CGI How-To/CGI HOW-TO.iso/java/cgi_j/cgi.jav

Text File | 1996-06-15 | 10.4 KB | 524 lines

import java.util.*;
import java.io.*;

public class Cgi extends Object
{

    public static boolean needsEncode(char x)
    {
        return !(Character.isDigit(x)||Character.isUpperCase(x)
                ||Character.isLowerCase(x)||(x==' '));
    }

    public static String decodeCGIData(String queryString)
    {
        StringBuffer tmp = new StringBuffer(queryString);
        decodeData(tmp);
        return tmp.toString();
    }

    public static void decodeData(StringBuffer queryString)
    {
        /* Temporary variables */
        int i = 0, j = 0, max = 0;
        char c;

        /*
        * Loop over the string.
        * We use two loop indices,
        * i is the actual current character
        * j is used to move ahead when hex codes are found
        * Two indices are needed since the string shrinks
        * as hex-codes are turned into single characters.
        */
        if(queryString != null) max = queryString.length();

        for (i=0, j=0; j < max; ++i, ++j)
        {
            /* If we have found hex-codes, j>i so copy the data down. */

            queryString.setCharAt(i,queryString.charAt(j));

            if ('+' == queryString.charAt(i)) /* Convert pluses to spaces */
            {
                queryString.setCharAt(i,' ');
            }
            else if ('%' == queryString.charAt(j))/* Convert hex codes */
            {
                /*
                * Get the first number of the hex code, and store it
                * as a char.
                */

                c = (char)(((queryString.charAt(j+1) >= 'A') ?
                            ((queryString.charAt(j+1) & 0xdf) - 'A') + 10
                            : (queryString.charAt(j+1) - '0')));
                /*
                * The first hex-code was the 16 places, so multiply
                * c by 16.
                */

                c *= 16;

                /*
                * Get the second number in the hex code and add that
                * to the value of c.
                * c now stores the correct character for the hex code.
                */
                c += (char)(((queryString.charAt(j+2) >= 'A') ?
                            ((queryString.charAt(j+2) & 0xdf) - 'A') + 10
                            : (queryString.charAt(j+2) - '0')));

                /* Replace the % char we copied with the actual character. */
                queryString.setCharAt(i,c);

                /* Move j past the hex-code */
                j += 2;
            }
        }

        /* Truncate the string to remove trailing characters */
        queryString.setLength(i);
    }

    public static String encodeCGIData(String aString)
    {
        StringBuffer tmp = new StringBuffer(aString);
        encodeData(tmp);
        return tmp.toString();
    }

    /* encodeData() encodes a string for CGI */
    public static void encodeData(StringBuffer aString)
    {
        int i,size,l,push = 0;

        if(aString.length() != 0)
        {

            /* figure out the size after encoding */
            l=aString.length();

            for(i=0;i<l;i++)
            {
                if(Cgi.needsEncode(aString.charAt(i)))
                {
                    push+=2;
                }
            }

            /* If we encountered characters to encode, encode them */
            if(push != 0)
            {
                /* Grow as needed */
                aString.setLength(l+push);

                /* Start encoded, back to front to reduce copying */
                for(i=l-1;i>=0;i--)
                {
                      if(Cgi.needsEncode(aString.charAt(i)))
                      {
                        int tmp;

                        tmp = (aString.charAt(i))%16;
                        aString.setCharAt(i+push,(char)((tmp>=10)? (tmp-10 + 'A') : (tmp+'0')));
                        push--;

                        tmp = (aString.charAt(i))/16;
                        aString.setCharAt(i+push,(char)((tmp>=10)? (tmp-10 + 'A') : (tmp+'0')));

                        push--;
                        aString.setCharAt(i+push,'%');
                    }
                    else/*push the other char back*/
                    {
                          aString.setCharAt(i+push,aString.charAt(i));
                    }
                }
            }

            l=aString.length();
            /*Convert the spaces to pluses */
            for(i=0;i<l;i++)
            {
                if(aString.charAt(i) == ' ') aString.setCharAt(i,'+');
            }

        }
    }

    /*
     * encodeDictionary() encodes a dictionary in the form
     * of CGI data.
     */
    public static String encodeDictionary(Hashtable dataDict)
    {
        StringBuffer returnString;
        Enumeration state;
        String key;
        Object value;
        StringBuffer buffer;
        boolean needAmp = false;

        /* allocate the string */
        returnString =new StringBuffer();
        buffer =new StringBuffer();

        /* Create a dictionary state */
        state = dataDict.keys();

        /* Calculate how long the string will be */

        while(state.hasMoreElements())
        {
            key = (String) state.nextElement();

            /* If this isn't a multiple value, encode and append it */
            if((key.length()!=0) && (key.charAt(0) != 'A')
                                && (key.charAt(1)!='_'))
            {
                value = dataDict.get(key);

                buffer.setLength(0);
                buffer.append(key);
                encodeData(buffer);

                if(needAmp)
                {
                    returnString.append('&');
                }

                returnString.append(buffer);
                returnString.append('=');

                if(value!=null)
                {
                    buffer.setLength(0);
                    buffer.append((String)value);
                    encodeData(buffer);
                }
                else
                {
                    buffer.setLength(0);
                }

                returnString.append(buffer);

                needAmp = true;
            }
        }

        return returnString.toString();
    }

    public static Hashtable parseData(String queryString)
    {
        /* Temporary variables */
        StringTokenizer cursor;
        String key,value;
        Hashtable dataDict = new Hashtable();

        cursor = new StringTokenizer(queryString,"&=",true);

        while(cursor.hasMoreElements())
        {

            key = null;/* Reset the tmp key */

            value = null;/* Reset the tmp value */

            key = cursor.nextToken();

