This site can’t provide a secure connection + Angular + VPN + Ubuntu 20.04

Sometimes when you using VPN connection with Ubuntu and run angular project command ng serve get next error.

I share 2 solutions:

Solution 1

1. run next command on your angular project.

ng serve --ssl true --ssl-cert "./ssl/localhost.crt" --ssl-key "./ssl/localhost.key"

Use incognito google chrome to go to http://localhost:4200

This solution work for me using Ubuntu 20.04

Solution 2

2. Go to developer tools Chrome 3 dots > More tools > Developer tools

2.1 Right click on the refresh button > select > Empty Cache and Hard Reload

2.2 Then type http://localhost:4200

References:

https://stackoverflow.com/questions/40430501/127-0-0-1-this-site-can-t-provide-a-secure-connection

https://stackoverflow.com/questions/57803161/how-to-connect-to-angular-nodejs-http-localhost4200-in-google-chrome

https://stackoverflow.com/questions/52846426/unable-to-get-angular-ng-serve-command-to-establish-an-https-context

N: Skipping acquire of configured file 'main/binary-arm64/Packages' - Ubuntu 20.10

 I share solution next error.

Edit file from path: 

sudo nano /etc/apt/sources.list.d/vscode.list

Comment or change next line on file.

Original line comment or update:

deb [arch=amd64,arm64,armhf] http://packages.microsoft.com/repos/vscode stable main

To:

deb [arch=amd64] http://packages.microsoft.com/repos/vscode stable main

That it is.

References: https://stackoverflow.com/questions/65306968/vs-code-n-skipping-acquire-of-configured-file-main-binary-arm64-packages/65310278#65310278

Query Working days monday to friday and saturday 1/2 + Oracle

I share query to get working days monday to friday and saturday 1/2, for example if you hire an employee start to work on (mm/dd/yyyy) 10/15/2020 then you to pay until 10/31/2020, the working day to pay is 13.5, because to omit sunday and sum 1/2 for saturday. 

Query:

SELECT

(SELECT (( TRUNC( to_date('10/31/2020', 'mm/dd/yyyy'), 'IW' ) - TRUNC( to_date('10/15/2020', 'mm/dd/yyyy'), 'IW' ) ) * 5 / 7

       + LEAST( to_date('10/31/2020', 'mm/dd/yyyy') - TRUNC( to_date('10/31/2020', 'mm/dd/yyyy'), 'IW' ) + 1, 5 )

       - LEAST( to_date('10/15/2020', 'mm/dd/yyyy') - TRUNC( to_date('10/15/2020', 'mm/dd/yyyy'), 'IW' ) + 1, 5 )) + 1

          AS WeekDaysDifference

FROM   dual)

+(

WITH t 

     AS (SELECT to_date('10/15/2020', 'mm/dd/yyyy') start_date, 

                to_date('10/31/2020', 'mm/dd/yyyy') end_date 

         FROM   dual) 

SELECT (Count(*)/2) numSaturday

FROM   (SELECT To_char(start_date + ( LEVEL - 1 ), 'fmday') dt 

        FROM   t 

        CONNECT BY LEVEL <= end_date - start_date + 1) 

WHERE  dt IN ( 'saturday' )) workingDays FROM DUAL;

Test:

References:

https://stackoverflow.com/questions/25400025/count-the-no-of-saturdays-and-sundays-in-date-range-oracle

https://stackoverflow.com/questions/12932965/sql-to-return-the-number-of-working-days-between-2-passed-in-dates

https://stackoverflow.com/questions/43632677/function-to-get-number-of-weekdays-between-two-dates-excluding-holidays/43633234#43633234

https://stackoverflow.com/questions/44203389/oracle-days-between-two-date-and-exclude-weekdays-how-to-handle-negative-number

RESTful Web Services from Oracle, HTTP Methods GET and POST

I share example how to consuming RESTful Web Services from Oracle, methods GET and POST with PL/SQL Anonymous Block, for this example i use http://jsonplaceholder.typicode.com/ json.

