Request.SetPostData() and GetPostData don't work. All strings are expected to be byte strings.

[stanfea]

Can't seem to get SetPostData() to work, should accept a list or a dict:

>> from cefpython3 import cefpython
>>> req = cefpython.Request.CreateRequest()
>>> req.SetPostData([])
Segmentation fault (core dumped)

Python 2.7.11+
cefpython 31.2-1

[cztomczak]

You are setting an empty data. Does the error occur also when setting non-empty data or when not calling SetPostData at all?

[stanfea]

I've tried with a dict {'key': 'value'} and with a list ["--data=1"]. It only seg faults when calling SetPostData.
At the moment I'm trying to rebuild cefpython from source to debug.

[cztomczak]

You can get stacktrace using gdb, no need to build from source to do that. See:
https://github.com/cztomczak/cefpython/wiki/InternalDevelopment#debug-cef-stack-trace

[cztomczak]

Here is the source code for SetPostData:
https://github.com/cztomczak/cefpython/blob/cefpython31/cefpython/request_cef3.pyx#L113

[stanfea]

The cef stacktrace isn't very useful:

Thread 1 "python2.7" received signal SIGSEGV, Segmentation fault.
__pyx_f_14cefpython_py27_9PyRequest_SetPostData (__pyx_v_self=<optimized out>, 
    __pyx_v_pyPostData=[], __pyx_skip_dispatch=<optimized out>)
    at cefpython.cpp:43604
43604   cefpython.cpp: No such file or directory.
(gdb) bt
#0  __pyx_f_14cefpython_py27_9PyRequest_SetPostData (
    __pyx_v_self=<optimized out>, __pyx_v_pyPostData=[], 
    __pyx_skip_dispatch=<optimized out>) at cefpython.cpp:43604
#1  0x00007fffe6531a30 in __pyx_pf_14cefpython_py27_9PyRequest_10SetPostData (
    __pyx_v_pyPostData=<optimized out>, __pyx_v_self=<optimized out>)
    at cefpython.cpp:43968
#2  __pyx_pw_14cefpython_py27_9PyRequest_11SetPostData (
    __pyx_v_self=<optimized out>, __pyx_v_pyPostData=<optimized out>)
    at cefpython.cpp:43946
#3  0x00000000004ca77e in call_function (oparg=<optimized out>, 
    pp_stack=0x7fffffffd690) at ../Python/ceval.c:4338
#4  PyEval_EvalFrameEx () at ../Python/ceval.c:2987
#5  0x00000000004ca39f in fast_function (nk=<optimized out>, 
    na=<optimized out>, n=<optimized out>, pp_stack=0x7fffffffd7e0, 
    func=<function at remote 0x7fffe4939668>) at ../Python/ceval.c:4435
#6  call_function (oparg=<optimized out>, pp_stack=0x7fffffffd7e0)
    at ../Python/ceval.c:4370
#7  PyEval_EvalFrameEx () at ../Python/ceval.c:2987
#8  0x00000000004ca39f in fast_function (nk=<optimized out>, 
    na=<optimized out>, n=<optimized out>, pp_stack=0x7fffffffd930, 
    func=<function at remote 0x7fffe49396e0>) at ../Python/ceval.c:4435
#9  call_function (oparg=<optimized out>, pp_stack=0x7fffffffd930)
    at ../Python/ceval.c:4370
---Type <return> to continue, or q <return> to quit---
#10 PyEval_EvalFrameEx () at ../Python/ceval.c:2987
#11 0x00000000004c2e05 in PyEval_EvalCodeEx () at ../Python/ceval.c:3582
#12 0x00000000004c2ba9 in PyEval_EvalCode (co=<optimized out>, 
    globals=<optimized out>, locals=<optimized out>) at ../Python/ceval.c:669
#13 0x00000000004f20ef in run_mod.lto_priv () at ../Python/pythonrun.c:1376
#14 0x00000000004eca72 in PyRun_FileExFlags () at ../Python/pythonrun.c:1362
#15 0x00000000004eb1f1 in PyRun_SimpleFileExFlags ()
    at ../Python/pythonrun.c:948
#16 0x000000000049e18a in Py_Main () at ../Modules/main.c:640
#17 0x00007ffff7811830 in __libc_start_main (main=0x49daf0 <main>, argc=3, 
    argv=0x7fffffffdd78, init=<optimized out>, fini=<optimized out>, 
    rtld_fini=<optimized out>, stack_end=0x7fffffffdd68)
    at ../csu/libc-start.c:291
#18 0x000000000049da19 in _start ()

Still trying to get cython debugging working.

