Question CGI / FastCGI and AJAX with C/C++

[igor_kavinski]

I need to understand the flow of AJAX in an application that is using CGI with C/C++. I can't wrap my head around what values are getting passed via CGI to the executable when AJAX is used. Once I understand this, I would like to upgrade to FastCGI as it is faster and more memory efficient. I would really appreciate if someone would volunteer to let me pick their brain. Thanks!

 

[Ken g6]

Wikipedia says environment variables - PATH_INFO for the URL and QUERY_STRING for GET - and stdin for POST.

Common Gateway Interface - Wikipedia

en.wikipedia.org

P. S. I wouldn't use such an insecure language for directly web-connected stuff if I could help it.

 

[igor_kavinski]

I already have connectivity via CGI using a CGI library. I suppose CGI could be made secure by using safe string handling functions/libraries? Also, I don't intend to use CGI over the internet but rather over an intranet. What I can't seem to figure out is how to successfully pass data using AJAX between the page and the C/C++ executable. Sample code showing such an interaction would be awesome. Thanks.

 

[Ken g6]

Oh. AJAX. AJAX is just JavaScript internally GETting (or POSTing to) a URL. The data returned need not look like a web page; JSON is a common format, but far from the only one. Security (of who can access that URL) can be handled by standard methods, or by you. Cookies or tokens generated after a login are common methods. Cookies are read by the HTTP_COOKIE environment variable, or, hopefully, your C/C++ CGI library. Regarding the security I mentioned earlier, if you have a C/C++ CGI library, it's probably sanitizing most of your data well enough.

You act like you want AJAX to communicate with a C/C++ executable that might already be running in the background. Is that the case? CGI starts brief, little, inherently-stateless processes. If you want to communicate with another process, you need to set up inter-process communication (IPC) yourself. A very basic method would be simple files that are watched for. What's available depends on your server's OS.

 

[igor_kavinski]

You act like you want AJAX to communicate with a C/C++ executable that might already be running in the background. Is that the case?

Only FastCGI can keep running in the background. That's my next step after I can do AJAX. I mainly want to do AJAX so it can update the page without refreshing the whole page. However, all around the web, I can only find mostly PHP AJAX code.

 

[Ken g6]

You're looking for the whole package. AJAX can be divided into the JS client and the web service. Here's some links to C++ web service packages:

https://stackoverflow.com/questions/6542676/web-services-in-c-and-c

 

[mxnerd]

Note: I'm NOT a programmer. Maybe just better at searching stuff, I think.

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Googled results:

Ajax: A New Approach to Web Applications

Ajax Frameworks

Why is CGI not used anymore for web applications?

Answer (1 of 4): It's not used (much) anymore because it was superseded by technologies that were faster, more secure, and offered better integration with the web server process. One bit of the CGI spec that is still in use everywhere is the standard method of passing URL parameters, e.g. https:...

www.quora.com

What has replaced CGI (common gateway interface) in today's web?

Answer (1 of 2): PHP is still a popular server side language. Other options are Java, C#.net, or newer frameworks such as node.js. If you are developing dynamic server side content in a cloud environment than functions as a service is becoming more popular such as AWS Lambda functions or Functio...

www.quora.com

FastCGI arg list

FastCGI Specification

Do you really have to use CGI/FastCGI with C?
javascript - JQuery AJAX + C CGI - Stack Overflow

Websockets

websocketd

-- Full duplex messaging between web browsers and servers

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No Ajax framework.

Asynchronously Updating a Webpage in a Standard HTML/CSS/JS Frontend

The ability to update data asynchronously is an important feature in many of the web applications we use regularly. The number of…

medium.com

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https://www.youtube.com/results?search_query=DEBUG+AJAX+ASYNC

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Asynchronous JavaScript Tutorial

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Web programming with c++

https://www.youtube.com/playlist?list=PLzTP3s658k6_4WmEEwOhm-vOR2_RolHLr

 

[igor_kavinski]

Thanks, ken_g6 and mxnerd. Lots of stuff to read through