168 lines
5.1 KiB
Markdown
168 lines
5.1 KiB
Markdown
# mbtiles
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Node.js utilities and [tilelive](https://github.com/mapbox/tilelive.js) integration for the [MBTiles](https://github.com/mapbox/mbtiles-spec) format.
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[](https://travis-ci.com/mapbox/node-mbtiles)
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[](https://ci.appveyor.com/project/Mapbox/node-mbtiles)
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# Installation
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```
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npm install @mapbox/mbtiles
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```
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```javascript
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var MBTiles = require('@mapbox/mbtiles');
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```
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# API
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### Constructor
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All MBTiles instances need to be constructed before any of the methods become available. *NOTE: All methods described below assume you've taken this step.*
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```javascript
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new MBTiles('./path/to/file.mbtiles?mode={ro, rw, rwc}', function(err, mbtiles) {
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console.log(mbtiles) // mbtiles object with methods listed below
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});
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```
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The `mode` query parameter is a opening flag of mbtiles. It is optional, default as `rwc`. Available flags are:
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- `ro`: readonly mode, will throw error if the mbtiles does not exist.
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- `rw`: read and write mode, will throw error if the mbtiles does not exist.
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- `rwc`: read, write and create mode, will create a new mbtiles if the mbtiles does not exist.
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### Reading
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**`getTile(z, x, y, callback)`**
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Get an individual tile from the MBTiles table. This can be a raster or gzipped vector tile. Also returns headers that are important for serving over HTTP.
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```javascript
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mbtiles.getTile(z, x, y, function(err, data, headers) {
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// `data` is your gzipped buffer - use zlib to gunzip or inflate
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});
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```
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**`getInfo(callback)`**
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Get info of an MBTiles file, which is stored in the `metadata` table. Includes information like zoom levels, bounds, vector_layers, that were created during generation. This performs fallback queries if certain keys like `bounds`, `minzoom`, or `maxzoom` have not been provided.
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```javascript
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mbtiles.getInfo(function(err, info) {
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console.log(info); // info
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});
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```
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**`getGrid(z, x, y, callback)`**
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Get a [UTFGrid](https://github.com/mapbox/utfgrid-spec) tile from the MBTiles table.
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```javascript
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mbtiles.getGrid(z, x, y, function(err, data) {
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// continue onwards
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});
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```
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### Writing
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**`startWriting`** AND **`stopWriting`**
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In order to write a new (or currently existing) MBTiles file you need to "start" and "stop" writing. First, [construct](#constructor) the MBTiles object.
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```javascript
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mbtiles.startWriting(function(err) {
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// start writing with mbtiles methods (putTile, putInfo, etc)
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mbtiles.stopWriting(function(err) {
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// stop writing to your mbtiles object
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});
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});
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```
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**`putTile(z, x, y, buffer, callback)`**
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Add a new tile buffer to a specific ZXY. This can be a raster tile or a _gzipped_ vector tile (we suggest using `require('zlib')` to gzip your tiles).
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```javascript
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var zlib = require('zlib');
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zlib.gzip(fs.readFileSync('./path/to/file.mvt'), function(err, buffer) {
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mbtiles.putTile(0, 0, 0, buffer, function(err) {
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// continue onward
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});
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});
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```
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**`putInfo(data, callback)`**
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Put an information object into the metadata table. Any nested JSON will be stringified and stored in the "json" row of the metadata table. This will replace any matching key/value fields in the table.
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```javascript
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var exampleInfo = {
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"name": "hello-world",
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"description":"the world in vector tiles",
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"format":"pbf",
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"version": 2,
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"minzoom": 0,
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"maxzoom": 4,
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"center": "0,0,1",
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"bounds": "-180.000000,-85.051129,180.000000,85.051129",
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"type": "overlay",
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"json": `{"vector_layers": [ { "id": "${layername}", "description": "", "minzoom": 0, "maxzoom": 4, "fields": {} } ] }`
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};
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mbtiles.putInfo(exampleInfo, function(err) {
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// continue onward
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});
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```
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**`putGrid(z, x, y, grid, callback)`**
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Inserts a [UTFGrid](https://github.com/mapbox/utfgrid-spec) tile into the MBTiles store. Grids are in JSON format.
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```javascript
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var fs = require('fs');
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var grid = JSON.parse(fs.readFileSync('./path/to/grid.json', 'utf8'));
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mbtiles.putGrid(0, 0, 0, grid, function(err) {
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// continue onward
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});
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```
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## Hook up to tilelive
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When working at scale, node-mbtiles is meant to be used within a [Tilelive](https://github.com/mapbox/tilelive) ecosystem. For example, you could set up an MBTiles file as a "source" and an S3 destination as a "sink" (using tilelive-s3). Assuming you have a system set up with an `mbtiles://` protocol that points to a specific file and authorized to write to the s3 bucket:
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```javascript
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var tilelive = require('@mapbox/tilelive');
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var MBTiles = require('@mapbox/mbtiles');
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var s3 = require('@mapbox/tilelive-s3');
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s3.registerProtocols(tilelive);
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MBTiles.registerProtocols(tilelive);
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var sourceUri = 'mbtiles:///User/hello/path/to/file.mbtiles';
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var sinkUri = 's3://my-bucket/tiles/{z}/{x}/{y}';
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// load the mbtiles source
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tilelive.load(sourceUri, function(err, src) {
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// load the s3 sink
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tilelive.load(sinkUri, function(err, dest) {
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var options = {}; // prepare options for tilelive copy
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options.listScheme = src.createZXYStream(); // create ZXY stream from mbtiles
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// now copy all tiles to the destination
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tilelive.copy(src, dst, options, function(err) {
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console.log('tiles are now on s3!');
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});
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});
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});
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```
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# Test
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```
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npm test
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```
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