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from functools import wraps

class exception_guard(object):
    """Guard against the given exception and raise a different exception."""

    def __init__(self, catchable, throwable=RuntimeError):
        if is_exception_class(catchable):
            self._catchable = catchable
        else:
            raise TypeError('catchable must be one or more exception types')

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OpenSSL Playground

Certificates

Print Certificate ( crt file )

openssl x509 -in stackexchangecom.crt -text -noout

Print Certificate ( pem file )

openssl x509 -in cert.pem -text -noout

Print Certificate ( cer file )

openssl x509 -inform der -in foobar.cer -noout -text

Read part of Certificate

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Ubuntu 16 – how to increase maximum file open limit ( ulimit -n )

If you are setting up nginx,chances are you will discover your worker_connections is at some low number, such as 1024. You can’t increase this number unless you increase kernel limit as well. First of all run cat /proc/sys/fs/file-max to discover your maximum limit.

abc@ubuntu:~$ cat /proc/sys/fs/file-max
1048576
abc@ubuntu:~$ ulimit -n
1024

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Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

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CREATE OR REPLACE FUNCTION pseudo_encrypt(VALUE bigint) returns bigint AS $$
DECLARE
l1 bigint;
l2 bigint;
r1 bigint;
r2 bigint;
i int:=0;
BEGIN
    l1:= (VALUE >> 32) & 4294967295::bigint;
    r1:= VALUE & 4294967295;

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from itertools import islice, chain

def batches_from_iterable(iterable, size):
    # Iterate over an iterable producing iterables of batches. Based on:
    # http://code.activestate.com/recipes/303279-getting-items-in-batches/
    iterator = iter(iterable)
    while True:
        try:        # Try get the first element in the iterator...
            head = (next(iterator),)
        except StopIteration:

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#define _GNU_SOURCE
#include <errno.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>

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#!/usr/bin/env bash

# abort if we get any error
set -e

_tag=$1
_branch="$(git rev-parse --abbrev-ref HEAD)"

if [ "${_tag}" == "" ]; then
    echo "Missing version param. ex './tag_release.sh v5.1.1'"

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A non-exhaustive list of WebGL frameworks and libraries. It is mostly for learning purposes as some of the libraries listed are outdated/not maintained anymore.

Engines and libraries

• three.js: JavaScript 3D library
• stack.gl: an open software ecosystem for WebGL, built on top of browserify and npm.
• PixiJS: Super fast HTML 5 2D rendering engine that uses webGL with canvas fallback
• Pex: Pex is a javascript 3d library / engine allowing for seamless development between Plask and WebGL in the browser.
• Babylon.js: a complete JavaScript framework for building 3D games with HTML 5 and WebGL
• Filament: Filament is a real-time physically based rendering engine for Android, iOS, Windows, Linux, macOS and WASM/WebGL
• ClayGL: A WebGL graphic library helping you to

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/* global createImageBitmap */

function loadImageWithImageTag(src) {
    return new Promise((resolve, reject) => {
        const img = new Image;
        img.crossOrigin = '';
        img.src = src;
        img.onload = () => { resolve(img); };
        img.onerror = () => { reject(img); };
    });