Genzer

About programms

• Death to the Dialog Box
• Defending Perpetual Intermediacy
• Are your exceptions silent?
• Teaching Users to Read
• You'll Never Have Enough Cheese
• Gold Plating
• Happy Talk Must Die
• The Broken Window Theory

Genzer

Time-based nonce

This is a simple time-based nonce that you can used in various situations. The nonce is designed to be time-based so you can use it with a short lifetime (e.g. 5 or 10 seconds).

Design decisions

TimestampedNonce uses 192 bits with:

• First 64 bits for the expiration timestamp, milliseconds since EPOCH.
• The next 128 bits is for entropy. This is secure enough in this situation.

Genzer

import java.util.concurrent.atomic.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.stream.*;
import java.util.*;
import cyclops.function.*;

/**
 * This class is my attempt to see if I can make an implementation of cyclops's Memoize.memoizeSupplier
 * simpler without relying on `synchronize` keyword (as the actual implementation), or `ConcurrentHashMap#computeIfAbsent`

Genzer

{
  "workflow": {
    "title": "No Body Leaves",
    "description": "Invite who ever leaves the channel again",
    "icon": "",
    "input_parameters": {
      "Ft08U92KCRPH__user_id": {
        "type": "slack#/types/user_id",
        "name": "Ft08U92KCRPH__user_id",
        "description": "The user who left the channel",

Genzer

Mitigate "Rate Limiting bypass" through AWS ALB if the application relies on X-Forwarded-For

This gist documents a tactic which works in a situation:

• Your Software System runs behind an AWS Application Load Balancer (ALB)
• Your Software System uses AWS WAF in conjunction with ALB.
• Your Software System handles Rate Limiting by itself.
• Your Software System Rate Limiting implementation make use of X-Forwarded-For header to determine the correct Client Source IP.

Genzer

import java.util.UUID;
import java.util.Base64;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

public class UuidShortener {

  /* NOTE:
   * The implementation was mostly copied from StackOverflow [1],
   * as well as the hint of using BIG_ENDIAN [2].

Genzer

//DEPS org.openjdk.jmh:jmh-generator-annprocess:1.36
// --javaagent=ap-loader@maxandersen=start,event=cpu,file=profile.html
package com.grokhard.benchmarking;

import org.openjdk.jmh.*;
import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.infra.Blackhole;

import java.util.stream.*;
import java.util.*;

Genzer

import java.util.*;
import java.util.stream.*;

import javax.naming.Context;
import javax.naming.NameNotFoundException;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;

Genzer

package com.grokhard.explorejavaconcurrency;

import static java.util.concurrent.TimeUnit.SECONDS;

import java.util.Objects;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**

Genzer

#!/usr/bin/env bash
set -e -u -o pipefail

# Send, in sequential order, 10 requests and prints only the HTTP Status Code and the total time of the request
# with a Connnection Time Out in 5 seconds.

URL="$1"
{
	for _ in {1..10};
	do