1. GET

DECLARE 
    req     utl_http.req; 
    res     utl_http.resp; 
    urlrest VARCHAR2(100) := 'http://jsonplaceholder.typicode.com/posts/1'; 
    name    VARCHAR2(4000); 
    buffer  VARCHAR2(4000); 
BEGIN 
    req := utl_http.Begin_request(urlrest, 'GET', ' HTTP/1.1'); 
    utl_http.Set_header(req, 'user-agent', 'mozilla/4.0'); 
    utl_http.Set_header(req, 'content-type', 'application/json'); 
    res := utl_http.Get_response(req); 

    LOOP 
        utl_http.Read_line(res, buffer); 
        dbms_output.Put_line(buffer); 
    END LOOP; 

    utl_http.End_response(res); 
EXCEPTION 
    WHEN utl_http.end_of_body THEN 
      utl_http.End_response(res); 
END; 

Test:

2. POST

DECLARE 
    req     utl_http.req; 
    res     utl_http.resp; 
    urlrest VARCHAR2(4000) := 'http://jsonplaceholder.typicode.com/posts'; 
    name    VARCHAR2(4000); 
    buffer  VARCHAR2(4000); 
    json    VARCHAR2(4000) := '{"title":"foo","body":"bar","userId":1}'; 
BEGIN 
    req := utl_http.Begin_request(urlrest, 'POST', ' HTTP/1.1'); 
    utl_http.Set_header(req, 'user-agent', 'mozilla/4.0'); 
    utl_http.Set_header(req, 'content-type', 'application/json'); 
    utl_http.Set_header(req, 'Content-Length', Length(json)); 
    utl_http.Write_text(req, json); 
    res := utl_http.Get_response(req); 

    BEGIN 
        LOOP 
            utl_http.Read_line(res, buffer); 

            dbms_output.Put_line(buffer); 
        END LOOP; 

        utl_http.End_response(res); 
    EXCEPTION 
        WHEN utl_http.end_of_body THEN 
          utl_http.End_response(res); 
    END; 
END; 

Test:

Kotlin - Multi-Threading in parallel and wait until all threads finish.

I share example how to execute Multi-Threading in parallel on Kotlin, is very useful if you want send a lot process simultaneously, In java you can use parallel stream and exist a lot examples, but it's almost the same.

I use an ExecutorService to manage pools of threads.

import java.util.concurrent.Executors
import java.util.concurrent.TimeUnit

fun main(args: Array<String>) {
    println("Started.....!")

    var listStr = arrayOf("test1", "test2", "test3",
            "test4", "test5", "test6", "test7", "test8", "test9", "test10")

    var es = Executors.newCachedThreadPool()

    for (item in listStr) {
        es.execute {
            println("item -> $item")
        }
    }

    es.shutdown()
    var finished = es.awaitTermination(1, TimeUnit.MINUTES)
    println("\\nFinished all threads $finished")

}

Run test: check test 3 execute after test 4 and test 2 execute after test 3. 

References:

https://winterbe.com/posts/2015/04/07/java8-concurrency-tutorial-thread-executor-examples/

https://howtodoinjava.com/java/multi-threading/executorservice-invokeall/

https://crunchify.com/how-to-run-multiple-threads-concurrently-in-java-executorservice-approach/

https://stackoverflow.com/questions/7939257/wait-until-all-threads-finish-their-work-in-java

Kotlin - Spring Data JPA calling Oracle Function

There are two way to call function in Spring Data JPA  with kotlin, I shares examples.

Create function in oracle.

CREATE OR replace FUNCTION Myfunction(value IN VARCHAR2) 
RETURN NUMBER 
IS 
  a NUMBER; 
  b NUMBER; 
BEGIN 
    RETURN a + b; 
END; 

Example 1, it won't work if your function is using DML statementes, but you can add annotation @Modifying annotation. 

import org.springframework.data.jpa.repository.Query
import org.springframework.data.repository.CrudRepository
import org.springframework.data.repository.query.Param

interface MyRepository: CrudRepository<YOUR_MODEL, YOUR_ID_MODEL>{
    @Query(nativeQuery = true, value = "SELECT myfunction(:value) FROM dual")
    fun myfunction(@Param("value") value: String?): Int?
}

Example 2: Create customer repository.

