wosephjeber

Renaming table in Ecto migration

I recently wanted to rename a model and its postgres table in a Phoenix app. Renaming the table was simple and documented, but the table also had constraints, sequences, and indexes that needed to be updated in order for the Ecto model to be able to rely on default naming conventions. I couldn't find any examples of what this would look like but was eventually able to figure it out. For anyone else in the same situation, hopefully this example helps.

In the example below, I'm renaming the Permission model to Membership. This model belongs to a User and an Account, so it has foreign key constraints that need to be renamed.

defmodule MyApp.Repo.Migrations.RenamePermissionsToMemberships do
  use Ecto.Migration

soheilhy

Virtual Hosts on nginx (CSC309)

When hosting our web applications, we often have one public IP address (i.e., an IP address visible to the outside world) using which we want to host multiple web apps. For example, one may wants to host three different web apps respectively for example1.com, example2.com, and example1.com/images on the same machine using a single IP address.

How can we do that? Well, the good news is Internet browsers

schweigert

I am passionate about Ruby, but its execution time compared to other languages is extremely high, especially when we want to use more complex algorithms. In general, data structures in interpreted languages become incredibly slow compared to compiled languages. Some algorithms such as ´n-body´ and ´fannkuch-redux´ can be up to 30 times slower in Ruby than Go. This is one of the reasons I was interested in embedding Go code in a Ruby environment.

For those who do not know how shared libraries operate, they work in a similar way as DLLs in Windows. However, they have a native code with a direct interface to the C compiler.

Note Windows uses the DLL system, and in this case, this does not necessarily have to be in native code.

One example is DLLs written in C#, which runs on a virtual machine. Because I do not use windows, I ended up not testing if it is poss

jbenet

a simple git branching model (written in 2013)

This is a very simple git workflow. It (and variants) is in use by many people. I settled on it after using it very effectively at Athena. GitHub does something similar; Zach Holman mentioned it in this talk.

Update: Woah, thanks for all the attention. Didn't expect this simple rant to get popular.

elderbas

def create_batch(conn, %{"people" => people_params}) do
  changesets = Enum.map(people_params, fn class ->
    Person.changeset(%Person{}, person)
  end)

  result = changesets
           |> Enum.with_index()
           |> Enum.reduce(Ecto.Multi.new(), fn ({changeset, index}, multi) ->
              Ecto.Multi.insert(multi, Integer.to_string(index), changeset)
           end)

josevalim

# In your test_helper.rb
class ActiveRecord::Base
  mattr_accessor :shared_connection
  @@shared_connection = nil

  def self.connection
    @@shared_connection || retrieve_connection
  end
end

bbonamin

tap "caskroom/cask"

cask "google-chrome"
cask "firefox"

brew "chromedriver"
brew "geckodriver"

ndarville

Business Models

Advertising

Models	Examples
Display ads	Yahoo!
Search ads	Google

ryansobol

Originally published in June 2008

When hiring Ruby on Rails programmers, knowing the right questions to ask during an interview was a real challenge for me at first. In 30 minutes or less, it's difficult to get a solid read on a candidate's skill set without looking at code they've previously written. And in the corporate/enterprise world, I often don't have access to their previous work.

To ensure we hired competent ruby developers at my last job, I created a list of 15 ruby questions -- a ruby measuring stick if you will -- to select the cream of the crop that walked through our doors.

What to expect

Candidates will typically give you a range of responses based on their experience and personality. So it's up to you to decide the correctness of their answer.

aspyct

# Sample implementation of quicksort and mergesort in ruby
# Both algorithm sort in O(n * lg(n)) time
# Quicksort works inplace, where mergesort works in a new array

def quicksort(array, from=0, to=nil)
    if to == nil
        # Sort the whole array, by default
        to = array.count - 1
    end