I have a python web application and I would like to run multiple scripts from it. Scripts are written in various languages, like bash, lua, perl, c++, ruby, etc. The thing is that I would like to first parse the script to replace the predefined building blocks with actual numbers. So for example, let's say I have the following bash script:
#!/bin/bash
ping -c 3 {{ip}}
Then I would like to pass that script into a wrapper with all the variables the script will need - in this case just the ip variable. The wrapper should replace all the variables with actual values, so if we inputed the ip variable as a value = 10.1.1.1, then the script should become:
#!/bin/bash
ping -c 3 10.1.1.1
And I want this functionality for all of the programming languages. So I'm using python, which should in turn use some kind of wrapper that accepts a script + arguments, and outputs corresponding output script.
I've found swig already, but don't know if it does what I want, so suggestions are greatly appreciated.
Thank you
It sounds like you want m4, which would handle this easily for all scripting languages. C++, being a compiled language, would be a totally different undertaking, but I'll assume you didn't really mean that.
There are multiple free m4 implementations; it's already going to be on every Linux box.
You definitely don't want SWIG, it does something completely different.
I would design the scripts to take command line arguments, read a common configuration file, or read environment variables, instead of trying to modify the internals of the scripts.
Are you really going to have your Python web application modify the C++ code, recompile it, and then run it? Something about that seems wrong to me. It would probably be slow.
Related
I have a simple C API (N simple functions). I want to wrap it into C#, Java and Python at the same time. How to call SWIG to create wrapper for multiple languages at the same time?
Something like this
swig.exe -c++ -csharp -java -namespace Bla outdir ./ -o ./BlaAPIWrapper.cxx BlaAPI.i
results in swig application crush
Assertion failed: !this_, file Modules/lang.cxx, line 332
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
Works fine for each language sepratly.
Just call it multiple times with different parameters, one for Java, one for C# etc..
You probably need some shell script to automate that, but once you create the script that generates the wrapper just call the script.
That's probably the easiest solution if swig don't allow multiple languages at one go, or if that feature is present but bugged (or if it is present but undocumented and you were not able to use it because missing important information).
I want to embed Python 3.x in our C++ application to allow scripting of maintenance and other tasks. It so far does everything we need including file manipulation.
The problem is that to meet some specifications (like PCI), we aren't allowed to arbitrarily run shell commands such as with subprocess.call or popen.
Is there a way to prevent and similar calls from working in embedded Python?
One option is to remove all the modules that allow running arbitrary shell commands, i.e.: subprocess.py*, os.py*... and include only the modules that the end users are allowed to have immediate access to.
Unless your application is really locked down I don't think you can prevent someone from loading their own python module from an arbitrary directory (with import) so I don't think you can prevent execution of arbitrary code as long as you have python embedded.
I'm working on a project simulating a stock market. People buy and sell a stock and I would like to call each turn a script to try a strategy against the market.
What I want is a function in C++ which send an vector of integer as argument to a vba or python script which return an array of 3 integers.
I've searched for a solution but all i could find is a way to execute a script in python, but I don't know how I can send and get an argument from this script.
I think my problem is common but i don't know where to head to find a solution.
Thank you!
(I'm not a native english speaker so sorry if I made grammar error)
On windows you use the function CreateProcess() to start another program. Use the full path of the python interpreter as the first argument. Start the second argument with the path to the python script.
If you can fit a string representing your vector in 32768 characters, you can supply the vector in the second argument to CreateProcess.
A more flexible option is create a child process with redirected in- and output, as shown here. You can then write the vector to the standard input of the python process and read the answer back from its standard output.
There are many ways to do this.
The way I would do it is to popen() your "script" [which would be something like "python myscript.py -arg1 -arg2"]. Depending on how large your vector is, you could either store it in a file or pass it as part of the arguments [there is a limit in Windows of something like 8KB for the argument string].
The output would then appear as the result from popen()'s pipe.
Use Boost.Python. It will help you to embed python in your app.
I want to experiment a bit with C++ as a server side language. I'm not looking for a framework, and simply want to achieve a silly old "Hello World" webapp using C++.
Is there an Apache HTTP server module that I can install?
