Question

So my C++ CGI program generates some html-page with several links. How can I make within the same C++ process that after clicking this links will be displayed some others pages with content depending on what hyperlink was clicked?

For now I just have variant that there will be other C++ CGI program that will read URL param with getenv, and this param will be different for every link from my first page. But I believe there must be a way of doing this with one C++ process.

Answer 1

You are trying to store session information in the memory of your CGI program. CGI protocol doesn’t allow this by itself. You must store session information somewhere else. Your options are:

• Output HTML where result of your calculations is embedded in URLs, so that next execution will see those results (if that information is sensitive, this is a security flaw – you may overcome this with safe encryption).
• Store results outside your C++ program memory (a file?). Then output a cookie or embed a session identifier in the URLs. In the next execution, you perform a lookup with session identifier then load those results from your server. You must take care to free old data to avoid space exhaustion.
• Turn your C++ application into a web server! Your C++ application will answer HTTP requests (it will not be only a CGI application). That may be overkill, but might be necessary. I think there are free open source libraries that helps on that, or you can develop an Apache (httpd) module.

Hope that answers your question!