Hussein Nasser

WebSockets technology is a bidirectional, full-duplex protocol for communication between client and server over the web. It has been standardized in 2011 and its fully compatible with HTTP. This protocol enables realtime applications such as chatting, notifications, live feed , multiplayer gaming and otheruse cases.

In this video we will explain what WebSockets are and why it was invented. we will then build a server and client using WebSockets. We will also talk about the pros and cons of WebSockets, and discuss some alternatives to this technology 

Chapters
0:00 Intro
2:00 HTTP
5:40 WebSockets
8:00 WebSockets Handshake
11:20 WebSockets Usecases
14:30 WebSockets Example Code
36:40 WebSockets Pros and Cons 
42:10 Do you have to use webSockets?

Source Code in the video for WebSockets 
https://github.com/hnasr/javascript_playground/tree/master/websocket-demo


HTTP
  * talk about request-response show a slide. Client initiate request all the time. Imagine building a chatting app? 

WebSockets 
- Slide showing bidrectional full duplex  standard web 
- 
How WebSockets Work?
- WebSockets handshake 
- Initial request is always HTTP which we all know creates a tcp connection, that request then http upgrade tells the server to use it as bidirectional.  
- Once done switches to binary protocol. 
- Ws:// wss:// protocol 

WebSocket use cases
- Chatting
- Live feeds
- Multiplayer gaming
- Progress bar/ logging/ uploading..

- WebSockets example (Server/Client) 
- WebServers Pros and Cons  

Pros
1. Full-duplex no need for constant polling  
2. compatible with HTTP, so proxies know to deal with it
3. Firewalls won’t block it doesn’t use a special port
Cons
1. Proxying is tricky, lots of proxies and transparent proxies don’t support it yet
2. Layer 7 load balancing is tricky, timeouts on the load balancer. 
3. More complicated to implement (simple telnet use HTTP)
4. Not ideal for all use cases - (microservices)


- Do you have to use Web Sockets ? ( alternatives  ) 
It is important to note that WebSockets is not the only HTTP realtime based solution, there are other ways to achieve real time such as eventsource, and long polling. 

- Load Balancing with WebSockets (bonus) 
- layer 4 
- Layer 7 (tunnel) 

Longpolling
Eventsource
WebSockets 

 
Sources: 

https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_servers

https://www.ably.io/concepts/websockets

https://link.medium.com/ljsSOsnW6Y

https://blog.stanko.io/do-you-really-need-websockets-343aed40aa9b



Cards
HTTP Crash Course https://www.youtube.com/watch?v=0OrmKCB0UrQ
TLS https://www.youtube.com/watch?v=AlE5X1NlHgg
What is a Web Servers https://www.youtube.com/watch?v=JhpUch6lWMw
Layer 4 vs Layer 7 Load Balancing https://www.youtube.com/watch?v=aKMLgFVxZYk





Support my work on PayPal
https://bit.ly/33ENps4
 
Become a Member on YouTube
https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

🧑‍🏫 Courses I Teach
https://husseinnasser.com/courses 

🏭 Backend Engineering Videos in Order
https://backend.husseinnasser.com

💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🎙️Listen to the Backend Engineering Podcast
https://husseinnasser.com/podcast 

Gears and tools used on the Channel (affiliates)

🖼️ Slides and Thumbnail Design 
Canva
https://partner.canva.com/c/2766475/647168/10068

