Alfredo Torre sentenza

Bitcoin

On October 31st 2008, the programmer/programmers known as Satoshi Nakamoto published this paper through a metzdowd.com cryptography mailing list that describes the Bitcoin currency and solves the problem of double spending so as to prevent the currency from being copied.

In January of 2009, he started mining, creating what is known as the “genesis block.” Bitcoin v0.1 was released six days later. By year-end, over 32,000 blocks had been added to this original block, producing a total of 1,624,250 bitcoins. Since all transactions are public on the blockchain, we know that only a quarter of those bitcoins have ever changed hands, leading some to speculate that Satoshi could be sitting on a stash of roughly one million bitcoins, worth ~$120 million at today’s exchange rate. Who is Satoshi Nakamoto

Papers

Transfer-encoding: chunked

When the server needs to send large amount of data, chunked encoding is used by the server because it did not exactly know how big (length) the data is going to be. In HTTP terms, when server sends response Content-Length header is omitted by the server. Instead server writes the length of current chunk in hexadecimal format followed by \r\n and then chunk, followed by \r\n (Content begins with chunk size in hex followed by chunk)

This feature can be used for progressive rendering; however the server needs to flush the data as much as possible so that client can render content progressively (in case of html,css etc)

This feature is often used when server pushes data to the client in large amounts - usually in giga bytes.

Source: https://stackoverflow.com/a/45086785/1977778

NetworkManager WiFi Power Saving

NetworkManager supports WiFi powersaving but the function is rather undocumented.

From the source code: wifi.powersave can have the following value:

NM_SETTING_WIRELESS_POWERSAVE_DEFAULT (0): use the default value
NM_SETTING_WIRELESS_POWERSAVE_IGNORE (1): don't touch existing setting
NM_SETTING_WIRELESS_POWERSAVE_DISABLE (2): disable powersave

Before updating to Symfony 3

General fixes

You need to launch this Symfony2 version fixer.

Security context fix

Then you have to change every occurrency of security.context with security.token_storage (see also this SO answer http://stackoverflow.com/a/29672308/1977778). You must update your codebase to match the security component improvements of version 2.6, as described here.

You should use merge operation on entities which are in detached state and you want to put them to managed state.

Merging should be done like this $entity = $em->merge($detachedEntity). After that $entity refers to the fully managed copy returned by the merge operation. Therefore if your $form contains detached entities, you should adjust your code like this:

$doctrineManager = $this->getDoctrine()->getManager();
foreach ($form->getData()->getEntities() as $detachedEntity) {
    $entity = $doctrineManager->merge($detachedEntity);  
    $doctrineManager->remove($entity);
}

$doctrineManager->flush();

What's a Progressive Web App?

Obviously, no install required
It loads quickly, even on flaky networks
Can send push notifications
May have an icon on the home screen (loading as a top-level)
Should support full-screen mode

Key features

Fundamental concepts

JSX: Allows us to write HTML like syntax which gets transpiled to lightweight JavaScript objects, thus being much more concise than pure old JS
Virtual DOM: A JavaScript representation of the actual DOM
React.createClass(): The way in which you create a new component
render(): Each component has to have this method in order to be rendered
ReactDOM.render: Renders a React component to a DOM node.
state: The internal data store (object) of a component. Each component has the ability to manage its own state and pass its state down to child components if needed.

	# Scala Installation
	wget https://downloads.lightbend.com/scala/2.12.2/scala-2.12.2.deb
	sudo dpkg -i scala-2.12.2.deb


	# sbt Installation
	echo "deb https://dl.bintray.com/sbt/debian /" \| sudo tee -a /etc/apt/sources.list.d/sbt.list
	sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 2EE0EA64E40A89B84B2DF73499E82A75642AC823
	sudo apt-get update
	sudo apt-get install sbt

	/** Given a Sequence of Integers Seq(2, 3, 4) - which represents the number 234 base 10 - increments
	* by one without converting types.
	*
	* @param s Seq[Int] The original sequence representation of the number
	* @return The incremented by one Sequence
	*/
	def sequenceIncrement(s: Seq[Int]): Seq[Int] = {
	sequenceIncrementRec(s.reverse, Seq.empty, carry = true).reverse
	}

	#Module dependencies
	# mod_rewrite
	# mod_ssl

	# This section is only needed if you want to redirect http traffic to https.
	# You can live without it but clients will have to type in https:// to reach gitlab.
	<VirtualHost *:80>
	ServerName domain.com
	ServerSignature Off