2.1 create custom repository

interface MyRepositoryCustom {

    fun myFunction(param1: String?): Int?
}

2.2 create a class, i use  SimpleJdbcCall.

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.jdbc.core.JdbcTemplate
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource
import org.springframework.jdbc.core.namedparam.SqlParameterSource
import org.springframework.jdbc.core.simple.SimpleJdbcCall


class MyRespositoryImpl : MyRepositoryCustom {

    @Autowired
    lateinit var jdbcTemplate: JdbcTemplate

    override fun myFunction(param1: String?): Int? {
        val jdbcCall = SimpleJdbcCall(jdbcTemplate).withFunctionName("myfunction")

        val paramMap: SqlParameterSource = MapSqlParameterSource()
                .addValue("value", param1)

        return jdbcCall.executeFunction(Int::class.java, paramMap)
    }
}

2.3 I extend customer repository on principal repository.

interface MyRepository: CrudRepository<YOUR_MODEL, YOUR_ID_MODEL>, MyRepositoryCustom {

That it is.

References:

https://stackoverflow.com/questions/45867348/spring-data-jpa-calling-oracle-function

Connect Oracle Database From Shell Script

There are two ways to connect Oracle from shell script.

1. You need to install SQL Plus Client on your server

2. You'll have install ORACLE on your server.

I share example for both.

Create file Oracle-ShellScript.sh

sudo nano Oracle-ShellScript.sh

Example with $ORACLE_HOME, add next lines into file. Check your path ORACLE_HOME

#!/bin/sh

#parameters DB

DATABASE_USER=$1

DATABASE_PASS=$2

IP=$3

SID=$4

DATE=`date +"%d%m%y"`

u="$USER"

echo "User name $u"

cd /home/$u

LOCATION=$PWD

echo "path ${LOCATION}"

ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe

export ORACLE_HOME

echo $ORACLE_HOME

dbConexion() {

$ORACLE_HOME/bin/sqlplus -s <<EOF> ${LOCATION}/log${DATE}.out

$DATABASE_USER/$DATABASE_PASS@//$IP:1521/$SID

select sysdate from dual;

EOF

}

dbValidate() {

p=`cat ${LOCATION}/log${DATE}.out | grep SYSDATE`

if [ -n "$p" ]

then

echo "Ok conexion"

rm ${LOCATION}/log${DATE}.out

else

echo "Bad conexion."

exit

fi

}

echo "Start process"

dbConexion

echo "Check conexion on DB"

dbValidate

echo "End process"

Example with SQL Plus client add next lines into file:

#!/bin/sh

#parameters DB

DATABASE_USER=$1

DATABASE_PASS=$2

IP=$3

SID=$4

DATE=`date +"%d%m%y"`

u="$USER"

echo "User name $u"

cd /home/$u

LOCATION=$PWD

echo "path ${LOCATION}"

dbConexion() {

sqlplus64 -s <<EOF> ${LOCATION}/log${DATE}.out

$DATABASE_USER/$DATABASE_PASS@//$IP:1521/$SID

select sysdate from dual;

EOF

}

dbValidate() {

p=`cat ${LOCATION}/log${DATE}.out | grep SYSDATE`

if [ -n "$p" ]

then

echo "Ok conexion"

rm ${LOCATION}/log${DATE}.out

else

echo "Bad conexion."

exit

fi

}

echo "Start process"

dbConexion

echo "Check conexion on DB"

dbValidate

echo "End process"

Test: Send the next argument to shell script user_db, password_db, ip and sid

sh Oracle-ShellScript.sh YOUR_USER_DB YOUR_PASSWORD_DB YOUR_IP YOUR_SID

Code on GitHub: https://github.com/HenryXiloj/Connect-to-oracle-shell-script