nileshtrivedi

Raspberry Pi on Internet via reverse SSH tunnel

HackerNews discussed this with many alternative solutions: https://news.ycombinator.com/item?id=24893615

I already have my own domain name: mydomain.com. I wanted to be able to run some webapps on my Raspberry Pi 4B running perpetually at home in headless mode (just needs 5W power and wireless internet). I wanted to be able to access these apps from public Internet. Dynamic DNS wasn't an option because my ISP blocks all incoming traffic. ngrok would work but the free plan is too restrictive.

I bought a cheap 2GB RAM, 20GB disk VM + a 25GB volume on Hetzner for about 4 EUR/month. Hetzner gave me a static IP for it. I haven't purchased a floating IP yet.

darconeous

Tesla Key Card Protocol

Researched by Robert Quattlebaum darco@deepdarc.com.

Last updated 2020-02-03.

oscherler

jsondiff: diff JSON in Git using gron

gron is an incredible tool that makes JSON greppable. But it also makes it diffable, which is great if you have JSON files in Git.

To use gron to diff JSON in Git, save the json-diff script below and make it executable. Then add a difftool as shown in gitconfig, and optionally create an alias to invoke it more easily. Then try it:

git init
echo '{"foo":42,"bar":"hello"}' > foo.json
git add foo.json && git commit -m 'Initial commit.'

marcan

#!/usr/bin/python3
#
# Simple Bloom filter implementation in Python 3
# Copyright 2017 Hector Martin "marcan" <marcan@marcan.st>
# Licensed under the terms of the MIT license
#
# Written to be used with the Have I been pwned? password list:
#   https://haveibeenpwned.com/passwords
#
# Download the pre-computed filter here (968MB, k=11, false positive p=0.0005):

ptarjan

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.

arapat

from pyspark import SparkContext
from pyspark.accumulators import AccumulatorParam

# Spark only implements Accumulator parameter for numeric types.
# This class extends Accumulator support to the string type.
class StringAccumulatorParam(AccumulatorParam):
    def zero(self, value):
        return value
    def addInPlace(self, val1, val2):
        return val1 + val2

spaze

2023 update

ℹ️ Please note this research is from 2016 when Opera has first added their browser "VPN", even before the "Chinese deal" was closed. They have since introduced some real VPN apps but this below is not about them.

🕵️ Some folks also like to use this article to show a proof that the Opera browser is a spyware or that Opera sells all your data to 3rd parties or something like that. This article here doesn't say anything like that.

---

When setting up (that's immediately when user enables it in settings) Opera VPN sends few API requests to https://api.surfeasy.com to obtain credentials and proxy IPs, see below, also see The Oprah Proxy.

The browser then talks to a proxy de0.opera-proxy.net (when VPN location is set to Germany), it's IP address can only be resolved from within Opera when VPN is on, it's 185.108.219.42 (or similar, see below). It's an HTTP/S proxy which requires auth.

barneygale

import sys, marshal, functools, subprocess

child_script = """
import marshal, sys, types;
fn, args, kwargs = marshal.load(sys.stdin)
marshal.dump(
    types.FunctionType(fn, globals())(*args, **kwargs),
    sys.stdout)
"""

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

jbinto

/* global ReactRedux, Redux, ReactDOM */

// "Getting Started with Redux" (by Dan Abramov)
// https://egghead.io/series/getting-started-with-redux

// This file on JSBin (by Jesse Buchanan):
// http://jsbin.com/wuwezo/74/edit?js,console,output

////////////////////////////////////////////////
//