Ervin Hegedüs, 26.04.2011 11:48:
Hello Python users,
I'm working on a Python module in C - that's a cryptographic module,
which uses a 3rd-party lib from a provider (a bank).
This module will encrypt and decrypt the messages for the provider web service.
Here is a part of source:
static PyObject*
mycrypt_encrypt(PyObject *self, PyObject *args)
{
int cRes = 0;
int OutLen = 0;
char * url;
char * path;
if (!PyArg_ParseTuple(args, "ss",&url,&path)) {
Use the "s#" format instead to get the length as well.
return NULL;
}
OutLen = strlen(url)*4;
outdata=calloc(OutLen, sizeof(char));
if (!outdata) {
handle_err(UER_NOMEM);
I assume this raises MemoryError?
return NULL;
}
cRes = ekiEncodeUrl (url, strlen(url)+1, outdata,&OutLen, 1, path);
if (cRes == 0) {
return Py_BuildValue("s", outdata);
You are leaking the memory allocated for outdata here.
And, again, use the "s#" format.
} else {
handle_err(cRes);
return NULL;
}
I assume this raises an appropriate exception?
return Py_None;
This is unreachable code.
where ekiEncodeUrl is in a 3rd-party library.
I should call this function from Python like this:
import mycrypt
message = "PID=IEB0001&MSGT=10&TRID=000000012345678"
crypted = mycrypt(mymessage, "/path/to/key");
Everything works fine, but sorry for the recurrent question: where
should I use the Py_INCREF()/Py_DECREF() in code above?
These two functions are not your problem here.
In any case, I recommend using Cython instead of plain C. It keeps you from
getting distracted too much by reference counting and other CPython C-API
details, so that you can think more about the functionality you want to
implement.
Stefan
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