I am trying to pass a string section to the the python function below it
I am uncertain why I am seeing this error. My understanding of this is that it is not getting a string, where it is expected. I have tried casting, but that is not working either. How can I solve this or get more debug info?
section = str('[log]')
some_var = 'filename ='
edit_ini('./bench_config.ini', section, some_var, 'logs/ops_log_1')
The function causing the error
def edit_ini(filename, section, some_var, value):
section = False
flist = open(filename, 'r').readlines()
f = open(filename+'test', 'w')
for line in flist:
line = str(line)
print line
if line.startswith(section):
section = True
if( section == True ):
if( line.startswith(some_var) ):
modified = "%s = $s", variable, value
print >> f, modified
section = False
else:
print >> f, line
f.close()
However I see the error:
Traceback (most recent call last):
File "bench.py", line 89, in <module>
edit_ini('./config.ini', section, some_var, 'logs/log_1')
File "bench.py", line 68, in edit_ini
if line.startswith(section):
TypeError: expected a character buffer object
You overwrite the passed-in section with section=False. The error is because you cannot call string.startswith( False ).
A way to debug python is to use pdb. This would have helped you find your problem here. You should read the spec, but heres a quick guide on how to use pdb.
import pdb
# your code ...
pdb.set_trace() # put this right before line.startswith(section)
Then when you run your code, you will execute up to right before the failure. Then you can print section in pdb, and see that it is False, and then try to figure out why it is False.
Related
I was trying following python code to simulate 'tail' command of *nix systems.
import sys
def tail(f):
print 'in tail with ',f
f.seek(0,2)
while True:
line = f.readline()
if not line:
time.sleep(0.1)
continue
yield line
if(len(sys.argv) >= 2):
print 'calling tail'
tail(open(sys.argv[1],'r'))
else:
print 'Give file path.\n'
I did an error (missed importing time module). However, what's odd is that no error was getting thrown and program was quitting silently.
Output (before commenting):
$ python tail.py /var/log/dmesg
calling tail
However if I comment lines following the one using the time module, the error does get thrown.
import sys
def tail(f):
print 'in tail with ',f
f.seek(0,2)
while True:
line = f.readline()
if not line:
time.sleep(0.1)
# continue
# yield line
if(len(sys.argv) >= 2):
print 'calling tail'
tail(open(sys.argv[1],'r'))
else:
print 'Give file path.\n'
Output (after commenting)
$ python tail.py /var/log/dmesg
calling tail
in tail with <open file '/var/log/dmesg', mode 'r' at 0x7fc8fcf1e5d0>
Traceback (most recent call last):
File "tail.py", line 14, in <module>
tail(open(sys.argv[1],'r'))
File "tail.py", line 8, in tail
time.sleep(0.1)
NameError: global name 'time' is not defined
Can anyone please explain why the error was not getting thrown in case one (before commenting)? Shouldn't a error be thrown as soon as interpreter comes on that line?
Corrected program:
import sys
import time
def tail(f):
print 'in tail with ',f
f.seek(0,2)
while True:
line = f.readline()
if not line:
time.sleep(0.1)
continue
yield line
if(len(sys.argv) >= 2):
print 'calling tail'
t = tail(open(sys.argv[1],'r'))
for i in t:
print i
else:
print 'Give file path.\n'
Output:
$ python tail.py hello.txt
calling tail
in tail with <open file 'hello.txt', mode 'r' at 0x7fac576b95d0>
hello there 1
hello there 2
hello there 3
Thanks for the responses.
Short Answer
First one is instantiating a generator (but not assigning it to a variable) and second one is a function call.
Long Answer
This is because of dynamic type checking of python, when you have the yield statement, your function behaves as a generator and this line -
tail(open(sys.argv[1],'r'))
means that you are instantiating the generator not calling a function. You'll get that error when you assign this instance to some variable and call the next method for generator which actually fires it up i.e. -
t = tail(open(sys.argv[1],'r')) # t is a generator here
t.next()
The other case in which you removed the yield statement, it started behaving as a normal function which means - tail(open(sys.argv[1],'r')) is a function call now, and hence it threw an error.
What I meant by dynamic is python doesn't check these kind of errors until it reaches that statement, which in first case wasn't.
With yield in the function, it is a generator. Generator functions only execute their contained code when the next value is requested. Simply calling a generator function merely creates that generator object. If you do so without doing anything with that object, such as looping through it, nothing will happen.
Removing the yield makes the function evaluate eagerly, so its code is actually executed.
