WORKING Promise and Then for Angular APP_INITIALIZER

 //const appInitializerFn = (infoService: InfoService) => {

//  return () => {

//    return infoService.loadInfo().then( (promise) => {alert("tete"); return promise } ).then(_ => Promise.resolve(true)).then(_ => alert("tetete"));

//  };

//};

//WORKING APPINITIALIZER FUNCTION

const appInitializerFn = (infoService: InfoService,  httpClient : HttpClient) => { 

return () => {

    //return infoService.loadInfo()

return Promise.resolve(true)

.then( (promise) => {alert("tete"); return promise } )

.then(_ => infoService.setConfig(new AppInfo("aaaa")))

.then(_ => alert("tetete"));

  };

}

INFO SERVICE

import { Injectable } from '@angular/core';

import { HttpBackend, HttpClient } from '@angular/common/http';

import { AppInfo } from './app-info';

@Injectable()

export class InfoService {

  info: any;

  constructor(private httpBackend: HttpBackend) {}

  loadInfo(): Promise<boolean> {

    // bypass HTTP interceptors by using HttpBackend

    const http = new HttpClient(this.httpBackend);

    return (

      http

        .get<AppInfo>('/assets/info')

        // convert to Promise per Angular's `useFactory` requirement (not officially documented)

        .toPromise()

        .then(response => {

          // using a class factory to keep AppInfo class getters in place

alert("1");

          this.info = response;

        })

        // returning `true` to satisfy `useFactory` contract (not officially documented)

        .then(_ => {  return Promise.resolve(true); } )

        .catch(error => {

          console.error('Error loading info', error);

          return Promise.resolve(false);

        })

    );

  }

setConfig(inInfo : any)

{

alert("hi"); console.log("fri service");console.log(inInfo);

this.info =  inInfo;

console.log(this.info);

}

}

APP-INFO.TS

export class AppInfo {

  clientId: string;

  constructor(cli: string) 

{

this.clientId = cli;

}

}

Difference between TAG hierarchies of BOOTSTRAP NAV and NAVBAR components

  --NAVBAR--                 --NAV--

NAVBAR                  ----------

NAVBAR-NAV                         NAV

NAV-ITEM                 NAV-ITEM

NAV-LINK                 NAV-LINK

Browser autocomplete behaviors

 Found the following strange autocomplete behaviors on both Google and Edge. 

Consider the following html for input : 

  <div class="form-group">

    <label for="emailid">Email Id :</label>

    <input type="email" class="form-control" placeholder="Enter User" id="emailid">

  </div>

In this code, note the following "HOTSPOTS" :

  <div class="form-group">

    <label for="emailid">Email Id :</label>

    <input type="email" class="form-control" placeholder="Enter User" id="emailid">

  </div> 

If you ever set these two hotspots to values like "email" , "emailaddress" , "user" , "password", the browser is likely to autofill this field. (tested with chrome and edge). 

To avoid this, just change the name slightly. e.g. from "email" to "emailid" . You will have to test which name is working by trial and error. But you have to make changes in these two places mostly, plus may be in the <label for="XXXX"> place. 

If you google on autocomplete behavior, most of the links will tell you to set autocomplete to "off" or some junk value "dsf" or some different value "differentname" or set name to some different value that id of the control. But practically none of these tricks work. 

I also found this SO https://stackoverflow.com/questions/55591018/autocomplete-off-in-html5 

which tells to include autocomplete="off" in form tag and then include a hidden input in the form with autocomplete="false". But this also did not work. 

<form autocomplete="off" >
    <input autocomplete="false" name="hidden" type="text" style="display:none;">

Surreal DB

 

Surreal DB does not start on alpine container, 

use ubuntu container instead 

1. Create an Ubuntu container 

docker run -d -p 17000:8000 --name ub_surreal ubuntu tail -f /dev/null

2. Exec the container  in it mode

docker exec -it -u 0 ub_surreal sh

3. Update apt  ( this is required to install curl)

apt update

This will take some time may be 2-3 mins because apt coming with container is bare minimum

4. Install curl

 

apt install curl

Press 'Y' when prompted 

5. 

curl -sSf https://install.surrealdb.com | sh

This will install surreal db. 

