Forem: Carlos Estrada

Creating a simple access middleware for nextjs route handlers

Carlos Estrada — Tue, 15 Apr 2025 00:46:09 +0000

In the past days I've been working into a simple demo app to understand how to work between a web application made with nextjs and a mobile app in flutter.

I'm not a big fan of the solutions provided by nextjs regarding the middleware aspect of the framework, instead I prefer the approach of laravel or express.

With that in mind I decide to build a wrapper function to add protection for specific endpoints.

So the first thing that I did was move my endpoints logic from a route.ts file to a controller.ts.

Second we create a simple function to receive the permission that the user should be have to access that endpoint, the Request and Params for the endpoint and finally the callback function to be called.

Wrapper function for the endpoints

import { NextRequest } from "next/server"
import { getToken } from "./get-token"

/**
 * Helper function to wrap the route handler methods to allow to check if the user
 * has the permission to access the endpoint.
 */
export const hasAccess = async (
    permission: string,
    req: NextRequest,
    params: any,
    method: Function
) => {
    const token = await getToken(req)

    if (!token) return Response.json({ message: "Unauthorized" }, { status: 401 })

    if (!token.permissions?.includes(permission))
        return Response.json({ message: "Forbidden" }, { status: 403 })

    return method(req, params)
}

Example of the endpoints

route.ts

import { GET as getItems, POST as createItem } from "./controller"
import { hasAccess } from "@/helpers/has-access"
import { PERMISSIONS } from "@/constants/permissions"
import { NextRequest } from "next/server"

const GET = (req: NextRequest, params: any) =>
    hasAccess(PERMISSIONS.items.getItems, req, params, getItems)

const POST = (req: NextRequest, params: any) =>
    hasAccess(PERMISSIONS.items.createItem, req, params, createItem)

export { GET, POST }

Controller.ts

import { NextRequest } from "next/server"
import { itemSchema } from "./schema"
import { pgQuery } from "@/lib/pg"
import { itemsQuery } from "./queries"
import getItems from "@/actions/items/get-items"

export async function GET() {
    try {
        const items = await getItems()
        return Response.json(items)
    } catch (error) {
        console.error(error)
        return Response.json({ error: "Something went wrong" }, { status: 500 })
    }
}

export async function POST(req: NextRequest) {
    try {
        const json = await req.json()
        const validated = itemSchema.parse(json)

        await pgQuery(itemsQuery.createOne, [validated.name, validated.description])

        return Response.json({ success: "Item created" }, { status: 201 })
    } catch (error) {
        console.error(error)
        return Response.json({ error: "Something went wrong" }, { status: 500 })
    }
}

I want to share this as a random tip for when you want to build simple demos and don't want to go with a more robust solution. After all the goal of this project is to learn how to communicate a mobile app and a web app, using the frameworks of flutter and nextjs.

Migration of nextjs 14 to next 15

Carlos Estrada — Thu, 20 Feb 2025 02:02:17 +0000

This post is about my personal experience migrating
projects from nextjs 14 to the new major release of
nextjs 15 and react 19.

Let's get to the point, I'm really interested and happy
for the new version of the Nextjs Framework.

For those who don't know, right now I'm a software developer
working full time with nextjs, and to be completily honest,
nextjs 14 was a really bad experience for me, I think was the
first technology that I can say, that I hate.

And part of the reasons of that were, the cache system used
in the route handler or api routes, the performance in the dev
environment without using --turbopack flag.

After sometime with next 15 with us (released in october 21 of 2024) and
with the version 15.1 (released in december 10 of 2024), I started the migration
of the template used inside the company to next 15 and react 19.

The migration was really easy, just running the codemons, updating the dependencies
that were used in the project (mostly shadcn components) and refactorizing some code
to be aligned with the future of nextjs (cookies, and params)

And I have to say, that I was really happy about the new speed in the development server
and the final removal of the cache by default of nextjs. Right now we are in the progress
of migrating projects using the next 14 version to the new one.

I have to say that I'm really interested in this new version of nextjs, I hope to bring
more content about it in the future.

Creating a todo app with JDBC

Carlos Estrada — Sat, 08 Feb 2025 17:04:21 +0000

Welcome to another post, today we will be looking about the JDBC, what is, how
can we use one, and most important creating a simple java application abouta todos app
that not only connects to a postgresql database.

