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Ivan Velichko iximiuz

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iximiuz / flask_static_files_cache_invalidator.py
Last active October 28, 2019 18:56
Flask: add static file's cache invalidator param to URLs generated by url_for(). Blueprints aware.
""" Inspired by http://flask.pocoo.org/snippets/40/ """
app = Flask(__name__)
@app.url_defaults
def hashed_url_for_static_file(endpoint, values):
if 'static' == endpoint or endpoint.endswith('.static'):
filename = values.get('filename')
if filename:
if '.' in endpoint: # has higher priority
@iximiuz
iximiuz / walkdir.js
Created March 13, 2019 13:43
Tiny recursive walkdir (aka readdir) in JavaScript
const fs = require('fs');
const path = require('path');
async function *walkdir(dir) {
const stack = [dir];
while (stack.length) {
const filename = stack.pop();
const stat = await fs.promises.stat(filename);
if (stat.isDirectory()) {
const files = (await fs.promises.readdir(filename))
@iximiuz
iximiuz / mean_median_mode_stddev.py
Last active August 15, 2018 09:45
Mean, median, mode and stddev calculation in Python 3
sample = [5, 3, 1, 2, 4]
n = len(sample)
mean = sum(sample)/n
median = (sample[n//2 - (n + 1)%2] + sample[n//2])/2
stddev = (sum((e - mean)**2 for e in sample)/n)**0.5
cnt = {}
for e in sample:
cnt[e] = cnt.get(e, 0)
cnt[e] += 1
mode = sorted(cnt.keys(), key=lambda e: (cnt[e], -e))[-1]
@iximiuz
iximiuz / python_parse_set_cookie_headers.py
Last active August 14, 2018 01:55
Parse Set-Cookie headers in Python
@iximiuz
iximiuz / indices.md
Created June 24, 2018 13:32 
i => j1 = 2*i           0 => 0     1 => 2    2 => 4
     j2 = 2*i+1         0 => 1     1 => 3    2 => 5

i = j//2                0 => 0     2 => 1    4 => 2
                        1 => 0     3 => 1    5 => 2


i => j1 = 2*i + 1       0 => 1    1 => 3    2 => 5
 j2 = 2*i + 2 0 => 2 1 => 4 2 => 6
@iximiuz
iximiuz / Socket.js
Last active January 19, 2017 09:55
AngularJS namespaced socket.io service concept
'use strict';
/**
* Пример использования socket.io namespaces в сервисе AngularJS.
*
* Цель: получить несколько отдельных каналов связи в рамках одного соединения.
*
* Проблема: так как сервисы в AngularJS являются синглтонами, не возможно
* получить несколько экземпляров сервиса Socket с разными значениями
* namespace. При этом хочется иметь отдельные сервисы, представляющие
@iximiuz
iximiuz / rvo_bench.cpp
Last active August 19, 2016 13:14
C++ Return value optimization benchmark
#include <chrono>
#include <iostream>
#include <stdlib.h>
#include <time.h>
#define SIZE_MEDIUM 4096
#define SIZE_LARGE 16*4096
#define ITER_COUNT 100000
using namespace std;
using namespace std::chrono;
@iximiuz
iximiuz / binomial_coefficients.py
Created June 8, 2016 16:40
Calculate binomial coefficients via Pascal's triangle
def next_row(prev_row):
row = [prev_row[0]] * (len(prev_row) + 1)
for idx in range(len(prev_row) - 1):
row[idx + 1] = (prev_row[idx] + prev_row[idx + 1])
return row
def binomial(n, k, cache=None):
""" Calculates binomial coefficients using Pascal's triangle.
0 1
@iximiuz
iximiuz / diff.txt
Created May 19, 2016 11:27
Python 2 vs Python 3 division operator
Input | Py2 | Py3
----------+-----+-----
5/2 | 2 | 2.5
----------+-----+-----
5//2 | 2 | 2
----------+-----+-----
5.0/2 | 2.5 | 2.5
----------+-----+-----
5.0//2 | 2.0 | 2.0
----------+-----+-----
@iximiuz
iximiuz / goaccess.md
Created May 16, 2016 11:57
Analyze Nginx access log with GoAccess

Run:

grep "07/May/2016" app_access.log | goaccess -a --log-format '%h %^[%d:%t %^] "%r" %s %b "%R" "%u"' --date-format '%d/%b/%Y' --time-format '%H:%M:%S' > goaccess_may07.html

More here