isValidBBCode.js

/*
 * BBCode.js - javascript BBCode module by Zhang Qingcheng <kinch.zhang@gmail.com>
 *
 * usage:
 *
 *     1. load this module
 *     <script type="text/javascript" src="<?php echo get_domain_name_by_app('js', true);?>/c/BBCode.js"></script>
 *
 *     2. get an instance to use it
 *     <script type="text/javascript">
 *         var bbcode = new BBCode();
 *
 *         if (! bbcode.isValid(bbcode))
 *         {
 *             alert('bbcode is invalid!');
 *
 *             return false;
 *         }
 *     </script>
 *
 */
(function(){
    var BBCode = window.BBCode = function() {}

    BBCode.prototype = {
        /**
         * check if the given bbcode is valid
         *
         * @param String bbcode
         * @returns Boolean true/false
         * @description this function returns true if the given bbcode in well-formed
         */
        'isValid' : function(content) {
            /*
             * 检查一段内容中包含的UBB的格式是否正确
             *
             */

            if (content.length == 0)
                return false;

            var stack = [];
            var depth = 0;
            var errors = 0;
            var unmatched = 0;
            var options = {
                'b' : 'no_arg',
                'i' : 'no_arg',
                'u' : 'no_arg',
                'url' : 'opt_arg',
                'img' : 'no_arg',
                'swf' : 'no_arg',
                'wmv' : 'no_arg',
                'rm' : 'no_arg',
                'media' : 'arg',
                'size' : 'arg',
                'quote' : 'no_arg',
                'list' : 'opt_arg',
                'color' : 'arg',
                'dstaic' : 'no_arg',
                'attach' : 'no_arg',
                'align' : 'arg',
                'p' : 'no_arg',
                'font': 'arg',
                'color' : 'arg',
                'table' : 'opt_arg',
                'tr' : 'opt_arg',
                'td' : 'opt_arg',
                'desc' : 'no_arg',
                'hide' : 'no_arg',
                'fly' : 'no_arg',
                'code' : 'no_arg',
                'email' : 'no_arg',
                '*': 'opt_arg',
                'tempfile': 'no_arg'
            };

            var strictRule = ['img', 'swf', 'wmv', 'media', 'rm', 'dstatic', 'email'];

            // strip faces and br if any
            if (content.indexOf('[face_') != -1)
                content = content.replace(/\[face_[0-9]+\]/g, '');

            if (content.indexOf('[br]') != -1)
                content = content.replace(/\[br\]/g, '');

            parseBBCode(content);

            console.info('all errer count: ' + errors);

            return (errors == 0) && (unmatched == 0);

            function in_array(needle, haystack, isStrict)
            {
                var found = false, key;

                for (key in haystack) {
                    if ((isStrict && haystack[key] === needle)
                        ||
                        (!isStrict && haystack[key] == needle)
                       )
                    {
                        found = true;
                        break;
                    }
                }

                return found;
            }

            function hasQuotes(str)
            {
                return (str.indexOf('"') != -1) ||
                        (str.indexOf("'") != -1);
            }

            function checkParam(param)
            {
                console.log('checking param: -> ' + param);
                if ((param[0] == '"' || param[0] == "'"))
                {
                    var last = param.length - 1;
                    if (param[0] != param[last])
                    {
                        console.log('quote not match: (' + param[0]);
                        return 1;
                    }
                    else if (hasQuotes(param.substring(1, last - 1)))
                    {
                        console.log('extra quotes found');
                        return 1;
                    }
                }
                else if (hasQuotes(param))
                {
                    return 1;
                }

                return 0;
            }

            function parseBBCode(content)
            {
                if (content.length == 0)
                    return true;

                if (depth < 1000)
                    depth++;
                else
                    throw "Max depth of 1000 recursion reached";

                var head = content.indexOf('[');
                var tail = content.indexOf(']');

                if ( head == -1 && tail == -1)
                    // no bbcode
                    return true;

                if ((head == -1 && tail > -1) ||
                    (head > -1 && tail == -1) ||
                    (head > -1 && tail > -1 && head > tail)
                   )
                {
                    errors++;

                    console.info('error count: ' + errors + '::head and tail not match');

                    return;
                }

                tag = content.substring(head + 1, tail);

                if (tag.length == 0) {
                    errors++;
                    console.info('error count: ' + errors + '::empty tag');

                    return;
                }

                if (tag[0] != '/') {
                    // open tag
                    console.info('enter opening tag: ' + tag);
                    // check paramters
                    var pos = tag.indexOf('=');

                    if (pos == -1) {
                        if (!options[tag]) {
                            // invalid tag
                            errors++;
                            console.info('error count: ' + errors + '::invalid tag name -> ' + tag);

                            return;
                        }

                        if (options[tag] == 'arg') {
                            errors++;
                            console.info('error count: ' + errors + '::tag -> ' + tag_name + ' should have arg');

                            return;
                        }

                        stack.push(tag);
                    } else {
                        var tag_name = tag.substring(0, pos);
                        if (!options[tag_name]) {
                            // invalid tag
                            errors++;
                            console.info('error count: ' + errors + '::invalid tag name -> ' + tag_name);

                            return;
                        }

                        if (options[tag_name] == 'no_arg') {
                            errors++;
                            console.info('error count: ' + errors + '::tag -> ' + tag_name + ' should have no arg');

                            return;
                        }

                        errors += checkParam(tag.substring(pos + 1));

                        if (errors > 0)
                            return;

                        stack.push(tag_name);
                    }

                    unmatched ++;
                    console.info('unmatch count: ' + unmatched);
                } else {
                    // close tag
                    tag_name = tag.substring(1);

                    if (!options[tag_name]) {
                        // invalid tag
                        errors++;
                        console.info('error count: ' + errors + '::invalid tag name or empty tag -> ' + tag_name);

                        return;
                    }

                    console.info('enter close tag: ' + tag);

                    unmatched --;
                    console.info('unmatch count: ' + unmatched);

                    if (stack.length == 0) {
                        errors++;
                        console.info('error count: ' + errors + '::stack is empty, too many close tag');

                        return;
                    }

                    // check if the open tag and closing tag is match 
                    open = stack.pop();

                    if (open != tag_name)
                    {
                        if (in_array(open, strictRule, true) || in_array(tag_name, strictRule, true))
                        {
                            errors++;
                            console.info('error count: ' + errors + '::have strict tag but not match -> open=' + open + ' and close=' + tag_name);

                            return;
                        }
                    }
                }

                parseBBCode(content.substring(tail + 1));
            }
        }
    }
})();