dyh_LrnHm

By Misc_Admin, 22 December, 2025

Clarification: Root of my learnings.
Thoughts
I am interested in a lot of things. On the other hand, IT will be a large part of it.
IT can based on topics which covers idea, concept, then software/application.
On the other hand, you can have topics that IT is only part of it.
It seems the top level should be Topic, which can later be classified if need to.
ToBeFiled
Legal

Website accessibility 👀

  • browser accessibility, WCAG, ...

Taiwan

Learning tool

NX monorepo 👀
Open Source Computer Vision Library 🌐

  • news letter to n @ gmail

International Phone Dial 👀
Thread/Async/aWait 👀
Human Language

AI Home 👀

MarsCode.com

  • AI code editor

PRIME NG 🌐

  • Angular UI library
  • used in NDE new portal

Solar Panel

  • jackery.com 🌐

    • good
    • IV curve of solar panel
      • Basically, there is the Voc - open circuit voltage
      • When slowly adding load (toward smaller resistance)
        • the voltage will drop while current increases
        • it will then reaches a point
          • lower the resistance do not increase the current but
            • the voltage drop accordingly
          • the voltage at the point is called Vmp - most power
    • a chart show max current can be as high as 9A !!
    • have products too

Programming in general

  • structure
    • library/modulized
  • log/debug
    • approach
      • library/module need provide property to set logging configuration
    • flag layout
      • feature
        • understand the logic - start purpose will do
        • locat fail - exit will do
        • reason of fail - middle will do
          • can have multiple levels
            • after call - value back
        • function called - in the called function
        • function steps with values
          • enter - purpose of the function + argument
          • middle -
          • exit - fail/success ...
          • what is good to log??

      0000-0000 0000-0000 0000-0000 0000-0000 |
      0000-0000 0000-0000 0000-0000 0000-0000

Debugger in general 👀

  • principle
  • Links to specific OS/Language/Platform ...

Development Platforms

WebAssembly

  • Youtube 🌐

    • can cal. internally and not access outside
    • js code interaction

Node + npm 👀 - node package managment

  • include npmjs.com

Reverse Proxy

OS

Standards/Protocol

  • SHA256

    • rublon.com 🌐
      //Windows
      > certutil -hashfile C:\file\path\my_file.exe SHA256
      PwrShll> Get-FileHash C:\file\path\my_file.exe -Algorithm SHA256
      //Linux
      > sha256sum my_file.exe
  • SSL

    • free CA provider
      • see 'Lets Encrypt' below
  • SMTP/EMail 👀
  • BASE64 👀
  • HTML - see Markup/standard below
  • CORS (Cross Origin Resource Sharing)

    • Guide to CORS - auth0.com 🌐

      • Quotes:
        • same-origin policy followed by XMLHttpRequest and fetch
        • JavaScript can only make calls to URLs that live on the same origin
        • the browser to decide whether to continue with the request
          • after receiving header from server like: Access-Control-Allow-Origin
        • Implied

          • This is about javascript's XMLHttpRequest() and fetch()
          • Browser stopped the process - not the server
      • show curl access to server - preflight
        curl -i -X OPTIONS localhost:3001/api/ping \
        -H 'Access-Control-Request-Method: GET' \
        -H 'Access-Control-Request-Headers: Content-Type, Accept' \
        -H 'Origin: http://localhost:3000'

        • The server will reply Access-Control-* headers to indicate the request be allowed
        • can help check what server is looking for
      • NodeJs Express server, and NodeJs client.
    • Complete Guide - reflectoring.io 🌐

      • What is an Origin? - An Origin in the context of CORS consists of three elements:
        • URI scheme, for example http:// or https://
        • Hostname like www.xyz.com
        • Port number like 8000 or 80 (default HTTP port)
      • NodeJs Express server, and NodeJs client.

Linux on Windows

.NET on Linux??

  • https://www.youtube.com/watch?v=g4aXwZ0RRss&t=467s
    - install git
    - 3:00
    - install .net core
    - Linux -install .net core sdk

    - > dotnet ...

