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/*
  Usage:
  var jsoncheck = require('./wantsJSON') // path to file with this middleware function
  app.use(jsoncheck)
  
  app.get('/', function(req,res,next){
    if (req.wantsJSON) {
      // serve JSON
    }
    if (req.wantsHTML) {

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# Example Dockerfile
FROM hello-world

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# Convert the .cer file into a .pem file:
$ openssl x509 -in aps_development.cer -inform der -out PushChatCert.pem

# Convert the private key’s .p12 file into a .pem file:
$ openssl pkcs12 -nocerts -in PushChatKey.p12 -out PushChatKey.pem

# Finally, combine the certificate and key into a single .pem file
$ cat PushChatCert.pem PushChatKey.pem > ck.pem

# At this point it’s a good idea to test whether the certificate works.

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Develop locally with Elasticsearch on OSX using Docker

Docker

Docker does not run natively on OSX, only Linux. Docker Machine was created to add a Linux VM environment to run Docker containers on OSX. Install using Homebrew:

brew install docker
brew install docker-machine
docker-machine create

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Deep Dive: PostgreSQL on AWS

When loading data

• disable backups (backup_retention=0)
• disable multi-AZ and autovacuum
• pg_dump -Fc (compressed) and pg_restore -j (parallel)
• Increase maintenance_work_mem

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func staticInsideFunction() {
    struct Temp { static var hasAnimated = false }
    if Temp.hasAnimated == false {
        // ... do something only on the first function call.
        Temp.hasAnimated = true
    } else {
        // ... do something on all subsequent function calls.
    }
}

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# Mixin to (i.e. include in) any worker class that does FB API calls and should be throttled.
module FacebookThrottle

  def perform_throttled(*args, &block)
    options = args.extract_options!
    user = User.find_by_fb_uid(options[:fb_uid])
    if user
      if !user.valid_facebook_token? # A bitwise flag managed by flag_shih_tzu gem
        puts "Skipping #{self.class} #{user.fb_uid}: Invalid Oauth Token for #{user}"
        return false

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Resources for Machine Learning in Ruby

Gems

• liblinear-ruby: Ruby interface to LIBLINEAR using SWIG

• classifier-reborn: Bayesian and LSI classification
  dependencies: GSL

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#import <UIKit/UIKit.h>
#import <ImageIO/ImageIO.h>
#import <MobileCoreServices/MobileCoreServices.h>

static UIImage *frameImage(CGSize size, CGFloat radians) {
    UIGraphicsBeginImageContextWithOptions(size, YES, 1); {
        [[UIColor whiteColor] setFill];
        UIRectFill(CGRectInfinite);
        CGContextRef gc = UIGraphicsGetCurrentContext();
        CGContextTranslateCTM(gc, size.width / 2, size.height / 2);

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# RSpec's subject method, both implicitly and explicitly set, is useful for
# declaratively setting up the context of the object under test. If you provide a
# class for your describe block, subject will implicitly be set to a new instance
# of this class (with no arguments passed to the constructor). If you want
# something more complex done, such as setting arguments, you can use the
# explicit subject setter, which takes a block.
describe Person do
  context "born 19 years ago" do
    subject { Person.new(:birthdate => 19.years.ago }
    it { should be_eligible_to_vote }