/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the Clear BSD license.
* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* Note:
* This work draws heavily from the public domain JSON serializer/deserializer
* at http://www.json.org/json.js. Rewritten so that it doesn't modify
* basic data prototypes.
*/
/**
* @requires OpenLayers/Format.js
*/
/**
* Class: OpenLayers.Format.JSON
* A parser to read/write JSON safely. Create a new instance with the
* <OpenLayers.Format.JSON> constructor.
*
* Inherits from:
* - <OpenLayers.Format>
*/
OpenLayers.Format.JSON = OpenLayers.Class(OpenLayers.Format, {
/**
* APIProperty: indent
* {String} For "pretty" printing, the indent string will be used once for
* each indentation level.
*/
indent: " ",
/**
* APIProperty: space
* {String} For "pretty" printing, the space string will be used after
* the ":" separating a name/value pair.
*/
space: " ",
/**
* APIProperty: newline
* {String} For "pretty" printing, the newline string will be used at the
* end of each name/value pair or array item.
*/
newline: "\n",
/**
* Property: level
* {Integer} For "pretty" printing, this is incremented/decremented during
* serialization.
*/
level: 0,
/**
* Property: pretty
* {Boolean} Serialize with extra whitespace for structure. This is set
* by the <write> method.
*/
pretty: false,
/**
* Constructor: OpenLayers.Format.JSON
* Create a new parser for JSON.
*
* Parameters:
* options - {Object} An optional object whose properties will be set on
* this instance.
*/
initialize: function(options) {
OpenLayers.Format.prototype.initialize.apply(this, [options]);
},
/**
* APIMethod: read
* Deserialize a json string.
*
* Parameters:
* json - {String} A JSON string
* filter - {Function} A function which will be called for every key and
* value at every level of the final result. Each value will be
* replaced by the result of the filter function. This can be used to
* reform generic objects into instances of classes, or to transform
* date strings into Date objects.
*
* Returns:
* {Object} An object, array, string, or number .
*/
read: function(json, filter) {
/**
* Parsing happens in three stages. In the first stage, we run the text
* against a regular expression which looks for non-JSON
* characters. We are especially concerned with '()' and 'new'
* because they can cause invocation, and '=' because it can cause
* mutation. But just to be safe, we will reject all unexpected
* characters.
*/
try {
if (/^[\],:{}\s]*$/.test(json.replace(/\\["\\\/bfnrtu]/g, '@').
replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').
replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {
/**
* In the second stage we use the eval function to compile the
* text into a JavaScript structure. The '{' operator is
* subject to a syntactic ambiguity in JavaScript - it can
* begin a block or an object literal. We wrap the text in
* parens to eliminate the ambiguity.
*/
var object = eval('(' + json + ')');
/**
* In the optional third stage, we recursively walk the new
* structure, passing each name/value pair to a filter
* function for possible transformation.
*/
if(typeof filter === 'function') {
function walk(k, v) {
if(v && typeof v === 'object') {
for(var i in v) {
if(v.hasOwnProperty(i)) {
v[i] = walk(i, v[i]);
}
}
}
return filter(k, v);
}
object = walk('', object);
}
if(this.keepData) {
this.data = object;
}
return object;
}
} catch(e) {
// Fall through if the regexp test fails.
}
return null;
},
/**
* APIMethod: write
* Serialize an object into a JSON string.
*
* Parameters:
* value - {String} The object, array, string, number, boolean or date
* to be serialized.
* pretty - {Boolean} Structure the output with newlines and indentation.
* Default is false.
*
* Returns:
* {String} The JSON string representation of the input value.
*/
write: function(value, pretty) {
this.pretty = !!pretty;
var json = null;
var type = typeof value;
if(this.serialize[type]) {
try {
json = this.serialize[type].apply(this, [value]);
} catch(err) {
OpenLayers.Console.error("Trouble serializing: " + err);
}
}
return json;
},
/**
* Method: writeIndent
* Output an indentation string depending on the indentation level.
*
* Returns:
* {String} An appropriate indentation string.
*/
writeIndent: function() {
var pieces = [];
if(this.pretty) {
for(var i=0; i<this.level; ++i) {
pieces.push(this.indent);
}
}
return pieces.join('');
},
/**
* Method: writeNewline
* Output a string representing a newline if in pretty printing mode.
*
* Returns:
* {String} A string representing a new line.
*/
writeNewline: function() {
return (this.pretty) ? this.newline : '';
},
/**
* Method: writeSpace
* Output a string representing a space if in pretty printing mode.