But also implementing a really basic ORM similar to the eloquen one from laravel.

Before starting let's look about what is a JDBC.

What is JDBC?

JDBC is the Java Database Connectivity api, that allows us to access virtually
any data source, is comprised of two packages:

java.sql
javax.sql

That are installed by default when we get the Java SE 8.

How can we use one?

For use the JDBC api with a particular database management system, we need
a JDBC technology-based driver to mediate between JDBC tehcnology and the
database.

This driver can be written in pure java or in a mixture or java and java native
interface (JNI) native methods.

Today we will be using the Postgresql JDBC driver
for our project.

Requirements

For this project you will be need the next:

Maven
Java
Postgresql (You can use docker)

Creating the project

For creating a new project with maven use the next command

mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.5 -DinteractiveMode=false

Here is the link of the docs if you want to learn more about this part Maven in 5 minutes

After the commands end, and you enter the folder let's create the database.

Creating the database

Postgresql installed in the OS

If you have installed postgresql in your system you only need to create a new database and
create the next table

create table tbl_jd_todos (
    id serial primary key,
    name varchar(255) not NULL,
    completed smallint default 0 not null,
    created_at timestamp default now()
)

After creating the table go to Creating an env file

Using docker

In case you want to use docker here is the docker-compose.yml file that we will
need:

services:
  jodos_db:
    image: postgres:15
    container_name: jodos_db
    env_file:
        - .env
    ports:
      - "${DB_PORT}:5432"
    volumes:
      - jodo-data:/var/lib/postgresql/data

volumes:
  jodo-data:
    name: jodo-data

We will need to create an .env file to specify the user, password, db and port of our app
so let's create one.

Creating an env file

In this section will be creating the .env file for our project.
For that let's create the file at the root of the project .env with
the next values:

DB_PORT=""
POSTGRES_USER=""
POSTGRES_PASSWORD=""
POSTGRES_DB=""

Fill the values of the env file and let's continue:

In case you are using docker, please run docker compose up and ensure
that you can connect to the database using a database manager tool like dbeaver

Installing dependencies

Let's continue and install all the dependencies for this project.

We will be using two the postgres-jdbc
and the dotenv java.

Let go to the above links and add the dependencies to your poml file. Your poml file
should be look like these:

 <dependencies>
     <!-- rest of dependencies -->
 <!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <version>42.7.5</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/io.github.cdimascio/dotenv-java -->
    <dependency>
        <groupId>io.github.cdimascio</groupId>
        <artifactId>dotenv-java</artifactId>
        <version>3.1.0</version>
    </dependency>
 </dependencies>

The java files for database and orm implementation

We will need two important things in this project one file for getting a connection
to our database and the base class for our models.

Let's begin creating the database file.

Create a DB.java file with the next code:

package com.caresle.jodos;

import java.sql.*;

import io.github.cdimascio.dotenv.Dotenv;

/**
 * DB
 */
public class DB {
  static String url;

  static {
    Dotenv dotenv = Dotenv.load();
    String port = dotenv.get("DB_PORT");
    String database = dotenv.get("POSTGRES_DB");
    String username = dotenv.get("POSTGRES_USER");
    String password = dotenv.get("POSTGRES_PASSWORD");
    url = "jdbc:postgresql://localhost:" + port + "/" + database + "?user=" + username + "&password=" + password; 
  }


  private static Connection connection;

  private DB() {}

  public static Connection getConnection() throws SQLException {
    if (connection == null || connection.isClosed()) {
      connection = DriverManager.getConnection(url);
    }
    return connection;
  }
}

In this file we are creating the url for connecting to our database, also definning
a method to get the connection of the database to be used by the model.

Next is time to create Model.java file.

This file will be in charge of providing the general methods to interact with the database
for our models. First of all this class will be an abstract class and we are going to define
the next props:

protected static String table;
protected Map<String, Object> attributes = new HashMap<>();

The first prop is the table name, and the second is the attributes of the model.

Let's now create the methods for set and get the attributes.

public void set(String key, Object value) {
  attributes.put(key, value);
}

public Object get(String key) {
  return attributes.get(key);
}

Remember that Object is the base class of all the java classes, so we can use it
to get the value of the attribute.

