source: trunk/gsdl3/src/java/org/greenstone/gsdl3/gs3build/util/URLString.java@ 5823

package org.greenstone.gsdl3.gs3build.util;



import java.applet.*;

import java.net.*;



public class URLString

{ private String url;



    private String urlbase(String url)

    { int index;

        String tailString, bodyString;

        int body;



        index = url.indexOf("//");

        tailString = url.substring(index+2, url.length());



        body = tailString.indexOf('/');

        bodyString = tailString.substring(0, body+1);



        tailString = url.substring(0, index+2) + bodyString;

        return tailString;

    }



    public URLString(String s)

    {   this.url = s;

    }



    public URLString(String s, String target)

    { // reconcile

        int sref;

        int cref;

        int c;



        // trim fragment identifiers

        target = noRef(target);

        if (target == null)

        {   this.url = s;

            return;

        }



        // test for absolute

        cref = target.indexOf(':');

        if (cref >= 0)

        { for (c = 0; c < cref; c ++)

            { if (target.charAt(c) != '+' &&

                        target.charAt(c) != '-' &&

                        target.charAt(c) != '.' &&

                        Character.isLetterOrDigit(target.charAt(c)) == false)

                { break;

                }

            }

        }

        else

        { c = 0;

        }



        if (c == cref)

        { // absolute reference

            String tmp;



            tmp = target.substring(0, c);

            tmp = tmp.toLowerCase();

            if (target.indexOf("//") == cref + 1)

            { if (target.lastIndexOf('/') == cref + 2)

                { target = target + "/";

                }

            }

/*          if (tmp.equals("http") == false)

            { this.url = null;

                return;

            }*/

            this.url = target;

        }

        else if (target.indexOf("//") == 0)

        { // absolute - implicit scheme (ie http).; also check for no trailing '/'

            if (target.lastIndexOf('/') == 1)

            { target = target + "/";

            }

            target = "http:" + target;

            this.url = target;

        }

        else

        { // relative - trim silly '/' at end

            if (target.charAt(0) == '/')    

            { // if we get a leading '/' then add it to the base of the url

                s = urlbase(s);

                target = target.substring(1);

                this.url = s + target;

//              System.out.println(this.url+"<"+s+"<"+target);

                return;

            }



            while(target.length() >= 2 && target.charAt(0) == '.' && target.charAt(1) == '.')

            { // move up a level on the left



                sref = s.lastIndexOf('/');

                s = s.substring(0, sref);



                target = target.substring(3);

            }

            // strip trailing leaf from s

            sref = s.lastIndexOf('/');

            s = s.substring(0, sref+1);

            // append s+target

            this.url = s + target;

        }



        // abandon the url if it is a call to a script

        if (this.url.indexOf('?') >= 0)

        { this.url = null;

        }

    }



    public static boolean dirParent(String parent, String child)

    {   while (child.length() >= parent.length())

        { child = child.substring(0, child.lastIndexOf('/'));



            if (parent.equals(child))

            {   return true;

            }

        }

        return false;

    }



    public static int dirPos(String from, String to)

    {   String fromdir;

        String todir;



        fromdir = from.substring(0, from.lastIndexOf('/'));

        todir   = to.substring(0, to.lastIndexOf('/'));



        if (fromdir.equals(todir))

        {   return 0;

        }

        if (fromdir.length() > todir.length())

        { if (dirParent(todir, fromdir) == true)

            {   return -1;

            }

        }

        else 

        {   if (dirParent(fromdir, todir) == true)

            { return 1;

            }

        }

        return -2;

    }



    public static int commonLevels(String a, String b)

    {   String  path_a, path_b;

        int         offset_a, offset_b;

        String  dir_a, dir_b;

        int         common;



        path_a  = path(a);

        path_b  = path(b);

        common  = 0;



        if (path_a == null || path_b == null)

        { return 0;

        }



        do

        { offset_a = path_a.indexOf('/');

            offset_b = path_b.indexOf('/');



            if (offset_a > 0)

            { dir_a     =   path_a.substring(0, offset_a);

                if (path_a.length() > offset_a + 1)

                {   path_a  = path_a.substring(offset_a+1);

                }

                else

                {   path_a  = null;

                }

            }

            else

            {   dir_a       =   path_a;

                path_a  = null;

            }



            if (offset_b > 0)

            {   dir_b       =   path_b.substring(0, offset_b);

                if (path_b.length() > offset_b + 1)

                {   path_b  = path_b.substring(offset_b+1);

                }

                else

                {   path_b  = null;

                }

            }

            else

            {   dir_b       =   path_b;

                path_b  = null;

            }



            if (dir_a.length() != dir_b.length() ||

                    dir_a.equals(dir_b) == false)

            {   return common;

            }

            common ++;

