Saturday, March 25, 2017

Visual Studio 2017 Xamarin stuck if you didn't install the SDK and NDK

I ran into this bug when I was upgrading from Visual Studio 2015 to 2017. I included the Xamarin option But I didn't include the Android SDK and NDK. I removed them from the install list. I did this because I already have both installed.

The "hang" occurs then you try opening the Xamarin in the Options window. Visual Studio will stop working here so you can't set the paths for Xamarin.

So I went digging through the Xamarin logs in the AppData folder. I know where the log folder is from a previous issue with Xamarin. Xamarin is a good idea but it's buggy as fuck. So navigate to %USERPROFILE%\AppData\Local\Xamarin\Logs\15.0\ folder and see which is the latest log and open it with your favorite text editor.

Once we confirm, if it's really the missing SDK and NDK paths, we then have to add them to Window's Registry.
  1. Open regedit
  2. Navigate to Computer\HKEY_CURRENT_USER\SOFTWARE\Xamarin\VisualStudio\15.0\Android
  3. Right-click and add new String Values
    • AndroidNdkDirectory - set it to the full path to where you install the NDK 
    • AndroidSdkDirectory - set it to the full path to where you install the SDK
  4. Close and restart the computer
And we should have fixed the issue.




Monday, March 6, 2017

Dealing with SSL HandShake failure with Python Requests (_ssl.c:590)

I was working with Requests trying to talk to a REST api when I encountered this SSL HandShake error. It was fairly easy to replicate because it happens every time I tried talking to a HTTPS endpoint or resource. It didn't matter if it was a GET or POST action. I suspect it'd be the same for other actions like PATCH or DELETE.

So what's the fix? Uninstall-install then maybe an update or upgrade.
  1. I updated Python to 2.7.11. You might not need to do this if your up-to-date. 
  2. I uninstalled requests. - $ pip uninstall requests
  3. I uninstalled urllib3. - $ pip uninstall urllib3
  4. Installed crypto dependencies or libs. This is where it gets hairy.

    First I had to update my machine's openSSL library. This could range from easy to hair pulling hard. Thankfully, I had brew on my machine so it was relatively easy.

    Anyhow you'll want to see this from the terminal after the update.

    $ openssl version
    OpenSSL 0.9.8zh 14 Jan 2016
    

    After you'll need to run this command:

    $ pip install pyopenssl ndg-httpsclient pyasn1
    

     This installs the rest of the crypto dependencies.
  5. I installed urllib3 back. - $ pip install urllib3
    I also installed urllib3[secure]. - $ pip install urllib3[secure]
    You might not need the secure version but I covering all the bases.
  6.  Install requests back. - $ pip install requests
    Same deal with urllib3, you might also want to install request with security.

    $ pip install request[security]
Why this works? I suspect that there's an installation-time check for either urllib3 (or requests) for the crypto stuff that keeps things from working without the uninstall-reinstall.





Tuesday, January 24, 2017

Doing query param request in Django

Typically, I want my API endpoint url to be flat like this:

mydomain.com/shit_api/v1/person/123

That url is pretty straight forward, it's trying to get a person with an ID of 123 from shit_api. But that's not always clear cut.

I've been working on a particular API that needed a pair of optional filters that we're a pain to work out in a regular expression. And this is where I found about Django's QueryDict object. With it I can write out API urls with params:

mydomain.com/shit_api/v1/something/?filter1=value1&filter2=value2

And on the urls and views, I can handle it as such:

#urls.py
urlpatterns = [
   url(r'^parts/$', SomethingView.as_view()), name='Something'),
]
...

#views.py
class SomethingView(View):
   def get(self, request, *args, *kwargs):
      fiter1_value = request.GET.get('filter1', 'default')
      fiter2_value = request.GET.get('filter2', 'default')

      #do more here

      return Response('some response')

The thing here is that request.GET.get() method having a default value. This make it that having it on the URL it isn't a problem. So call like:

mydomain.com/shit_api/v1/something/

Will still work.

Bonus since I don't have to deal with a convoluted regular expression. Yehey!