The first thing that we will create is the delete method, because is the easiest one.

public boolean delete() throws SQLException {
  String sql = "DELETE FROM " + table + " WHERE id = ?";

  try (Connection connection = DB.getConnection()) {
    PreparedStatement statement = connection.prepareStatement(sql);
    statement.setObject(1, attributes.get("id"));
    return statement.executeUpdate() > 0;
  }
}

Here we are usingt the id attribute of the model to delete the record from the database.
Also we are propagating the exception to the caller.

Now we will be creating a helper method for set the parrams of the model.

private void setParameters(PreparedStatement statement) throws SQLException {
  int index = 1;

  Set<String> keys = attributes.keySet();
  keys.remove("id");

  for (String key: keys) {
    statement.setObject(index++, attributes.get(key));
  }
}

This method will be used in the insert and update methods. So let's create the insert method.

private boolean insert() throws SQLException {
  String columns = String.join(", ", attributes.keySet());
  String valuesPlaceholder = String.join(", ", Collections.nCopies(attributes.size(), "?"));

  String sql = "INSERT INTO " + table + " (" + columns + ") VALUES (" + valuesPlaceholder + ")";

  try (Connection connection = DB.getConnection()) {
    PreparedStatement statement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
    setParameters(statement);

    int affectedRows = statement.executeUpdate();

    if (affectedRows > 0) {
      ResultSet resultSet = statement.getGeneratedKeys();

      if (resultSet.next()) {
        attributes.put("id", resultSet.getLong(1));
      }
    }
    return affectedRows > 0;
  }
}

And now the update method.

private boolean update() throws SQLException {
  int id = (int)attributes.get("id");
  Set<String> keys = attributes.keySet();

  keys.remove("id");
  String setClause = String.join(" = ?, ", keys) + " = ?";
  String sql = "UPDATE " + table + " SET " + setClause + " WHERE id = ?";

  try ( Connection connection = DB.getConnection()) { 
    PreparedStatement statement = connection.prepareStatement(sql);
    setParameters(statement);
    statement.setObject(keys.size() + 1, id);
    return statement.executeUpdate() > 0;
  }
}

Finally we will create the method for use update and insert, because they are private and the only difference is
the id attribute.

public boolean save() throws SQLException {
  if (attributes.containsKey("id")) {
      return update();
  }

  return insert();
}

And here are some static methods for findById and findAll.

FindById

public static <T extends Model> T findById(Class<T> modelClass, long id) {
  String sql = "SELECT * FROM " + table + " WHERE id = ?";

  try (Connection connection = DB.getConnection()) {
    PreparedStatement statement = connection.prepareStatement(sql);
    statement.setLong(1, id);
    ResultSet resultSet = statement.executeQuery();

    if (resultSet.next()) {
      try {
        T instance = modelClass.getDeclaredConstructor().newInstance();

        ResultSetMetaData metaData = resultSet.getMetaData();

        for (int i = 1; i <= metaData.getColumnCount(); i++) {
            instance.set(metaData.getColumnName(i), resultSet.getObject(i));
        }

        return instance;
      } catch (Exception e) {
        throw new RuntimeException("Error creating instance of " + modelClass.getName(), e);
      }
    }
  } catch (SQLException e) {
    System.err.println("SQL ERROR" + e.getMessage());
    e.printStackTrace();
  }
  return null;
}

FindAll

public static <T extends Model> ArrayList<T> all(Class<T> modelClass) {
  ArrayList<T> models = new ArrayList<>();
  try (Connection connection = DB.getConnection()) {
    String sql = "SELECT * FROM " + table;
    PreparedStatement statement = connection.prepareStatement(sql);

    ResultSet resultSet = statement.executeQuery();

    while (resultSet.next()) {
      try {
        T instance = modelClass.getDeclaredConstructor().newInstance();

        ResultSetMetaData metaData = resultSet.getMetaData();

        for (int i = 1; i <= metaData.getColumnCount(); i++) {
            String columnName = metaData.getColumnName(i);
            Object value = resultSet.getObject(i);
            instance.set(columnName, value);
        }

        models.add(instance);
      } catch (Exception e) {
        throw new RuntimeException("Error creating instance of " + modelClass.getName(), e);
      }
    }
  } catch (SQLException e) {
    System.err.println("SQL ERROR" + e.getMessage());
    e.printStackTrace();
  }
  return models;
}