            /* If we have a key, try to read the value */

            if( key != null)
            {

                /*
                * See if the next character is a &,
                * if it is the key has an empty value.
                */

                if(cursor.hasMoreElements()&&
                    (cursor.nextToken().equals("=")))
                {
                    value = cursor.nextToken();
                    if(cursor.hasMoreElements())
                        cursor.nextToken();//Get rid of seperator

                    /*
                    * Decode the key and value
                    */

                    key = decodeCGIData(key);
                    value = decodeCGIData(value);
                }
                else/* Key has an empty value */
                {
                    /*
                    * Decode the key, then
                    * print the key and an empty value
                    */
                    if(cursor.hasMoreElements())
                        cursor.nextToken();//Get rid of seperator

                    key = decodeCGIData(key);

                    value = new String("");
                }

                /*
                * Insert the value into the dictionary, but
                * allow for multiple values on key.
                * Put multiple values into an Array, with the key,
                * A_key.
                */

                /* Check if this is a multiple value */
                if((dataDict.get(key)) != null)
                {
                    /* Create the name for the array key */
                    String aName;

                    aName = "A_"+key;

                    /* Check if the array is in the dict, already */

                    if((dataDict.get(aName))!=null)
                    {
                        /* Add the new value to the array */
                        Vector theArray;

                        theArray = (Vector) dataDict.get(aName);

                        theArray.addElement(value);

                        /* Set the dictionaries value, to the latest */

                        dataDict.put(key, value);
                    }
                    else /* If not, ... */
                    {
                        /* Create the array */
                        Vector theArray = null;
                        theArray = new Vector();

                        /* Add the first value to the array */
                        theArray.addElement(dataDict.get(key));

                        /* Add the new value to the array */
                        theArray.addElement(value);

                        /* Set the dictionaries value, to the latest */
                        dataDict.put(key, value);

                        /* Add the array to the dictionary */
                        dataDict.put(aName,theArray);
                    }
                }
                else /* If not, simple insert the value */
                {
                    dataDict.put(key, value);
                }

            }

        }

        return dataDict;
    }

    public static String readGetData()
    {
        String queryString;
        queryString = System.getProperty("QUERY_STRING");

        if(queryString == null)
        {
            queryString = new String("");
        }

        return queryString;
    }

    public static String  readPostData()
    {
        /* The data after it is read in */
        String queryString;

        /* The amount of data to read */
        int contentLength,i;

        /* Temporary variables for storing envvar and reading*/
        String sizeString;
        byte data[] = null;

        /* Read the environment variable CONTENT_LENGTH */

        sizeString = System.getProperty("CONTENT_LENGTH");


        /* If the env. var. existed, convert the string to an integer */

        if (sizeString!=null)
        {
            contentLength = Integer.parseInt( sizeString );
            data = new byte[contentLength];
        }
        else
        {
            contentLength = 0;
        }

        if ( data != null)
        {
            i = 0;

            try
            {
                while( i < contentLength)
                {
                        data[ i++ ] = (byte) System.in.read();
                }
            }
            catch(IOException exp)
            {
                data = null;
            }
            /* Set the arguement to point to the data. */

            if(data != null) queryString = new String(data,0);
            else queryString = new String("");

        }
        else
        {
            queryString = new String("");
        }

        return queryString;
    }

    public static String readData()
    {
        String requestType = null;
        String retVal = null;


        /* Read the request type */

        requestType = System.getProperty("REQUEST_METHOD");

        /*
         * If it is a GET request use readGetData,
         * otherwise, if it is a POST request, use readPostData.
         */

        if((requestType != null) && requestType.equals("GET"))
        {
            retVal = readGetData();
        }
        else if((requestType != null) && requestType.equals("POST"))
        {
            retVal = readPostData();
        }
        else
        {
             retVal = new String("");
        }

        return retVal;
    }

    public static Hashtable readParse()
    {
        Hashtable returnData = null;
        String data;

         data = readData();

        if(data!=null) returnData = parseData(data);

        return returnData;
    }

    public static void main(String argv[])
    {
          FileInputStream raw;
          DataInputStream input;
          String key,value;
          String curLine;
          Hashtable data,decodedData;
         String encodedData;
          Enumeration cursor;
          int matches,total,ind;

          if(argv.length > 0)
        {
            try
            {
                raw = new FileInputStream(argv[0]);
                input = new DataInputStream(raw);
                data = new Hashtable();

                while(input.available() != 0)
                {
                    curLine = input.readLine();
                    ind = curLine.indexOf(' ');

                    key = curLine.substring(0,ind);
                    value = curLine.substring(ind+1);
                    data.put(key,value);
                }

                encodedData = encodeDictionary(data);
                decodedData = parseData(encodedData);

                cursor = data.keys();
                matches = 0;
                total = 0;

                while(cursor.hasMoreElements())
                {
                    key = (String)cursor.nextElement();
                    value = (String)decodedData.get(key);

                    if(data.get(key).equals(value))
                    {
                        matches++;
                        System.out.println(data.get(key) + " = " + value);
                    }
                    else
                    {
                        System.out.println(data.get(key) + " != " + value);
                    }
                    total++;
                }

                if(matches == total)
                {
                    System.out.println("Test succeeded.");
                }
                else
                {
                    System.out.println("Test failed.");
                }


                input.close();
                raw.close();
            }
            catch(IOException exp)
            {
                System.out.println("Encountered IO exception!");
            }
        }
        else
        {
            System.out.println("usage: java Cgi filename");
            System.out.println("The file should have space seperated keys and values\n");
        }
    }

}