I found a handy tool for making a websocket right on your shell.
It is websocketd : http://websocketd.com/

Its phisolophy is so simple :

Just read incoming text from stdin and write outgoing text to stdout. Messaging is simple.

Read its docs, I follow the ez tutorial 10 second tutorial and see how cool does it work.
Let make something cool with this, we got a UNIX tool that print out to stdout in real-time with changes of end file.

Ok cool, change the command to

websocketd --port=8080 tail -f logs/web_access.log

Tada ! Open the webpage that listens the websocket you made and see the magic :D You can tracking access log of website or system in real-time way.

Docker is the fast and clean way to run Linux programs.

We can run a PHP project via PHP built-in server and Docker.

docker run -it -p 8080:8080 -v `pwd`:/code php:7 php -S 0.0.0.0:8080 -t /code/web /code/web/server.php

With server.php content is

<?php

$filename = __DIR__.preg_replace('#(\?.*)$#', '', $_SERVER['REQUEST_URI']);
if (php_sapi_name() === 'cli-server' && is_file($filename)) {
    return false;

}

// Run application below
$app = new Application();
$app->run();

When you have a object x and assign y = x, y will be a ref of x (it looks like pointer of C). So changing property of y means changing property of x.

Ex :

x = {"a": 1, "b": 2}
y = x
y['a'] = 100
print x['a'] # Result is 100

So if you want clone the value, use copy lib :

import copy
x = {"a": 1, "b": 2}
y = copy.deepcopy(x)
y['a'] = 100
print x['a'] # Result is 1

Can upload an file via FTP by curl tool with handy script :

curl -T file_need_to_upload ftp://hostname --user user:passwd

To create the n-to-m relationship in Eloquent, we create a table stand between 2 tables.
Eg:

We have the db schema :

In the model Post and Tag, we define a relation :

• App\Model\Post.php

public function tags() {
    return $this->belongsToMany('App\Model\Tag', 'post_tag', 'post_id', 'tag_id');
}

• App\Model\Tag.php

public function posts() {
    return $this->belongsToMany('App\Model\Post', 'post_tag', 'tag_id', 'post_id');
}

After that, we can use the relation to fetch the related data, like

$post = Post::firstOrFail(1);
$tags = $post->tags; // return the Collections class contains tags

or

$tag = Tag::where('name', '=', 'php')->first();
$posts_of_tag = $tag->posts; // return the Collections class contains posts

When updating or creating post, we have to sync with tags by

$tag_ids = [2, 3 ,4]; // Get tag ids from tag names
$post->tags()->sync($tag_ids);

unicode_thing = u"Xin chào mọi người"
a = '{}'.format(unicode_thing)

will cause the error UnicodeEncodeError: 'ascii' codec can't encode character u'\xe0' in position 6: ordinal not in range(128)

The solution is add u prefix the pattern (it means using unicode pattern) :

unicode_thing = u"Xin chào mọi người"
a = u'{}'.format(unicode_thing)

Reality, if using function on indexed field, you will broke indexing by accident.
Eg:

WHERE MONTH(`date`) = 11 AND YEAR(`date`) = 2015

Solution is transform the query to comparison query, like this :

WHERE `date` >= '2015-11-01' AND `date` < '2015-12-01'

• Open the preference of any Application by Cmd + ,.
• Press Cmd + ~ to go previous App when switching App on Cmd + Tab
• Copy screenshot to clipboard by Cmd + Ctl + Shift + 3
• Press Option when click to notification center is putting it on “Do no disturb” mode.

• To open directly the Console Dev Tools, press Cmd + Opt + J in MacOSX.
• To debug easily the any files of extension, open the url chrome-extension://<extension-id>/<file-name> in address bar.