    - > dotnet new sonsole -...
    - > dotnet run

    https://www.youtube.com/watch?v=oFyj-qGMqAA
    - do not need VS
    - basically, need the .sln file
    - > MSBuild.exe Bld.xml

    https://www.youtube.com/watch?v=Amvq1WbmFmA
    - run .net core web from command line
    - > dotnet run (from project directory)
    - will show ports - both https and http
    - in browser, navigate to the port

    https://www.youtube.com/watch?v=RQLzp2Z8-BE
    - .net sdk

    - > dotnet --info
    - > dotnet restore
    - > dotnet build
    - > dotnet run - from project folder not solution
    - > dotnet publish -p:PublishSingleFile=true
    - dotnet do rely on MSBuild

NE/State Apps 👀

  • Employee Development Center, E1/W2, Open Enrollment ...
    • state email, different password
      • r=2080 20211119
  • Workday/Employee Work Center
    • login with state email
    • Where open enrollment is
      • inbox -one item/open-enrollment -get started
  • INSIDE NDE
    • inside NDE
      • Training Professional Development
        • Smart goal
          • Goal and objective

NDE Database Notes 👀 - not project specific
(My) NDE PC Setups 👀
Misc
Art/font 👀
Biology/Genetics ... etc

English 👀
Music 👀
Physics/Chemistry 👀
US Government 👀
Business/Econ/Finance 👀
Misc 👀 - Home, Law, Phone
Education
NDE Public Data 👀
CEDS 👀
EdFact 🌐

  • continue old CCD and more ??

[2024 new race]

Ed-Fi
SLDS
NDE provided IT training 👀
API tools
Postman 👀

  • test API

Swagger 👀

  • Document API
  • Usually pre-build into MS API project
    • DH: I think it look into controller, ... and build:
      • the documentation and
      • the testing front end
        Scalar 👀
  • similar to Swagger
    • DH: was pre-build into MS' newer(.net 9??) API

Database
Products/Program

  • MySql
  • Maria DB
    • an Open source version/clone of MySql
    • Wikipedia 🌐
  • Microsoft DB
    • see Microsoft below

Multi Media 👀

  • video, music, picture, graph, 3D, 2D, record
  • .MP4, .Jpeg, .npg, ...

IT - Misc
Useful free program - Youtube 🌐

AI related 👀

GPU/CUDA

Email

Learning resources

To Be Filed/complete/studied

  • Crystal Report
  • Dapper
  • Dependency Injection
    • Wiki 🌐

      • A class(receiver/client) receive/get-injected an object(service) to use from an injector
      • Points
        • Interface needed for the service
        • receiver don't need to know how to construct the object
    • Mine

      • Wouldn't this be achieved by initialize a class with the service object??
      • So the point really is: who is the injector?
        • If we look at the .NET core or Angular/ReAct it look like injector are part of the framework/compiler etc. something that is kept away from programmer. The 'frameworks' likely look at the parameter signature of a constructor/method and look the class in the project, then create one and call the constructor/method.
        • So, the main thing is that system/framework did the initialization.
      • Pro
      • Con
        • What if two classes with the same (usage) interface is defined?
        • Do we really need let framework/compiler to take control?
          • We can achieve this by
            • create a service creator object
            • pass the object to receiver
            • via interface of the service creator, asked to create service.
        • This is a design choice, do we need turn it into language feature?

Javascript Observable/Promise 👀

  • Promise
  • Observable, Subscribe, Subject, behavior subject ...

Container Software

  • Docker 👀
  • Podman
    • open source
    • Youtube 🌐
    • Youtube 🌐
    • Youtube 🌐

      • about Podman
        • open source
        • Daemon-less
        • follow OCI (Open Container Initiative) specifications for container and container images
        • OR OCI management tool
        • Rootless - can run as normal user
        • Container run in a Pod - Pod can run multiple containers
        • interact with runc - c for container
          • an CLI that can create and run container

HTTP/headers

Unix diff

  • diff is tightly related to patch source file
    • The output of diff is sent to other system to patch the BgnFl
    • At patch side, you only have BgnFl
  • > diff [|-c|-u] BgnFl TrgtFl
    • No option