🎙️ Mic Gear
Shure SM7B Cardioid Dynamic Microphone  
https://amzn.to/3o1NiBi

Cloudlifter
https://amzn.to/2RAeyLo

XLR cables
https://amzn.to/3tvMJRu

Focusrite Audio Interface
https://amzn.to/3f2vjGY


📷 Camera Gear
Canon M50 Mark II
https://amzn.to/3o2ed0c

Micro HDMI to HDMI 
https://amzn.to/3uwCxK3

Video capture card
https://amzn.to/3f34pyD

AC Wall for constant power
https://amzn.to/3eueoxP


Stay Awesome,
Hussein

WebSockets Crash Course - Handshake, Use-cases, Pros & Cons and more

In this tutorial, we will go through the basic steps on how to write a python script to read and write data on a Postgres database. We will start by describing what we have setup. I have a postgres instance running on a docker container which I will be using for this tutorial. You can watch this video that I made to learn how to spin up a postgres docker container https://www.youtube.com/watch?v=5QNL7_i-ay8  obviously you don’t have to use docker you can still instal postgres phsyically on your machine or if you have a server running postgres that should do the trick. We will then start from scratch as usual using visual studio code and python3. We will talk about the #psycopg2 library and how to install it. we will start by establishing a connection to postgres, we will talk about cursors, client-side cursors, server-side cursors the differences. Then we will execute a cursor to retrieve all rows in the table and display them. we will then insert a row to the database and commit the changes 

Our Source Code
https://github.com/hnasr/psycopg2/blob/master/db.py

More details on the official site here 
http://initd.org/psycopg/docs/usage.html


🏭 Software Architecture Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXNP6mQchJVP3S-3oKGEuw9

💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🛰 Network Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQUBSgBXilKhRMJ1ACqr7pTr

🏰 Load Balancing and Proxies Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQVMeBmWI2AhxULWEeo7AaMC

🐘 Postgres Videos 
https://www.youtube.com/playlist?list=PLQnljOFTspQWGrOqslniFlRcwxyY94cjj

🧮 Programming Pattern Videos 
https://www.youtube.com/playlist?list=PLQnljOFTspQV1emqxKbcP5esAf4zpqWpe

🛡 Web Security Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQU3YDMRSMvzflh_qXoz9zfv

🦠 HTTP Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQU6zO0drAYHFtkkyfNJw1IO


🐍 Python Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQU_M83ARz8mDdr4LThzkBKX

🔆 Javascript Videos 
https://www.youtube.com/playlist?list=PLQnljOFTspQWab0g3W6ZaDM6_Buh20EWM


Enjoy guys!
Stay awesome
Hussein

Step-by-Step Python and Postgres Tutorial with psycopg2

Get my Fundamentals of Database Engineering udemy course to learn more , link redirects to udemy with coupon applied https://database.husseinnasser.com 

This is a practical video on Database Indexing where I explain what is an index, why do we need it and how it can improve the performance of the queries. Also how (if used incorrectly) it can slow down your queries


intro 0:00 
What is an index 0:30 
Describe Table 2:15 
SELECT [ID] WHERE ID 4:00 
SELECT [NAME] WHERE ID 6:30
SELECT [ID] WHERE [NAME] (No index) 9:20
SELECT [ID] WHERE NAME LIKE 11:12 
CREATE INDEX ON [NAME] 12:00
SELECT [ID] WHERE NAME (Indexed) 12:50
SELECT [1D] WHERE NAME LIKE (Indexed) 14:30 
Summary 16:00 

Support my work on PayPal
https://bit.ly/33ENps4
 
Become a Member on YouTube
https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

🧑‍🏫 Courses I Teach
https://husseinnasser.com/courses 

🏭 Backend Engineering Videos in Order
https://backend.husseinnasser.com



💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🏰 Load Balancing and Proxies Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQVMeBmWI2AhxULWEeo7AaMC

🏛️ Software Archtiecture Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXNP6mQchJVP3S-3oKGEuw9

📩 Messaging Systems
https://www.youtube.com/playlist?list=PLQnljOFTspQVcumYRWE2w9kVxxIXy_AMo

Become a Member 
https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

Support me on PayPal
https://bit.ly/33ENps4

Stay Awesome,
Hussein

Database Indexing Explained (with PostgreSQL)

If you ever wondered the difference between stateless and stateful applications, REST, horizontal scaling versus vertical scaling? We tackle those in a small example. Hope you guys enjoy this quick video. We explain the advantages and disadvantages of each application. 


0:00 Intro
1:14 Stateful Application
8:40 Stateless Application 

Online diagram tool used in this video: Http://www.gliffy.com 

Checkout the rest of the content for more software engineering topics by example. 

