DEV Community: Cress

I'm going to buy an Oracle license when this war is over.

Cress — Tue, 29 Jul 2025 15:34:40 +0000

I tried to buy an Oracle license but couldn't. Because the system we are developing has users in Russia office.

https://www.oracle.com/jp/corporate/security-practices/corporate/governance/global-trade-compliance.html

Any company or national of Cuba, Iran, North Korea, Syria, and the Crimea region, Ukraine's Donbas and other Russian controlled areas of Ukraine as they exist in fact, Belarus*, Russia* and Venezuela*. Export licensing of commodities or services intended for these countries is presumed denied;

That is not only Oracle but also the other products from the United States.

That means we can't cut over our system unless Russia stops their war.

We will be forced to make difficult decision, such as making our system not to be used Russia users, or quitting our all projects.

A few fools are giving us a lot of trouble.

What's wrong with being against the war?

What I have become able to do by studying English

Cress — Wed, 14 Aug 2024 12:25:33 +0000

I had studied English at foreign insurance company for 1 year since April 2023. My colleagues at that time came from various countries, such as China, France, and India.

What I have become able to do are following:

Request for restarting application servers
Request for retrieving a log file and putting it into the shared file server
Writing email for my resignation announcement

After that, I have become a banker since April 2024. I have communicated with EMEA, Americas, and APAC in English.

What I have become able to do additionally are following:

Request for filling out for a network usage application
Response for inquiries regarding system usage from foreign offices
Apology for delay in sharing project overview

I still can't have daily conversations.

Announcement

Cress — Sat, 29 Jun 2024 05:16:38 +0000

I graduate from my business for June on the last business day of June. I would like to appreciate for my supporters and apologize for my unsatisfactory results.

It was only a short period of 20 business days since I started business on 3rd June and terminated on 28th. Although I have learned the business for June and have many opportunities in the future, I am also very disappointed that the last business day has come.

By the way, July comes soon. I will do my best using my experience of June.

Thank you.

Graduation from senior engineer

Cress — Thu, 07 Mar 2024 16:10:38 +0000

I will graduate from senior engineer at the end of this month.
From next month, I will become a banker at a Japanese famous mega bank.

My technical field was open technologies such as Java, Oracle, and Linux. I have been involved in IT system development for life insurance business for 14 years. I could gain experiences of IT and finance.

Additionally, I have studied English very hard since last year. Because I could not talk about business with my colleagues without English. My business was widen because of English, and I could know that there are many more talented engineers in the world.

Now I will be involved in international information systems for the mega bank. Although I will become not to make programs by myself, I will improve information systems by different approach.

I will graduate from senior engineer soon.

Thank you.

My purpose of studying foreign languages

Cress — Mon, 21 Aug 2023 06:43:43 +0000

One of my colleagues is a young engineer from France. He is so talented that he will become an executive. When he becomes an executive, he should take us to an exclusive Japanese restaurant. For that day, I must study French as well as English.

Create a web application for a small business by Next.js with Slack authentication

Cress — Sat, 27 May 2023 11:56:54 +0000

Creating a web application, it is hard work that implementing a login authentication. Login authentication, reissuance forgotten password, password change and etc. are required. But using NextAuth.js and Slack, you don't need for preparing these yourself. It is very easy and recommended for small businesses.

Create LOCAL server with HTTPS enabled

Slack requires that the application URL uses HTTPS, even for local development. In this case, local-ssl-proxy is easy and useful.

Configure on Slack side

Follow quickstart.

https://api.slack.com/authentication/quickstart

Create a client ID and a client secret

Click "Create a new Slack app" button.
In "Your Apps" page, click "Create New App" and choose "From scratch"
Enter your app name and pick a workspace to develop your app in.
Click "Create App" button.

Then, in "App Credentials" section of "Basic Information" page, you can see its client ID and client secret.

Configure a redirect URL

In "Add features and functionality" section of "Basic Information" page, click "Permissions".
In Redirect URLs of "OAuth & Permissions" page, click "Add New Redirect URL" button.
Enter "https://localhost:3001" and click "Add" button.
Click "Save URLs" button.

Then you can use authentication by Slack.