And here is the example of creating a Todo model.

package com.caresle.jodos;

import java.util.ArrayList;

/**
 * Todo
 */
public class Todo extends Model {
  static {
    table = "tbl_jd_todos";
  }

  public Todo() {}

  public static Todo findById(long id) {
    return (Todo) Model.findById(Todo.class, id);
  }

  public static ArrayList<Todo> all() {
    return (ArrayList<Todo>) Model.all(Todo.class);
  }
}

Creating the menu for the app

Let's create the class UI.java for handle the menu and their actions

package com.caresle.jodos;

import java.util.ArrayList;
import java.util.Scanner;

public class Ui {
  static int LIST = 1;
  static int CREATE = 2;
  static int EDIT = 3;
  static int COMPLETE = 4;
  static int DELETE = 5;
  static int EXIT = 6;

  public static void print() {
    System.out.println("=\tSELECT THE OPTION\t=");
    System.out.println("1) List all todos");
    System.out.println("2) Create a new todo");
    System.out.println("3) Edit a todo");
    System.out.println("4) Mark a todo as completed");
    System.out.println("5) Delete a todo");
    System.out.println("6) Exit");
  }

  public static void listTodos() {
    ArrayList<Todo> todos = Todo.all();

    for (Todo todo: todos) {
      System.out.println(todo);
    }
  }

  public static void createTodo(Scanner scanner) {
    System.out.println("Enter the todo:");
    scanner.nextLine();
    String todo = scanner.nextLine();
    try {
      Todo newTodo = new Todo();
      newTodo.set("name", todo);
      newTodo.set("completed", 0);
      newTodo.save();
    } catch (Exception e) {
      System.err.println("ERROR: " + e.getMessage());
    }
  }

  public static void editTodo(Scanner scanner) {
    System.out.println("Enter the id of the todo to edit:");
    long id = scanner.nextLong();
    Todo todo = Todo.findById(id);
    System.out.println("Enter the new todo:");
    scanner.nextLine();
    String todoName = scanner.nextLine();
    todo.set("name", todoName);
    try {
      todo.save();
    } catch (Exception e) {
      System.err.println("ERROR: " + e.getMessage());
    }
  }

  public static void completeTodo(Scanner scanner) {
    System.out.println("Enter the id of the todo to complete:");
    long id = scanner.nextLong();
    Todo todo = Todo.findById(id);
    todo.set("completed", 1);
    try {
      todo.save();
    } catch (Exception e) {
      System.err.println("ERROR: " + e.getMessage());
    }
  }

  public static void deleteTodo(Scanner scanner) {
    System.out.println("Enter the id of the todo to delete:");
    long id = scanner.nextLong();
    Todo todo = Todo.findById(id);
    try {
      todo.delete();
    } catch (Exception e) {
      System.err.println("ERROR: " + e.getMessage());
    }
  }
}

Joining all the parts

Now in the App.java file we will add all the parts to create the app.

package com.caresle.jodos;

import java.util.Scanner;

public class App {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    int option = 0;

    while (option != Ui.EXIT) {
      Ui.print();
      option = scanner.nextInt();

      if (option == Ui.LIST) {
        Ui.listTodos();
        continue;
      }

      if (option == Ui.CREATE) {
        Ui.createTodo(scanner);
        continue;
      }

      if (option == Ui.EDIT) {
        Ui.editTodo(scanner);
        continue;
      }

      if (option == Ui.COMPLETE) {
        Ui.completeTodo(scanner);
        continue;
      }

      if (option == Ui.DELETE) {
        Ui.deleteTodo(scanner);
        continue;
      }
    }

    scanner.close();
  }
}

Conclusion

With this post we have learned how to create a simple java application with jdbc and
how to create a simple orm for our models.

Java project, creating a cli

Carlos Estrada — Wed, 29 Jan 2025 14:15:20 +0000

In today's post we will be talking about my experience
working in a cli project for the past few days.

One of the things that I wanted to focus this year was Java
so after completing some challenges of advent of code and doing
a little bit of practice in the general language I decide to start
creating a little project to learn more about the language and to have
a more close experience with the general development of a java application.

So let's beggin.

What we are building

We are building a simple cli application that emulates three comands of the
unix system, this are ls, mv and ifconfig the reason for choose these three
where the next.