🏭 Software Architecture Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXNP6mQchJVP3S-3oKGEuw9

💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🛰 Network Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQUBSgBXilKhRMJ1ACqr7pTr

🏰 Load Balancing and Proxies Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQVMeBmWI2AhxULWEeo7AaMC

🐘 Postgres Videos 
https://www.youtube.com/playlist?list=PLQnljOFTspQWGrOqslniFlRcwxyY94cjj

🧮 Programming Pattern Videos 
https://www.youtube.com/playlist?list=PLQnljOFTspQV1emqxKbcP5esAf4zpqWpe

🛡 Web Security Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQU3YDMRSMvzflh_qXoz9zfv

🦠 HTTP Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQU6zO0drAYHFtkkyfNJw1IO


🐍 Python Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQU_M83ARz8mDdr4LThzkBKX

🔆 Javascript Videos 
https://www.youtube.com/playlist?list=PLQnljOFTspQWab0g3W6ZaDM6_Buh20EWM


Stay Awesome
-Hussein Nasser
www.husseinnasser.com

Stateful vs Stateless Applications (Explained by Example)

Google recent paper on protective load balancing in TCP attempts to improve packet drops and latency by making the host change the flow path using the IPv6 Flow label. The Linux kernels gets the PLB support in Linux 6.2 this December, let us discuss with this is. 

0:00 Intro 
2:11 DCTCP
5:30 ECMP Routing
7:30 TCP PLB
11:20 Linux Kernel Support PLB

References
https://www.phoronix.com/news/TCP-PLB-Linux
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=957ed5e7129f2ce85dd76e4cdce749388295467d
https://dl.acm.org/doi/pdf/10.1145/3544216.3544226
https://www.rfc-editor.org/rfc/rfc2460#appendix-A
https://en.wikipedia.org/wiki/Equal-cost_multi-path_routing
https://www.rfc-editor.org/rfc/rfc8257
https://en.wikipedia.org/wiki/IPv6_packet
https://www.ietf.org/id/draft-lapukhov-bgp-ecmp-considerations-09.html


Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon)
https://backend.husseinnasser.com

Fundamentals of Networking for Effective Backends udemy course (link redirects to udemy with coupon)
https://network.husseinnasser.com

Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon)
https://database.husseinnasser.com

Introduction to NGINX  (link redirects to udemy with coupon)
https://nginx.husseinnasser.com

Python on the Backend (link redirects to udemy with coupon)
https://python.husseinnasser.com

Become a Member on YouTube
https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

Buy me a coffee if you liked this
https://www.buymeacoffee.com/hnasr

Arabic Software Engineering Channel 
https://www.youtube.com/channel/UChWZsjdoRvZ0T9QWZOD6UpA

🔥 Members Only Content
https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg
 


🏭 Backend Engineering Videos in Order
https://backend.husseinnasser.com

💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🎙️Listen to the Backend Engineering Podcast
https://husseinnasser.com/podcast 

Gears and tools used on the Channel (affiliates)

🖼️ Slides and Thumbnail Design 
Canva
https://partner.canva.com/c/2766475/647168/10068
 

Stay Awesome,
Hussein

Google pushes TCP Protective Load Balancing to Linux Kernel 6.2

I’m a big believer that database systems share similar core fundamentals at their storage layer and understanding them allows one to compare different DBMS objectively. For example, How documents are stored in MongoDB is no different from how MySQL or PostgreSQL store rows.
Everything goes to disk, the trick is to fetch what you need from disk efficiently with as fewer I/Os as possible, the rest is API.

In this video I discuss the evolution of MongoDB internal architecture on how documents are stored and retrieved focusing on the index storage representation. I assume the reader is well versed with fundamentals of database engineering such as indexes, B+Trees, data files, WAL etc, you may pick up my database course to learn the skills.
Let us get started.

