autogen.js

'use strict';

let Promise = require('bluebird'),
    checkType = require('@kartotherian/input-validator'),
    core;

function Autogen(uri, callback) {
    let self = this,
        query;
    Promise.try(() => {
        query = checkType.normalizeUrl(uri).query;
        checkType(query, 'mingen', 'zoom');
        self.mingen = query.mingen;
        checkType(query, 'maxgen', 'zoom');
        self.maxgen = query.maxgen;
        checkType(query, 'minstore', 'zoom');
        self.minstore = query.minstore;
        checkType(query, 'maxstore', 'zoom');
        self.maxstore = query.maxstore;
        checkType(query, 'storage', 'string', true);
        checkType(query, 'generator', 'string', true);
        return core.loadSource(query.storage);
    }).then(storage => {
        self.storage = storage;
        return core.loadSource(query.generator);
    }).then(generator => {
        self.generator = generator;
    }).return(this).nodeify(callback);
}

Autogen.prototype.getTile = function(z, x, y, callback) {
    let self = this;
    return self.storage
        .getTileAsync(z, x, y)
        .catch(err => {
            if ((self.mingen !== undefined && z < self.mingen) ||
                (self.maxgen !== undefined && z > self.maxgen) ||
                !core.isNoTileError(err)
            ) {
                throw err;
            }
            let p = self.generator.getTileAsync(z, x, y);
            if (
                (self.minstore === undefined || z >= self.minstore) &&
                (self.maxstore === undefined || z <= self.maxstore)
            ) {
                // on error, log and ignore
                p = p.spread((tile, headers) =>
                    self.storage.putTileAsync(z, x, y, tile)
                        .catch(err => core.log('error', err))
                        .return([tile, headers]));
            }
            return p;
        }).nodeify(callback, { spread: true });
};

Autogen.prototype.getInfo = function(callback) {
    return this.storage.getInfo(callback);
};


Autogen.initKartotherian = function(cor) {
    core = cor;
    core.tilelive.protocols['autogen:'] = Autogen;
};

module.exports = Autogen;