LAMP / LEMP development note 30-Sept-2019

Count Apache's (httpd) concurrent connections
https://www.2daygeek.com/linux-check-apache-concurrent-connections-netstat-ss-command/


$htpasswd -b -c ~/temp/password admin test101

https://www.networkworld.com/article/2874387/mission-impossible-memorizing-ipv6-addresses.html

 Chrome & Firfox Dark mode seem cool.

https://stackoverflow.com/questions/19646567/is-there-a-way-to-get-client-connections-count-in-aws-elb

ELB actually runs on EC2 (?), which would only make sense, and would explain why it can't scale up extremely rapidly in response to traffic spikes.

YOU CAN’T PROTECT WHAT YOU CAN’T SEE
https://medium.com/tenable-techblog/lessons-from-aws-nlb-timeouts-5028a8f65dda

https://stackoverflow.com/questions/6375654/how-to-add-date-string-to-each-line-of-a-continuously-written-log-file

Difference between ESTABLISHED and LISTENING
https://askubuntu.com/questions/854354/difference-between-established-and-listening
https://users.cs.northwestern.edu/~agupta/cs340/project2/TCPIP_State_Transition_Diagram.pdf


 Ton of document ab Linux bash
 https://ocaml.github.io/ocamlunix/pipes.html

https://ocaml.github.io/ocamlunix/ocamlunix.html

 https://ocaml.github.io/ocamlunix/ocamlunix.pdf

 https://github.com/ocaml/ocamlunix/

 $ date -Iseconds
2016-09-09T12:18:23+0200

 awk -v var="$TIMESTAMP"

Queue
 https://stackoverflow.com/questions/18396452/design-a-datastructure-to-return-the-number-of-connections-to-a-web-server-in-la

htdigest [ -c ] passwdfile realm username

https://stackoverflow.com/questions/600079/how-do-i-clone-a-subdirectory-only-of-a-git-repository

http://www.andymboyle.com/2011/11/02/quick-csv-to-json-parser-in-python/
https://www.codementor.io/garethdwyer/flask-vs-django-why-flask-might-be-better-4xs7mdf8v

https://stackoverflow.com/questions/419163/what-does-if-name-main-do

http://www.andymboyle.com/2011/11/02/quick-csv-to-json-parser-in-python/

https://realpython.com/python-testing/

Damn encoding

function w1250_to_utf8($text) {
    // map based on:
    // http://konfiguracja.c0.pl/iso02vscp1250en.html
    // http://konfiguracja.c0.pl/webpl/index_en.html#examp
    // http://www.htmlentities.com/html/entities/
    $map = array(
        chr(0x8A) => chr(0xA9),
        chr(0x8C) => chr(0xA6),
        chr(0x8D) => chr(0xAB),
        chr(0x8E) => chr(0xAE),
        chr(0x8F) => chr(0xAC),
        chr(0x9C) => chr(0xB6),
        chr(0x9D) => chr(0xBB),
        chr(0xA1) => chr(0xB7),
        chr(0xA5) => chr(0xA1),
        chr(0xBC) => chr(0xA5),
        chr(0x9F) => chr(0xBC),
        chr(0xB9) => chr(0xB1),
        chr(0x9A) => chr(0xB9),
        chr(0xBE) => chr(0xB5),
        chr(0x9E) => chr(0xBE),
        chr(0x80) => '€',
        chr(0x82) => '‚',
        chr(0x84) => '„',
        chr(0x85) => '…',
        chr(0x86) => '†',
        chr(0x87) => '‡',
        chr(0x89) => '‰',
        chr(0x8B) => '‹',
        chr(0x91) => '‘',
        chr(0x92) => '’',
        chr(0x93) => '“',
        chr(0x94) => '”',
        chr(0x95) => '•',
        chr(0x96) => '–',
        chr(0x97) => '—',
        chr(0x99) => '™',
        chr(0x9B) => '’',
        chr(0xA6) => '¦',
        chr(0xA9) => '©',
        chr(0xAB) => '«',
        chr(0xAE) => '®',
        chr(0xB1) => '±',
        chr(0xB5) => 'µ',
        chr(0xB6) => '¶',
        chr(0xB7) => '·',
        chr(0xBB) => '»',
    );
    return html_entity_decode(mb_convert_encoding(strtr($text, $map), 'UTF-8', 'ISO-8859-2'), ENT_QUOTES, 'UTF-8');
}
https://www.php.net/manual/en/function.mb-convert-encoding.php


https://smallbusiness.chron.com/microsoft-excel-wont-show-japanese-characters-77317.html

https://www.php.net/manual/en/language.operators.errorcontrol.php
Is there any equivalent in Python ?

https://stackoverflow.com/questions/1088387/what-specific-productivity-gains-do-vim-emacs-provide-over-gui-text-editors
https://stackoverflow.com/questions/14132003/is-emacs-worth-learning

https://github.com/jazzband/django-pipeline/issues/602
https://stackoverflow.com/questions/17353213/init-for-unittest-testcase
https://stackoverflow.com/questions/16870663/how-do-i-validate-a-date-string-format-in-python

https://stackoverflow.com/questions/3501382/checking-whether-a-variable-is-an-integer-or-not

Testing IP based access
To test multiple IP access, for example for IP connection count, order, we can:
- Use PC + mobile (with Mobile 3G/4G/5G) to test
- PC + mobile (with VPN like Orbot)
- PC with VPN + mobile Wifi (same network)
- A PC + a VPS server  (can be temporary created or permanent one, delete after test if not needed)


https://mortada.net/can-integer-operations-overflow-in-python.html
https://stackoverflow.com/questions/2484156/is-str-replace-replace-ad-nauseam-a-standard-idiom-in-python
https://stackoverflow.com/questions/9573244/how-to-check-if-the-string-is-empty
https://stackoverflow.com/questions/21388541/how-do-you-check-in-python-whether-a-string-contains-only-numbers

https://stackoverflow.com/questions/38398018/ip-address-and-command-logs-for-git-clone-pull-and-push