I want to work with files
I want to know more about how ifconfig is build under the hook

Building the project

The first step that I take was trying a tool to manage all of my code,
so after a quick search I found that maven is one of the options in the java
ecosystem for this task. So I quickly follow the basic getting started guide in
the docs, and get the basic skeleton of my project.

Then I decide to spent sometime trying to figure out how to do testing in java with
JUnit however, after a while, found a bit difficult to test the cli, in part for a lack
of experience in the general ecosystem and more specially in the cli word.

For overcoming this, the decision was really simple, focus on building first the commands
and later on, how I grow and learn more about java and their ecosystem came back and add
them to the project.

Creating LS

So the first command that I create was LS, I won't lie, the first thing that I did was
asking to chatgpt how is does this in java, I was expecting for my experience with javascript
to use classes and methods from the IO (fs in javascript). I never though that the File
class, has a build in method for listing the files inside a directory and that for that
to work we need to create a new instance of file with the option ..

File directory = new File(".");
File[] files = directory.listFiles();

I also add a simple text indicating if the file was a Folder, Hidden or a File

Creating mv

Creating this command was in general really similar to the ls the main difference is that
I start creating a simple function that move a specif file and then later on I add
the posibility to pass two arguments the originalPath and the destinyPath for the files.

Creating ifconfig

For creating this command I follow the same process that in the pass two, I ask chatgpt to
generate a basic code for the command and then either I add some more steps in front of What
chatgpt gives to me, or I went to the java docs to learn about the classes that where being
used in the command. For example here I learn more about the java.net package.

And a general overview of how to work with that package and Enumeration.

Conclusion

I think that in the next projects I will be focusing in another things to start to understand
java better, for example the next one is a simple connection to a database using a JDBC

Here is the code for the project junix

How I am learning java

Carlos Estrada — Wed, 22 Jan 2025 02:10:16 +0000

As the title suggest today's post will be focus in how I spend the free
time that I have to learn about the java programming language.

So let's breakdown the points that we will discus

Learning the language
Personal Projects
Ecosystem

Learning the language

First of all I want to clarify that Java is not my first language so the time that take's me learn it
maybe to you will be less or higher depending in your experience.

Right now For learning the language I'm doing some advent of code challenges, just to getting familiar
with the general langauge, how to import pacakges, how to read from a file, how to handle exceptions,
the datatypes, etc.

This thing is getting almost everything in the days that I spend learning about the language. However
I'm doing also some projects to learn more about so let's jump to that section

Personal Projects

Regarding the personal projects right now I'm creating a simple CLI with command similar to linux
I decide to call the project junix. Some of the commands that I'm recreating are ls, mv and ifconfig.

When I have any question I go to chatgpt and ask for some clarifications, I personally try not to ask chapgpt for
the solution right away, instead asking if my asummsion is correct, bringing my experience from another programming languages
like javascript to java.

For example instead of asking I want a ifconfig command writting in java I ask something like this I want to know if there is a set of classes in java for doing something similar to the ifconfig of linux (I don't want to use external packages just the stl)

And of course in some cases chatgpt gives me the code, but instead of just copy and pasting I look at the classes that It's using
to learn where should I go for documentation, one example is the Idea of using java.net so I go to the docs at oracle and find that
package and start looking what things has, specially the ones that is using chatgpt to compare what chapie says and what I'm looking
in the docs.

Ecosystem

With the ecosystem of java I'm starting learning about the differents things that has to offer for example the build system like
maven or gradle, also the testing libraries like junit

Conclusion

Right now I'm still in the process of learning, however i expect to end the junix (this first personal project of java) at the end of
this month. Also I want to do at least 2-3 projects without a framework to really understand the java build system and their general
process I hope for the end of february to start looking to frameworks like spring boot.

Neetcode Roadmap Part 1

Carlos Estrada — Wed, 15 Jan 2025 18:30:05 +0000

In 2024 one of the things that I wanted to improve was my programming logic,
but not only my logic, in fact I wanted to increase my understanding of algorithms,
you know, be one of those person that can understan what big O.

One of the resource that I use for this goal was the roadmap of the youtube channel Neetcode.

In today's post I will share my progress in the roadmap so far. Right now I had completed
64 problems of 150 in the page.