0:00 Intro
2:00 SQL vs NOSQL 
18:00 MongoDB first version MMAPV1 
26:30 MongoDB Wired Tiger 
38:00 Clustered Collections 

Follow me on Medium
https://medium.com/@hnasr/membership

Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon)
https://backend.husseinnasser.com

Fundamentals of Networking for Effective Backends udemy course (link redirects to udemy with coupon)
https://network.husseinnasser.com

Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon)
https://database.husseinnasser.com

Introduction to NGINX  (link redirects to udemy with coupon)
https://nginx.husseinnasser.com

Python on the Backend (link redirects to udemy with coupon)
https://python.husseinnasser.com

Follow me on Medium
https://medium.com/@hnasr/membership

Become a Member on YouTube
https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

Buy me a coffee if you liked this
https://www.buymeacoffee.com/hnasr

Arabic Software Engineering Channel 
https://www.youtube.com/channel/UChWZsjdoRvZ0T9QWZOD6UpA

🔥 Members Only Content
https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg
 


🏭 Backend Engineering Videos in Order
https://backend.husseinnasser.com

💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🎙️Listen to the Backend Engineering Podcast
https://husseinnasser.com/podcast 

Gears and tools used on the Channel (affiliates)

🖼️ Slides and Thumbnail Design 
Canva
https://partner.canva.com/c/2766475/647168/10068
 

Stay Awesome,
Hussein

MongoDB Internal Architecture

The User Interface/User Experience has great impact on the backend architecture and scalability. In this podcast I discuss three UI/UX that affected backend design and scalability. 

0:00 Intro
1:40 UI vs UX
4:30 Google Chrome OmniBox 
12:30 1 out of X Page
20:00 YouTube Notification

Resources
https://blog.apnic.net/2020/08/21/chromiums-impact-on-root-dns-traffic/


Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon)
https://backend.husseinnasser.com

Fundamentals of Networking for Effective Backends udemy course (link redirects to udemy with coupon)
https://network.husseinnasser.com

Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon)
https://database.husseinnasser.com

Introduction to NGINX  (link redirects to udemy with coupon)
https://nginx.husseinnasser.com

Python on the Backend (link redirects to udemy with coupon)
https://python.husseinnasser.com

Become a Member on YouTube
https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

Buy me a coffee if you liked this
https://www.buymeacoffee.com/hnasr

Arabic Software Engineering Channel 
https://www.youtube.com/channel/UChWZsjdoRvZ0T9QWZOD6UpA

🔥 Members Only Content
https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg
 


🏭 Backend Engineering Videos in Order
https://backend.husseinnasser.com

💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🎙️Listen to the Backend Engineering Podcast
https://husseinnasser.com/podcast 

Gears and tools used on the Channel (affiliates)

🖼️ Slides and Thumbnail Design 
Canva
https://partner.canva.com/c/2766475/647168/10068
 

Stay Awesome,
Hussein

How UI/UX can break the backend

Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon)
https://database.husseinnasser.com

Shopify posted a blog on tips to for scalable payment system, one tip peeked my interest related to switching from UUID to ULID. I explore the reasoning behind this in this video.

https://shopify.engineering/building-resilient-payment-systems

0:00 Intro
1:30 idempotency
6:30 UUID vs ULID
9:50 Clustered Index
13:30 Why UUID4 Inserts are slow 
17:15 How ULID helps Shopify
22:00 Problem with tail pages
25:00 Does ULID help in all cases?


Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon)
https://backend.husseinnasser.com

Fundamentals of Networking for Effective Backends udemy course (link redirects to udemy with coupon)
https://network.husseinnasser.com

Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon)
https://database.husseinnasser.com

Follow me on Medium
https://medium.com/@hnasr/membership


Introduction to NGINX  (link redirects to udemy with coupon)
https://nginx.husseinnasser.com

Python on the Backend (link redirects to udemy with coupon)
https://python.husseinnasser.com

Become a Member on YouTube
https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

Buy me a coffee if you liked this
https://www.buymeacoffee.com/hnasr

Arabic Software Engineering Channel 
https://www.youtube.com/channel/UChWZsjdoRvZ0T9QWZOD6UpA

🔥 Members Only Content
https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg
 


🏭 Backend Engineering Videos in Order
https://backend.husseinnasser.com

💾 Database Engineering Videos
https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2

🎙️Listen to the Backend Engineering Podcast
https://husseinnasser.com/podcast 

Gears and tools used on the Channel (affiliates)

🖼️ Slides and Thumbnail Design 
Canva
https://partner.canva.com/c/2766475/647168/10068
 

Stay Awesome,
Hussein