Server-Side Data Processing
Documentation
In many cases, before being handed out to the client, data is processed on the server. The DevExtreme HTML5 Widgets support this scenario. In this demo, the data source of the Chart widget loads weather data for a selected month from an OData service. Each time the month is changed, the data source sends a new query to the service.
weatherbase.com
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import React from 'react';
import DataSource from 'devextreme/data/data_source';
import 'devextreme/data/odata/store';
import Chart, {
ValueAxis,
ArgumentAxis,
CommonPaneSettings,
Grid,
Series,
Label,
Legend,
Size,
Border,
Tooltip,
Export
} from 'devextreme-react/chart';
import SelectBox from 'devextreme-react/select-box';
import { months } from './data.js';
class App extends React.Component {
constructor(props) {
super(props);
this.chartDataSource = new DataSource({
store: {
type: 'odata',
url: 'https://js.devexpress.com/Demos/WidgetsGallery/odata/WeatherItems'
},
postProcess: function(results) {
return results[0].DayItems;
},
expand: 'DayItems',
filter: ['Id', '=', 1],
paginate: false
});
this.onValueChanged = (data) => {
this.chartDataSource.filter(['Id', '=', data.value]);
this.chartDataSource.load();
};
}
render() {
return (
<div id={'chart-demo'}>
<Chart
title={'Temperature in Barcelona, 2012'}
dataSource={this.chartDataSource}>
<Size height={420} />
<ValueAxis
grid={{ opacity: 0.2 }}
valueType={'numeric'}
>
<Label customizeText={this.customizeLabel} />
</ValueAxis>
<ArgumentAxis type={'discrete'}>
<Grid visible={true} opacity={0.5} />
</ArgumentAxis>
<CommonPaneSettings>
<Border
visible={true}
width={2}
top={false}
right={false}
/>
</CommonPaneSettings>
<Series
argumentField={'Number'}
valueField={'Temperature'}
type={'spline'}
/>
<Legend visible={false} />
<Export enabled={true} />
<Tooltip
enabled={true}
customizeTooltip={customizeTooltip} />
</Chart>
<div className={'action'}>
<SelectBox
id={'selectbox'}
width={150}
valueExpr={'id'}
displayExpr={'name'}
items={months}
defaultValue={1}
onValueChanged={this.onValueChanged} />
<div className={'label'}>Choose a month:
</div>
</div>
</div>
);
}
customizeLabel(e) {
return `${e.valueText}${'°C'}`;
}
}
function customizeTooltip(arg) {
return {
text: `${arg.valueText}${'°C'}`
};
}
export default App;
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';
ReactDOM.render(
<App />,
document.getElementById('app')
);
<!DOCTYPE html>
<html>
<head>
<title>DevExtreme Demo</title>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.1.4/css/dx.common.css" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.1.4/css/dx.light.css" />
<link rel="stylesheet" type="text/css" href="styles.css" />
<script src="https://unpkg.com/core-js@2.4.1/client/shim.min.js"></script>
<script src="https://unpkg.com/systemjs@0.21.3/dist/system.js"></script>
<script type="text/javascript" src="config.js"></script>
<script type="text/javascript">
System.import('./index.js');
</script>
</head>
<body class="dx-viewport">
<div class="demo-container">
<div id="app"></div>
</div>
</body>
</html>
#selectbox {
float: right;
}
.action {
width: 270px;
margin-top: 20px;
}
.label {
padding-top: 9px;
}
export const months = [{
id: 1,
name: 'January'
}, {
id: 2,
name: 'February'
}, {
id: 3,
name: 'March'
}, {
id: 4,
name: 'April'
}, {
id: 5,
name: 'May'
}, {
id: 6,
name: 'June'
}, {
id: 7,
name: 'July'
}, {
id: 8,
name: 'August'
}, {
id: 9,
name: 'September'
}, {
id: 10,
name: 'October'
}, {
id: 11,
name: 'November'
}, {
id: 12,
name: 'December'
}];
System.config({
transpiler: 'plugin-babel',
paths: {
'npm:': 'https://unpkg.com/'
},
defaultExtension: 'js',
map: {
'react': 'npm:react@16/umd/react.development.js',
'react-dom': 'npm:react-dom@16/umd/react-dom.development.js',
'prop-types': 'npm:prop-types/prop-types.js',
'devextreme': 'npm:devextreme@19.1',
'devextreme-react': 'npm:devextreme-react@19.1',
'jszip': 'npm:jszip@3.1.3/dist/jszip.min.js',
'quill': 'npm:quill@1.3.6/dist/quill.js',
'devexpress-diagram': 'npm:devexpress-diagram',
// SystemJS plugins
'plugin-babel': 'npm:systemjs-plugin-babel@0/plugin-babel.js',
'systemjs-babel-build':
'npm:systemjs-plugin-babel@0/systemjs-babel-browser.js'
},
packages: {
'devextreme': {
defaultExtension: 'js'
},
'devextreme-react': {
main: 'index.js'
}
},
babelOptions: {
sourceMaps: false,
stage0: true,
react: true
}
});