YAGA IndexedDB Tile Cache
A tile storage and cache that uses the browsers IndexedDB to store the spatial map tiles.
Key features
- On the fly downloading, storing and serving
- Maximal age and auto upgrading of tiles as long as there is a connection
- Seeding in your browser with a bounding box and a zoom level range
- Possibility to serve tiles as base64 data-url including its content type
- Well tested and documented
- Written in and for TypeScript
How to use
At first you have to install this library with npm or yarn:
npm install --save @yaga/indexed-db-tile-cache
# OR
yarn install --save @yaga/indexed-db-tile-cacheAfter that you can import this module into your application with the typical node.js or TypeScript way.
keep in mind that you have to use browserify to package the libraries from the node.js environment into your browser
ones, such as Buffer or request.
Working with a tile-cache
JavaScript
const indexedDbTileCache = require('@yaga/indexed-db-tile-cache');
// if you use the precompiled version you can use it similar, just with this change:
// const indexedDbTileCache = window.yaga.tileCache;
const options = {
databaseName: "tile-cache-data", // optional
databaseVersion: 1, // optional
objectStoreName: "OSM", // optional
tileUrl: "http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png", // optional
tileUrlSubDomains: ["a", "b", "c"], // optional
crawlDelay: 500, // optional
maxAge: 1000 * 60 * 60 * 24 * 7, // optional
};
const tileCache = new indexedDbTileCache.IndexedDbTileCache(options);
// get a tile from cache or download if not available:
tileCache.getTileAsDataUrl({x:0, y: 0, z: 0}).then(function(dataUrl) {
const img = document.createElement("img");
img.src = dataUrl;
document.body.appendChild(img);
}, function(err) {
console.error(err);
});
// seed an area:
tileCache.on("seed-progress", function (progress) {
console.log(progess.remains + ' of ' + progress.total + 'tiles remains...');
});
tileCache.seedBBox({
maxLat: 10,
maxLng: 10,
minLat: 1,
minLng: 1,
}).then(function(duration) {
console.log('Seeding completed in ' + duration + 'ms');
}, function(err) {
console.error(err);
});TypeScript
import {
IIndexedDbTileCacheOptions,
IIndexedDbTileCacheSeedProgress,
IndexedDbTileCache,
} from "@yaga/indexed-db-tile-cache";
const options: IIndexedDbTileCacheOptions = {
databaseName: "tile-cache-data", // optional
databaseVersion: 1, // optional
objectStoreName: "OSM", // optional
tileUrl: "http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png", // optional
tileUrlSubDomains: ["a", "b", "c"], // optional
crawlDelay: 500, // optional
maxAge: 1000 * 60 * 60 * 24 * 7, // optional
};
const tileCache = new IndexedDbTileCache(options);
// get a tile from cache or download if not available:
tileCache.getTileAsDataUrl({x:0, y: 0, z: 0}).then((dataUrl: string) => {
const img = document.createElement("img");
img.src = dataUrl;
document.body.appendChild(img);
}, (err) => {
console.error(err);
});
// seed an area:
tileCache.on("seed-progress", (progress: IIndexedDbTileCacheSeedProgress) => {
console.log(`${ progess.remains } of ${ progress.total } tiles remains...`);
});
tileCache.seedBBox({
maxLat: 10,
maxLng: 10,
minLat: 1,
minLng: 1,
}).then((duration: number) => {
console.log(`Seeding completed in ${ duration }ms`);
}, (err) => {
console.error(err);
});There are more methods available, for further information take a look at the API documentation...
Precompiled version
If you just want to use this library without having the pros of a module loader, you can also run the npm dist task
for a packaged and precompiled version.
At first run:
npm run distAfter that you have a dist.js and a dist.min.js in this project root folder. Now you can use this library like this:
<html>
<head>
<script src="dist.min.js"></script>
<script>
const tileCache = new yaga.tileCache.IndexedDbTileCache();
</script>
</head>
</html>NPM script tasks
-
npm test: Runs the software tests with karma and leaves a coverage report under the foldercoverage. -
npm run browser-test: Prepares the tests to run directly in your browser. After running this command you have to openbrowser-test/index.htmlin your browser of choice. -
npm run dist: Creates an isolated package (without module loader) and registers the module underwindow.yaga.tileCache.*. -
npm run doc: Creates the API documentation withtypedocand places the documentation in the foldertypedoc.
Contribution
Make an issue on GitHub, or even better a pull request and try to fulfill the software tests.
License
This library is under ISC License © by Arne Schubert and the YAGA Development Team.