But is the issue reproduceable on your end?

[cztomczak]

The stacktrace at least says something useful - the error is in the cefpython code. It fails on this line:

postData.get().RemoveElements()

https://github.com/cztomczak/cefpython/blob/cefpython31/cefpython/request_cef3.pyx#L116

I looked at upstream CEF code and postdata is set to NULL when it's empty, meaning that postData.get() may return NULL. Thus you can't call RemoveElements() on it.

Looks like these functions (GetPostData, SetPostData) were never really tested.

This code also fails:

req.SetMethod("POST")
req.GetPostData()

Fails on this line:

if postData.get().GetElementCount() == 0:
            return {}

https://github.com/cztomczak/cefpython/blob/cefpython31/cefpython/request_cef3.pyx#L69

Similarly, postData.get() returns NULL, thus segmentation fault when calling GetElementCount().

Fix: always check postData.get() for non-NULL value before calling a method on it.

[cztomczak]

Already fixed in my local repo, will commit today. Pasting test code which passes OK x6 after fixes:

from cefpython3 import cefpython as cef

print("Test 1")
req = cef.Request.CreateRequest()
req.SetMethod("POST")
req.SetPostData([])
print("OK")

print("Test 2")
req = cef.Request.CreateRequest()
req.SetMethod("POST")
req.SetPostData(["--key=value"])
print("OK")

print("Test 3")
req = cef.Request.CreateRequest()
req.SetMethod("POST")
req.SetPostData({"key":"value"})
req.GetPostData()
print("OK")

print("Test 4")
req = cef.Request.CreateRequest()
req.SetMethod("POST")
req.GetPostData()
print("OK")

print("Test 5")
req = cef.Request.CreateRequest()
req.SetPostData(["--key=value"])
print("OK")

print("Test 6")
req = cef.Request.CreateRequest()
req.GetPostData()
print("OK")

[cztomczak]

Fixed in bfc0a25. v55.2 released. Please test.

[cztomczak]

This issue seems to be still unresolved. req.GetPostData returns an empty dict. Code:

print("Test postdata")
req = cef.Request.CreateRequest()
req.SetMethod("POST")
req.SetPostData({"key":"value"})
print(req.GetPostData())

Reported on the Forum:
https://groups.google.com/d/topic/cefpython/KtFsudPlFHE/discussion

[ritu1337]

Tested on v57.0, v55.3 and v55.2.
Also doesn't work from within the RequestHandler.

[cztomczak]

The code in question is here:

1. https://github.com/cztomczak/cefpython/blob/master/src/request.pyx#L65
2. https://github.com/cztomczak/cefpython/blob/master/src/request.pyx#L117

If someone can analyze the code and find the bug that would be helpful.

[sonya75]

You are missing this line at the end of SetPostData function:-
self.GetCefRequest().get().SetPostData(postData)

[cztomczak]

@sonya75 Thanks Sonya, that was it!

Fixed in revision 82ed469.

This time tested properly. Code:

from cefpython3 import cefpython as cef

print("Test 1")
req = cef.Request.CreateRequest()
req.SetMethod("POST")
req.SetPostData(["--key=value"])
print(req.GetPostData())

print("Test 2")
req = cef.Request.CreateRequest()
req.SetMethod("POST")
req.SetPostData({"key":"value"})
print(req.GetPostData())

Output:

Test 1
['--key=value']
Test 2
{'key': 'value'}

The fix was applied to master branch and will be available in the next release (schedule not yet known). If you want this applied now, then apply the fix from the commit above to the "cefpython57" branch and follow the quick instructions from the docs/Build-instructions.md document to build the cefpython module from sources by using prebuilt CEF binaries from GitHub. With these quick instructions building cefpython takes about 10 minutes.

[cztomczak]

Further fixes for Python 3 in rev 4c5cf09.