Tutorial by Examples: l

Produce a patch-compatible diff

Sometimes you just need a diff to apply using patch. The regular git --diff does not work. Try this instead: git diff --no-prefix > some_file.patch Then somewhere else you can reverse it: patch -p0 < some_file.patch

Git • Git Diff

Building your own modules

You can also reference an object to publicly export and continuously append methods to that object: const auth = module.exports = {} const config = require('../config') const request = require('request') auth.email = function (data, callback) { // Authenticate with an email address } au...

Node.js • Exporting and Consuming Modules

Handling Exception In Node.Js

Node.js has 3 basic ways to handle exceptions/errors: try-catch block error as the first argument to a callback emit an error event using eventEmitter try-catch is used to catch the exceptions thrown from the synchronous code execution. If the caller (or the caller's caller, ...) used try/ca...

Node.js • Exception handling

Completely uninstall Node.js on Mac OSX

In Terminal on your Mac operating system, enter the following 2 commands: lsbom -f -l -s -pf /var/db/receipts/org.nodejs.pkg.bom | while read f; do sudo rm /usr/local/${f}; done sudo rm -rf /usr/local/lib/node /usr/local/lib/node_modules /var/db/receipts/org.nodejs.*

Node.js • Uninstalling Node.js

Install nvm on Mac OSX

INSTALLATION PROCESS You can install Node Version Manager using git, curl or wget. You run these commands in Terminal on Mac OSX. curl example: curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.3/install.sh | bash wget example: wget -qO- https://raw.githubusercontent.com/creatio...

Node.js • nvm - Node Version Manager

Perfectly aligned buttons inside cards with flexbox

It's a regular pattern in design these days to vertically align call to actions inside its containing cards like this: This can be achieved using a special trick with flexbox HTML <div class="cards"> <div class="card"> <p>Lorem ipsum Magna proident ...

CSS • Flexible Box Layout (Flexbox)

Hello world program

This is a shell session showing how to create a "Hello world" program and run it with Cargo: $ cargo new hello --bin $ cd hello $ cargo run Compiling hello v0.1.0 (file:///home/rust/hello) Running `target/debug/hello` Hello, world! After doing this, you can edit the progra...

Rust • Cargo

Log for a range of lines within a file

$ git log -L 1,20:index.html commit 6a57fde739de66293231f6204cbd8b2feca3a869 Author: John Doe <[email protected]> Date: Tue Mar 22 16:33:42 2016 -0500 commit message diff --git a/index.html b/index.html --- a/index.html +++ b/index.html @@ -1,17 +1,20 @@ <!DOCTYPE HTML> ...

Git • Browsing the history

Validate IP Addresses

Validates a value is a valid IP address var_dump(filter_var('185.158.24.24', FILTER_VALIDATE_IP)); var_dump(filter_var('2001:0db8:0a0b:12f0:0000:0000:0000:0001', FILTER_VALIDATE_IP)); var_dump(filter_var('192.168.0.1', FILTER_VALIDATE_IP)); var_dump(filter_var('127.0.0.1', FILTER_VALIDATE_IP)); ...

PHP • Filters & Filter Functions

Taking a screenshot and video (for kitkat only) from a device display

Screen shot: Option 1 (pure adb) The shell adb command allows us to execute commands using a device's built-in shell. The screencap shell command captures the content currently visible on a device and saves it into a given image file, e.g. /sdcard/screen.png: adb shell screencap /sdcard/screen.png...

Android • ADB (Android Debug Bridge)

Recording the display

4.4 Recording the display of devices running Android 4.4 (API level 19) and higher: adb shell screenrecord [options] <filename> adb shell screenrecord /sdcard/demo.mp4 (press Ctrl-C to stop recording) Download the file from the device: adb pull /sdcard/demo.mp4 Note: Stop the scre...

Android • adb shell

Absolute/Relative Imports

In Python 3, PEP 404 changes the way imports work from Python 2. Implicit relative imports are no longer allowed in packages and from ... import * imports are only allowed in module level code. To achieve Python 3 behavior in Python 2: the absolute imports feature can be enabled with from __futu...

Python Language • Incompatibilities moving from Python 2 to Python 3

Implementation using RuntimeInitializeOnLoadMethodAttribute

Since Unity 5.2.5 it's possible to use RuntimeInitializeOnLoadMethodAttribute to execute initialization logic bypassing MonoBehaviour order of execution. It provides a way to create more clean and robust implementation: using UnityEngine; sealed class GameDirector : MonoBehaviour { // Beca...

unity3d • Singletons in Unity

Forbid null values

To forbid null values in your table columns, add the :null parameter to your migration, like this: class AddPriceToProducts < ActiveRecord::Migration def change add_column :products, :float, null: false end end

Ruby on Rails • ActiveRecord Migrations

Russian Doll Caching

You may want to nest cached fragments inside other cached fragments. This is called Russian doll caching. The advantage of Russian doll caching is that if a single product is updated, all the other inner fragments can be reused when regenerating the outer fragment. As explained in the previous sec...

Ruby on Rails • Caching

SQL Caching

Query caching is a Rails feature that caches the result set returned by each query. If Rails encounters the same query again for that request, it will use the cached result set as opposed to running the query against the database again. For example: class ProductsController < ApplicationControl...

Ruby on Rails • Caching

Add the google maps javascript tag to the layout header

In order to have google maps work properly with turbolinks, add the javascript tag directly to the layout header rather than including it in a view. # app/views/layouts/my_layout.html.haml !!! %html{:lang => 'en'} %head - # ... = google_maps_api_script_tag The google_maps_api_s...

Ruby on Rails • Using GoogleMaps with Rails

Geocode the model

Suppose, your users and/or groups have profiles and you want to display address profile fields on a google map. # app/models/profile_fields/address.rb class ProfileFields::Address < ProfileFields::Base # Attributes: # label, e.g. "Work address" # value, e.g. "Willy-Bran...

Ruby on Rails • Using GoogleMaps with Rails

Show addresses on a google map in the profile view

On the profile view, show the profile fields of a user or group in a list as well as the address fields on a google map. - # app/views/profiles/show.html.haml %h1 Contact Information .profile_fields = render @profile_fields .google_map{data: address_fields: @address_fields.to_json } The ap...

Ruby on Rails • Using GoogleMaps with Rails

Initialize the map using a coffee script class.

Provided an App.GoogleMap coffee script class, the google map can be initialized like this: # app/assets/javascripts/google_maps.js.coffee # ... class App.GoogleMap map_div: {} map: {} constructor: (map_div)-> @map_div = map_div @init_map() @reference_the_map_as_dat...

Ruby on Rails • Using GoogleMaps with Rails