urlconverter.java

来自「Jive是基于JSP/JAVA技术构架的一个大型BBS论坛系统,这是Jive论坛」· Java 代码 · 共 286 行

/**
 * $RCSfile: URLConverter.java,v $
 * $Revision: 1.2 $
 * $Date: 2002/07/10 19:08:07 $
 *
 * Copyright (C) 1999-2001 CoolServlets, Inc. All rights reserved.
 *
 * This software is the proprietary information of CoolServlets, Inc.
 * Use is subject to license terms.
 */

package com.jivesoftware.forum.filter;

import com.jivesoftware.forum.*;

/**
 * A ForumMessageFilter that converts URL's to working HTML web links.
 * <p>
 * The patterns recognized are <code>ftp://path-of-url</code>,
 * <code>http://path-of-url</code>, <code>https://path-of-url</code>
 * <code>[url path-of-url]descriptive text[/url]</code> and
 * <code>[url=path-of-url]descriptive text[/url]</code>
 * the <code>[url]</code> allows any path to be defined as link.
 */
public class URLConverter extends ForumMessageFilter {

    private boolean filteringSubject;
    private boolean filteringBody;
    private boolean newWindowEnabled;

   /**
    * Creates a new filter not associated with a message. This is
    * generally only useful for defining a template filter that other
    * fitlers will be cloned from.
    */
    public URLConverter() {
        filteringSubject = false;
        filteringBody = true;
        newWindowEnabled = false;
    }

    /**
     * Clones a new filter that will have the same properties and that
     * will wrap around the specified message.
     *
     * @param message the ForumMessage to wrap the new filter around.
     */
    public ForumMessageFilter clone(ForumMessage message){
        URLConverter filter = new URLConverter();
        filter.filteringBody = filteringBody;
        filter.filteringSubject = filteringSubject;
        filter.newWindowEnabled = newWindowEnabled;

        filter.message = message;
        return filter;
    }

    public boolean isCacheable() {
        return true;
    }

    //FROM THE FORUMMESSAGE INTERFACE//

    /**
     * Returns the subject of the message with URLs changed to working links if
     * filtering on the subject is enabled.
     *
     * @return the filtered message subject.
     */
    public String getSubject() {
        if (filteringSubject) {
            return convertURL(message.getSubject());
        }
        else return message.getSubject();
    }

    /**
     * Returns the body of the message with URLs changed to working links if
     * filtering on the body is enabled.
     *
     * @return the filtered message body.
     */
    public String getBody() {
        if (filteringBody) {
            return convertURL(message.getBody());
        }
        else return message.getBody();
    }

    //OTHER METHODS//

    /**
     * Returns true if filtering on the subject is enabled.
     *
     * @return true if filtering on the subject is enabled.
     */
    public boolean isFilteringSubject() {
        return filteringSubject;
    }

    /**
     * Enables or disables filtering on the subject.
     *
     * @param filteringSubject toggle value for filtering on subject.
     */
    public void setFilteringSubject(boolean filteringSubject) {
        this.filteringSubject = filteringSubject;
    }

    /**
     * Returns true if filtering on the body is enabled.
     *
     * @return true if filtering on the body is enabled.
     */
    public boolean isFilteringBody() {
        return filteringBody;
    }

    /**
     * Enables or disables filtering on the body.
     *
     * @param filteringBody toggle value for filtering on body.
     */
    public void setFilteringBody(boolean filteringBody) {
        this.filteringBody = filteringBody;
    }

    /**
     * Returns true if URL clicks will open in a new window.
     *
     * @return true if new window mode is enabled.
     */
    public boolean isNewWindowEnabled() {
        return newWindowEnabled;
    }

    /**
     * Enables or disables the new window mode. When active, URL clicks will
     * open in a new window.
     *
     * @param enabled true if new window mode should be enabled.
     */
    public void setNewWindowEnabled(boolean enabled) {
        this.newWindowEnabled = enabled;
    }

    /**
     * This method takes a string which may contain URLs
     * and replaces them with working links.  It does this
     * by adding the html tags &lt;a href&gt; and &lt;/a&gt;.
     * <p>
     * The patterns recognized are <code>ftp://path-of-url</code>,
     * <code>http://path-of-url</code>, <code>https://path-of-url</code>
     * <code>[url path-of-url]descriptive text[/url]</code> and
     * <code>[url=path-of-url]descriptive text[/url]</code>
     * the <code>[url]</code> allows any path to be defined as link.
     *
     * @param input the text to be converted.
     * @return the input string with the URLs replaced with links.
     */
    private String convertURL(String input) {
        // Check if the string is null or zero length
        //  -- if so, return what was sent in.
        if (input == null || input.length() == 0 ) {
            return input;
        }