If you actually iterated over the generator, it would produce an error if/when readline() produced an empty line. Since such an empty line can only occur at the end of a file (what look like blank lines actually contain a single linefeed character), putting it in a loop doesn't make sense anyway. Instead of this:
while True:
line = f.readline()
if not line:
time.sleep(0.1)
continue
yield line
Use this:
for line in f:
yield line
And instead of this:
if(len(sys.argv) >= 2):
print 'calling tail'
tail(open(sys.argv[1],'r'))
You should actually execute the generator's contents, with something like this:
if(len(sys.argv) >= 2):
print 'calling tail'
for line in tail(open(sys.argv[1],'r')):
print line
Hi I tried to generate the genesis file but get this error:
C:\Python34>python mk_genesis_block.py --extradata 0x11bbe8db4e347b4e8c937c1c837
0e4b5ed33adb3db69cbdb7a38e1e50b1b82fa > genesis_block.json
File "mk_genesis_block.py", line 293
print json.dumps(evaluate(), indent=4)
^
SyntaxError: invalid syntax
Edit:
Here is the surrounding lines:
if __name__ == '__main__':
print json.dumps(evaluate(), indent=4)
Then it's EOF. The whole file can be viewed here
Since the offending line seems to be only output, I commented it and got another error:
C:\Python34>python -tt mk_genesis_block.py --extradata 0x11bbe8db4e347b4e8c937c1
c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa > genesis_block.json
Traceback (most recent call last):
File "mk_genesis_block.py", line 124, in <module>
EXTRADATA = (d[2:] if d[:2] == '0x' else d).decode('hex')
AttributeError: 'str' object has no attribute 'decode'
which in conjunction with the other error makes me wonder whether a string instead of a json object is being operated on? Here is the whole arg parsing part:
# Grab the extra data command line argument
if '--extradata' in sys.argv:
d = (sys.argv+[None])[sys.argv.index('--extradata') + 1]
EXTRADATA = (d[2:] if d[:2] == '0x' else d).decode('hex')
else:
EXTRADATA = ''
I also made a test file importing the json package, dumps and decode methods work.
print in python3 is a method not a statement print( "text" ) ... also I believe str.decode was remove in python3 ... instead use codecs.decode(my_str,encoding)
I have been stuck with this error for a couple of hours now. Not sure what is wrong. Below is the piece of code
NameError: global name 'GetText' is not defined
class BaseScreen(object):
def GetTextFromScreen(self, x, y, a, b, noofrows = 0):
count = 0
message = ""
while (count < noofrows):
line = Region(self.screen.x + x, self.screen.y + y + (count * 20), a, b)
message = message + "\n" + line.text()
count += 1
return message
class HomeScreen(BaseScreen):
def GetSearchResults(self):
if self.screen.exists("Noitemsfound.png"):
return 'No Items Found'
else:
return self.GetTextFromScreen(36, 274, 680, 20, 16)
class HomeTests(unittest.TestCase):
def test_001S(self):
Home = HomeScreen()
Home.ResetSearchCriteria()
Home.Search("0009", "Key")
self.assertTrue("0009" in Home.GetSearchResults(), "Key was not returned")
Basescreen class has all the reusable methods applicable across different screens.
Homescreen inherits Basescreen.
In HomeTests test case class, the last step is to Home.GetSearchResults() which in turn calls a base class method and the error.
Note:
I have another screenclass and testcaseclass doing the same which works without issues.
I have checked all the importing statements and is ok
'GetText' in the error message is the name of method initially after which i changed it to GetTextFromScreen
Error message is still pointing to a line 88 in code which is not there any more. Module import/reloading issue?
Try clearing out your *.pyc files (or __pycache__ if using 3+).
You asked:
Error message is still pointing to a line 88 in code which is not there any more. Module import/reloading issue?
Yes. The traceback (error messages) will show the current (newest saved) file, even if you haven't run it yet. You must reload/reimport to get the new file.
The discrepancy comes from the fact that traceback printouts read from the script file (scriptname.py) saved on your drive. However, the program is run either from the module saved in memory, or sometimes from the .pyc file. If you fix an error by changing your script, and save it to your drive, then the same error will still occur if you don't reload it.
If you're running interactively for testing, you can use the reload function:
>>> import mymodule
>>> mymodule.somefunction()
Traceback (most recent call last):
File "mymodule.py", line 3, in somefunction
Here is a broken line
OhNoError: Problem with your file
Now, you fix the error and save mymodule.py, return to your interactive session, but you still get the error, but the traceback shows the fixed line
>>> mymodule.somefunction()
Traceback (most recent call last):
File "mymodule.py", line 3, in somefunction
Here is the fixed line
OhNoError: Problem with your file
So you have to reload the module:
>>> reload(mymodule)
<module 'mymodule' from '/path/to/mymodule.py'>
>>> mymodule.somefunction()
Success!
