carto/lib/mess/renderer.js

341 lines
12 KiB
JavaScript

var path = require('path'),
fs = require('fs'),
External = require('./external'),
Step = require('step'),
_ = require('underscore')._,
sys = require('sys');
require.paths.unshift(path.join(__dirname, '..', 'lib'));
var mess = require('mess');
/**
* Convert a two-element-per-item Array
* into an object, for the purpose of checking membership
* and replacing stuff.
* @param {Array} list a list.
*/
var to = function(list) {
return list && list[0] && _.reduce(list, function(m, r) {
if (r && r.length > 1) {
m[r[0]] = r[1];
}
return m;
}, {});
};
mess.Renderer = function Renderer(env) {
var env = {
data_dir: env.data_dir || '/tmp/',
local_data_dir: env.local_data_dir || '',
validation_data: env.validation_data || false
};
return {
env: env,
/**
* Wrapper for downloading externals: likely removable
*
* @param {String} uri the URI of the resource.
* @param {Function} callback
*/
grab: function(uri, callback) {
new(External)(this.env).process(uri, callback);
},
/**
* Download any file-based remote datsources.
*
* Usable as an entry point: does not expect any modification to
* the map object beyond JSON parsing.
*
* @param {Object} m map object.
* @param {Function} callback
*/
localizeExternals: function(m, callback) {
var that = this;
Step(
function() {
var group = this.group();
m.Layer.forEach(function(l) {
if (l.Datasource.file) {
that.grab(l.Datasource.file, group());
}
});
if (m.Layer.length == 0) group()();
},
function(err, results) {
var result_map = to(results);
m.Layer = _.map(_.filter(m.Layer,
function(l) {
return l.Datasource.file &&
result_map[l.Datasource.file];
}),
function(l) {
l.Datasource.file = result_map[l.Datasource.file];
return l;
}
);
callback(err, m);
}
);
},
/**
* Download any remote stylesheets
*
* @param {Object} m map object.
* @param {Function} callback
*/
localizeStyle: function(m, callback) {
var that = this;
Step(
function() {
var group = this.group();
m.Stylesheet.forEach(function(s) {
if (!s.id) {
that.grab(s, group());
}
});
group()();
},
function(err, results) {
var result_map = to(results);
for (s in m.Stylesheet) {
if (!m.Stylesheet[s].id) {
m.Stylesheet[s] = result_map[m.Stylesheet[s]];
}
}
callback(err, m);
}
);
},
/**
* Compile (already downloaded) styles with mess.js,
* calling callback with an array of [map object, [stylesheet objects]]
*
* Called with the results of localizeStyle or localizeExternals:
* expects not to handle downloading.
*
* @param {Object} m map object.
* @param {Function} callback
*/
style: function(m, callback) {
var that = this;
Step(
function() {
var group = this.group();
m.Stylesheet.forEach(function(s) {
if (s.id) {
group()(null, [s.id, s.data]);
} else {
fs.readFile(s, 'utf-8', function(err, data) {
group()(err, [s, data]);
});
}
});
},
function(e, results) {
var options = {},
group = this.group();
for (var i = 0, l = results.length; i < l; i++) {
new(mess.Parser)(_.extend(_.extend({
filename: s
}, that.env), this.env)).parse(results[i][1], function(err, tree) {
if (err) {
mess.writeError(err, options);
throw err;
} else {
try {
group()(err, [
results[i][0],
tree.toCSS({ compress: false }),
tree]);
return;
} catch (e) {
throw e;
return;
}
}
});
}
},
function(err, results) {
if (err) {
callback(err);
return;
}
var result_map = to(results);
for (s in m.Stylesheet) {
if (!m.Stylesheet[s].id) {
m.Stylesheet[s] = result_map[m.Stylesheet[s]];
} else {
m.Stylesheet[s] = result_map[m.Stylesheet[s].id];
}
}
callback(err, [m, results]);
}
);
},
/**
* Prepare full XML map output. Called with the results
* of this.style
*
* @param {Array} res array of [map object, stylesheets].
