ASP.NET Core Run Middleware behave differently with different browser.

Question

ASP.NET Core Run Middleware behave differently with different browser.

Amit Singh Rawat 731

Below is my middleware code:

app.UseStaticFiles(new StaticFileOptions
{
OnPrepareResponse = ctx =>
{
ctx.Context.Response.Headers[HeaderNames.CacheControl] =
"public,max-age=10"; // Here I placed my first breakpoint
}
});
app.Run(async context =>
{
await context.Response.WriteAsync("<html><body><a href='images/image1.jpg' target='_blank'>Click for Image1</a></body></html>"); // Here is my Second Breakpoint
});

I placed a break point within Run Middleware as well as with in UseStaticFiles Middleware.
I just cached the static files for 10 seconds.
Then I click on Anchor tag created with in my run middle ware from browser. When I hit this anchor tag from chrome. First time it hit both the break point and rightly so. From next time onward, it only hit Second break point. If it is cached then it should not hit our application. And cache is working that's why UseStaticFiles is not hit.

But when I hit via Firefox. From second request onward it never hit our Run Middleware. Even after cache duration is over. After 10 second it hit UseStaticFiles but not RUN middleware.

What is happening. Any idea?

Yiyi You - MSFT 521 Reputation points

2021-07-27T05:32:04.877+00:00

Hi,@Amit Singh Rawat ,
check response headers in Chrome and FireFox,is there any difference?
Amit Singh Rawat 731 Reputation points

2021-07-27T07:20:23.04+00:00

Hi @Yiyi You - MSFT ,
I only set the cache control property in middleware. It's and empty project. No view no controller. Nothing.
I verified and Response header is same in both the browsers. Also, checked with edge.
Edge is also behaving same as chrome.
Firefox is behaving differently or correct I would say.

----Update
Checked with internet explorer as well. It is working correct like Firefox.

So, Firefox and internet explorer behave similar and chrome and edge behave same.

AgaveJoe 30,126

You did not share the entire startup.cs file so we cannot verify where you placed the configuration. I created a test using your code and caching works as expected. I recommend reading the previous link which might change your point of view.

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseStaticFiles(new StaticFileOptions
            {
                OnPrepareResponse = ctx =>
                {
                    ctx.Context.Response.Headers[HeaderNames.CacheControl] = "public,max-age=10";
                }
            });

            app.Run(async context =>
            {
                await context.Response.WriteAsync("<html><body><a href='images/image1.jpg' target='_blank'>Click for Image1</a></body></html>"); // Here is my Second Breakpoint
            });
        }

Amit Singh Rawat 731 Reputation points

2021-07-27T12:35:25.9+00:00
I tried this behavior in 5 different systems and with all four browsers which I had specified. Not sure how it works for you. Have you placed debugger. Its all about break points and not serving file from cache. If file is cached then it shouldn't send request to the server. There must be some silly mistake from my side but I am not able to figure it out.

As already specified it is an empty project template. Visual studio 2019 and .Net 5.

Below is my startup.cs file.

namespace Demo
{
public class Startup
{
// This method gets called by the runtime. Use this method to add services to the container.
// For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
public void ConfigureServices(IServiceCollection services)
{

} // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. public void Configure(IApplicationBuilder app, IWebHostEnvironment env) { StaticFileOptions options = new StaticFileOptions() { OnPrepareResponse = ctx => { ctx.Context.Response.Headers[HeaderNames.CacheControl] = $"public, max-age=20"; } }; app.UseStaticFiles(options); app.Run(async context => { await context.Response.WriteAsync("Terminator."); }); } }

}

1 answer

Your answer

Yiyi You - MSFT 521 Reputation points

2021-07-27T05:32:04.877+00:00

Hi,@Amit Singh Rawat ,
check response headers in Chrome and FireFox,is there any difference?
Amit Singh Rawat 731 Reputation points

2021-07-27T07:20:23.04+00:00

Hi @Yiyi You - MSFT ,
I only set the cache control property in middleware. It's and empty project. No view no controller. Nothing.
I verified and Response header is same in both the browsers. Also, checked with edge.
Edge is also behaving same as chrome.
Firefox is behaving differently or correct I would say.

----Update
Checked with internet explorer as well. It is working correct like Firefox.

So, Firefox and internet explorer behave similar and chrome and edge behave same.
AgaveJoe 30,126 Reputation points

2021-07-27T12:01:52.137+00:00

You did not share the entire startup.cs file so we cannot verify where you placed the configuration. I created a test using your code and caching works as expected. I recommend reading the previous link which might change your point of view.

public void Configure(IApplicationBuilder app, IWebHostEnvironment env) { if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } app.UseStaticFiles(new StaticFileOptions { OnPrepareResponse = ctx => { ctx.Context.Response.Headers[HeaderNames.CacheControl] = "public,max-age=10"; } }); app.Run(async context => { await context.Response.WriteAsync("<html><body><a href='images/image1.jpg' target='_blank'>Click for Image1</a></body></html>"); // Here is my Second Breakpoint }); }
Amit Singh Rawat 731 Reputation points

2021-07-27T12:35:25.9+00:00

I tried this behavior in 5 different systems and with all four browsers which I had specified. Not sure how it works for you. Have you placed debugger. Its all about break points and not serving file from cache. If file is cached then it shouldn't send request to the server. There must be some silly mistake from my side but I am not able to figure it out.

As already specified it is an empty project template. Visual studio 2019 and .Net 5.

Below is my startup.cs file.

namespace Demo
{
public class Startup
{
// This method gets called by the runtime. Use this method to add services to the container.
// For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
public void ConfigureServices(IServiceCollection services)
{

} // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. public void Configure(IApplicationBuilder app, IWebHostEnvironment env) { StaticFileOptions options = new StaticFileOptions() { OnPrepareResponse = ctx => { ctx.Context.Response.Headers[HeaderNames.CacheControl] = $"public, max-age=20"; } }; app.UseStaticFiles(options); app.Run(async context => { await context.Response.WriteAsync("Terminator."); }); } }

}

Answer 1

Fei Xue - MSFT 1,111

Please check the cache-control headers for the static files to see whether this http header is added to the response expected and cache settings in the browser to see if the cache is disabled. If the browser doesn't follow the http cache headers, it is recommend that submit the issue for that specific browsers.

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ASP.NET Core Run Middleware behave differently with different browser.

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