Files
node-mbtiles/index.js
2011-05-09 11:38:41 -04:00

102 lines
3.6 KiB
JavaScript

var MBTiles = require('./lib/mbtiles'),
zlib = require('zlib'),
Buffer = require('buffer').Buffer,
Step = require('step');
module.exports = {
MBTiles: MBTiles,
pool: function(datasource, options) {
return {
create: function(callback) {
var resource = new MBTiles(
datasource,
options,
function() { callback(resource); }
);
},
destroy: function(resource) {
resource.db.close(function() {});
}
}
},
serve: function(resource, options, callback) {
switch (options.format) {
case 'layer.json':
Step(
function() {
resource.metadata('formatter', this.parallel());
resource.metadata('legend', this.parallel());
},
function(err, f, l) {
var layer = {};
f && (layer.formatter = f);
l && (layer.legend = l);
options.jsonp && (layer = options.jsonp + '(' + JSON.stringify(layer) + ');');
callback(null, [layer, { 'Content-Type': 'text/javascript' }]);
}
);
break;
case 'grid.json':
var grid;
Step(
function() {
resource.grid(options.x, options.y, options.z, this);
},
function(err, buf) {
if (err) throw err;
if (!Buffer.isBuffer(buf))
buf = new Buffer(buf, 'binary');
var inflated = zlib.inflate(buf);
this(null,inflated);
},
function(err, buf) {
if (err) throw err;
grid = buf.toString();
resource.grid_data(options.x, options.y, options.z, this);
},
function(err, gd) {
if (err) return callback(err);
// Manually append grid data as a string to the grid buffer.
// Ideally we would
//
// JSON.stringify(_.extend(JSON.parse(grid), { data: gd }))
//
// But calling JSON stringify will escape UTF8 characters of a
// high enough ordinal making the grid data unusable. Instead,
// manipulate the JSON string directly, popping the trailing }
// off and splicing the grid data in at the "data" key.
grid = grid.substr(0, grid.length - 1)
+ ', "data":'
+ JSON.stringify(gd)
+ '}';
options.jsonp && (grid = options.jsonp + '(' + grid + ');');
callback(err, [grid, { 'Content-Type': 'text/javascript' }]);
}
);
break;
default:
resource.tile(options.x, options.y, options.z, function(err, image) {
callback(err, [image, { 'Content-Type': 'image/png' }]);
});
break;
}
},
store: function(step, resource, data, callback) {
switch (step) {
case 'setup':
resource.setup(callback);
break;
case 'tiles':
resource.insertTiles(data, callback);
break;
case 'grids':
resource.insertGrids(data, callback);
break;
case 'finish':
callback();
break;
}
}
};