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@michalc
michalc / spec.json
Last active July 4, 2021 20:15
World Bank + Vega-lite
{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"width": 630,
"height": 630,
"data": {
"values": [
{
"type": "Feature",
"id": 0,
"geometry": {
@michalc
michalc / libcrypto-decrypt-aes-ctr-little-endian.py
Last active September 13, 2021 05:27
Use libcrypto (OpenSSL) directly from Python with ctypes without compiling anything: AES decrypt with a little endian CTR counter
from contextlib import contextmanager
from ctypes import POINTER, cdll, c_char_p, c_void_p, c_int, create_string_buffer, byref
from sys import platform
# Uses a _little_ endian CTR counter, which OpenSSL doesn't directly support.
# Could be used to decrypt AES-encrypted ZIP files
def decrypt_aes_256_ctr_little_endian(
key, ciphertext_chunks,
get_libcrypto=lambda: cdll.LoadLibrary({'linux': 'libcrypto.so', 'darwin': 'libcrypto.dylib'}[platform])
):
@michalc
michalc / postman-hawk.js
Last active September 21, 2021 05:44
Postman pre-request script for Hawk authentication in custom header
/*****************************************************************************/
const hawkId = pm.variables.get('hawk_id');
const hawkKey = pm.variables.get('hawk_key');
const hawkHeader = pm.variables.get('hawk_header') || 'authorization';
/*****************************************************************************/
const timestamp = parseInt(new Date().getTime() / 1000);
const nonce = CryptoJS.enc.Base64.stringify(CryptoJS.lib.WordArray.random(6));
class MyPipeline(_PipelineV2):
# Everything is a method so nothing happens on import time for flexibility (although possibly
# does a bit of discovery magic... need to think about that...)
# Everything is a _static_ method: nothing on self since things are run on different bits of hardware,
# and gets any run-time dependencies injected in
#
# _PipelineV2 won't actually have any code: other parts of the system will interrogate its
# subclasses as needed. For example
# - Code in Data Flow would construct a DAG
# - The test harness would the run this and upstream pipelines synchronously
@michalc
michalc / asyncio_read_write_lock.py
Last active January 3, 2022 09:46
Python asyncio read-write lock, using a generic first-in-first-out lock
import asyncio
import collections
import contextlib
class Read(asyncio.Future):
@staticmethod
def is_compatible(holds):
return not holds[Write]
class Write(asyncio.Future):
@michalc
michalc / make_8gb_legacy_zip.py
Created January 3, 2022 16:37
Generating a Zip 2.0 file that's (just under) 8GiB
# Often it's claimed that a Zip 2.0 file cannot be bigger than 4GiB
# Here's how to make one that's just under 8GiB
from datetime import datetime
from stream_zip import stream_zip, ZIP_32
now = datetime.now()
perms = 0o600
def files():
for i in range(0, 0xffff):
@michalc
michalc / decrypt-ses-emails-in-s3.py
Last active November 16, 2022 03:49
Decrypt KMS-encrypted SES emails in an S3 bucket
import base64
import json
import boto3
from cryptography.hazmat.primitives.ciphers.aead import AESGCM
s3 = boto3.resource('s3')
bucket = s3.Bucket('my-bucket')
kms_client = boto3.client('kms')
@michalc
michalc / normalise_environment.py
Last active October 8, 2023 07:05
Structured data in environment variables: nested dictionaries and lists
def normalise_environment(key_values):
''' Converts denormalised dict of (string -> string) pairs, where the first string
is treated as a path into a nested list/dictionary structure
{
"FOO__1__BAR": "setting-1",
"FOO__1__BAZ": "setting-2",
"FOO__2__FOO": "setting-3",
"FOO__2__BAR": "setting-4",
"FIZZ": "setting-5",
@michalc
michalc / aws_sig_v4_headers.py
Created October 23, 2018 05:33
Function that calculates AWS signature version 4 headers
import datetime
import hashlib
import hmac
import urllib.parse
def aws_sig_v4_headers(access_key_id, secret_access_key, pre_auth_headers,
service, region, host, method, path, query, payload):
algorithm = 'AWS4-HMAC-SHA256'
@michalc
michalc / cloudfoundry-check-stacks.py
Created November 14, 2023 07:38
Check the stack of apps in CloudFoundry
import json
import os
from urllib.parse import urlparse, parse_qsl
import requests
from rich import box
from rich.console import Console
from rich.table import Table
with open(f'{os.environ["HOME"]}/.cf/config.json') as f: