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Morteza Jangjoo
Morteza Jangjoo

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app.UseOutputCache() in ASP.NET Core

Using app.UseOutputCache() in ASP.NET Core (Razor Pages + API + Conditional Caching)

Output Caching is a feature introduced in .NET 7 that helps improve performance by caching full HTTP responses in memory and serving them directly for repeated requests.

What is Output Caching?

Output caching stores the full server-generated response so that if the same request comes in again, the server can return the cached response without recomputing the result.

Benefits:

  • Faster response time
  • Reduced server load
  • Easy to configure per endpoint or via policy

How to Enable Output Caching

In Program.cs, add the caching service and middleware:

var builder = WebApplication.CreateBuilder(args); builder.Services.AddOutputCache(); // Register output caching builder.Services.AddRazorPages(); builder.Services.AddControllers(); builder.Services.AddOutputCache(options => { options.AddPolicy("TimePolicy", policy => { policy.Expire(TimeSpan.FromSeconds(20)) .SetVaryByQuery("noCache"); }); }); var app = builder.Build(); app.UseRouting(); app.UseOutputCache(); // Enable caching middleware app.UseEndpoints(endpoints => { endpoints.MapRazorPages(); endpoints.MapControllers(); });
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📄 Razor Page Example

Pages/Index.cshtml:

@page @model IndexModel <h1>Welcome</h1> <p>This page is not cached by default.</p>
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Pages/Index.cshtml.cs:

using Microsoft.AspNetCore.Mvc.RazorPages; public class IndexModel : PageModel { public void OnGet() { } }
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API Example with Conditional Cache

Here’s an API that returns the current server time and supports bypassing cache via a query parameter:

[ApiController] [Route("api/[controller]")] public class TimeController : ControllerBase { [HttpGet("now")] [OutputCache(PolicyName = "TimePolicy")] public IActionResult GetTime([FromQuery] bool noCache = false) { if (noCache) { HttpContext.Response.Headers["Cache-Control"] = "no-store"; } return Ok(new { Time = DateTime.Now }); } }
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Output Cache vs Response Cache

Feature Output Cache Response Cache
Location Server (in-memory) Client/CDN (via headers)
Setup Middleware HTTP headers
Logic Control Fully programmable Limited
Best for APIs, dynamic content Static/public responses

Download Full Sample Project

The complete ready-to-push-to-GitHub sample project is available here:

👉 Download OutputCacheSample (GitHub-Ready ZIP)

Includes:

  • Razor Page
  • API with conditional cache
  • OutputCache policy config

Final Notes

Output caching is simple to add but highly effective in boosting web application performance. You can easily customize its behavior with route, query, or header parameters.

I’m Morteza Jangjoo and “Explaining things I wish someone had explained to me”

🏷 Tags:

aspnetcore, dotnet, caching, performance

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