Create your application

.env.development.local

Put information depending your environment into .env.development.local file as below:

SLACK_CLIENT_ID = "<Your client ID>"
SLACK_CLIENT_SECRET = "<Your client secret>"
NEXTAUTH_URL = "https://localhost:3001"
NEXTAUTH_SECRET = "changeit"

Values for SLACK_CLIENT_ID and SLACK_CLIENT_SECRET are what you get in "Create a client ID and a client secret" section.

/api/auth/[...nextauth].ts

This is the minimal configuration.

import NextAuth from "next-auth/next"
import SlackProvider from "next-auth/providers/slack"

export const authOptions = {
  providers: [
    SlackProvider({
      clientId: <string>process.env.SLACK_CLIENT_ID,
      clientSecret: <string>process.env.SLACK_CLIENT_SECRET
    })
  ]
}

export default NextAuth(authOptions)

pages/_app.tsx

Surround Component with SessionProvider.

import '@/styles/globals.css'
import { SessionProvider } from 'next-auth/react'
import type { AppProps } from 'next/app'

export default function App({ Component, pageProps: { session, ...pageProps } }: AppProps) {
  return (
    <SessionProvider session={session}>
      <Component {...pageProps} />
    </SessionProvider>
  )
}

Example: index.tsx

It shows login button. As you logged in, it shows your name and logout button.

import React from "react"
import { signIn, signOut, useSession } from "next-auth/react"
import { Button } from "react-bootstrap"
import "bootstrap/dist/css/bootstrap.min.css"

export default function Home() {
  const {data: session, status} = useSession()

  if (status === "loading") {
    return <p>Loading...</p>
  }

  if (status === "authenticated") {
    return (
      <>
        <p>You are logged in as {session.user?.name}</p>
        <Button onClick={() => signOut()}>Logout</Button>
      </>
    )
  } else {
    return (
      <Button onClick={() => signIn("slack")}>Login</Button>
    )
  }
}

Integration with Prisma

NextAuth.js has an adapter for using Prisma. Sessions can be managed in databases.

https://authjs.dev/reference/adapter/prisma

Installation

npm install next-auth @prisma/client @next-auth/prisma-adapter
npm install -D prisma

Prisma setup

An example using MySQL is shown.

npx prisma init --datasource-provider mysql

Then, edit prisma.schema file as below:

// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "mys"
  url      = env("DATABASE_URL")
}

model Account {
  id                 String  @id @default(cuid())
  userId             String
  type               String
  provider           String
  providerAccountId  String
  ok                 Boolean?
  refresh_token      String?  @db.Text
  access_token       String?  @db.Text
  expires_at         Int?
  token_type         String?
  scope              String?
  id_token           String?  @db.Text
  state              String?
  session_state      String?

  user User @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@unique([provider, providerAccountId])
}

model Session {
  id           String   @id @default(cuid())
  sessionToken String   @unique
  userId       String
  expires      DateTime
  user         User     @relation(fields: [userId], references: [id], onDelete: Cascade)
}

model User {
  id            String    @id @default(cuid())
  name          String?
  email         String?   @unique
  emailVerified DateTime?
  image         String?
  accounts      Account[]
  sessions      Session[]
}

model VerificationToken {
  identifier String
  token      String   @unique
  expires    DateTime

  @@unique([identifier, token])
}

Edit following line in .env.development.local file according to your environment.

DATABASE_URL="mysql://johndoe:randompassword@localhost:3306/mydb"

Run a command as below:

npx prisma generate

Now Prisma client has been generated.

/api/auth/[...nextauth].ts

Add adapter property to authOptions.

import { PrismaAdapter } from "@next-auth/prisma-adapter"
import { PrismaClient } from "@prisma/client"
import NextAuth from "next-auth/next"
import SlackProvider from "next-auth/providers/slack"

const prisma = new PrismaClient()

export const authOptions = {
  adapter: PrismaAdapter(prisma),
  providers: [
    SlackProvider({
      clientId: <string>process.env.SLACK_CLIENT_ID,
      clientSecret: <string>process.env.SLACK_CLIENT_SECRET
    })
  ]
}

export default NextAuth(authOptions)

Initialize database

npx prisma migrate dev --name init

For your information

Don't worry that outsiders can't log in even if they have an other domain Slack account. Because the client ID you got is tied to your Slack domain, only your Slack domain member can log in. It is not always necessary to hold user information in your database.