If i can do the PHP equivalent of :
<?php
$personName = "Peter Pan";
echo "Hello " . $personName;
I'd be most thrilled! Thanks in advance!
cgi would do this. Just have your C++ app spit its output to stdout and your mod_cgi will handle it
You might want to have a look at http://www.webtoolkit.eu/wt or www.tntnet.org instead.
"mod_c++" doesn't make sense; Once you're talking about compiled programs, Apache doesn't care what language the binary comes from. mod_cgi allows Apache to invoke such a binary (regardless of it's source language) in response to HTTP requests. Read more here:
http://library.thinkquest.org/16728/content/cgi/cplusplus.html
Suppose for the moment the OP wanted something that was "like mod_php, mod_perl". Given the right configuration, it would be monumentally easy for the "mod_c++" to look at the source files, and compiled files and decide whether it had to do a "one off" compilation task. In fact this is how make works.
I know the OP probably didn't mean that it had to be "interpreted", but it's certainly not impossible to allow apache to compile cpp files on the fly if needed [this is how jsp works, btw].
I did create a mod_cpp once. It basically was written in c, but loaded a .so which was in turn written in C++.
Its performance was really good, but lacked a lot of things that we take for granted in things like PHP (sessions, HTML un/escaping, etc). It did use a template engine to separate the HTML from the C++.
I tell you, the initial set-up was a lot of work (the mod_cpp part); after that, it was kinda easy to write the .so's. I even tried to create an sf.net project to open-source it, but I never got around to actually porting it :-(
In summary: I did not find anything like that on the net, did it myself and found out to be a lot more work then I anticipated, but the result was very cool! This helped me a lot: Apache Modules
I'm not saying there is no such thing, but if there is it would be monumentally inefficient. C++ is a compiled language, not an interpretive one, so the putative Apache C++ module would have to invoke the C++ compiler to compile the code before executing it. This would be very, very slow, apart from other problems.
How do you pass options to an executable? Is there an easier way than making the options boolean arguments?
EDIT: The last two answers have suggested using arguments. I know I can code a workable solution like that, but I'd rather have them be options.
EDIT2: Per requests for clarification, I'll use this simple example:
It's fairly easy to handle arguments because they automatically get parsed into an array.
./printfile file.txt 1000
If I want to know what the name of the file the user wants to print, I access it via argv[1].
Now about how this situation:
./printfile file.txt 1000 --nolinebreaks
The user wants to print the file with no line breaks. This is not required for the program to be able to run (as the filename and number of lines to print are), but the user has the option of using if if s/he would like. Now I could do this using:
./printfile file.txt 1000 true
The usage prompt would inform the user that the third argument is used to determine whether to print the file with line breaks or not. However, this seems rather clumsy.
Command-line arguments is the way to go. You may want to consider using Boost.ProgramOptions to simplify this task.
You seem to think that there is some fundamental difference between "options" that start with "--" and "arguments" that don't. The only difference is in how you parse them.
It might be worth your time to look at GNU's getopt()/getopt_long() option parser. It supports passing arguments with options such as --number-of-line-breaks 47.
I use two methods for passing information:
1/ The use of command line arguments, which are made easier to handle with specific libraries such as getargs.
2/ As environment variables, using getenv.
Pax has the right idea here.
If you need more thorough two-way communication, open the process with pipes and send stuff to stdin/listen on stdout.
You can also use Window's PostMessage() function. This is very handy if the executable you want to send the options to is already running. I can post some example code if you are interested in this technique.
The question isn't blazingly clear as to the context and just what you are trying to do - you mean running an executable from within a C++ program? There are several standard C library functions with names like execl(), execv(), execve(), ... that take the options as strings or pointer to an array of strings. There's also system() which takes a string containing whatever you'd be typing at a bash prompt, options and all.
I like the popt library. It is C, but works fine from C++ as well.
It doesn't appear to be cross-platform though. I found that out when I had to hack out my own API-compatible version of it for a Windows port of some Linux software.
You can put options in a .ini file and use the GetPrivateProfileXXX API's to create a class that can read the type of program options you're looking for from the .ini.
You can also create an interactive shell for your app to change certain settings real-time.
EDIT:
From your edits, can't you just parse each option looking for special keywords associated with that option that are "optional"?