mainul35

FWIW: I didn't produce the content presented here (the outline from Edmond Lau's book). I've just copy-pasted it from somewhere over the Internet, but I cannot remember what exactly the original source is. I was also not able to find the author's name, so I cannot give him/her the proper credits.

---

Effective Engineer - Notes

• By Edmond Lau
• Highly Recommended 👍
• http://www.theeffectiveengineer.com/

What's an Effective Engineer?

mainul35

function manageLoginSession() {
    let totalTabs: number;

    window.onload = function(e) {
      let accessToken = sessionStorage.getItem("accessToken");
      let refreshToken = sessionStorage.getItem("refreshToken");
      let expiresAt = sessionStorage.getItem("expiresAt");
      if (accessToken !== null && refreshToken !== null && expiresAt !== null) {
        localStorage.setItem("accessToken", accessToken);
        localStorage.setItem("refreshToken", refreshToken);

mainul35

How to Install GraalVM Community Edition on Linux

Note: Tested on Fedora only

1. Download the new release of GraalVM and unpack it anywhere in your filesystem:

$ tar -xvzf graalvm-ce-1.0.0-rc14-linux-amd64.tar.gz

mainul35

1. Download from the official site.

2. Extract it.

   sudo tar -zxvf graalvm-ce-java11-linux-amd64-20.0.0.tar.gz

3. Move it to /usr/lib/jvm/

   mv graalvm-ce-java11-20.0.0 /usr/lib/jvm/

4. Check your java alternatives

sudo update-alternatives --config java

mainul35

https://computingforgeeks.com/how-to-install-postgresql-on-fedora/

mainul35

Login to PostgreSQL from terminal with Postgres DB user

Note that, in following lines, you have first entered into postgres user't terminal (Of your OS) root Then by using psql command, you have entered into the postgres DB user's shell

[mainul35@localhost ~]$ sudo su postgres
bash-5.0$ psql
could not change directory to "/home/mainul35": Permission denied
psql (11.7)
Type "help" for help.

mainul35

Background story

It is a common scenario that we often forget out database password. When we try to log in to our mysql DB, we face the following error message. If we use a password:

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

If we don't use a password:

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

mainul35

```
# Database connection url: r2dbc:postgresql://host/bd_name
spring.r2dbc.url=r2dbc:postgresql://localhost/r2dbc_test
# Connection username
spring.r2dbc.username=postgres
# Connection Password
spring.r2dbc.password=
```

mainul35

@Configuration
@EnableR2dbcRepositories(basePackages = "com.mainul35.repositories")
public class DatabaseConfig extends AbstractR2dbcConfiguration {

    @Value("${datasource.host}")
    private String host;
    @Value("${datasource.port}")
    private int port;
    @Value("${datasource.database}")
    private String database;

mainul35

@SpringBootApplication
public class ReactivespringApplication implements CommandLineRunner {

    @Autowired
    private DatabaseClient databaseClient;
    @Autowired
    private ReservationRepository reservationRepository;

    public static void main(String[] args) {
        SpringApplication.run(ReactivespringApplication.class, args);