So let's take a look at what I've learn.

Here is the breakdown of the things

It's hard
I need to solve more problem to truly said that I dominate that section
Feels amazing to complete every single challenge.

Let's take a deep look at those points.

It's hard

At the beginning for me, was like "Alright this thing shouldn't be so difficult" and I was totally wrong
of course there is a lot of easy challenges and problems that just with brute force solution you can solve
but here the point (at least for me) It to learn in how to come with the best possible solution, being the
most efficient one. And for second time I wasn't expecting to be this hard. For example some of the problems
in the tree section I have to understand and work more with recursion, one thing that always has been one of
my weak points. Right now I still having a lot of problems trying to understand some of the ideas, so yeah
that was take us to the next point.

I need to solve more problems to truly said that I dominate that section

No matter that I almost complete like 5 or 6 sections, I feel like the need to practice more to be able to
solve not only the problem more easily but also because I want to truly feel confortable writting tree algorithms,
recursion or working with sliding window.

So in the near future after I complete the roadmap I will spend more time solving problems in leetcode
to solidify this knowledge.

Feels amazing to complete every single challenges

I feel like problem after problem, no matter if took me a week or I have to spend more time that I expected
at the beginning after I see that the problem was completed I only can feel a really relaxing feeling inside me.

Conclusion

In short I need more practice to feel good with these problems but also I expect this year to complete this roadmap
I have around 1/3 of the roadmap made, but still a long way left, so let's see how the things evolve in the future.

My Study Schedule for 2025

Carlos Estrada — Wed, 08 Jan 2025 14:09:04 +0000

Welcome back, today I will share with you my personal schedule for this 2025
for learning and practicing all that we discuss in the previous post.

So first things first let take a look at the schedule:

Let's break down the schedule in two parts the working days and the weekends.

Working days

Because I have a full time job as a Software developer, I don't have as much time
as I wantend. These days my main focus is to create the habit of working even when I have
a job. Removing my job from the schedule we have three points to talk about here.

English Study

I'm currently learning english with the goal to be able to talk and share ideas on this language.
So for that to become a reallity I decide to start the year setting a real time to seat down and
study the language and improve my listening, writting and speaking.

Right now is just one hour because I want to build the habit to study english no matter what at that time.

Public Projects

This section is dedicated a the projects that I will build for the comunity and in a public way in my github.
Not only to build a better portfolio but also to share something with all of you.

Java Study

Because one of the things that I want to learn this year is spring boot, I decide to in my working days
I will using around 1:30 for learning to use the framework, language and tooling.

Weekends

In the other side when we are talking about weekends the schedule becomes a lot more heavy because we will
focus on improving some specific areas where I'm bad. And of couse taking more time for study and working on
my portfolio.

Here the two points that we add respect to the working days are the next one:

Sql Study

As one of the most used skills at my current job, I need to learn and improve my current sql understanding
with the objective that with this, my day to day at the office will be a lot relaxing.

Neetcode Roadmap

And finally neetcode roadmap is because I want to improve my programming logic and understand better the data structures
like trees, graphs, etc. Right now I have 61 problems solved from the roadmap.

Conclusions

This is how right now I intend to handle my study schedule, however, I will look again at this shcedule within few months
from here, just to see how much as help me (or not)

Welcome 2025 here is what I will learn

Carlos Estrada — Wed, 01 Jan 2025 12:44:08 +0000

Hello everyone welcome to this first post of 2025.

Today I want to share my personal roadmap of this year.
From the technologies that I will learn to some personal goals
that I want to get.

Things that I want to learn this 2025
Tech stack for 2025
Personal goals
Conclusion

Things that I want to learn this 2025

This are the new technologies that I want to learn this year.

SQL
Java and Spring Boot

With SQL I want to have a more deep understanding of it, being able to use
and understand the differents tools that offers, like Indexes, triggers, procedures, etc

Java in the other hand is because I want to focus on backend development, untill now I've been
a full stack developer, so my main focus for this year is to move to a more backend development area.

Tech stack for 2025

For my personal stack in this 2025 year, I will go with the next

Laravel for the backend
React for the frontend
Docker
PostgreSQL

Java and Spring Boot I will be using them in learning project but for most of
the new projects I will go with Laravel, because I want to brushin up my knowledge
with that framework

Personal goals

Here is the list of personal goals that I have for this year.

