Barkin Simsek woswos

Useful PostgreSQL Queries & Commands

All sizes in MB, change /1024/1024 to /1024/1024/1024 for GB.

Databases sizes

Without system databases

select
datname as database,
(pg_database_size(datname)/1024/1024) as size

Steam Client on APFS Case Sensitive Mac OS Drive

If you are using APFS Case Sensitive File system and trying to use Steam, it will flicker & silently fail or show the following error message:

steam requires that '~/library/application support/steam/steam.appbundle/steam/contents/macos' be on a case-insensitive filesystem.

To fix the issue, follow the instruction here.

Run from your user account, NOT ROOT!

WiFi AP+STA:

painlessMesh: https://gitlab.com/painlessMesh/painlessMesh
easyMesh: https://github.com/Coopdis/easyMesh
ESP-Mesh: https://www.espressif.com/en/products/software/esp-mesh/overview
ESP8266 WiFi Mesh: https://github.com/esp8266/Arduino/tree/master/libraries/ESP8266WiFiMesh

ESP-Now:

ESP-Now BATMAN: http://games.workshy.co.uk/search/label/ESP-Now https://www.youtube.com/watch?v=vp-HlMjX07k

The problem

In some cases, it is possible that PostgreSQL tables get corrupted. This can happen in case of hardware failures (e.g. hard disk drives with write-back cache enabled, RAID controllers with faulty/worn out battery backup, etc.), as clearly reported in this wiki page. Furthermore, it can happen in case of incorrect setup, as well.

One of the symptoms of such corruptions is the following message:

ERROR: missing chunk number 0 for toast value 123456 in pg_toast_45678

This almost surely indicates that a corrupted chunk is present within a table file. But there is a good way to get rid of it.

Python docstring reStructuredText style

Python Signatures

Signatures of functions, methods and class constructors can be given like they would be written in Python.

	// Tracking cursor position in real-time without JavaScript
	// Demo: https://twitter.com/davywtf/status/1124146339259002881

	package main

	import (
	"fmt"
	"net/http"
	"strings"
	)

	"""
	Given a dictionary, transform it to a string. Then byte encode that string. Then base64 encode it and since this will go
	on a url, use the urlsafe version. Then decode the byte string so that it can be else where.
	"""
	data = base64.urlsafe_b64encode(json.dumps({'a': 123}).encode()).decode()

	# And the decode is just as simple...
	data = json.loads(base64.urlsafe_b64decode(query_param.encode()).decode())
	# Byte encode the string, base64 decode that, then byte decode, finally transform it to a dictionary

	import serial
	from serial.tools import miniterm
	import subprocess, sys, re, os

	class ESPMiniterm(miniterm.Miniterm):
	def handle_menu_key(self, c):
	if c == '\x15': # ctrl-u
	self.upload_file()
	else:
	super(ESPMiniterm, self).handle_menu_key(c)

	"""A program that encodes and decodes hidden messages in images through LSB steganography"""
	from PIL import Image, ImageFont, ImageDraw
	import textwrap

	def decode_image(file_location="images/encoded_sample.png"):
	"""Decodes the hidden message in an image

	file_location: the location of the image file to decode. By default is the provided encoded image in the images folder
	"""
	encoded_image = Image.open(file_location)