Latest Posts

Rails relations

Posted on February 16, 2018 by Peter Andersson

problem You know when you want to select records depending on the values of related records (like belongs_to fields) ? scenario class TradingSignal < ActiveRecord::Base […]

Development, Ruby on Rails

Rails HATM (Has and belongs to many)

Posted on February 12, 2018 by Peter Andersson

Nested forms with HABTM and HasManyThrough Start with the models has_many :events # creates …… accepts_nested_attributes_for :events, :allow_destroy => true # creates…. attr_accessible :events_attributes # […]

Development, Ruby on Rails

Running a script “later”

Posted on February 5, 2018 by Peter Andersson

You know how it is, you need to download a 3GB install kit, but don’t want to disturb the missuz by clogging all the bandwidth. […]

Development, Linux, Network, Ruby on Rails

Hitta exponentialfunktion från två punkter

Posted on January 26, 2018 by Peter Andersson

Exempel 1 : Hitta den exponentialfunktion som går genom punkterna (1, 2) och (3, 5) Hitta basen a som kvoten mellan y2 och y1 a […]

Development, Math, Tankar

Docker – dealing with images

Posted on January 14, 2018 by Peter Andersson

I keep this blog item handy: Docker – Clean Up After Yourself! It talks about how to maintain and clean up the “leftovers” from running […]

Docker

Developing Rails apps using Docker

Posted on January 1, 2018 by Peter Andersson

This article assumes that you have docker, docker-compose and docker-machine installed. For OSX use Docker Toolbox at docker.com/toolbox. For Linux install docker and docker-compose using […]

Docker

Swedish VPS providers

Posted on January 1, 2018 by Peter Andersson

Huvudsakligen från https://sulo.se/2011/02/24/svenska-vps-leverantorer-en-prisjamforelse/ https://www.fsdata.se/server/vps http://www.glesys.se/vps.php https://www.oderland.se/tjanster/cloudvps/ http://www.patrikweb.net/content/section/24/51/ http://www.ipeer.se/linux-vps.php https://www.crystone.se/vps http://www.surftown.se/vps/priser http://www.space2u.com/vps.php http://www.itstaden.se/Serverdrift/Virtuell+Server.html Virtuell Privat Server http://www.internetverket.se/premium-vps Molntjänster http://www.adminor.net/vps http://www.securehosting.se/index.php/virtual-servers http://foretag.netit.se/?page_id=564 http://acon.se/tjanster/virtuell-server/ https://www.dalnix.se/tjanster/

Docker, Heroku, Network

Heroku

Posted on January 1, 2018 by Peter Andersson

Heroku Rails Receipes Running a migration heroku run rake db:migrate Clearing a PG database on heroku heroku pg:reset DATABASE WARNING: Destructive action postgresql-flexible-10203 will lose […]

Development, Heroku, Ruby on Rails

CSS and SASS in Rails

Posted on January 1, 2018 by Peter Andersson

A good article about organising CSS/SASS in Rails http://www.mattboldt.com/organizing-css-and-sass-rails/ Basically you have this in yourapp/assets/stylesheets/application.css /* NOTE: Not Application.scss */ /* *= require_self *= require […]

Development, HTML and CSS, Ruby on Rails

Redefining Rails Models: Going Beyond Rails and Sometimes, Beyond Tables

Posted on January 1, 2018 by Peter Andersson

Harnessing ActiveRecord Outside Rails ActiveRecord, the model component of Rails, is well-known for its versatility. It can be used within Rails, of course, but did […]

Development, Ruby on Rails

CSS Tips

Posted on December 27, 2017 by Peter Andersson

To center an image, use margin: auto; and make it into a block element: img { display: block; margin: auto; width: 40%; } Highlight alla länkar som inte länkar nånstans! a[href=”#”], a[href=””], a:not([href]) […]

Development, HTML and CSS

Rails Templates

Posted on December 27, 2017 by Peter Andersson

Just use them! Save a bunch of time when startiung a new project. Here’s my latest fav: Rails 5.1 with Bootstrap, Font Awesome and Devise. […]

Development, Ruby on Rails

Java Dates and Periods

Posted on December 6, 2017 by Peter Andersson

Period and Duration are not just alternatives, they work very different. Duration is designed to work in exact measurements in seconds and nanoseconds. However, Period […]

Development, Java

Rails Console tips

Posted on November 16, 2017 by Peter Andersson

Sometimes you want to test queries etc from the Rails Console that requiers you to be logged in (for example via Devise). This is how […]

Development, Ruby on Rails

Rails Resources

Posted on October 12, 2017 by Peter Andersson

Gems you NEED 12 gems every rails developer should know 2016 7 must have gems to install on any project 8 useful ruby on rails […]

