CGI How-To/CGI HOW-TO.iso/chap4/4_4/comp_c/cgilib.c

C/C++ Source or Header | 1996-06-15 | 12.5 KB | 654 lines

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "cgilib.h"

#define NEEDS_ENCODE(x) (!(islower(x)||isupper(x)||isdigit(x)||(x==' ')))

void decodeData(char *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.
    * The loop ends when the '\0' character has been "copied".
    */
    if(queryString) max = strlen(queryString) + 1;

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

        queryString[i] = queryString[j];

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

            c = ((queryString[j+1] >= 'A') ?
                        ((queryString[j+1] & 0xdf) - 'A') + 10
                        : (queryString[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 += ((queryString[j+2] >= 'A') ?
                        ((queryString[j+2] & 0xdf) - 'A') + 10
                        : (queryString[j+2] - '0'));

            /* Replace the % char we copied with the actual character. */
            queryString[i] = c;

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

/* encodeData() encodes a string for CGI */
void encodeData(String aString)
{
  int x,size,l,push = 0;

  if(aString->string != NULL)
    {

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

      for(x=0;x<l;x++)
    {
      if(NEEDS_ENCODE(aString->string[x]))
        {
          push+=2;
        }

    }

      /* If we encountered characters to encode, encode them */
      if(push != 0)
    {
      /* Grow as needed */
      string_setSize(aString,l+push+1,0);

      /* Start encoded, back to front to reduce copying */
      for(x=l;x>=0;x--)
        {

          if((NEEDS_ENCODE(aString->string[x]))
         &&(aString->string[x] != '\0'))
           {
             int tmp;

             tmp = (aString->string[x])%16;
             aString->string[x+push] = (tmp>=10)? (tmp-10 + 'A') : (tmp+'0');
             push--;

             tmp = (aString->string[x])/16;
             aString->string[x+push] = (tmp>=10)? (tmp-10 + 'A') : (tmp+'0');

             push--;
             aString->string[x+push] = '%';
           }
          else/*push the other char back*/
        {
          aString->string[x+push] = aString->string[x];
        }
        }
    }

      /*Convert the spaces to pluses */
      for(x=0;aString->string[x] != '\0';x++)
    {
      if(aString->string[x] == ' ') aString->string[x] = '+';
    }

    }
}

/*
 * encodeDictionary() encodes a dictionary in the form
 * of CGI data.
 */
String encodeDictionary(Dictionary dataDict)
{
  String returnString = 0;
  DictState state;
  char *key;
  void *value;
  String buffer;
  int needAmp = 0;

  /* allocate the string */
  returnString = string_alloc(512);
  buffer = string_alloc(128);

  /* Create a dictionary state */
  state = dict_initState(dataDict);

  /* Calculate how long the string will be */

  while(dict_nextState(&state))
    {
      key = state.curNode->key;

      /* If this isn't a multiple value, encode and append it */
      if(key && strncmp(key,"A_",2))
     {
       value = state.curNode->value;

       string_setStringValue(buffer,key);
       encodeData(buffer);

       if(needAmp)
         {
           string_appendChar(returnString,'&');
         }

       string_appendString(returnString,buffer->string);
       string_appendChar(returnString,'=');

       if(value)
         {
           string_setStringValue(buffer,value);
           encodeData(buffer);
         }
       else
         {
           string_empty(buffer);
         }

       string_appendString(returnString,buffer->string);

       needAmp = 1;
     }
    }

  string_free(buffer);
  return returnString;
}

int parseData(char *queryString, Dictionary dataDict)
{
    /* Temporary variables */
    char *cursor = (char *)0;

    char *key = (char *)0, *value = (char *)0;

    char *sbegin = (char *)0, *send = (char *)0;

    int charsToCopy = 0;