        } while (path_a != null && path_b != null);



        return common;

    }



    public static String dirLevelName(String url, int level)

    {   String  lpath;

        String  dir;

        int         thislevel = 0;

        int         offset;



        lpath = path(url);

        if (lpath == null)

        { return null;

        }

        do

        { offset = lpath.indexOf('/');



            if (offset >= 0)

            {   dir = lpath.substring(0, offset);

                lpath = lpath.substring(offset+1);

            }

            else

            {   dir = lpath;

            }



            thislevel ++;



            if (level == thislevel)

            { return dir;

            }

        } while (offset >= 0);



        return null;

    }



    public static int dirLevel(String url)

    {   String  lpath;

        int         level;

        int         offset;



        lpath = path(url);

        if (lpath == null)

        {   return 0;

        }

        level = 0;

        do

        { offset = lpath.indexOf('/');

            if (offset >= 0)

            {   lpath = lpath.substring(offset+1);

            }

            level ++;

        } while (offset >= 0);



        return level;

    }



    public static String tidyURL(String urlString, boolean permitScript)

    {   int cref;

        int c;

        int sref;

        String tmp, s;



        s = urlString;

        cref = s.indexOf(':');

        if (cref >= 0)

        { for (c = 0; c < cref; c ++)

            { if (s.charAt(c) != '+' &&

                        s.charAt(c) != '-' &&

                        s.charAt(c) != '.' &&

                        Character.isLetterOrDigit(s.charAt(c)) == false)

                { break;

                }

            }

        }

        else

        { c = 0;

        }



        if (cref == c)

        { tmp = s.substring(0, c).toLowerCase();

            s = tmp + s.substring(c, s.length());

            if (s.lastIndexOf('/') == cref + 2)

            { s = s + "/";

            }

        }

        else

        { sref = s.indexOf("//");

            if (sref == 0)

            { s = "http:" + s;

            }

            else

            { s = "http://" + s;

            }

            if (s.lastIndexOf('/') == 6)

            { s = s + "/";

            }

        }

        return s;

    }

    public static String tidyURL(String urlString)
    {   return tidyURL(urlString, false);
    }



    public static URL toURL(String urlString)

    { URL reply;



      try

        { reply = new URL(URLString.tidyURL(urlString));

        }

        catch (MalformedURLException ex)

        { return null;

        }

        return reply;

    }



  public void tidy()

    { this.url = tidyURL(this.url);

    }



    public boolean isNull()

    { if (this.url == null)

        { return true;

        } 

        return false;

    }



    public static boolean isForeign(String home, URL url)

    { if (url.toString().length() < home.length())

        { return true;

        }



        if (home.equals(url.toString().substring(0, home.length())))

        { return false;

        }

        return true;

    }


    /**
     *  Remove any trailing "#localanchor" local reference from a URL string
     *
     *  @param  <code>String</code> the original url
     *  @return <code>String</code> the cleaned url, sans local references
     */
    public static String noRef(String target)
    {   if (target == null)
        {   return null;
        }
        if (target.indexOf('#') >= 0)
        { if (target.indexOf('#') == 0)
            { return null;
            }
            target = target.substring(0, target.indexOf('#'));
        }
        return target;
    }

    /**
     *  Obtain the trailing local anchor reference from a URL, 
     *  if it exists.
     *    e.g. for http://www.test.mdx.ac.uk/example/index.html#credits the
     *         response would be "credits"
     *
     *  @param  <code>String</code> the original url.
     *  @return <code>String</code> the local reference.  <code>null</code> is
     *                              returned if no local reference exists.
     */
    public static String subRef(String target)
    {   if (target.indexOf('#') >= 0)
        {   return target.substring(target.indexOf('#')+1);
        }
        return null;
    }

    /**
     *  Clean a URL of the form GET parameters.
     *
     *  @param  <code>String</code> the original url, with GET message parameters
     *  @return <code>String</code> the cleaned url.
     */
    public static String noParameters(String url)
    {   int                     c;

        c = url.indexOf("?");
        if (c < 0)
        {   return url;
        }
        return url.substring(0, c);
    }

    /**
     *  Obtain the form parameters from a url
     *
     *  @param  <code>String</code> the original url, with GET message parameters
     *  @return <code>String</code> the form "GET" parameters.  The leading '?' is
     *                              preserved in the reply.  If no parameters were
     *                              given, the result is <code>null</code>.
     */
    public static String formParameters(String url)
    {   int                     c;

        c = url.indexOf("?");
        if (c < 0)
        {   return null;
        }
        return url.substring(c);
    }

    /**
     *  Flatten a URL, making the '?' and '&' items into underscores
     *
     *  @param  <code>String</code> the original url, with GET message parameters
     *  @return <code>String</code> the "flattened" url
     */
    public static String flattenedUrl(String oldUrl)
    {   StringBuffer    reply;
        int                     c;
        boolean             modified = false;

