resource-query.js

/**
 * This module provides querying functionality 
 */
 

exports.jsonQueryCompatible = true;
var operatorMap = {
	"": "eq",
	"!": "ne",
}
var parseQuery = exports.parseQuery = function(/*String*/query, parameters){
	if(exports.jsonQueryCompatible){
		query = query.replace(/%3C=/g,"=le=").replace(/%3E=/g,"=ge=").replace(/%3C/g,"=lt=").replace(/%3E/g,"=gt=");
	}
	// convert FIQL to normalized call syntax form 
	query = query.replace(/=([!\w]*=)?([\+\*\-:\w%\._]+)/g, function(t, operator, value){
		operator = operator ? operator.substring(0, operator.length - 1) : "";
		operator = operatorMap[operator] || operator;
		return "." + operator + '(' + value + ")";
	});
	if(query.charAt(0)=="?"){
		query = query.substring(1);
	}
	var topTerms = [];
	var term= {operator:"and", values: topTerms};
	var leftoverCharacters = query.replace(/(\))|([&\|,])?([\+\*\$\-:\w%\._]*)(\(?)/g,
		 //      |<-delim-- propertyOrValue -(> |<-closedParan->
		function(t, closedParan, delim, propertyOrValue, openParan){
			if(delim){
				if(delim === "&"){
					forceOperator("and");
				}
				if(delim === "|"){
					forceOperator("or");
				}
			}
			if(openParan){
				var paths = propertyOrValue.split(".");
				var newTerm = {
					operator: paths[paths.length - 1],
					parent: term
				};
				if(paths.length > 2){
					newTerm.property = paths.slice(0, -1);
				}
				else if(paths.length === 2){
					newTerm.property = paths[0];
				}
				call(newTerm);
			}
			else if(closedParan){
				term = term.parent;
				if(!term){
					throw new URIError("Closing paranthesis without an opening paranthesis");
				}
			}
			else if(propertyOrValue){
				term.values.push(stringToValue(propertyOrValue, parameters));
			}
			return "";
		});
	if(term.parent){
		throw new URIError("Opening paranthesis without a closing paranthesis");
	}
	if(leftoverCharacters){
		// any extra characters left over from the replace indicates invalid syntax
		throw new URIError("Illegal character in query string encountered " + leftoverCharacters);
	}
	
	function call(newTerm, parent){
		newTerm.values = [];
		term.values.push(newTerm);
		term = newTerm;
	}
	function forceOperator(operator){
		if(!term.operator){
			term.operator = operator;
		}
		else if(term.operator !== operator){
			var last = term.values.pop();
			call({
				operator:operator,
				parent: term.parent
			});
			term.values.push(last);
		}
	}
	Object.defineProperty(topTerms, "toString", {
		enumerable: false,
		value: function() {
			var qs = "?";
			for (var i = 0; i < this.length; i++) {
				var term = this[i];
				qs += term.conjunction || "";
				if (term.type == "comparison") {
					qs += term.name + term.comparator + term.value;
				}
				else if (term.type == "call") {
					qs += term.name + "(" + term.parameters + ")"
				}
				else {
					// FIXME should we throw here?
				}
			}
			if (qs == "?") return "";
			return qs;
		}
	});
	return topTerms;
}
exports.QueryFunctions = function(){
	
}
exports.QueryFunctions.prototype = {
	sort: function(){
		var terms = [];
		for(var i = 0; i < arguments.length; i++){
			var sortAttribute = arguments[i]; 
			var firstChar = sortAttribute.charAt(0);
			var term = {attribute: sortAttribute, ascending: true};
			if (firstChar == "-" || firstChar == "+") {
				if(firstChar == "-"){
					term.ascending = false;
				}
				term.attribute = term.attribute.substring(1);
			}
			terms.push(term);
		}
		this.sort(function(a, b){
			for (var i = 0; i < terms.length; i++) {
				var term = terms[i];
				if (a[term.attribute] != b[term.attribute]) {
					return term.ascending == a[term.attribute] > b[term.attribute] ? 1 : -1;
				}
			}
			return true; //undefined?
		});
		return this;
	},
	"in": function(){
		return Array.prototype.indexOf.call(arguments, this.valueOf()) > -1;
	},
	contains: function(value){
		if(arguments.length === 1){
			return this.indexOf(value) > -1;
		}
		else{
			var self = this;
			return Array.prototype.some.call(arguments, function(value){
				return self.indexOf(value) > -1;
			});
		}
	},
	select: function(first){
		if(arguments.length == 1){
			return this.map(function(object){
				return object[first];
			});
		}
		var args = arguments;
		return this.map(function(object){
			var selected = {};
			for(var i = 0; i < args.length; i++){
				var propertyName= args[i];
				if(object.hasOwnProperty(propertyName)){
					selected[propertyName] = object[propertyName];
				}
			}
			return selected;
		});
	},
	slice: function(){
		return this.slice.apply(this, arguments);
	}
};
exports.executeQuery = function(query, options, target){
	if(typeof query === "string"){
		query = parseQuery(query, options && options.parameters);
	}
	var functions = options.functions || exports.QueryFunctions.prototype;
	var inComparision = false;
	var js = "";
	query.forEach(function(term){
		if(term.type == "comparison"){
			if(!options){
				throw new Error("Values must be set as parameters on the options argument, which was not provided");
			}
			if(!inComparision){
				inComparision = true;
				js += "target = target.filter(function(item){return ";
			}
			else{
				js += term.conjunction + term.conjunction;
			}
			var index = (options.parameters = options.parameters || []).push(term.value);
			if(term.comparator == "="){
				term.comparator = "==";
			}
			js += "item." + (term.name instanceof Array ? term.name.join(".") : term.name) + term.comparator + "options.parameters[" + (index -1) + "]";
			
