zkoss/zk

/* ServletFns.java

    Purpose:
        
    Description:
        
    History:
        Mon Apr 11 15:13:44     2005, Created by tomyeh

Copyright (C) 2005 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
    This program is distributed under LGPL Version 2.1 in the hope that
    it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.web.fn;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.io.Writer;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.zkoss.lang.Library;
import org.zkoss.lang.Strings;
import org.zkoss.web.servlet.dsp.DspException;
import org.zkoss.web.servlet.dsp.action.ActionContext;
import org.zkoss.web.servlet.http.Encodes;
import org.zkoss.web.servlet.xel.RequestContext;
import org.zkoss.web.servlet.xel.RequestContexts;
import org.zkoss.web.theme.StandardTheme;
import org.zkoss.web.theme.StandardTheme.ThemeOrigin;
import org.zkoss.web.theme.Theme;

/**
 * Providing servlet relevant functions for EL.
 *
 * @author tomyeh
 */
public class ServletFns {
    protected ServletFns() {
    }

    /** Encodes a URL.
     *
     * <p>If an URI contains "*", it will be replaced with a proper Locale.
     * For example, if the current Locale is zh_TW and the resource is
     * named "ab*.cd", then it searches "ab_zh_TW.cd", "ab_zh.cd" and
     * then "ab.cd", until any of them is found.
     *
     * <blockquote>Note: "*" must be right before ".", or the last character.
     * For example, "ab*.cd" and "ab*" are both correct, while
     * "ab*cd" and "ab*\/cd" are ignored.</blockquote>
     *
     * <p>If an URI contains two "*", the first "*" will be replaced with
     * a browser code and the second with a proper locale.
     * The browser code depends on what browser
     * the user are used to visit the web site.
     * Currently, the code for Internet Explorer is "ie", Safari is "saf",
     * Opera is "opr" and all others are "moz".
     * Thus, in the above example, if the resource is named "ab**.cd"
     * and Firefox is used, then it searches "abmoz_zh_TW.cd", "abmoz_zh.cd"
     * and then "abmoz.cd", until any of them is found.
     */
    public static String encodeURL(String uri) throws ServletException {
        return Encodes.encodeURL(getCurrentServletContext(), getCurrentRequest(), getCurrentResponse(), uri);
    }

    /**
     * Encodes a URL with theme key injected. 
     * @param s the string to encode
     * @return the encoded string or null if s is null
     * @throws UnsupportedEncodingException 
     * @since 6.0.0
     */
    public static final String encodeThemeURL(String s) throws ServletException {
        if (s == null)
            return null;

        return encodeURL(resolveThemeURL(s));
    }

    private static final String THEME_FOLDER_ROOT = "org.zkoss.theme.folder.root";

    /**
     * Resolves a URL to point to resource served by the current theme. 
     * @param url the default theme url to resolve
     * @return the resolved url or null if url is null
     * @since 6.5.2
     */
    public static final String resolveThemeURL(String url) {
        if (url == null)
            return null;

        String themeName = ThemeFns.getCurrentTheme();
        String prefix = Library.getProperty(THEME_FOLDER_ROOT, "theme");

        String resolved = null;

        if (Strings.isBlank(themeName) || StandardTheme.DEFAULT_NAME.equals(themeName))
            resolved = url;
        else {
            Theme theme = ThemeFns.getThemeRegistry().getTheme(themeName);
            if (theme instanceof StandardTheme) {
                if (((StandardTheme) theme).getOrigin() == ThemeOrigin.JAR)
                    resolved = url.replaceFirst("~./", "~./" + themeName + "/");
                else
                    resolved = url.replaceFirst("~./", "/" + prefix + "/" + themeName + "/");
            }
        }
        return resolved;
    }

    /** Returns the current EL context. */
    public static RequestContext getCurrentContext() {
        return RequestContexts.getCurrent();
    }

    /** Returns the current output. */
    public static Writer getCurrentOut() throws IOException {
        return getCurrentContext().getOut();
    }

    /** Returns the current servlet context, or null if not available. */
    public static ServletContext getCurrentServletContext() {
        return getCurrentContext().getServletContext();
    }

    /** Returns the current servlet request, or null if not available. */
    public static ServletRequest getCurrentRequest() {
        return getCurrentContext().getRequest();
    }

    /** Returns the current servlet response, or null if not available. */
    public static ServletResponse getCurrentResponse() {
        return getCurrentContext().getResponse();
    }

    /** Renders the DSP fragment from EL.
     *
     * @param ac the action context; never null.
     */
    public static void render(ActionContext ac) throws DspException, IOException {
        ac.renderFragment(null);
    }
}