    /* For example take queryString = "key=value&key1=value1" */

    if(queryString != (char *)0)
      {
        cursor = queryString;
      }
    else
      {
        return 0;
      }

    do{/* Loop while we are finding keys */

        key = 0;/* Reset the tmp key */

        value = 0;/* Reset the tmp value */

        /*
         * Reset the search pointer, sbegin
         *
         *   key=value&key1=value1
         *   ^         ^
         *   |         |
         *  pass 1    pass 2
         *
         */

        sbegin = cursor;

        /*
         * Move sbegin past any next special char, & or =
         *
         *   key=value&key1=value1
         *   ^         ^
         *   |         |
         *  pass 1    pass 2
         *
         */

        sbegin += strspn(sbegin, "=&");

        /* Check if we are at the end of the query string */

        if(*sbegin == '\0') /* If at end, make the key and cursor = NULL */
        {
            cursor = (char *) 0;
            key = cursor;
        }
        else /* Otherwise, find the key */
        {
            /* Reset the number of characters in the key */

            charsToCopy = 0;


            /*
             * Find the end of the key
             *
             *   key=value&key1=value1
             *      ^          ^
             *      |          |
             *     pass 1     pass 2
             *
             */
            send = sbegin + strcspn(sbegin,"=&");

            /* Check if the end of the key is the end of the string */

            if('\0' != (*send)) /* If not, calculate the length of key */
            {
                /*
                 * Find send past the =
                 *
                 *   key=value&key1=value1
                 *       ^          ^
                 *       |          |
                 *      pass 1     pass 2
                 *
                 */
                send++;
                charsToCopy = strlen(sbegin) - strlen(send) - 1;
            }
            else /* Otherwise, key is whats left */
            {
                charsToCopy = strlen(sbegin);
            }

            /* Move the cursor to the end of the key */

            cursor = send;

            /* Allocate memory for the key */

            key = (char *) malloc(sizeof(char)*(charsToCopy +1));

            /* Copy the correst number of characters to the key string */

            strncpy(key,sbegin,charsToCopy);

            /* End the key string with a '\0' */

            key[charsToCopy] = '\0';
        }

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

        if( key && (*key != '\0')){

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

            if(('\0' != *cursor)
                    &&('&' != *cursor))
            {
                /*
                 * Find the beginning of the value
                 *
                 *   key=value&key1=value1
                 *       ^          ^
                 *       |          |
                 *      pass 1     pass 2
                 *
                 */

                sbegin = cursor;
                sbegin += strspn(sbegin, "=&");

                /* Check if we found a vlaue */

                if(*sbegin == '\0') /* If not set the value and cursor to 0 */
                {
                    cursor = (char *) 0;
                    value = cursor;
                }
                else /* Otherwise, find the value */
                {
                    /* Reset the length of the value string */

                    charsToCopy = 0;

                    /*
                     * Find the end of the value
                     *
                     *   key=value&key1=value1
                     *            ^           ^
                     *            |           |
                     *           pass 1      pass 2
                     *
                     */

                    send = sbegin + strcspn(sbegin,"=&");

                    /* Check if the value is at the end of the string */

                    if('\0' != (*send)) /* If not, calculate the length */
                    {
                        /*
                        * Move send past the &
                        *
                        *   key=value&key1=value1
                        *       ^          ^
                        *       |          |
                        *      pass 1     pass 2
                        *
                        */
                        send++;
                        charsToCopy = strlen(sbegin)
                                    - strlen(send) - 1;
                    }
                    else /* Otherwise, the length is from the start to '\0'*/
                    {
                        charsToCopy = strlen(sbegin);
                    }

                    /*
                     * Reset the cursor
                     *
                     *   key=value&key1=value1
                     *            ^           ^
                     *            |           |
                     *           pass 1      pass 2
                     *
                     */

                    cursor = send;

                    /* Allocate space for the value string */

                    value = (char *)
                        malloc(sizeof(char)*(charsToCopy +1));

                    /* Copy the value string, and add a '\0' */

                    strncpy(value,sbegin,charsToCopy);
                    value[charsToCopy] = '\0';
                }

                /*
                 * Decode the key and value then,
                 * print them
                 */

                decodeData(key);
                decodeData(value);