Build projects in public (from start to finish)
Write at least one post per week
Contribute to open source
Do 1 video per month (with my voice) about what I've learning through the week

Conclusion

I just want to make a little post about what I will be learning and some of my personal goals for this year.
At the end of the year I will come back to this post and made a review about all the points listed here.

Backend challenge #6

Carlos Estrada — Sun, 03 Nov 2024 16:13:26 +0000

Welcome to the 6 challenge of these series of backend development challenge.

Requirements to start the challenge

Before starting this challenge it’s important that you have finish the #5.

About the challenge

In todays challenge you will be in charge of three important task.

Creating the rating endpoint for the employees
Sending an email with information about some employees.
Exporting your data to a excel/csv file.

Rating endpoint

Add a new endpoint with the crud operation for the ratings of the employee. Here is the body that should be recieved by the backend on the post action.

// Example of post
{
    "employee_id": 1,
    "reviewed_by_name": "User 1",
    "reviewed_by": 2,
    "aspects": [
        {
            "score": 66,
            "aspect_reviewed": "team_work",
        },
        {
            "score": 56,
            "aspect_reviewed": "time_managment",
        }
    ]
}

Sending an email

The first part of the challenge focus on sending an email to someone with the next information (you can use mailpit for testing the emails that you send).

[To]: test@test.com # change for whatever you want
[Subject]: Employee <Employee Name> has a new Rating with an average 
score of <avg_score>

[Body]:
The employee <Employee Name> had a new rating by <Reviewed by Name> with an
average score of <avg_score>

Here a list of the aspect reviewed
- <aspect-1> : <score>
- <aspect-2> : <score>
- ....

The email should be send after the creation of the rating

Export data to excel/csv

Add and option to export your employees data as a csv file, this exported data should containt all the information inside the employees table

It’s not necessary to add and endpoint for this, just create a function/class/etc that creates the csv or excel file.

The file name should be employee_name and then the file extension

Conclusion

This all for this 6 challenge of this backend development series

Backend challenge #5

Carlos Estrada — Sun, 20 Oct 2024 16:35:04 +0000

Welcome to the 5 challenge of these series of backend development challenge.

This challenge will be the first part of four(5-8), so let’s begin.

Requirements to start the challenge

PostgreSQL installed in your system (I recomend to use docker)

About the challenge

In this challenge you will have to complete the next task

Create a database in postgresql using the next diagram
Generate and Import data from a csv into your database
Create the next endpoints for the next routes
- Employees
- Departments
- Employees types

Generating and importing data from a csv

Now that you have your database please generate the next data, you can use websites like mockaroo to generate the data. Or if you tech stack allows you to create seeders (like laravel) instead of generating a csv generate the according seeders for the database.

100 Records for employees
4 Records for departments
10 Records for vacations
10 Records for incapacities
30 Records for Employees ratings
The employees types are the next base, temporary and inter

Endpoints of the app

Here is the list of the endpoints that you need to create and the expected responses of each

Employees

// GET api/employees
[
    {
        // All the data in the table employees
        "employee_type": "base",
        "department": "IT",
    } 
]

// GET api/employees/[id]
{
    // all the information that you pass in the previous one plus
    "ratings": [
        {
            // All the records in `employees_ratings` that match
            // the employee_id
        }
    ],
    "incapacities": [
        {
            // all the information of the table incapacities
        }
    ],
    "vacations": [
        {
            // all the information of the vacations table
        }
    ]
}

For the post and put, right now is just enough to only receive the data on the employees table, the image field can be send like a simple string for example image.png

The put and delete methods should be called on api/employees/[id]

Departments

// GET api/departments
[
    {
        // all the information on the departments table
    }
]

// GET api/departments/[id]
{
    // same as before
}

The put and delete methods should be called on api/departments/[id]

Employees types

// GET api/employees_types
[
    { 
        // all the information on the corresponding table 
    }
]

// GET api/employees_types/[id]
{
    // all the information on the corresponding table
}

The put and delete methods should be called on api/employees_types/[id]

And this is all for this challenge, see you in the next one

Reto de backend #2

Carlos Estrada — Sun, 06 Oct 2024 20:38:52 +0000

Bienvenido al segundo post de esta serie de retos de backend.

