how to get a GET/POST variable with a c++ CGI program?
Question
my google-fu has failed me, I'm looking for a basic way to get GET/POST data from an html forum page on my server to use in a c++ CGI program using only basic libraries.
(using an apache server, on ubuntu 22.04.1)
here's the code I've tried
the HTML page:
<!doctype html>
<html>
<head>
<title>Our Funky HTML Page</title>
</head>
<body>
Content goes here yay.
<h2>Sign Up </h2>
<form action="cgi-bin/a.cgi" method="post">
<input type="text" name="username" value="SampleName">
<input type="password" name="Password" value="SampleName">
<button type="submit" name="Submit">Text</button>
</form>
</body>
</html>
and here's the c++ code I've tried:
#include <stdio.h>
#include <stdlib.h>
int main()
{
printf("Content-type:text/plain\n\n");
printf("hello World2\n");
// attempt to retrieve value of environment variable
char *value = getenv( "username" ); // Trying to get the username field
if ( value != 0 ) {
printf(value);
} else {
printf("Environment variable does not exist."); // if it failed I get this message
}
printf("\ncomplete\n");
return 0;
}
I get the feeling 'getenv' is not the right thing to use here.. it works for things like "SERVER_NAME" though.
any thoughts?
1 answers
solution1
0 ACCPTED 2022-11-18 14:53:53
okay, 2 different methods, depending if it's a post or get method:
-GET- html:
<!doctype html>
<html>
<head>
<title>Website title obv</title>
</head>
<body>
Content goes here yay.
<h2>Sign Up </h2>
<form action="cgi-bin/a.cgi" method="get">
<input type="text" name="username" value="SampleName">
<input type="password" name="Password" value="SampleName">
<button type="submit" name="Submit">Text</button>
</form>
</body>
</html>
and the c++ (script?) to read the get values:
#include <stdio.h>
#include <iostream>
int main()
{
printf("Content-type:text/plain\n\n");
char *value = getenv( "QUERY_STRING" ); // this line gets the data
if ( value != 0 ) {
printf(value);
} else {
printf("Environment variable does not exist.");
}
return 0;
}
you have to manually parse the data
-POST-
html: just change 'get' to 'post'
c++:
#include <stdio.h>
#include <iostream>
#include <string>
#include <stdlib.h>
int main()
{
printf("Content-type:text/plain\n\n");
for (std::string line; std::getline(std::cin, line);) {
std::cout << line << std::endl;
}
return 0;
return 0;
}
again, you'll have to manually parse the data, but now you have those values to play around with yourself.
have fun!
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.