Author Archives: Yuji Tomita

This is just an error thrown if you try to give pickle.loads() a random object.

I think this fact should be way closer to the top of google results for this error.

I had just mistaken some variable names and didn’t realize my object could possibly not be the base64 string it was supposed to be : )

Our wifi has two broadcast modes.. 5ghz and 2ghz.

If I’m on the 2ghz network, I get 10-20% packet loss and huge 500ms-2000ms latency.

I switched to the 5ghz network and I’m not having these issues. I’m not looking into this issue any further, but if you happen to be on a dual band router experiencing sudden network sluggishness on OSX Lion, try another wifi signal.

Searching this is somehow not very productive. It’s bordering on impossibility.

If you’re wondering where exactly an apt-get package installed the source / relevant source files into your system, you sometimes need to use dpkg -L to list all files associated with a package.

I’ve done some ugly greps in the past across a huge portion of the filesystem – not a pretty sight.

First try the whereis command, the locate command, and which command if you know an executable from your package.

If you’re just looking for the source though it’s often difficult.

Use dpkg to find apt-get installed source files

Use dpkg -l to list all packages installed by apt-get. Grep it to find your package name.

Use dpkg -L my_package_name to find all source files. A quick glance and you’ll see where your lost code is : )

$> dpkg -l | grep my_package # find the package name
$> dpkg -L my_package_name

I’ve always dealt with line wrapping problems on OSX and my terminal. Specifically, iPython. I finally looked for a solution, and the problem was not having python readline installed.

My iPython looked like this:

After a simple google search, a user named minrk on github pointed out that iPython actually complains about “leopard libedit detected”, meaning iPython could not find the readline module.

Yes, a better message is in order….

Anyways, sudo easy_install readline and you’re done.

sudo easy_install readline

Magic.

I needed to install libcurl4-gnutls-dev before proceeding with installing the braintree python client library.

apt-get install libcurl4-gnutls-dev
pip install braintree

Somehow my git broke over night (computer has not even reset) causing this cryptic error.
After digging, I noticed that my project directory is now owned by root

All I got was “aborting” as a message when I tried to pull in changes from remote. It didn’t even give a hint as to what was wrong.

When I tried to check out, I got a better error message: “could not detach head”.
Google searches lead me to believe it’s a permission issue.

I look around and notice that ls -l shows my git folder owned by root.

sudo chown -R me my_project

Done!

AJAX, django signals, and class based view awesomeness.

I’ve started using a combination of class based views and signals that is very powerful and extensible.

A personalized class based view base class

I’ve set up a BaseView class in my project which inherits from django.views.generic.base.View that sets sensible defaults for my AJAX classes.

For example, I have an AJAXBaseView class which defines four attributes: errors, messages, data, and success. It also has a response_data property that formats the data in a specific way for my JavaScript.

This setup ensures I use the same format for my ajax responses across my project.

    class AJAXBaseView(View):
    	def __init__(self, *args, **kwargs):
    		super(BaseView, self).__init__(*args, **kwargs)
		
    		# set sensible default class instance attributes.
    		self.errors = []
    		self.messages = []
    		self.data = {}
    		self.success = False

		
    	@property
    	def response_data(self):
    		"""
    		Format response data
    		"""
    		return {
    			'success': self.success,
    			'errors': self.errors,
    			'data': self.data,
    			'messages': self.messages,
    		}
    		
    
    class MyAJAXView(AJAXBaseView):
        def get(self, request):
            some_signal.send(sender=MyAJAXView, instance=self) 
            # modifies instance.errors/messages
            
            return http.HttpResponse(json.dumps(self.response_data))
            

It also works great with signals since I always pass the view class to the signal. The signal can directly modify the instance error/message/data attributes, and the view will automatically format the data to our ajax format.

Access to the request object in class based view initialization

I was looking for a good place for the equivalent of __init__ with access to the request object that I could override. I found it in the dispatch method.

Since I generally don’t override it, it’s a great and DRY place for some base class code.

class CartBaseView(BaseView):
	def get_cart_from_request(self, request):
        # magically get cart
        return magic_cart
        
        
	def dispatch(self, request, *args, **kwargs):
		self.cart = self.get_cart_from_request(request)
		return super(CartBaseView, self).dispatch(request, *args, **kwargs)
		
		
class ViewCartView(CartBaseView):
    def get(self, request):
        print self.cart
        # sweet!
        
        
    def post(self, request):
        print self.cart

Class based views are extremely powerful and I’m loving them.

This was driving me mad – permission denied as root.

My problem was that the “env” folder was not a real virtualenv but a plain old empty directory.

As soon as I deleted the environment I was trying to PIP install to, pip correctly setup a new virtualenv and the permissions problems disappeared.

Sound has been a royal pain to get working on this machine.

OSX 10.6 Snow Leopard and 10.7 lion both have problems.

This one died on me with my last software update.

The key is to use multibeast and to make sure you enable only the exact hardware in the Non-DSDT HDA Enabler and to remove all Voodoo kexts and HDA enablers in your extensions.

My card is a 887, so I selected 887/888b

If you have ANY others selected, your sound will break and the machine will falsely identify your card as a 892 or some such.