* @param {Function} callback
*/
template: function(err, res, callback) {
if (err) {
callback(err);
return;
}
var m = res[0],
stylesheets = res[1],
entities = _.template('<?xml version="1.0" ' +
'encoding="utf-8"?>\n' +
'<!DOCTYPE Map[\n' +
'<% for (ref in externals) { %>' +
' <!ENTITY <%= ref %> SYSTEM "<%= externals[ref] %>">\n' +
'<% } %>]>\n'),
styles = _.template('<StyleName><%= name %></StyleName>'),
layer = _.template('\n <Layer\n id="<%= id %>"\n' +
' name="<%= name %>"\n' +
' srs="<%= srs %>">\n' +
'<% for (s in styles) { %>' +
' <StyleName><%= styles[s] %></StyleName>\n' +
'<% } %>' +
' <Datasource>\n<% for (n in Datasource) { %>' +
' <Parameter name="<%= n %>"><%= Datasource[n] %>' +
'</Parameter>\n' +
'<% } %> </Datasource>\n' +
' </Layer>\n'),
stylesheet_tmpl = _.template(' <% for (i in Stylesheet) { %>' +
'<%= Stylesheet[i] %>\n' +
'<% } %>\n'),
// referencing externals in the body of the map
references = _.template('<% for (ref in externals) { %>' +
'&<%= ref %>;\n' +
'<% } %>'),
// for the Map[] doctype: XML entities to
// organize code
entity_list = { externals: [], symbols: [] };
/**
* Index a hash of the CSS rules in all stylesheets
* This is performance-critical: necessary to test
* at some point
*
* @param {Array} stylesheets
* @return {Array} list of selectors.
*/
var ruleHash = function(stylesheets) {
return _.flatten(_.map(stylesheets, function(s) {
return _.map(s[2].rules, function(r) {
if (r && r.selectors && r.selectors[0]._css) {
return r.selectors[0]._css;
}
});
}));
};
var findBackground = function(stylesheets) {
var b = '#FFFFFF';
_.each(stylesheets, function(s) {
_.each(s[2].rules, function(r) {
if (r && r.selectors && r.selectors[0]._css &&
r.selectors[0]._css === 'Map') {
var bg = _.detect(r.rules, function(rule) {
return rule.name == 'background-color';
});
if (bg) {
b = bg.value.toCSS({ compress: false });
}
}
});
});
return b;
};
/**
* Add styles to a layer object
*
* @param {Object} layer the layer object.
* @param {Array} stylesheets the results of ruleHash().
* @return Formalized layer definition with .styles = [].
*/
var styleIntersect = function(layer, stylesheets) {
var hash = ruleHash(stylesheets),
classes = _.map((layer['class'] || '').split(' '),
function(c) {
return 'class-' + c.trim();
}),
layer_id = 'id-' + layer.id;
layer.styles = [];
_.each(hash, function(h) {
if (h && (h.search(layer_id) != -1)) {
layer.styles.push(h);
}
});
_.each(hash, function(h) {
_.each(classes, function(c) {
if (h && (h.search(c) != -1)) {
layer.styles.push(c);
}
});
});
return layer;
};
var output = [entities(entity_list)];
// TODO: must change when background colors are available
output.push('<Map background-color="' +
findBackground(stylesheets)
+ '" srs="+proj=merc +a=6378137 +b=6378137 '
+ '+lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m '
+ '+nadgrids=@null +no_defs">\n');
// using array joins here: faster in IE7, unclear in general.
m.Layer.forEach(function(l) {
l = styleIntersect(l, stylesheets);
output.push(layer(l));
});
output.push(references(entity_list));
output.push(stylesheet_tmpl(m));
output.push('</Map>');
callback(null, output.join(''));
},
/**
* Prepare a JML document (given as a string) into a
* fully-localized XML file ready for Mapnik2 consumption
*
* @param {String} str the JSON file as a string.
* @param {Function} callback to be called with err, XML representation.
*/
render: function(str, callback) {
var m = JSON.parse(str),
that = this;
this.localizeExternals(m, function(err, res) {
that.localizeStyle(res, function(err, res) {
that.style(res, function(err, res) {
that.template(err, res, function(err, res) {
callback(err, res);
});
});
});
});
}
};
};
module.exports = mess;