xantari
commented
4 years ago Update. I created a middleware as follows:
/// <summary>
/// Asset Link Middleware
/// 2/27/2020 - MRO: Custom middleware that alters the response body to make the kentico assets show up from our own domain.
// See: https://github.com/Kentico/kontent-delivery-sdk-net/issues/193
// https://jeremylindsayni.wordpress.com/2019/02/18/adding-middleware-to-your-net-core-mvc-pipeline-that-formats-and-indents-html-output/
// https://docs.microsoft.com/en-gb/aspnet/core/fundamentals/middleware/index?view=aspnetcore-2.2
/// </summary>
public class AssetLinkMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger<AssetLinkMiddleware> _logger;
public AssetLinkMiddleware(RequestDelegate next, ILogger<AssetLinkMiddleware> logger)
{
_next = next;
_logger = logger;
}
public async Task InvokeAsync(HttpContext httpContext, IOptions<ProjectOptionsBase> projectOptions)
{
var body = httpContext.Response.Body;
using (var updatedBody = new MemoryStream())
{
httpContext.Response.Body = updatedBody;
_logger.LogInformation("here {@httpContext}", httpContext.Response.ContentType);
await _next(httpContext);
_logger.LogInformation("after next {@httpContext}", httpContext.Response.ContentType);
httpContext.Response.Body = body;
updatedBody.Seek(0, SeekOrigin.Begin);
if (httpContext.Response.ContentType.Contains("text/html")) //Only manipulate the html data coming back, ignore all other file types (such as jpg, png, etc)
{
var newContent = new StreamReader(updatedBody).ReadToEnd();
string assetUrl = projectOptions.Value.AssetUrl;
string[] kenticoCdnUrls = projectOptions.Value.KenticoAssetCDNUrls;
for (int i = 0; i < kenticoCdnUrls.Length; i++)
newContent = newContent.Replace(kenticoCdnUrls[i], assetUrl);
await httpContext.Response.WriteAsync(newContent);
}
else //Return the asset bytes (jpg, pdf, other binary content)
{
await updatedBody.CopyToAsync(httpContext.Response.Body);
}
}
}
}Registered in Startup.cs as follows. The two key points are the registration of the AssetLinkMiddleware and the Asset link controller routing.
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseStatusCodePagesWithReExecute("/Error/{0}");
app.UseExceptionHandler("/Error/500"); //Internal server error occurred
// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
app.UseHsts();
}
// Add IIS URL Rewrite list
// See https://docs.microsoft.com/en-us/aspnet/core/fundamentals/url-rewriting
var options = new RewriteOptions().AddIISUrlRewrite(env.ContentRootFileProvider, "IISUrlRewrite.xml");
app.UseRewriter(options);
app.UseHttpsRedirection();
// Write streamlined request completion events, instead of the more verbose ones from the framework.
// To use the default framework request logging instead, remove this line and set the "Microsoft"
// level in appsettings.json to "Information".
app.UseSerilogRequestLogging();
app.UseStaticFiles();
app.UseRouting();
app.UseWhen(context => context.Request.Path.StartsWithSegments("/webhooks/webhooks", StringComparison.OrdinalIgnoreCase), appBuilder =>
{
appBuilder.UseMiddleware<SignatureMiddleware>();
});
app.UseMiddleware<AssetLinkMiddleware>();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllerRoute(
name: "areas",
pattern: "{area:exists}/{controller=Home}/{action=Index}/{id?}");
endpoints.MapControllerRoute(
name: "sitemap",
defaults: new { controller = "Sitemap", action = "Index" },
pattern: "sitemap.xml");
endpoints.MapControllerRoute(
name: "preview",
pattern: "preview/{*urlSlug}", defaults: new { controller = "Preview", action = "Index" });
endpoints.MapControllerRoute(
name: "news",
pattern: "news/{action=Index}/{page?}", defaults: new { controller = "News", action = "Index" });
endpoints.MapControllerRoute(
name: "assets",
pattern: "assets/{**urlFragment}", defaults: new { controller = "Assets", action = "Index" });
endpoints.MapControllerRoute(
name: "default",
pattern: "{controller=LandingPage}/{action=Index}/{codename?}");
endpoints.MapDynamicControllerRoute<SitemapRouteTransformer>("pages/{**slug}");
});My ProjectOptionsBase:
public class ProjectOptionsBase
{
.....
.....
public string[] KenticoAssetCDNUrls { get; set; }
public string AssetUrl { get; set; }
}My appsettings.config that maps to my project options base:
"KenticoAssetCDNUrls": [
"preview-assets-us-01.kc-usercontent.com:443",
"assets-us-01.kc-usercontent.com:443"
],
"AssetUrl": "localdevwwwcore.arrt.org/Assets",
petrsvihlik
lukasturek
Simply007
Motivation
Our current website serves up many PDF files. They can be easily found using google.
Such as this: https://www.google.com/search?sxsrf=ALeKk032G0vKTmeNlvlepndVXztTtzAJpg%3A1582830339114&source=hp&ei=AhNYXrCKN5nN0PEP7eyykA8&q=ARRT+rules+and+regulations&oq=ARRT+rules+and+regulations&gs_l=psy-ab.3..0.8034.11005..11150...2.0..0.209.4317.0j24j2......0....1..gws-wiz.....10..35i39j0i131j35i362i39j0i10j0i22i30j0i22i10i30.0Ws3sH2JO30&ved=0ahUKEwiwk9zAtvLnAhWZJjQIHW22DPIQ4dUDCAg&uact=5
You will see that one of the links is this: https://www.arrt.org/docs/default-source/governing-documents/arrt-rules-and-regulations.pdf?sfvrsn=3f9e02fc_42
As you can see it is being served up from our domain.
However, it seems that with Kentico Kontent we do not have flexibility of defining an Asset Link URL Resolver.
We can create Content Item Resolvers, but not Asset Link Resolvers.
Instead what is being surfaced right now in the above example might be something like this:
https://preview-assets-us-01.kc-usercontent.com:443/406ac8c6-58e8-00b3-e3c1-0c312965deb2/ba8df0e1-69da-44f4-b197-9aceafb39979/arrt-rules-and-regulations.pdf
This has some negative ramifications for our business as follows:
We need the ability to define an asset link resolver in the Kentico client builder registration.
Right now the approach we are attempting is the following:
Is this the best way to do it for now?
Not sure on performance or if those kc-usercontent.com links can dynamically change and we need to define a whole list of potential CDN servers?
Proposed solution
Introduce Asset Link Url Resolver, much like the Content Item resolver you already have.
Alternative solutions: