What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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Node.js project for reading temperatures from DHT11 – DHT22 and send it to an MQTT Broker via Raspberry Pi – link

Create a budget Temperature and Humidity Wireless monitor with Raspberry Pi and DHT sensors.

Each sensor, if using Pi Zero W and DHT22, costs about 35€

The linked project is a Node.js wrapper that can be added to the Raspberry crontab and:

– reads the temperature from the attached sensor
– sends it to an MQTT broker

Then, you can read the temperature from your central Home Assistant

In the next days I’ll write a detailed post about the complete project, that consists of a central hub (Raspberry Pi + Home Assistant) and many Raspberry Pi Zero W as sensors for the rooms.

Stay tuned for the detailed post in few days

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An example of response time and server costs optimization – link and link

I’m sure that you know Troy Hunt. And if you don’t…he is the creator of https://haveibeenpwned.com , a database containing over 500 million passwords from previous data breaches in big companies like LinkedIn, Adobe etc…

He recently added a free-to-use and free-to-integrate API for searching if a password is in the pwned database, sending only the first 5 digits of the SHA-1 hash of the password, with a simple call like this

https://api.pwnedpasswords.com/range/21BD1

This can be integrated in every password form (web, application) and suggest users if their password is in the pwned database.

But we are not here to talk about the service 🙂 but how it scaled a lot and why it is so fast.

Click on the first link for a very interesting article about how he optimized performances (calls below 50ms) of the hosting.

In the second link, you can find another very interesting article that focus on the costs, and how it’s possible to spend LESS THAN 1$/month to run a service that receives more than 140 million hits per month.

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Analyze disk usage on Unix with ncdu – link

Linux o MacOS without free space? Do you want to find quickly that folder with a bunch of .old|.bak|.wtf files that you haven’t touched in the last 10 years?

#Linux
apt-get install ncdu 

#Mac
brew install ncdu

From Wikipedia:

ncdu (NCurses Disk Usage) is a disk utility for Unix systems. Its name refers to its similar purpose to the du utility, but ncdu uses a text-based user interface under the [n]curses programming library.[1] Users can navigate the list using the arrow keys and delete files that are taking up too much space by pressing the ‘d’ key. Version 1.09 and later can export the file listing in JSON format.

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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What is Branch Prediction – link

An impressive explanation of what is branch prediction and how knowing it could help us to write more efficient code. Read the whole question and the accepted answer, it’s worth it

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Distributed JWT Token Cracker – link

A tool written in Javascript by Luciano Mammino (more info in the link), for cracking JWT Token via bruteforce. This tool is distributed, it means that you can publish a server (take track of the job) and as many client as you want, to increase the cpu power.

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How to fix npm broken dependencies – link

You are using a fantastic npm dependency but…there is a bug. And you can’t modify the source in the node_modules because at every npm install/update you lose your modifications? Don’t worry, this tool will save your life (personally, I prefer to fork and update the dependency directly on Github…but “de gustibus”)

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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Linux quick tips & commands for performance monitoring

Here is my list of commands that I use to understand why a Linux machine is hanging, running slow or having unexpected behavior

Process analysis, load average, wa, cpu/ram used, disk usage
top
htop
iotop

Process tree, uninterruptible sleep process (D)
ps auxf –> D state processes are in uninterruptible sleep
ps axl –> under the WCHAN column you can see on which kernel function uninterruptible sleep processes are stuck

Stats over time
vmstat 1
iostat 1

Network
netstat
ss -l (network queue length)

Tracing
lsof
strace -e trace=open <application> <— trace an application
strace -e trace=open -p <pid> <— trace a pid

 

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Ultra fast http server for local file sharing

python -m http.server 7777

warning: this command shares the content of the current directory via the choosen port (in this case 7777) to the WHOLE WORLD. Use carefully and remember to close it when you have finished

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Bash parameter expansion in depth – link

An useful article that explains in depth how parameter expansion works in bash

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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Quickstart with Elasticsearch – link

I always wanted to try Elasticsearch but the time is never enough. I found this 5 minutes tutorial that is a good start point.

One quicker variant is to use the elasticsearch docker image to do all the tests. At this link you will find how, shortly:

docker pull docker.elastic.co/elasticsearch/elasticsearch:5.4.1

docker run -p 9200:9200 -e "http.host=0.0.0.0" -e "transport.host=127.0.0.1" docker.elastic.co/elasticsearch/elasticsearch:5.4.1

Another thing to do, in all the example curl commands of the provided links you must add the authentication. For example, the command

curl -XPUT 'http://localhost:9200/blog/user/dilbert' -d '{ "name" : "Dilbert Brown" }'

must be changed in

curl --user elastic:changeme -XPUT 'http://localhost:9200/blog/user/dilbert' -d '{ "name" : "Dilbert Brown" }'

adding –user elastic:changeme (default user-password of the Elasticsearch docker image).
Enjoy

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Chain of Responsibility Pattern – link

and why is different from the Decorator Pattern: link and link

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Comment one line programmatically with sed

Quick tip: suppose we have this line in /etc/php5/cgi/php.ini file

disable_functions = pcntl_alarm,pcntl_fork

if we want to comment this line programmatically, simply do

sed -e '/disable_functions/ s/^;*/;/' -i /etc/php5/cgi/php.ini

 

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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JQ, an useful tool for handling JSON – link and link

JQ is a very useful command line tool for handling JSON.
It permits you to extract parts of a JSON using a simple syntax.

Look at this example

If you want to take the Title and the Acronym (and change their name):

curl 'https://www.lombax.it/documents/json.json' | jq '.glossary | {MyTitle: .title, MyAcronym: .GlossDiv.GlossList.GlossEntry.Acronym}'

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Explore utf8mb4 performance in the new MySQL 8.0 (not yet released) – link

MySQL 8.0 is in the last phases of the development process and it brings a lot of new features. One of this is an huge increase in performances even using the news utf8mb4 encoding.

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HTTPS on StackOverflow – link

Implementing HTTPS on a website may seem simple and straightforward. But what happens when you manage the world biggest Q&A site with hundreds of domains?
Enjoy this (long but good) post by Nick Craver

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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Inspect and inject HTTP/HTTPS requests with mitmproxy – link

Mitmproxy is an useful tool for web developers. It permits to inspect web requests (https requests to) acting as a middleware between your browser and the final url. Yes, modern browser inspectors gives us the inspection functionalities without installing anything, but mitmproxy permits you to block/pause the requests and inject/change the content manually. You can add filters on specific words/patterns in the request (url, cookies and so on), and then mitmproxy will block the request and wait for your input. Then, you will be able to change the request content. This is useful expecially when debugging complex request/response flows: you will be able to do all the flow via browser, and then add a “breakpoint” only when needed. Cool

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Cloud Computing comes at a price – link

Short story of a startup that forgot that “pay per use” is not always as cheap as it seems…expecially if you don’t make correct planning

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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Cars and satellite insurance, how to do it (wrong) – link

Andrea Scarpino tell us how he discovered a big security issue in the API provided by his insurance company. With a little bit of reverse engineering on the satellite device provided by the company, he was able to retrieve all the personal informations of all the insurance customers.

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Interactice shell scripts with expect command – link

Everyone have tried, at least once, to automate a task writing a simple bash script.
However, how to handle a prompt (for example a password prompt?).

`expect` is a simple program that, with an easy-to-learn syntax permits you to write scripts that expect for a specific prompt before sending something back

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MySQL multiple keys and indexes, did you know? by Enomis-

Let’s assume that we have this simple table with an huge quantity of data:

CREATE TABLE test (
id INT NOT NULL,
last_name CHAR(30) NOT NULL,
first_name CHAR(30) NOT NULL,
PRIMARY KEY (id),
INDEX name (last_name,first_name)
);

as you can see, we have an index on last_name, first_name

Now, try to query it:

select * from test where first_name=’Fabio’ and last_name=’Lombardo’; // time: 0.5sec

select * from test where last_name=’Lombardo’ and first_name=’Fabio’; // time: 0.01sec

Why this difference?
In MySQL, multiple indexes must be queried in the exact order they have been declared.

More informations:

– Multiple-Column Indexes
– Avoiding Full Table Scans
– Index Hints

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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Check the technology behind a website. Is it WordPress? Is it Joomla? – link

Do you want to know what technology power up a website? Tired of inspecting html and headers for clues? Is it WordPress? Is it Joomla? Don’t worry, simply paste the URL in the provided link and enjoy the results

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ES6 Overview In 350 Bullet Points – link

A quick and easy recap of all the new features and syntax changes of ES6

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Testing code that emits output and native functions in PHP – link

You know (and if you don’t, you should!!! :-), the scope of TDD is to test pieces of software to avoid that it breaks when you change something. It’s very useful because you can simply “run tests” and be sure (if you wrote and structured them correctly) that your changes didn’t affect anything. However, writing good tests is not as simple as it seems, and TDD have various type of tests (for example Unit Tests, Integration Tests, Behavior Tests and so on).