When you need HTTPS on LOCAL environment, local-ssl-proxy is the best solution

Cress — Mon, 22 May 2023 03:15:09 +0000

Implementing single-sign-on (SSO) with nextauth.js and Slack, LOCAL environment also needs HTTPS support. In this case, it is very easy and useful that using local-ssl-proxy like a reverse proxy server.

This article is for Windows PC.

Installing local-ssl-proxy

Local-ssl-proxy only supports global installation. Install as below:

npm install -g local-ssl-proxy

An example usage is below:

npx local-ssl-proxy --source 3001 --target 3000

In this example, an application is running on port 3000. Run local-ssl-proxy on port 3001 targeting for port 3000.

https://github.com/cameronhunter/local-ssl-proxy

It works but SSL warnings

You'll get a warning because the certificate is self-signed, this is safe to ignore during development.

Create an effective certificate using mkcert.

Installing scoop

On Windows, it is very easy that installing mkcert using scoop. Following the quickstart, run as below:

Set-ExecutionPolicy RemoteSigned -Scope CurrentUser
irm get.scoop.sh | iex

https://scoop.sh/

Installing mkcert

Mkcert is the best solution for creating certificates on Windows. It is easier than installing OpenSSL and others as below:

scoop bucket add extras
scoop install mkcert

This installation should be failed without Git. Install Git first if you don’t have.

https://github.com/FiloSottile/mkcert

Running mkcert

Create a local certificates authority (CA). The following command must be run as administrator privilege. If you have run as not administrator privilege, redo with running mkcert -uninstall.

mkcert -install

Then, create a key and a certificate for localhost as below:

mkcert localhost

You should have gotten localhost-key.pem and localhost.pem.

Running local-ssl-proxy with the certificate enabled

npx local-ssl-proxy --key localhost-key.pem --cert localhost.pem --source 3001 --target 3000

Running local-ssl-proxy every time is exhausting

Npm-run-all is the best solution. It can run multiple commands for serial or parallel. Install as below:

npm install -D npm-run-all

Then, change package.json as below:

/* package.json */
{
  "scripts": {
    "dev": "npm-run-all -p dev:*",
    "dev:app": "next dev",
    "dev:ssl": "local-ssl-proxy --key localhost-key.pem --cert localhost.pem --source 3001 --target 3000"
    /* snipped */
  }
  /* snipped */
}

Running npm run dev, commands matching with dev:* will be run for parallel.

https://www.npmjs.com/package/npm-run-all

Wildcard not expanded on powershell

Cress — Sun, 21 May 2023 18:33:13 +0000

What we want to do

python myapp.py folder/*.txt

Correct usage

python myapp.py (Get-Item folder/*.txt)

ORA-28000: the account is locked

Cress — Sat, 20 May 2023 03:48:18 +0000

Who locked oracle database account?

If you have any idea, let me know right now!
But no one does, so we need to find out who locked it.

Survey method

For windows, you can find the error logs on Event Viewer. For Linux and others, on the Oracle alert logs. Its location is below:

$ORACLE_BASE/diag/rdbms/<SID>/<SID>/trace/alert_<SID>.log

First, find the line "ORA-28000: the account is locked". Then, find the line "ORA-01017: invalid username/password; logon denied" just before it. Because the most likely cause is wrong password.
You can find the source host name printed.

Shout the source host name

That is the culprit.

Corrective action

Make sure all members understand the above steps and that no one can escape from administrator.

For English studying...

Cress — Sat, 20 May 2023 02:55:36 +0000

My new boss is a man from France.
Body language doesn't work to him.
I should study English again.

The above is a part of a famous song in Japan.

I am publishing a tech blog in Japanese, following:
https://qiita.com/cress_cc

But there is not enough tech information in Japanese, and so is English.
Therefore, I'll write tech articles while studying English.

Sorry for my poor English, and thank you for reading.