Ruby on Rails

The problem with Rails Asset Pipeline that I always stumble upon

Posted on August 13, 2017 by Peter Andersson

You know how it is, you develop using Rails and it is going great! Tailwind and downhill, you develop with an amazing speed. Then when […]

Ruby on Rails

Rails and Devise – Login using either username or email

Posted on August 7, 2017 by Peter Andersson

This is essentially a no-nonsense step-by-step description of the most common case from: https://github.com/plataformatec/devise/wiki/How-To:-Allow-users-to-sign-in-using-their-username-or-email-address 1) add a field to the User table rails generate migration […]

Ruby on Rails

Javascript in 2017

Posted on August 6, 2017 by Peter Andersson

The JS environment is, as we know, “complicated”. Every browser uses a different JavaScript engine: Chrome runs V8, Firefox runs SpiderMonkey, and Internet Explorer uses […]

Javascript

Moving the MySQL data directory

Posted on June 5, 2017 by Peter Andersson

Has this happened to you? You run for a while on the default installation of MySQL. The data increases and suddenly you realize that the […]

MySQL

How to setup a Raspberry Pi as a NAS using Samba

Posted on April 29, 2017 by Peter Andersson

http://www.simonthepiman.com/how_to_setup_windows_file_server.php

Linux, Network, Raspberry Pi, Samba

Capistrano!

Posted on April 27, 2017 by Peter Andersson

How to deploy a Rails 4 app with Git and Capistrano

Ruby on Rails

Calculating Historical Volatility

Posted on April 27, 2017 by Peter Andersson

Historical Volatility shows how volatile an asset has been. There are numerous ways of calculating it, and I will show the most simple one here. […]

Development, Trading

The Builder Pattern

Posted on April 23, 2017 by Peter Andersson

Reasoning I won’t even go into why you should learn patterns. Patterns are canned knowledge! A problem the Builder Pattern solve It helps you avoid […]

Development, Java, Patterns

Adding Stripe Payments to your Rails application

Posted on March 30, 2017 by Peter Andersson

If you need to process payments, for example charging the user for using your great new website, Stripe is a great contender. An alternative is […]

Development, Ruby on Rails

Setting up 1000 Devise user accounts using fixtures

Posted on March 24, 2017 by Peter Andersson

Seting up a one Devise user (version 3.5.1 and later) is simple in file <app>/test/fixtures/users.yml: tom: id: 11 name: TestUser email: test@example.org encrypted_password: <%= Devise::Encryptor.digest(User, ‘password’) […]

Development, Ruby on Rails

IOS App that scrolls both vertically and horizontally

Posted on March 18, 2017 by Peter Andersson

Great example on how you create a “Netflix-lookalike” app with scrolling in bort vertical and horizontal direction. https://github.com/ThornTechPublic/HorizontalScrollingCollectionView

Development, IOS, XCode

Test and Maximize network thruput

Posted on March 18, 2017 by Peter Andersson

I had to transfer lots (LOTS) of video files from my IMAC where I had catptured a bunch of older DV tapes. Since space ran […]

Linux, Network, OSX

A workflow to sort pictures and movies by date captured (EXIF data)

Posted on March 14, 2017 by Peter Andersson

I have lots and lots of home made movies, mostly in the form of DV-tapes and SD-cards. (This workflow also works for photos and other […]

Imaging, Linux, OSX, Photo, Video

Hibernate and Java annotations

Posted on March 1, 2017 by Peter Andersson

So….. I wanted to use something as neat and powerful as Rails’ ActiveRecord. I had used hibernate a bit a long time ago, and frankly […]

Development, Java

The Lazy Investor

Posted on February 18, 2017 by Peter Andersson

I have started a new project. Since I do a fair share of investing, both in futures and stocks, I have tried several different ways […]

Java, Ruby on Rails, Trading

CheatSheet for creating an XCode IOS app with a UITableView

Posted on May 13, 2016 by Peter Andersson

Setup Create a standard ViewController (NOT a TableViewController!) Drag a Table onto the ViewController. Snap to edges, Reset to “Suggested Constraints”. Option Cmd Shift = […]

Development, IOS, XCode

Javascript-länkar att lägga till samlingen

Posted on April 24, 2016 by Peter Andersson

Om ‘use strict’: http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more/ Modular Javascript/CommonJS: https://addyosmani.com/writing-modular-js/ Babel: Code for ES6 and still be backwards compatible with older browsers: https://babeljs.io JSX In depth: http://facebook.github.io/react/docs/jsx-in-depth.html

Development, Javascript

Facebook React Native

Posted on April 13, 2016 by Peter Andersson

Det finns flera ramverk som ger möjlighet att skriva appar i Javascript, och sedan kompilera dem för den målmiljö man är intresserad av (oftast iOS […]

Development, Javascript, React

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