In this link we focus on Unit Tests. In Unit Tests, the difficult part is to decouple things and test all classes as separate, independent entities and test them against their interfaces. You test that, when the contract is respected (when you call their method with the correct dependencies), the class behaves as expected.

To create a successfull Unit Test, it’s very important to test objects only against their interfaces and to mock (see Mockery for php, for example) all their dependencies. With mocks, you create fake dependencies (objects) and check the correct sending/receiving on messages by/to the tested class. You focus mainly on the “communication” between the tested object and the rest of the world. With mocks, you can test a single object without having to integrate all the things together (for example, you can test a query builder without having to use a real database during the test phase).

However, when it comes to native php functions, it seems difficult to create mocked functions and objects. With this guide, you will learn some useful trick and Php language features that will help you in the building of your Unit Tests.

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

What is this? Every day I read a lot of articles about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

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Monitor your AWS CloudTrail events with Slack and GorillaStack – link

Although it is based on a commercial product, at the provided link you can find a free Slack Bot that will monitor all your AWS CloudTrail events and alert you when something happen. Personally,  I added some triggers to increase the security of our AWS Account: I get an alert when a user login to the AWS Console, when an AWS EC2 Instance is created, rebooted or terminated. It is very easy to install: after adding it to slack, a Cloudformation template that creates everything will be provided, basically an IAM Role, an S3 Bucket, a Lambda function and all the needed CloudTrail configurations are created automatically with a simple step-by-step procedure.

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Expose your local development website over a public URL – link

So, you have created a brand new website and you want to show to your customer. But you haven’t yet deployed it to the hosting provider, it’s only available on your local machine via http://localhost. No worries, with ngrok you will be able to share it immediately, via a public URL, writing a simple command. No need to setup a VPN, and event supporting SSL.

Simply install it, write this in your terminal

ngrok http 80

and your site will be publicly available on an URL similar to this: http://xyza335.ngrok.io

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What is CQRS? – link and link

Martin Fowler gives us a brief explanation of what is CQRS and its benefits. By splitting the model in two parts (one dedicated to the **query** and the other dedicated to the **command** part) structured applications with complex domains can have huge benefits. But be aware that all comes to a price…don’t over engineer 🙂

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That’s all for today’s LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂

Hello there! With this post I want to inaugurate a new section of this blog: LombaXMonday!
One of the things that my wife complains about me is the fact that I don’t read books. However, it doesn’t mean that I don’t read. I’m an avid reader of news of all kinds regarding technology, programming and IT.
Every day I read a lot of links about computer programming and languages, infrastructures, new technologies, quick tips, trends, architectures and so on. I read them immediately or put in my “read later” list. All my readings helped me to grow and learn new things…so why don’t share them with my readers? For this reason, I decided to publish and share, every monday, a list of the links I came accross during the past days.

Ok, now that I explained why, let’s begin with the first LombaXMonday

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A roadmap to becoming a web developer in 2017 – link

This article suggests a learning path to become a web developer in 2017. It differentiates between frontend, backend and devops. Despite its content can be debatable, you can give it a look even if you are an experienced web developer, so you can evaluate if you lacks of some nice-to-have skills and start learning again.

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Composition over Inheritance – link

Ok, many of you knows, I don’t like Javascript and the frontend in general 🙂
However, I think that the concepts explained in this video are useful also for backend developers and can be easily ported to the PHP ecosystem. Learn how to create your objects using Composition and avoid the headaches of the classic Inheritance.

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The art of command line (Italian) – link

Do you think to be a master of the command line? Do you think that Bash has no secrets for you? You are wrong. For sure. Did you know the ctrl-r shortcut? And ctrl-w?
Spend a little time studying the linked article and learn how to master – REALLY – the command line. You will never stop to use these new tips.
Note: The article is in Italian

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That’s all for the first LombaXMonday, if you liked it, have any question or want to let me know that this article sucks, don’t hesitate to add a comment 🙂