		}
		else if(term.type == "call"){
			if(inComparision){
				js += "});";
				inComparision = false;
			}
			if(term.name instanceof Array){
				var path = term.name;
				var index = (options.parameters = options.parameters || []).push(term.parameters);
				js += "target = target.filter(function(item){return " + 
						"functions['" + path[path.length - 1] + "'].apply(" + "item." + path.slice(0, -1).join(".") + ",options.parameters[" + (index -1) + "]);});";				
			}
			else if(functions[term.name]){
				var index = (options.parameters = options.parameters || []).push(term.parameters);
				js += "target = functions." + term.name + ".apply(target,options.parameters[" + (index -1) + "]);";
			}
			else{
				throw new URIError("Invalid query syntax, " + term.name + " not implemented");
			}
		}
		else{
			throw new URIError("Invalid query syntax, unknown type");
		}
	});
	if(inComparision){
		js += "});";
		first = false;
	}
	var results = eval(js + "target;"); 
	if(options.start || options.end){
		var totalCount = results.length;
		results = results.slice(options.start || 0, (options.end || Infinity) + 1);
		results.totalCount = totalCount;
	}
	return results;
}
function throwMaxIterations(){
	throw new Error("Query has taken too much computation, and the user is not allowed to execute resource-intense queries. Increase maxIterations in your config file to allow longer running non-indexed queries to be processed.");
}
exports.maxIterations = 10000;
function stringToValue(string, parameters){
	switch(string){
		case "true": return true;
		case "false": return false;
		case "null": return null;
		default:
			// handle arrays
			if (string.indexOf(',') > -1) {
				var array = [];
				string.split(',').forEach(function(x){
					array.push(stringToValue(x, parameters));
				});
				return array;
			}
			// handle scalars
			var number = parseFloat(string, 10);
			if(isNaN(number)){
				if(string.indexOf(":") > -1){
					var date = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)Z$/.exec(string);
		            if (date) {
		                return new Date(Date.UTC(+date[1], +date[2] - 1, +date[3], +date[4],
		                    +date[5], +date[6]));
		            }
					var parts = string.split(":",2);
					switch(parts[0]){					
						case "boolean" : return Boolean(parts[1]);
						case "number" : return parseFloat(parts[1], 10);
						case "string" : return decodeURIComponent(parts[1]);
						case "date" : return new Date(stringToValue(parts[1]));
						case "null" : return null;
						default: 
							throw new URIError("Unknown type " + parts[0]);
					}
				}
				if(string.charAt(0) == "$"){
					return parameters[parseInt(string.substring(1)) - 1];
				}
				string = decodeURIComponent(string);
				if(exports.jsonQueryCompatible){
					if(string.charAt(0) == "'" && string.charAt(string.length-1) == "'"){
						return JSON.parse('"' + string.substring(1,string.length-1) + '"');
					}
				}
				return string;
			}
			return number;
	}
	
};
function convertComparator(comparator){
	switch(comparator){
		case "=lt=" : return "<";
		case "=gt=" : return ">";
		case "=le=" : return "<=";
		case "=ge=" : return ">=";
		case "==" : return "=";
	}
	return comparator;
}

function convertPropertyName(property){
	if(property.indexOf(".") > -1){
		return property.split(".").map(function(part){
			return decodeURIComponent(part);
		});
	}
	return decodeURIComponent(property);
}