*
* Returns:
* {String} A space.
*/
writeSpace: function() {
return (this.pretty) ? this.space : '';
},
/**
* Property: serialize
* Object with properties corresponding to the serializable data types.
* Property values are functions that do the actual serializing.
*/
serialize: {
/**
* Method: serialize.object
* Transform an object into a JSON string.
*
* Parameters:
* object - {Object} The object to be serialized.
*
* Returns:
* {String} A JSON string representing the object.
*/
'object': function(object) {
// three special objects that we want to treat differently
if(object == null) {
return "null";
}
if(object.constructor == Date) {
return this.serialize.date.apply(this, [object]);
}
if(object.constructor == Array) {
return this.serialize.array.apply(this, [object]);
}
var pieces = ['{'];
this.level += 1;
var key, keyJSON, valueJSON;
var addComma = false;
for(key in object) {
if(object.hasOwnProperty(key)) {
// recursive calls need to allow for sub-classing
keyJSON = OpenLayers.Format.JSON.prototype.write.apply(this,
[key, this.pretty]);
valueJSON = OpenLayers.Format.JSON.prototype.write.apply(this,
[object[key], this.pretty]);
if(keyJSON != null && valueJSON != null) {
if(addComma) {
pieces.push(',');
}
pieces.push(this.writeNewline(), this.writeIndent(),
keyJSON, ':', this.writeSpace(), valueJSON);
addComma = true;
}
}
}
this.level -= 1;
pieces.push(this.writeNewline(), this.writeIndent(), '}');
return pieces.join('');
},
/**
* Method: serialize.array
* Transform an array into a JSON string.
*
* Parameters:
* array - {Array} The array to be serialized
*
* Returns:
* {String} A JSON string representing the array.
*/
'array': function(array) {
var json;
var pieces = ['['];
this.level += 1;
for(var i=0, len=array.length; i<len; ++i) {
// recursive calls need to allow for sub-classing
json = OpenLayers.Format.JSON.prototype.write.apply(this,
[array[i], this.pretty]);
if(json != null) {
if(i > 0) {
pieces.push(',');
}
pieces.push(this.writeNewline(), this.writeIndent(), json);
}
}
this.level -= 1;
pieces.push(this.writeNewline(), this.writeIndent(), ']');
return pieces.join('');
},
/**
* Method: serialize.string
* Transform a string into a JSON string.
*
* Parameters:
* string - {String} The string to be serialized
*
* Returns:
* {String} A JSON string representing the string.
*/
'string': function(string) {
// If the string contains no control characters, no quote characters, and no
// backslash characters, then we can simply slap some quotes around it.
// Otherwise we must also replace the offending characters with safe
// sequences.
var m = {
'\b': '\\b',
'\t': '\\t',
'\n': '\\n',
'\f': '\\f',
'\r': '\\r',
'"' : '\\"',
'\\': '\\\\'
};
if(/["\\\x00-\x1f]/.test(string)) {
return '"' + string.replace(/([\x00-\x1f\\"])/g, function(a, b) {
var c = m[b];
if(c) {
return c;
}
c = b.charCodeAt();
return '\\u00' +
Math.floor(c / 16).toString(16) +
(c % 16).toString(16);
}) + '"';
}
return '"' + string + '"';
},
/**
* Method: serialize.number
* Transform a number into a JSON string.
*
* Parameters:
* number - {Number} The number to be serialized.
*
* Returns:
* {String} A JSON string representing the number.
*/
'number': function(number) {
return isFinite(number) ? String(number) : "null";
},
/**
* Method: serialize.boolean
* Transform a boolean into a JSON string.
*
* Parameters:
* bool - {Boolean} The boolean to be serialized.
*
* Returns:
* {String} A JSON string representing the boolean.
*/
'boolean': function(bool) {
return String(bool);
},
/**
* Method: serialize.object
* Transform a date into a JSON string.
*
* Parameters:
* date - {Date} The date to be serialized.
*
* Returns:
* {String} A JSON string representing the date.
*/
'date': function(date) {
function format(number) {
// Format integers to have at least two digits.
return (number < 10) ? '0' + number : number;
}
return '"' + date.getFullYear() + '-' +
format(date.getMonth() + 1) + '-' +
format(date.getDate()) + 'T' +
format(date.getHours()) + ':' +
format(date.getMinutes()) + ':' +
format(date.getSeconds()) + '"';
}
},
CLASS_NAME: "OpenLayers.Format.JSON"
});