6. Start surreal db

surreal start --log debug --user root --pass root memory

This will start surreal and keep it started. 

7. Open another command prompt and again open the same container with EXEC command: 

docker exec -it -u 0 ub_surreal sh

8. Now you can give the command and use surrealdb. 

For example you can give the following command: 

curl --request POST --header "Accept: application/json"    --header "NS: test" --header "DB:test" --user "root:root"  --data "INFO FOR DB;"  http://localhost:8000/sql

you should get a response like 

[{"time" : "47.432ms" , "status" : "OK" , "result" : { "d1" : {} , "dt" : {}, "sc" : {} , "tb" : {}}}]

https://www.freecodecamp.org/news/how-to-use-surrealdb-with-fresh-framework/

========================================================================

Start Surreal using dockerfile

1. Execute the following dockerfile:

========================================================================

Dockerfile

========================================================================

FROM ubuntu

RUN apt update 

RUN apt-get install -y  curl 

RUN curl -sSf https://install.surrealdb.com | sh

CMD surreal start --log debug --user root --pass root memory

========================================================================

NOTE the use of  apt and apt-get : apt-get has more features than apt, 

i.e. apt is a stripped down vesrion of apt-get

2. Build the above docker file:

docker build  -t surreal-image . 

NOTE : image name must be all smalls.

3. Run it: 

docker run -p 17000:8000 -d --name surrealdb surreal-image

4. Execute it: 

docker exec -it -u 0 surrealdb sh

5. Execute the following command on shell: 

surreal sql -c http://localhost:8000

You will be presented with surreal sql prompt. ( >) 

>info for db <Enter>

[{"time" : "23.728ms" , "status" : "ERR" , "detail" : "Specify a namespace to use"}]

6. Now exit sql shell by pressing ctrl + C and enter the following command: 

surreal sql -c http://localhost:8000 --ns test --db test

>info for db

[{"time" : "50.292ms" , "status" : "OK" , "result" : { "d1" : {} , "dt" : {}, "sc" : {} , "tb" : {}}}]

> create account set name = 'test' , created_at = time::now()

> CREATE author:john SET name.first = 'John' ,  name.last = 'Adams' , name.full = string::join(' ', name.first, name.last) , age = 29, admin  = true,  signup_at = time::now();

> select * from author, account;

KUBERNETES COMMANDS

 minikube version 

kubectl version 

minikube start   #starts cluster 

kubectl cluster-info

kubectl get nodes

kubectl get pods

kubectl get services

kubectl create deployment kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1

kubectl proxy 

kubectl get pods -o  go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}'

$export POD_NAME=$(kubectl get pods -o  go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')

kubectl get pods -o  go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}'

C# Linq Min method

// Online C# Editor for free

// Write, Edit and Run your C# code using C# Online Compiler

using System;

using System.Linq;

using System.Collections.Generic;

public class HelloWorld

{

    public static void Main(string[] args)

    {

        List<test> testlist = new List<test>();

        testlist.Add(new test { id = 5});

        testlist.Add(new test { id = 7});

        testlist.Add(new test { id = 2});

        testlist.Add(new test { id = 8});

        //find the min

        var min = testlist.Min(x=>x.id);

        

        //get the object with min component

        var y = testlist.Where(x=>x.id == min).FirstOrDefault();

        Console.WriteLine ($"The min is  {min} {y}  {y.id}");

    }

    

    public class test { 

        public int id { get;set;} 

    } 

}

Output: 

The min is  2 HelloWorld+test  2

NOTE: {y} prints "HelloWorld+test" which is the object hierarchy of parent class and contained class.

Nuget PMC Error while adding migration: The entity type 'Employee' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. For more information on keyless entity types, see https://go.microsoft.com/fwlink/?linkid=2141943.

 This happens when you dont define primary key for an entity type. 

Define a primary key either explicitly or implicitly.