在 ASP.NET Core Configuration 中使用 array

這是之前專案遇到的需求：在 config 中設定多個值來供 application 使用，印象中之前有用過但沒找到筆記，順便嘗試一下不同做法，筆記一下

基本環境說明

macOS Monterey 12.1
.NET SDK 6.0.100

範例 config

{
    "ConfigArray": ["Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"]
}

使用方式

使用 IConfiguration

var configs= app.Configuration.GetSection("ConfigArray").Get<string[]>();

完整程式碼 Program.cs

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();

// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

var configs= app.Configuration.GetSection("ConfigArray").Get<string[]>();

foreach (var config in configs)
{
    Console.WriteLine(config);
}

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

使用 Options pattern

建立對應的 poco

需要讓 porperty name 與 config key 一致才能正確綁定

namespace ArrayConfig;

namespace ArrayConfig;

public class Weekdays
{
    public string[] ConfigArray { get; set; } = Array.Empty<string>();
}

註冊 config

builder.Services.Configure<Weekdays>(builder.Configuration);

取用 config array

var configs=app.Services.GetRequiredService<IOptions<Weekdays>>()?.Value.ConfigArray;

完整程式碼 Program.cs

using ArrayConfig;
using Microsoft.Extensions.Options;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();

// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

builder.Services.Configure<Weekdays>(builder.Configuration);

var app = builder.Build();

var configs=app.Services.GetRequiredService<IOptions<Weekdays>>()?.Value.ConfigArray;
foreach (var config in configs)
{
    Console.WriteLine(config);
}

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

心得

就程式碼數量來看絕對是直接從 IConfiguration 取用完勝，但 Options pattern 有強型別的好處也不失為種好做法，但兩者在使用上需要注意個問題，詳細內容請參考 ASP.NET Core Configuration 中的 array 沒有正確覆寫

完整程式碼請參考 yowko/ArrayConfig

文章目錄

在 ASP.NET Core Configuration 中使用 array

基本環境說明

使用方式

心得

參考資訊