      • minimum info to turn BgnFl into TrgtFl
      • // Command followed with needed info
        3a5,7 // at line 3 of BgnFl
        > line 5 of TrgtFl
        > line 6 of TrgtFl
        > line 7 of TrgtFl

        5,7d9 // delete line 5-7 of BgnFl; we just after line 9 of TrgtFl
        < line 5 of BgnFl // of no importance

        5,7c7,9 // 5-7 of BgnFl is replaced by 7-9 of TrgtFl
        > line 7 of TrgtFl
        > line 8 of TrgtFl
        > line 9 of TrgtFl

    • -c (contex mode for human; turn BgnFl into TrgtFl)

      • provide info on BgnFl, TrgtFl
      • lines from both files displayed in its own list
      • - mean remove, + mean add
        • Turn BgnFl to TrgtFl, - for BgnFl only, + for TrgtFl only
    • -u (unified mode for human; turn BgnFl into TrgtFl)

      • Similar to -c, but lines from both file are mingled

dyh_LrnWndws 👀 - under 'Microsoft'
Topics

  • security

    • digital security tech 👀

      • hash, encryption (public/private/symmetric key)
        • openssl, ...
      • sign/signature
      • Authentication/Authorizaton
      • Jwt, OATH, SAML, ...
    • points
      • you have to authenticate
        • you can have different method
      • authorization
        likely to be end point dependent
      • state
        • session
          • state is controlled at server;
          • not get hacked
          • can be part of the process control
        • API/Stateless
          • state can be hacked
          • design have to be state hack free
            • check if an operation is 'currently' allowed
            • or required info in one call
  • Regular Expression 👀

Applications/Tools
Stock/Finance Related

MultiMedia

WSO2 Identity Server 👀

  • ...

SoapUI

  • -SOAP -Project Name=Nm -Initial WSDL=http://...?WSDL -Create Requests=uncheck -OK
  • -right click a function -New request -give a name -OK

Git 👀

  • update-ref, fetch, merge, ...

Let's Encrypt

  • free CA provider
  • Lets Encrypt - digitalocean Doc 🌐

    • Many done by CertBot automatically

    > sudo apt install certbot python3-certbot-apache

    //firewall
    > sudo ufw status // check status
    > sudo ufw allow 'Apache Full' // add full(80+443)
    > sudo ufw delete allow 'Apache' // remove 80

    //CertBot script
    > sudo certbot --apache
    - will ask for email
    - will ask acknoledgement
    - will ask permission for contact
    - will let you pick websites to apply Let's Encrypt
    - report things done
    - will ask if redirect port 80
    - will report things done and future maintainance
    - certificate have been saved at ...
    - key file has been saved at: ...
    - cert will expire on ...
    - To obtain a new/tweaked cert: > certbot with "certonly" option
    - Manually renew all: > certbot renew
    - Backup Certbot configuration at /etc/letsencrypt

    //check auto-renewal
    - cert valid for 90 days
    //service certbot.timer run by cron.d twice a day
    > sudo systemctl status certbot.timer //check status
    > sudo certbot renew --dry-run //dry run about the renew

  • Revoke - Official Doc 🌐

    • likely via CertBot
    • Need a reason code
      • keyCompromise, superseded, cessationOfOperation
    • Ways to prove ourself
      • account issued to - this is the best approach
        > certbot revoke --cert-path /etc/letsencrypt/archive/${YOUR_DOMAIN}/cert1.pem
      • related account issued to
        > certbot certonly --manual --preferred-challenges=dns -d ${YOUR_DOMAIN} -d nonexistent.${YOUR_DOMAIN}
        ...other details
      • private key - more for if key compromised
        > openssl pkey -outform DER -in /PATH/TO/privkey.pem -pubout | openssl sha256
        > certbot revoke --cert-path /PATH/TO/cert.pem --key-path /PATH/TO/privkey.pem --reason keyCompromise

Editor

Code Hosting/Collaborating sites

Program/App Style

  • API/BackEnd-FrontEnd style
    • RPC
      • function essential
    • REST API
      • resource essential
    • GraphQL 👀

Markup/Standards

Programming Languages

Microsoft

Platforms/Libraries

Other

  • Ed-Fi