This is an ASP.NET MVC application on .NET Core 3.1, with Swashbuckle.AspNetCore 6.1.4 (latest). When I try to load the Swagger UI at /swagger/index.html, I'm getting a 404. It appears that the Swagger middleware isn't handling the request and it's making its way to the static files middleware instead. What's infuriating is that this used to work just fine, but I can't figure out what changes I made recently would have caused this problem.
My Startup.cs file had this (fairly standard):
app.UseSwagger();
app.UseSwaggerUI(options =>
{
options.RoutePrefix = "swagger";
options.SwaggerEndpoint($"{SWAGGER_VERSION}/swagger.json", "My API");
options.EnableDeepLinking();
});
app.UseStaticFiles();
When I noticed the 404 happening, I tried to load the JSON file in my browser, but got the IIS Express 404 page, which had something curious. Even though the HTTP request was for swagger.json, the error page said:
Requested URL: https://localhost:44316/wwwroot/swagger/v1/swagger.js
Physical path: C:\Users\hcheng\source\repos\[xxx]\src\[xxx.yyyy]\wwwroot\swagger\v1\swagger.js
So IIS changed the file extension, and then tried to find a non-existent Javascript file in the wwwroot folder. Note that I also have URL rewriting, but none of my rewrite rules are applicable here (I even commented that out entirely, which didn't change anything).
I was able to solve this by changing the endpoint to be swaggerjson, which works fine. However, this didn't resolve the 404 for index.html. And for this one, it's something similar:
Requested URL: https://localhost:44316/wwwroot/swagger/index.html
Physical path: C:\Users\hcheng\source\repos\[xxx]\src\[xxx.yyyy]\wwwroot\swagger\index.html
I added some dummy middleware into the pipeline, like so:
app.UseSwagger(); // options omitted
app.UseSwaggerUI(); // options omitted
app.Use(async (context, next) => await next()); // breakpoint here
app.UseStaticFiles();
app.Use(async (context, next) => await next()); // breakpoint here
Now when I tried loading /swagger/index.html I hit the first breakpoint, but not the second, which confirms my theory that the Swagger middleware isn't handling the request, and it's the static files one that is doing it instead.
UPDATE: It turns out when I hit these breakpoints, the request is actually for favicon.ico; the request for /swagger/index/html doesn't hit these at all, which means IIS is totally bypassing ASP.NET here.
I really have no idea what I've done to make this not work. This behavior originally started when I had Swashbuckle 5.6.3 installed, but this persists even after upgrading to 6.1.4.
This problem has also extended to my ElmahCore implementation, which indicates that it's probably a larger issue. For Elmah, the CSS and JS requests are also 404s and again, it's the static files middleware handling those requests instead of the Elmah middleware.
Any help would be greatly appreciated.
