Architecting a RESTFul C++ api to interface with Python

Question

I have a web-application developed in Python and need to make calls to some underlying C++ code for computationally intensive tasks. I'm currently using the C-api integrated in python, but I want to fundamentally change my solution: I want the C++ code to directly receive HTTP requests from the front end and to do its computation separate of python. I also want to enable the user to ask the C++ code for data with GET requests etc. The C++ interfaces with a Postgres database (if that matters).

I'm wondering if any of you have some technology suggestions or resources to go peruse through?

Community · Accepted Answer · 2017-05-23 12:23:41Z

4

There's a pretty long discussion about this topic here that'll probably leave you unsatisfied. Bottom line is that there's no single best practice for this kind of thing. Choices seem boil down to one of these approaches:

Run your C++ code behind a web server as an apache/ISAPI module or as a FastCGI server.
Run an embedded web server in your C++ process like Libmicrohttpd.
Use a more full-blown C++ web framework like Silicon (very new, looks pretty cool) or pion.

edited May 23, 2017 at 12:23

CommunityBot

11 silver badge

answered Nov 24, 2015 at 2:19

Mark Waterman

9717 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Anisotropic Over a year ago

Silicon looks really interesting. I did not know getting c++ to work with the web would require so much activation energy ;)

Mark Waterman Over a year ago

Yeah, C++ web development is not for the faint of heart. I had a similar project a couple of years ago where I had to expose a C API as a REST service and decided against taking this path--I ended up writing my web logic in Go and used cgo to handle the interop. It was pretty clean because Go was basically designed for this kind of stuff. So, unless you're intent of tackling a big project, I'd just punt and use one of the many straightforward Python REST frameworks out there since you obviously have the Python-to-C++ interop stuff figured out already.

Octopus · Accepted Answer · 2015-11-25 10:18:51Z

For a RESTful API to work, all you really need to do is to have a program that responds to web requests. That can actually be achieved quite easily if you are willing to run basic CGI and you can use Apache's default settings to get you going immediately.

For example the following C program generated the output that follows.

#include <unistd.h>
#include <stdio.h>

extern char **environ;

void main (int argc, char* argv[]) {

    printf("Content-Type: text/html\n\n");

    printf("<html> <head>\n");
    printf("<title>Hello, world!</title>");
    printf("</head>\n");
    printf("<body>\n");
    printf("<h1>Hello, world!</h1>\n");

    printf("<ul>");
    int i = 0;
    while(environ[i]) {
        printf("<li>%s</li>\n", environ[i++]);
    }
    printf("</ul>");

    printf("</body> </html>\n");
}

Then I compiled the code to a file called sample which I put in /var/www/cgi-bin and then I called up http://localhost/cgi-bin/sample?a=100&b=test which produced the following (roughly):

Hello, world!

UNIQUE_ID=VlWFh2o2Wu4o73LCT4efZgAAAAk
HTTP_HOST=192.168.1.12
HTTP_CONNECTION=keep-alive
HTTP_ACCEPT=text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
HTTP_UPGRADE_INSECURE_REQUESTS=1
HTTP_USER_AGENT=Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36
HTTP_ACCEPT_ENCODING=gzip, deflate, sdch
HTTP_ACCEPT_LANGUAGE=en-GB,en-US;q=0.8,en;q=0.6
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
SERVER_SIGNATURE=
SERVER_SOFTWARE=Apache/2.4.6 (CentOS)
SERVER_NAME=192.168.1.12
SERVER_ADDR=192.168.1.12
SERVER_PORT=80
REMOTE_ADDR=192.168.1.100
DOCUMENT_ROOT=/var/www/html
REQUEST_SCHEME=http
CONTEXT_PREFIX=/cgi-bin/
CONTEXT_DOCUMENT_ROOT=/var/www/cgi-bin/
SERVER_ADMIN=root@localhost
SCRIPT_FILENAME=/var/www/cgi-bin/sample
REMOTE_PORT=58551
GATEWAY_INTERFACE=CGI/1.1
SERVER_PROTOCOL=HTTP/1.1
REQUEST_METHOD=GET
QUERY_STRING=a=100&b=test
REQUEST_URI=/cgi-bin/sample?a=100&b=test
SCRIPT_NAME=/cgi-bin/sample

That should at least get you up and going with the nitty-gritty. Then you can worry about tailoring your web config if necessary or preparing the code for a production environment.

Now its just a matter of extending that idea by writing it in C++ and using standard C++ libraries to do whatever you want and to respond to your requests in a RESTful way.

If you do plan on moving it into a production environment in the end then you ought to look into configuring Apache for FastCGI. That's a small project in itself, but it won't change the way you write your C++ code.

Collectives™ on Stack Overflow

Architecting a RESTFul C++ api to interface with Python

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related