        // replace ? with _
        // replate & with _
        reply = new StringBuffer(oldUrl);
        for (c = 0; c < reply.length(); c ++)
        {   if (reply.charAt(c) == '?' ||
                    reply.charAt(c) == '&')
            {   reply.setCharAt(c, '_');
                modified = true;
            }
        }

        if (modified == true)
        {   c   = oldUrl.indexOf(".html");
            if (c >= 0)
            {   while (c < oldUrl.length() - 5)
                {   reply.setCharAt(c, reply.charAt(c+5));
                    c ++;
                }
                reply.setCharAt(c ++, '.');
                reply.setCharAt(c ++, 'h');
                reply.setCharAt(c ++, 't');
                reply.setCharAt(c ++, 'm');
                reply.setCharAt(c ++, 'l');
            }
        }

        return reply.toString();
    }


    /**
     *  Provide the complete pathname in the given url
     *    eg. "example/index.html" for http://www.test.mdx.ac.uk/example/index.html
     *
     *  @param  <code>String</code> url of page
     *  @return <code>String</code> leaf file name
     */
    public static String pathName(String url)

    {   int offset;

        String remainder;



        if (url == null)

        { return null;

        }



        offset = url.indexOf("//");

        if (offset < 0)

        { return null;

        }



        remainder = url.substring(offset + 2);

        offset = remainder.indexOf('/');

        if (offset < 0)

        {   return null;

        }

        return remainder.substring(offset + 1);

    }



    /**
     *  Provide the leaf filename in the given url
     *    eg. "index.html" for http://www.test.mdx.ac.uk/example/index.html
     *
     *  @param  <code>String</code> url of page
     *  @return <code>String</code> leaf file name
     */
    public static String leafName(String url)

    {   int offset;

        int dot;



        if (url == null)

        {   return null;

        }

        offset = url.lastIndexOf('/');

        if (offset < 0)

        { return null;

        }

        if (offset == url.length() - 1)

        { return null;

        }

        dot = url.lastIndexOf('/');

        if (dot < offset)

        {   return null;

        }

        return url.substring(offset+1);

    }


    /**
     *  Provide the hostname in the given url
     *    eg. "www.test.mdx.ac.uk" for http://www.test.mdx.ac.uk/example/index.html
     *
     *  @param  <code>String</code> url of page
     *  @return <code>String</code> host name
     */

    public static String host(String url)

    {   String scheme, tail;

        int      spos;



        spos = url.indexOf("//");

        if (spos >= 0)

        { scheme = url.substring(0, spos + 2);

            tail = url.substring(spos + 2, url.length());

            // do sub-areas

            spos = tail.indexOf('/');

            if (spos >= 0)

            { tail = tail.substring(0, spos+1);

            }

            scheme = scheme + tail;

            return scheme;

        }

        return null;

    }



    /**
     *  Return the logical path of the url on the remote server
     *    eg. "example" for http://www.test.mdx.ac.uk/example/index.html
     *
     *  @param  <code>String</code> url of page
     *  @return <code>String</code> logical path
     */
    public static String path(String url)

    { String tail;

        int offset;

        String leaf;



        if (url == null)

        { return null;

        }



        offset  = url.indexOf("//");

        if (offset < 0)

        {   return null;

        }



        tail        = url.substring(offset+2);

        offset  = tail.indexOf('/');

        if (offset < 0)

        {   return null;

        }



        tail        = tail.substring(offset+1);

        if (tail == null || tail.length() == 0)

        {   return null;

        }



        offset  = tail.lastIndexOf('/');

        if (offset < 0)

        { return null;

        }

        else

        {   tail = tail.substring(0, offset);

        }

        return tail;

    }



    /**
     *  Give the 'dot' extension of a url; 
     *    eg. "html" for http://www.test.mdx.ac.uk/example/index.html
     *
     *  @param <code>String</code> url
     *  @return <code>String</code> extension.
     */
    public static String extension(String url)

    { int offset;

        String leaf;



        if (url == null)

        { return null;

        }



        offset = url.lastIndexOf('/');

        if (offset >= 0 && offset < url.length() - 1)

        { leaf = url.substring(offset+1, url.length());

            offset = leaf.lastIndexOf('.');

            // if we've got an extension then use it

            if (offset >= 0)

            { int poffset;

                // get parameter offset
                poffset = leaf.indexOf('?');
                if (poffset < 0)
                {   poffset = leaf.length();
                }

                // give leaf value
                return leaf.substring(offset, poffset);

            }

            else

            { return null;

            }

        }

        return null;

    }



    public static String extension(URL url)

    { return extension(url.toString());

    }



    public String toString()

    { return this.url;

    }

}