ndn-js
Version:
A JavaScript client library for Named Data Networking
140 lines (128 loc) • 4.96 kB
JavaScript
/**
* Copyright (C) 2015-2019 Regents of the University of California.
* @author: Jeff Thompson <jefft0@remap.ucla.edu>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
* A copy of the GNU Lesser General Public License is in the file COPYING.
*/
/** @ignore */
var Name = require('./name.js').Name; /** @ignore */
var NdnRegexTopMatcher = require('./util/regex/ndn-regex-top-matcher.js').NdnRegexTopMatcher;
/**
* An InterestFilter holds a Name prefix and optional regex match expression for
* use in Face.setInterestFilter.
*
* Create an InterestFilter to match any Interest whose name starts with the
* given prefix. If the optional regexFilter is provided then the remaining
* components match the regexFilter regular expression as described in doesMatch.
* @param {InterestFilter|Name|string} prefix If prefix is another
* InterestFilter copy its values. If prefix is a Name then this makes a copy of
* the Name. Otherwise this creates a Name from the URI string.
* @param {string} regexFilter (optional) The regular expression for matching
* the remaining name components.
* @constructor
*/
var InterestFilter = function InterestFilter(prefix, regexFilter)
{
if (typeof prefix === 'object' && prefix instanceof InterestFilter) {
// The copy constructor.
var interestFilter = prefix;
this.prefix = new Name(interestFilter.prefix);
this.regexFilter = interestFilter.regexFilter;
this.regexFilterPattern = interestFilter.regexFilterPattern;
}
else {
this.prefix = new Name(prefix);
if (regexFilter) {
this.regexFilter = regexFilter;
this.regexFilterPattern = InterestFilter.makePattern(regexFilter);
}
else {
this.regexFilter = null;
this.regexFilterPattern = null;
}
}
};
exports.InterestFilter = InterestFilter;
/**
* Check if the given name matches this filter. Match if name starts with this
* filter's prefix. If this filter has the optional regexFilter then the
* remaining components match the regexFilter regular expression.
* For example, the following InterestFilter:
*
* InterestFilter("/hello", "<world><>+")
*
* will match all Interests, whose name has the prefix `/hello` which is
* followed by a component `world` and has at least one more component after it.
* Examples:
*
* /hello/world/!
* /hello/world/x/y/z
*
* Note that the regular expression will need to match all remaining components
* (e.g., there are implicit heading `^` and trailing `$` symbols in the
* regular expression).
* @param {Name} name The name to check against this filter.
* @return {boolean} True if name matches this filter, otherwise false.
*/
InterestFilter.prototype.doesMatch = function(name)
{
if (name.size() < this.prefix.size())
return false;
if (this.hasRegexFilter()) {
// Perform a prefix match and regular expression match for the remaining
// components.
if (!this.prefix.match(name))
return false;
return new NdnRegexTopMatcher(this.regexFilterPattern).match
(name.getSubName(this.prefix.size()));
}
else
// Just perform a prefix match.
return this.prefix.match(name);
};
/**
* Get the prefix given to the constructor.
* @return {Name} The prefix Name which you should not modify.
*/
InterestFilter.prototype.getPrefix = function() { return this.prefix; };
/**
* Check if a regexFilter was supplied to the constructor.
* @return {boolean} True if a regexFilter was supplied to the constructor.
*/
InterestFilter.prototype.hasRegexFilter = function()
{
return this.regexFilter != null;
};
/**
* Get the regex filter. This is only valid if hasRegexFilter() is true.
* @return {string} The regular expression for matching the remaining name
* components.
*/
InterestFilter.prototype.getRegexFilter = function() { return this.regexFilter; };
/**
* If regexFilter doesn't already have them, add ^ to the beginning and $ to
* the end since these are required by NdnRegexTopMatcher.
* @param {string} regexFilter The regex filter.
* @return {string} The regex pattern with ^ and $.
*/
InterestFilter.makePattern = function(regexFilter)
{
var pattern = regexFilter;
if (!(pattern.length >= 1 && pattern[0] == '^'))
pattern = "^" + pattern;
if (!(pattern.length >= 1 && pattern[-1] == '$'))
pattern = pattern + "$";
return pattern;
};