            }
            else/* Key has an empty value */
            {
                /*
                 * Decode the key, then
                 * print the key and an empty value
                 */

                decodeData(key);

                value = malloc(sizeof(char) * 1);
                value[0] = '\0';
            }

            /*
             * 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(dict_isKey(dataDict,key))
            {
                /* Create the name for the array key */
                char *aName;

                aName = (char *) malloc((strlen(key)+3) * sizeof(char));

                sprintf(aName,"A_%s",key);

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

                if(dict_isKey(dataDict,aName))
                {
                    /* Add the new value to the array */

                    Array theArray = 0;

                    theArray = (Array) dict_valueForKey(dataDict,aName);

                    array_addItem(theArray,value);

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

                    dict_setValueForKey(dataDict, key, value);

                }
                else /* If not, ... */
                {
                    /* Create the array */

                    Array theArray = 0;

                    theArray = array_alloc(3);

                    /* Add the first value to the array */

                    array_addItem(theArray, dict_valueForKey(dataDict,key));

                    /* Add the new value to the array */

                    array_addItem(theArray,value);

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

                    dict_setValueForKey(dataDict, key, value);

                    /* Add the array to the dictionary */

                    dict_setValueForKey(dataDict, aName, (void *)theArray);

                }


                free(aName);
            }
            else /* If not, simple insert the value */
            {
                dict_setValueForKey(dataDict, key, value);
            }

        }

    }while(key && ('\0' != *key) && ('\0' != *cursor));

    return 1;/* Return 1 for success */
}

void readGetData(char **aString)
{
    /* The data after it is read in */
    char *queryString;
    int len = 0;

    queryString = getenv("QUERY_STRING");

    if(queryString)
      {
        len = strlen(queryString);

        *aString = malloc(sizeof(char) * len);

        strcpy(*aString,queryString);
      }
    else
      {
        len = 1;

        *aString = malloc(sizeof(char) * len);

        **aString = '\0';
      }
}
void readPostData(char **aString)
{
    /* The data after it is read in */
    char *queryString;

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

    /* Temporary variables for storing envvar and iterating */
    char *sizeString;
    int i;

    /* Read the environment variable CONTENT_LENGTH */

    sizeString = getenv("CONTENT_LENGTH");


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

    if (sizeString)
    {
        contentLength = atoi( sizeString );
    }
    else
    {
        contentLength = 0;
    }

    /*
     * If there is a non-zero amount of data,
     * alloc a string big enough to hold it.
     */
    if ( 0 != contentLength)
    {
        /* Notice that we add one to hold the null, '\0', character. */
        queryString = (char *) malloc(sizeof(char) * (contentLength + 1) );
    }
    else
    {
        queryString = (char *) 0;
    }

    /* If the malloc succeeded, read the data. */

    if ( queryString )
    {
        i = 0;

        /*
         * Use fgetc to read the data,
         * iterating until the exact number of characters is read.
        */
        while( i < contentLength)
        {
                queryString[ i++ ] = fgetc(stdin);
        }

        /* Add the null, '\0', character to the end. */

        queryString[ i ] = '\0';

        /* Set the arguement to point to the data. */

        *aString = queryString;

    }
    else
        {
        *aString = malloc(sizeof(char));

        **aString = '\0';
        }
}

void readData(char **aString)
{
    char *requestType = (char *) 0;


    /* Read the request type */

    requestType = getenv("REQUEST_METHOD");

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

    if(requestType && !strcmp(requestType,"GET"))
    {
        readGetData(aString);
    }
    else if(requestType && !strcmp(requestType,"POST"))
    {
        readPostData(aString);
    }
    else
    {
             *aString = malloc(sizeof(char));

        **aString = '\0';
    }
}

Dictionary readParse()
{
    Dictionary returnData;
    char *data;

    returnData = dict_alloc();

     readData(&data);

    if(data) parseData(data, returnData);

    if(data) free(data);

    return returnData;
}