sanjar-notes / backend Goto Github PK

Link to course: https://frontendmasters.com/courses/fullstack-v2/

Why + what?
Consider the example of an Ecommerce store, the general buy process has the following steps:
Place order -> Pay -> Dispatch -> *transition from warehouses -> arrive at local warehouse -> out for delivery -> delivered -> cancel/return? -> refund?

A lot is going on here. I have of courses omitted multiple possible states at each point.

Checkout:

• https://github.com/aasm/aasm - for Ruby, mentioning here because it is a popular library
• https://dev.to/davidkpiano/you-don-t-need-a-library-for-state-machines-k7h
• https://statecharts.dev/
• SCXML - https://www.w3.org/TR/scxml/

https://youtube.com/playlist?list=PLOspHqNVtKAAXDobTc9kBWwnfgzNV2k_a - databases, streaming, OS level concepts, SQL, querying etc

https://youtu.be/78k5-LZwLBo?si=ZqZQz27Usjx-VFNX

50 Billion messages per day at WhatsApp.

It's good to know when to switch the tool

Monitoring system, IDK what those are.
Examples - Grafana, Prometheus

Link: https://network.husseinnasser.com

https://github.com/milanm/Cloud-Product-Mapping

Was reading Networking by Forouzan, but it's too long and time consuming. Not practically useful if read page to page.

Context

I want an app where my cursor position is shown to the person I'm video calling (say we're going through some code on their browser). It's one way comm, but how do I send my cursor coordinates without them 'listening' or the other way around.

The issue is I don't want to create a chrome plugin with a 'server' app that you need to install

Questions

1. Is it possible to run a server inside a browser tab? Maybe only a temporary one.
2. Reliable direct ping - Even if I do install a server app (in addition to the browser extension), how would I ping their server. Ik both are connected to the backbone via ISP, but are they reliably pingable? I don't wish to add a centralized server - that's a privacy issues and also that I need to pay for it.

Explore

1. How p2p works, without a server?
2. Pros and cons of being addressable but not having a dedicated server connected to the backbone. Scope: latency, cost, bottlenecks
3. Handshake structures if this is possible?
4. How do torrents work? See the protocol
5. How websockets can work in such a system?

The home/ files could be useful. Archived https://github.com/sanjar-notes/rest-web

https://youtu.be/-MTSQjw5DrM

sanjar-notes/distributed-computing-systems#1

https://youtube.com/c/sudoCODE

REST API expectations

1. Mehul Mohan

Express full tutorial - https://youtu.be/SccSCuHhOw0

Middlewares in Express - https://youtu.be/lY6icfhap2o

These videos are exhaustive.

sanjar-notes/db#9

• Internal Architecture - Hussein Nasser - done - drive/page-level abstraction, fixed min write length restriction in modern file systems/dbs, indexing support and working
• Why Discord moved from MongoDB to Cassandra
• 2x faster reads/writes with clustered collection feature

https://blog.jim-nielsen.com/2019/moving-from-ejs-to-jsx/
https://blog.r0b.io/post/using-jsx-without-react/

Maybe https://kentcdodds.com/blog/react-jsx-as-a-server-side-templating-language

https://youtu.be/0CSyIBHQy9g?si=IzT7_RVjUYgjPK63 ~2h Freecodecamp
Much needed

https://twitter.com/newsycombinator/status/1516567815683248130?t=RCI904YCLfLEy2Zr-OGxXA&s=19

https://youtube.com/playlist?list=PLUU3EzfPr915ebZONvUVHKm8Bls6D7EgA

• Yesterday, I wrote some Ruby (Rails) code just because request keys that were decided for an API differed from the column name (which Rails defaults to for request keys).

• This mapping code was non-trivial, since one has to not reset something if the request doesn't have the key (think undefined vs null in JS). - Also, the form used on the frontend had a set of generic validators, for showing wrongly entered values. I had to add a custom validator if value was 'oneOf' a given array of fixed values.

• at a discussion during the backend code review, the lead backend engineer suggested the changes were cosmetic, perhaps useless. So the team leads got together and decided to use ENUMS on the frontend whose name matched the decided keys but values would match the BE column names exactly. The PR, branch is now useless.

I thought this was a stupid way to code, atleast if you own both the server and client app.

• The backend has the strongest validation of all, since it ingests data.
• the frontend validations depend directly on backend validations. Of course, how the UI can be decided in the frontend code.

