docs._extensions.20_prerendering.md Maven / Gradle / Ivy
---
layout: page
title: Prerendering Extension
permalink: /extensions/prerendering
---
## Prerendering
A data provider can configure datasets being pre-/rerendered regularly for given time intervals
(`lastMonth`, `lastWeek`, or `lastDay`). A client experience may be instant access rather than
to wait for that kind of fixed time intervals. Also, prerendered charts are easy to integrate via
html tags without making requests to render charts dynamically.
On prerendering mode only single series charts are rendered (no chart overlay).
### Job Configuration
A prerendering job can run at a given rate (as
Cron Expression,
e.g. every Sunday at 04:00 in the morning). Such job can be configured and added to the Job scheduler
available by default, for example via Spring:
```xml
```
### Configuration Location
Prerendering (styles, intervals, legend, etc.) can be configured for datasets having a particular
phenomenon or each individually (overriding a possibly matching phenomenona config). A general
configuration section applies to all further config unless overridden (within a `config` entry).
For example:
```json
{
"generalConfig" : {
"width": "800",
"height": "500",
"locale" : "de",
"grid" : true,
"generalize" : false
},
"phenomenonStyles": [
{
"id" : "3",
"title" : "Station: %1$s, Phenomenon: %2$s [{ %8$s}] (w/ legend)",
"chartQualifier" : "with_legend",
"interval": [
"lastWeek",
"lastMonth"
],
"config" : {
"legend" : true
},
"style": {
"chartType": "line",
"properties": {
"color": "#00ffff",
"lineType": "solid",
"width": 2
}
}
}
],
"datasetStyles": [
{
"id" : "16",
"interval": [
"lastWeek",
"lastMonth"
],
"style": {
"chartType": "bar",
"properties": {
"interval": "byDay",
"width": 0.8,
"color": "#0000ff"
}
}
}
]
}
```
{:.n52-callout .n52-callout-info}
`timeseriesStyles` and `seriesStyles` mean the same as `datasetStyles` and is kept
for backwards compatibility reasons.
### Placeholders
To add fine grained title configuration on a phenomenona group a
[`String.format` template](https://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html#syntax)
can be used.
Choose one of the following
* `%1$s`: Platform label
* `%2$s`: Phenomenon label
* `%3$s`: Procedure label
* `%4$s`: Category label
* `%5$s`: Offering label
* `%6$s`: Feature label
* `%7$s`: Service label
* `%8$s`: Unit of Measure
Use the template for the title config within config file config-task-prerendering, e.g. `Platform: %1$s, Phenomenon: %2$s [{ %8$s}]`.
### Accessing prerendered charts
{:.n52-callout .n52-callout-todo}
`datasets//images/`