web services in c with cgi

I was trying to setup a simply webservice to reply to POST requests. Earlier this was being done in tomcat which seem a little overkill to me since I already had a webserver up and running. So, a quick c program to respond to request is all that I needed. And here is the result.

/*
 * =====================================================================================
 *
 *       Filename:  Login.cpp
 *
 *    Description:
 *
 *        Version:  1.0

 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Amit Agarwal (),
 *   Organization:
*
* == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == =
    */
#include <stdio .h>
#include <stdlib .h>
#include <string .h>


#define MAXLEN 1024

#ifdef DBG
#define DEBUG(a,b) fprintf(stderr, a, b);
#else
#define DEBUG(a,b) 
#endif

#define HEAD "n"
#define TAIL ""

int main(void)
{

    char input[MAXLEN];
    char * data;
    char*lenstr;
    long len;


    printf("%s%c%cnn",
           "Content-Type:text/xml;charset=iso-8859-1", 13, 10);

    // len = getenv("QUERY_STRING"); // This is for GET
    lenstr = getenv("CONTENT_LENGTH");
    DEBUG( "Length string is %sn", lenstr);

    if(lenstr == NULL || sscanf(lenstr,"%ld",&len)!=1 || len > MAXLEN)
        printf("Error in invocation - wrong FORM probably.");
DEBUG( "Length is %ldn", len);
{
int count=0;
while ( count < len )
input[count++] = getchar();
input[count]='?';
DEBUG ( "Read characters = %dn", count)
}

//fprintf(stderr, "VAlue is %sn", input);
///unencode(input + 5 , input + len, data);

data = input;
DEBUG("Data value is %sn", data);

printf(HEAD);
printf("Everything else goes heren");
printf(TAIL);

fprintf(stderr, "Sent resp: tid[%s], eaid[%s], tcode[%s]n", tid, eaid, tcode);
}
</string></stdlib></stdio>

Additionally, the makefile:

colorgcc – Color your compiler output on Fedora

Lets start with installing colorgcc :

sudo yum install colorgcc

Now once that is done, you will need to ensure that the call to g++, gcc and others that you want to use, you will need to create a link in the “~/bin” directory, like so:

for i in g++ gcc c++ cc 
do
    ln -s $(which colorgcc) ~/bin/$i
done

The one liner above will create the links for colorgcc as **** your favourite compiler in your homedir. Don’t forget to add the bin diretory to your PATH variable:

Inotify Example - Introduction to Inotify with a C Program Example

<a href="http://www.thegeekstuff.com/2010/04/inotify-c-program-example/">Inotify Example: Introduction to Inotify with a C Program Example:

<a class="zem_slink freebase/en/inotify" href="http://en.wikipedia.org/wiki/Inotify" title="Inotify" rel="wikipedia">inotify utility is an effective tool to monitor and notify <a class="zem_slink freebase/en/file_system" href="http://en.wikipedia.org/wiki/File_system" title="File system" rel="wikipedia">filesystem changes. You can specify a list of files and directories that needs to be monitored by inotify. This <a class="zem_slink freebase/guid/9202a8c04000641f8000000000023d0f" href="http://en.wikipedia.org/wiki/Library" title="Library" rel="wikipedia">library is used by various other programs. For example, <a class="zem_slink freebase/en/cpan" href="http://www.cpan.org/" title="CPAN" rel="homepage">CPAN module Linux::Inotify is developed based on this library.
iNotify Execution Flow