		// Build the response in a buffer
        StringBuffer buf = 	 new StringBuffer(input.length() + 25);
        char[] 		 chars = input.toCharArray();
        int 		 len =   input.length();
        
        int index = -1, i = 0;
        int j = 0, oldend = 0;
        int u1, u2;
        char cur;

		// Handle the occurences of the ftp:// , http:// , https:// patterns
        // and the [url] pattern.
        while (++index < len) {
        	cur = chars[i = index];

			// save valuable cpu resources by expanding the tests here instead of calling String.indexOf() 
			j = -1;
			if ((cur == 'f' && index < len-6 && chars[++i] == 't' &&
                chars[++i] == 'p') || (cur == 'h' && (i = index) < len-7 &&
                chars[++i] == 't' && chars[++i] == 't' && chars[++i] == 'p' &&
				(chars[++i] == 's' || chars[--i] == 'p')))
            {
				if (i < len-4 && chars[++i] == ':' && chars[++i] == '/' && chars[++i] == '/') {
					j = ++i;
				}
			}

			// did we find http or ftp?
			if (j > 0) {
        		// check context, dont handle patterns preceded by any of '"<=
        		if (index == 0 || ((cur=chars[index-1]) != '\'' && cur != '"'
                    && cur != '<' && cur != '='))
                {
	                cur = chars[j];
	                // now collect url pattern upto next " <\n\r\t"
	                while (j < len) {
	                    // Is a space?
	                    if (cur == ' ') break;
	                    if (cur == '\t') break;
	                    // Is a quote?
	                    if (cur == '\'') break;
	                    if (cur == '\"') break;
	                    // Is html?
	                    if (cur == '<') break;
	                    if (cur == '[') break;
	                    // Is a Unix newline?
	                    if (cur == '\n') break;
	                    // Is Win32 newline?
	                    if (cur == '\r' && j < len-1 && chars[j+1] == '\n')
	                        break;

	                    j++;
	                    if (j < len) {
	                        cur = chars[j];
	                    }
	                }
                    // Check the ending character of the URL. If it's a ".,)]"
                    // then we'll remove that part from the URL.
	                cur = chars[j-1];
                    if (cur == '.' || cur == ',' || cur == ')' || cur == ']')
                    {
                        j--;
                    }
	                buf.append(chars, oldend, index - oldend);
	                buf.append("<a href=\"");
	                buf.append(chars, index, j - index);
	                buf.append('\"');
	                if (newWindowEnabled) {
	                    buf.append(" target=\"_blank\"");
	                }
                    buf.append('>');

	                buf.append(chars, index, j - index);
	                buf.append("</a>");
        		}
                else {
		            buf.append(chars, oldend, j - oldend);
        		}
                oldend = index = j;
			}
            else if (cur == '[' &&  index < len - 6 &&
                       chars[i = index + 1] == 'u' && chars[++i] == 'r' &&
                       chars[++i] == 'l' && (chars[++i] == '=' || chars[i] == ' '))
            {
				j = ++i;
        		u1 = u2 = input.indexOf("]", j);
        		if (u1 > 0) {
        			u2 = input.indexOf("[/url]", u1+1);
        		}
        		if (u2 < 0) {
		            buf.append(chars, oldend, j-oldend);
        			oldend = j;
        		} else {
		            buf.append(chars, oldend, index-oldend);
	                buf.append("<a href =\"");
                    // Check the user entered URL for a "javacript:" or "file:" link. Only
                    // append the user entered link if it doesn't contain 'javascript:' and 'file:'
                    String href = input.substring(j, u1).trim();
                    if (href.indexOf("javascript:") == -1 && href.indexOf("file:") == -1) {
                        buf.append(href);
                    }
	                if (newWindowEnabled) {
	                    buf.append("\" target=\"_blank");
	                }
	                buf.append("\">");
	                buf.append(input.substring(u1+1, u2).trim());
	                buf.append("</a>");
	                oldend = u2+6;
        		}
				index = oldend;        		
            }
        }
        if (oldend < len) {
	        buf.append(chars, oldend, len-oldend);
        }
        return buf.toString();
    }
}