[[oktatas:programozas:csharp:dotnetcore:web_api|< Web API]]

====== Dotnet Core - Egyszerű REST API ======

  * **Szerző:** Sallai András
  * Copyright (c) 2024, Sallai András
  * Licenc: [[https://creativecommons.org/licenses/by-sa/4.0/|CC Attribution-Share Alike 4.0 International]]
  * Web: https://szit.hu

===== Bevezetés =====

Egyszerű REST API készítés dotnet használatával, kontroller nélkül.

  * https://github.com/oktat/emp_api_dotnet.git


Telepítéshez Nuget csomagokat használunk:
  * https://www.nuget.org/


===== Projekt készítése =====

  dotnet new webapi -minimal -o app01

===== Függőség telepítése =====

  dotnet add package Pomelo.EntityFrameworkCore.MySql

===== Könyvtárszerkezet =====

<code txt>
app01/
  |-bin
  |-database/
  |  `-create.sql
  |-obj/
  |-Properties/
  |-app01.csproj
  |-app01.sln
  |-appsettings.Development.json
  |-appsettings.json
  |-DataService.cs
  |-Emplyoee.cs
  `-Program.cs
</code>

===== Fejlesztői szerver =====

  dotnet watch run


===== Adatbázis =====


<code mysql database/create.sql>
create database if not exists sargabt;
 
use sargabt;
 
create table if not exists employees (
    Id int not null primary key auto_increment,
    Name varchar(50),
    City varchar(50),
    Salary double
);

grant all privileges
on sargabt.*
to sargabt@localhost
identified by 'titok';
</code>


===== Kapcsolódás az adatbázishoz =====

<code csharp DataService.cs>
using Microsoft.EntityFrameworkCore;
 
class DataService : DbContext {
    string str = "Server=localhost; User ID=sargabt; Password=titok; Database=sargabt";
 
    public DbSet<Employee> Employees { get; set; }
 
    protected override void OnConfiguring(DbContextOptionsBuilder ob)
    {
        ob.UseMySql(str, ServerVersion.AutoDetect(str));
    } 
}
</code>

===== Modell =====

<code csharp Employee.cs>
public class Employee {
    public int Id { get; set; }
    public string Name { get; set; } = "";
    public string City { get; set; } = "";
    public double Salary { get; set; }
    
}
</code>

===== Routing =====

<code csharp Program.cs>
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
var db = new DataService();

app.MapGet("/employees", () => {
    var emps = db.Employees.ToList();
    return emps;
});

app.MapPost("/employees", (Employee emp) => {
    db.Employees.Add(emp);
    db.SaveChanges();
    return Results.Created(@"/employeeitems/{emp.Id}", emp);
});

app.MapPut("/employees/{id}", (int id, Employee inputEmp) => {
    var emp = db.Employees.Find(id);
    if (emp is null ) return Results.NotFound();
    emp.Name = inputEmp.Name;
    emp.City = inputEmp.City;
    emp.Salary = inputEmp.Salary;
    db.SaveChanges();
    return Results.NoContent();
});

app.MapDelete("/employees/{id}", (int id) => {
    if(db.Employees.Find(id) is Employee emp) {
        db.Employees.Remove(emp);
        db.SaveChanges();
        return Results.NoContent();
    }
    return Results.NoContent();
});

app.Run();
</code>

===== Végpontok =====

Teles végpont példa:
  * localhost:5216/employees

^  Végpont  ^  Metódus  ^  Auth  ^  Leírás  ^
| /employees | GET | nem | Az összes dolgozó lekérése |
| /employees | POST | nem | Új dolgozó hozzáadása |
| /employees/{id} | PUT | nem | Dolgozó adatainak frissítése |
| /employees/{id} | DELETE | nem | Dolgozó törlése |


===== Swagger hozzáadása =====

  dotnet add package Swashbuckle.AspNetCore

==== Vázlat ====

<code csharp Program.cs>
var builder = WebApplication.CreateBuilder(args);

var services = builder.Services;
services.AddEndpointsApiExplorer();
services.AddSwaggerGen();

var app = builder.Build();

if (app.Environment.IsDevelopment()) {
    app.UseDeveloperExceptionPage();
}

app.UseSwagger();

app.MapGet("/msg", () => "működik");

app.UseSwaggerUI();
app.Run();
</code>

==== Kód ====


A "var app = builder.Build(); előtt:
<code csharp>
var services = builder.Services;
services.AddEndpointsApiExplorer();
services.AddSwaggerGen();
</code>

A "var db = new DataService();" után:
<code csharp>
app.UseSwagger();
</code>


Az "app.Run();" előtt:
<code csharp>
app.UseSwaggerUI();
</code>



==== Teljes kód ====



<code csharp Program.cs>
var builder = WebApplication.CreateBuilder(args);

var services = builder.Services;
services.AddEndpointsApiExplorer();
services.AddSwaggerGen();

var app = builder.Build();
var db = new DataService();

app.UseSwagger();

app.MapGet("/employees", () => {
    var emps = db.Employees.ToList();
    return emps;
});

app.MapPost("/employees", (Employee emp) => {
    db.Employees.Add(emp);
    db.SaveChanges();
    return Results.Created(@"/employeeitems/{emp.Id}", emp);
});

app.MapPut("/employees/{id}", (int id, Employee inputEmp) => {
    var emp = db.Employees.Find(id);
    if (emp is null ) return Results.NotFound();
    emp.Name = inputEmp.Name;
    emp.City = inputEmp.City;
    emp.Salary = inputEmp.Salary;
    db.SaveChanges();
    return Results.NoContent();
});

app.MapDelete("/employees/{id}", (int id) => {
    if(db.Employees.Find(id) is Employee emp) {
        db.Employees.Remove(emp);
        db.SaveChanges();
        return Results.NoContent();
    }
    return Results.NoContent();
});

app.UseSwaggerUI();
app.Run();

</code>

===== Források =====

  * https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api?view=aspnetcore-8.0 (2024)
  * https://learn.microsoft.com/en-us/aspnet/core/fundamentals/minimal-apis?view=aspnetcore-8.0 (2024)
  * https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-web-api?view=aspnetcore-8.0&tabs=visual-studio-code (2024)