I'm working with a pice of software written in python from US CERT to do some fuzzing. Included in the software is a minimizer.py tool which is designed to be ran against certain test cases that cause crashes in order to determine exactly which byte mutations are causing the crash.
However when attempting to run the tool it's spitting an error at me. Google searches for both the tool and the error are drawing a blank. Attempting to troubleshoot it myself with limited python experience is not helping either. Any ideas on whats causing the error so I can fix it and get the tool working?
command line options being used are: minimizer.py --stringmode
The error output is as follows:
Traceback (most recent call last):
File "C:\FOE2\tools\minimize.py", line 234, in <module>
main()
File "C:\FOE2\tools\minimize.py", line 183, in main
config = Config(cfg_file).config
File "C:\FOE2\certfuzz\campaign\config\__init__.py", line 76, in __init__
self._set_derived_options()
File "C:\FOE2\certfuzz\campaign\config\foe_config.py", line 93, in _set_derived_options
t = Template(self.config['target']['cmdline_template'])
TypeError: 'NoneType' object has no attribute '__getitem__'
Segments of code from both of the files in last two lines of error are:
__init__.py:
def __init__(self, config_file):
self.file = config_file
self.config = None
self.load()
self._set_derived_options()
self.validations = []
self._add_validations()
self.validate()
def _set_derived_options(self):
pass
And then from foe_config_.py (added the preceding lines of code just in case they are relevant.):
class Config(ConfigBase):
def _add_validations(self):
self.validations.append(self._validate_debugger_timeout_exceeds_runner)
def _set_derived_options(self):
# interpolate program name
# add quotes around $SEEDFILE
t = Template(self.config['target']['cmdline_template'])
#self.config['target']['cmdline_template'] = t.safe_substitute(PROGRAM=self.config['target']['program'])
self.config['target']['cmdline_template'] = t.safe_substitute(PROGRAM=quoted(self.config['target']['program']), SEEDFILE=quoted('$SEEDFILE'))
It's hard to tell from the code you posted, but it looks like __init__ sets self.config to None. Then it calls _set_derived_options which uses self.config here:
t = Template(self.config['target']['cmdline_template'])
But self.config hasn't changed from being None. You wouldn't expect None['target'] to give you anything (other than an Exception), but I think that is essentially what you're doing here.
I'm running python2.5 and trying to use the astLib library to analyse WCS information in astronomical images. I try and get the object instanciated with the following skeleton code:
from astLib import astWCS
w = astWCS.WCS('file.fits') # error here
where file.fits is a string pointing to a valid fits file.
I have tried using the alternate method of passing a pyfits header object and this fails also:
import pyfits
from astLib import astWCS
f = pyfits.open('file.fits')
header = f[0].header
f.close()
w = astWCS.WCS(header, mode='pyfits') # error here also
The error is this:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/home/astro/phrfbf/build/lib/python2.6/site-packages/astLib/astWCS.py", line 79, in __init__
self.updateFromHeader()
File "/home/astro/phrfbf/build/lib/python2.6/site-packages/astLib/astWCS.py", line 119, in updateFromHeader
self.WCSStructure=wcs.wcsinit(cardstring)
File "/home/astro/phrfbf/build/lib/python2.6/site-packages/PyWCSTools/wcs.py", line 70, in wcsinit
return _wcs.wcsinit(*args)
TypeError: in method 'wcsinit', argument 1 of type 'char *'
When I run in ipython, I get the full error here on the pastebin
I know the astWCS module is a wrapped version of WCStools but i'd prefer to use the Python module as the rest of my code is in Python
Can anyone help with this problem?
Just found out the updated version of this library has fixed the problem, thanks for everyone's help
Oh sorry, I should have seen. Looking at the pastebin in more detail, the only error I can think of is that, for some reason the header has unicode in it. It can't be converted to char *, and you get the error. I tried searching for something in the header, but everything looks okay. Can you do this and post the output in another pastebin?
import pyfits
f = pyfits.open('file.fits')
header = f[0].header
f.close()
for x, i in enumerate(header.iteritems()):
if len(str(i[1])) >= 70:
print x, str(i[1])
cardlist = header.ascardlist()
cardstring = ""
for card in cardlist:
cardstring = cardstring + str(card)
print repr(cardstring)
Or, if you can check the header of your fits file for "funny" characters, getting rid of them should solve the issue.