So, if the backend could just generate a "type" file with

1. key names
2. value type
3. Possible values
4. Validators to be used by the front-end (if calculable directly, i.e. can be checked without database lookup, atleast)

This would solve a lot of communication tasks, and cosmetic mappings.

1. What is SSE
2. SSE core improvement - avoid the cost of TLS handshake, for sending 'close' signal
3. Are WebSockets really an evolution over HTTP, SSE
4. TCP is quite free, and HTTP has the request-response sequentiality constraint

sse-ws-http-tcp (ChatGPT conv)

I still have some doubts, ChatGPT was hallucinating about minute details, it seems.

https://youtu.be/XBu54nfzxAQ

https://www.atatus.com/blog/, docker, k8s, redis, mqs. ~500 blogs

What is logging in backend lingo.
Examples - APM, Loki

1. https://youtu.be/j8Yxff6L_po - 27 min
2. https://youtube.com/playlist?list=PLZlA0Gpn_vH9yI1hwDVzWqu5sAfajcsBQ - playlist
3. https://youtu.be/2PPSXonhIck - 37 min

https://discord.com/blog/how-discord-stores-billions-of-messages

I have not learnt about database abstractions like ORMs, CLI tools, etc.

Learn them

Important. Knowledge about scaling stuff and what things matter - allow for more efficiency and simplification (less instances, less app code).

• Use TPM and other discrete circuits for standard tasks like TLS, instead of CPU.
• Kernel space and user space configs. Example - multiple threads listen on the same port.
• HTTP 1.1 simpler than 2
• Parsing, early detect missed, and cost of it.

Video: https://youtu.be/gSQoA4SYhJY?si=yTGTZByLeKbPAX_R - What happens before the backend gets the Request - Hussein Nasser

Important for growth phase/roles for an app/company.

https://youtube.com/@ByteByteGo

source: https://www.reddit.com/r/ExperiencedDevs/comments/pyleqb/recommendation_reading_booksblogs_for_best/

• https://cloud.google.com/apis/design | https://slack.engineering/how-we-design-our-apis-at-slack | https://opensource.zalando.com/restful-api-guidelines | https://learn.microsoft.com/en-us/azure/architecture/best-practices/api-design | https://apisyouwonthate.com/
• https://sre.google/sre-book/table-of-contents general backend principles for large orgs
• Book - The Design of Web APIs by Arnaud Lauret

  The Design of Web APIs by Arnaud Lauret is the best I've found so far. I've looked at a lot of other resources, including some mentioned already in this thread, and have been generally unimpressed. Apart from Fielding's paper, which everyone should read as a primer, I haven't seen anything better when it comes to an in depth look at RESTful design.

https://youtu.be/-RCnNyD0L-s

REST APIs made easy - SudoCode

Gaurav Sen at YouTube
https://youtu.be/FqljO9B5grM (8 min)

3 sources (all may be the same)

• Udemy
• YouTube - contains the most amount of content, and almost same as Udemy

https://www.atlassian.com/microservices

• History of CORS - StrangeLoop, includes other web security constructs
• Same Origin Policy - MDN

I want to learn this because it's a full-duplex communication protocol, which HTTP isn't.
Resources:

1. Wikipedia - WebSocket
2. MDN - WebSocket
3. Skim/read this book: WebSocket

The goal is to just understand enough to think about the effects of this tech, i.e. implementation details are necessary only if they change the interface of the tech.

Learn about HTTP (in depth) from the following resources:

1. Wikipedia - HTTP
2. MDN - HTTP
3. Skim/read this book: HTTP in action

Remember, the goal is to learn as less as possible, but understand as much as possible. Implementation details matter, only if they change the interface of the tech.

https://youtu.be/a-sBfyiXysI

1. Prisma seems OK. Docs, Tutorial - WebDevSimplified. Problems with - HackerNews it
2. Popular ORMs and info - LogRocket

https://youtu.be/LTH9m4HkeYY?si=c1R3XA7ubhSarzrW "I wish I had 10 years ago"

Kafka/RabbitMQ - examples.
A message queue is a job batching/handling system.
What is it, add it.

https://youtube.com/playlist?list=PL978B2CE2D788F745

https://www.instagram.com/p/CcNLCOer19h/?igshid=YmMyMTA2M2Y=

https://www.linkedin.com/posts/gkcs_white-papers-for-software-engineers-version-activity-7060467360062709760-n0KV

e.g. Spanner, BigTable, Borg