En el primer reto nos enfrentamos a crear un api sin conexion a base de datos. En esta ocasion subiremos un poco la dificultad.

Api endpoint con conexion a base de datos sql

Descripcion del proyecto

Necesitamos llevar un registro del peso de un cliente llamado Ramon, entonces para eso necesitamos crear un sistema con lo siguiente.

Requisitos

Guardar el siguiente formato del peso

{
  "weight": 125.5,
  "date": "2024-02-12"
}

Guardar la informacion en una base de datos sqlite (Al final puedes encontrar la sintaxis para crear la tabla de pesos)
La api debera tener solo un endpoint con el nombre de weights
Puede actualizar, eliminar, crear y leer la data de los pesos
Envia un id en el json cuando sea eliminar o actualizar

Punto de inicio

Las rutas deberian ser como las siguientes

GET localhost/api/weights

POST localhost/api/weights

PUT localhost/api/weights

DELETE localhost/api/weights

En el metodo delete y put necesitas pasar un id dentro del body del json para eliminar o actualizar.

SQL para el proyecto

Tabla de pesos

CREATE TABLE weights (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  weight DOUBLE,
  weight_date DATE
);

Reto de backend #1

Carlos Estrada — Sun, 06 Oct 2024 20:38:13 +0000

Si quieres empezar tu camino en el desarrollo backend, bienvenido a esta seria que decidi llamar Retos de backend donde iremos realizando diversos proyectos para empezar a entender diferentes conceptos del desarrollo backend.

Comenzaremos desde 0 hasta convertirnos en todo un backend developer. Toda esta serie se basara en desarrollar proyectos, compartire algunos objetivos y caracteristicas de cada uno de los proyectos y la implementacion quedara en tus manos.

Puedes usar cualquier base de datos, framework, lenguaje de programacion, etc. La decision queda en ti.

Api de un solo endpoint (No Conexion de base de datos)

Descripcion del proyecto

Construir un api con solo un endpoint en el cual podamos realizar lo siguiente.

Obtener una lista de los elementos disponibles
Crear un elemento
Actualizar un elemento de la lista
Eliminar un elemento

Requisitos

Hacer las 4 acciones basicas (crear, leer, actualizar y eliminar)
La informacion debera estar guardada en un arreglo

Ejemplo de un endpoint para el projecto

<sitio>.com/<endpoint>

# Ejemplo
localhost/dogs/get
localhost/dogs/post
localhost/dogs/put
localhost/dogs/delete

No requerido pero recomendado

En lugar de tener una url para cada accion, dejalo todo en la misma

localhost/dogs/ # En base al metodo de la peticion realiza una cosa u otra

Forem: Carlos Estrada

Creating a simple access middleware for nextjs route handlers

Wrapper function for the endpoints

Example of the endpoints

route.ts

Controller.ts

Migration of nextjs 14 to next 15

Creating a todo app with JDBC

What is JDBC?

How can we use one?

Requirements

Creating the project

Creating the database

Postgresql installed in the OS

Using docker

Creating an env file

Installing dependencies

The java files for database and orm implementation

Creating the menu for the app

Joining all the parts

Conclusion

Java project, creating a cli

What we are building

Building the project

Creating LS

Creating mv

Creating ifconfig

Conclusion

How I am learning java

Table of contents

Learning the language

Personal Projects

Ecosystem

Conclusion

Neetcode Roadmap Part 1

It's hard

I need to solve more problems to truly said that I dominate that section

Feels amazing to complete every single challenges

Conclusion

My Study Schedule for 2025

Working days

Weekends

Conclusions

Welcome 2025 here is what I will learn

Table of contents

Things that I want to learn this 2025

Tech stack for 2025

Personal goals

Conclusion

Backend challenge #6

Requirements to start the challenge

About the challenge

Rating endpoint

Sending an email

Export data to excel/csv

Conclusion

Backend challenge #5

Requirements to start the challenge

About the challenge

Generating and importing data from a csv

Endpoints of the app

Reto de backend #2

Api endpoint con conexion a base de datos sql

Descripcion del proyecto

Requisitos

Punto de inicio

SQL para el proyecto

Reto de backend #1

Api de un solo endpoint (No Conexion de base de datos)

Descripcion del proyecto

Requisitos

No requerido pero recomendado