"
                  value={file_path || []}
                  onChange={(id, value) => {
                    onChangeBlock(block, {
                      ...data,
                      [id]: value,
                    });
                  }}
                />
              </Form>
            </div>

            <SidebarPortal selected={selected}>
              <Segment.Group raised>
                <header className="header pulled">
                  <h2>{title}</h2>
                </header>
                <Segment className="sidebar-metadata-container" secondary>
                  No file selected
                  <Icon name={icon} size="100px" color="#b8c6c8" />
                </Segment>
              </Segment.Group>
            </SidebarPortal>
          </>
        ) : (
          <WrappedComponent {...props} />
        )}
      </div>
    );
  };
};

export default withBlockDataSource;

Make sure to export this new HOC from the src/hocs/index.js file with:

export withFileData from './withFileData';
export withBlockDataSource from './withBlockDataSource';

Within src/DataTable/DataTableEdit.js now import the newly added withBlockDataSource higher-order component.

Make use of it by replacing the DataTableEdit component, and it's export with:

import React from 'react';
import { InlineForm, SidebarPortal } from '@plone/volto/components';
import tableSVG from '@plone/volto/icons/table.svg';

import { withBlockDataSource } from '@plone-collective/volto-datatable-tutorial/hocs';

import { TableSchema } from './schema';
import DataTableView from './DataTableView';

import './datatable-edit.less';

const DataTableEdit = (props) => {
  const { selected, onChangeBlock, block, data } = props;
  const schema = TableSchema(props);

  return (
    <>
      <SidebarPortal selected={selected}>
        <InlineForm
          schema={schema}
          title={schema.title}
          onChangeField={(id, value) => {
            onChangeBlock(block, {
              ...data,
              [id]: value,
            });
          }}
          formData={data}
        />
      </SidebarPortal>
      <DataTableView {...props} />
    </>
  );
};

export default withBlockDataSource({
  icon: tableSVG,
  title: 'Data table',
  getFilePath: ({ data: { file_path } }) => file_path?.[0],
})(DataTableEdit);