Swagger UI not displaying when deploying API on IIS

Question

Well, I'm using Swagger for my API documentation and it works perfectly in localhost, the problem begins when I host it on the IIS. For somereason it just doesn't work anymore

localhost:

https://localhost:44381/swagger/index.html

api:

http://200.155.29.14/SimuladorFrete/Swagger/index.html

All I get when I try to open the Swagger after deploying it in the ISS is a blank page and a 500 internal server error, which doesn't say the exception.

Here is my Configure method (startup.cs)

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

    }
    app.UseHttpsRedirection();

    app.UseRouting();

    app.UseAuthorization();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
    });
    app.UseSwagger();
    app.UseStaticFiles();
    app.UseSwaggerUI(c =>
    {
        if (env.IsDevelopment())
        {
            c.SwaggerEndpoint("/swagger/v1/swagger.json", "Web API V1");
        }
        else
        {
            // To deploy on IIS
            c.SwaggerEndpoint("/SimulaFrete/swagger/v1/swagger.json", "Web API V1");
        }

    });
}

and here's my ConfigureServices method:

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers().AddNewtonsoftJson();

    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1",

      new OpenApiInfo
      {

          Title = "Simulador de frete por Unidade",
          Version = "v1",
          Description = "Métodos da API de simulação de frete",
          Contact = new OpenApiContact
          {
              Name = "Catalde Technology",
              Url = new Uri("https://www.catalde.com"),
              Email = "[email protected]"
          }
      });

        string caminhoAplicacao =
            PlatformServices.Default.Application.ApplicationBasePath;
        string nomeAplicacao =
            PlatformServices.Default.Application.ApplicationName;
        string caminhoXmlDoc =
            Path.Combine(caminhoAplicacao, $"{nomeAplicacao}.xml");

        c.IncludeXmlComments(caminhoXmlDoc);
        c.ResolveConflictingActions(apiDescriptions => apiDescriptions.First()); //This line
    });
}

And there's my Controller code which has only this method:

[HttpPost]
public ContentResult Post([FromBody]dadosFrete xml)
{
    // code logic
}

try this for .NET 7 https://stackoverflow.com/questions/63058563/publishing-web-api-with-swagger-on-iis/75087754#75087754 — Debraj Banerjee
– Debraj Banerjee, Commented Jan 11, 2023 at 19:51

Luke_ · Accepted Answer · 2021-02-20 00:56:15Z

63

You need to temporarily add the production clause in your condition before you can see the swagger in the production environment. See the yellow highlighted section in the attached image. env.IsProduction()

edited Feb 20, 2021 at 0:56

Luke_

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answered Feb 19, 2021 at 11:00

Adeshina Alani

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8 Comments

Luke_ Over a year ago

You didnt add the image correctly, use ![description](link) instead

EduardoUstarez Over a year ago

It works to me if (env.IsDevelopment() || env.IsProduction()), thanks

dotnetdevcsharp Over a year ago

This answer just made me feel like a flipping idiot well spoted why on earth does boiler plate code add it here.

rtfmpliz Over a year ago

it works for me in Net6 minimal API if (app.Environment.IsDevelopment() || app.Environment.IsProduction()) { app.UseSwagger(); app.UseSwaggerUI(); }

Marc Roussel Over a year ago

I would put the UseSwagger and UseSwaggerUI outside of the condition and not put things in the condition that is related to development. Since the us of swagger is necessary for both environment there's no reason to add both statement in the if

|

Twenty · Accepted Answer · 2023-04-01 17:31:08Z

13

Try this. To set relative path.

app.UseSwaggerUI(c =>
{
    string swaggerJsonBasePath = string.IsNullOrWhiteSpace(c.RoutePrefix) ? "." : "..";
    c.SwaggerEndpoint($"{swaggerJsonBasePath}/swagger/v1/swagger.json", "My API");
});

if this solution not work. Then check publish setting. The issue is that running dotnet publish with -r Release does not produce XML file. However, dotnet publish with -r Debug does in fact produce the file. This explains why people are only getting this issue when they are deploying to environments OTHER than locally. You can simplify find out in Project > Your Project properties > Build Tab

edited Apr 1, 2023 at 17:31

Twenty

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answered Jun 15, 2020 at 23:27

vipul nanavare

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1 Comment

Hoppeduppeanut Over a year ago

While this might answer the question, you should edit your answer to include an explanation of how this code block answers the question. This makes your answer much more useful to those who come across the same issue later on.

kuradac · Accepted Answer · 2022-08-13 22:49:43Z

4

The following worked for me. I was able to get it working locally on IIS.

You'll need to publish the project to a folder and point IIS to that folder.
Edit the Configure method and move out Swagger out of env.IsDevelopment and use vipul's solution above to fix the path.

 if (env.IsDevelopment())
 {
   app.UseDeveloperExceptionPage();
 }
 app.UseSwagger();
 app.UseSwaggerUI(c =>
 {
   string swaggerJsonBasePath = string.IsNullOrWhiteSpace(c.RoutePrefix) ? "." : "..";
   c.SwaggerEndpoint($"{swaggerJsonBasePath}/swagger/v1/swagger.json", "Web API");

 });

answered Aug 13, 2022 at 22:49

kuradac

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Comments

Andy Danger Gagne · Accepted Answer · 2021-02-19 16:34:56Z

1

Take a look at how to use multiple environments in .net core. Some options are

using a launch.json file for your different environments (dev/stage/prod) (local dev only)
Adding an environment variable named ASPNETCORE_ENVIRONMENT with development, stage or production
Or making a web.config to deploy to IIS and add the value

<PropertyGroup>
<EnvironmentName>Development</EnvironmentName>
</PropertyGroup>

For IIS, it all depends on the version of IIS. Older versions of IIS, I believe you can only go with web.config.

answered Feb 19, 2021 at 16:34

Andy Danger Gagne

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Comments

RobAtPaxMondeo · Accepted Answer · 2023-03-29 04:07:25Z

1

I know this is old, but it is top ranking in Google for this issue. None of the above worked for me.I wasn't getting a 500 (or a 404), just a blank Swagger page. I could also open swagger.json OK My real problem was that the Sys Admins don't allow anything other than IE on a server here, so I was testing my deployment (before they had opened the firewall ports) locally using IE. Swagger page opens, but displays nothing in IE. Bending the rules, I installed Edge and swagger was working fine. Hope this saves someone else a wasted morning.

answered Mar 29, 2023 at 4:07

RobAtPaxMondeo

111 silver badge1 bronze badge

Comments

unvascorriendo · Accepted Answer · 2023-12-06 17:36:47Z

1

I spent several days troubleshooting. it turned out if I publish in x86 the page displays just fine.

answered Dec 6, 2023 at 17:36

unvascorriendo

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Comments

djangojazz · Accepted Answer · 2024-06-06 01:46:43Z

Super old I know but I would not do the accepted answer. You essentially are saying development and production are the same in your code. Bad, BAD, REALLY BAD IDEA to hard code your system as two things. Really you should go into IIS and set the environment variables to have 'ASPNETCORE_ENVIRONMENT' be correct on your IIS site to what you want. Doing it hard coded is not a good idea and leaving on Swagger in production is not advised for many reasons.

So go into IIS.
Go to your site by clicking on it.
Click 'Configuration Editor' under the 'Management' Section on the main viewing pane
Ensure at the top the section is 'system.webServer/aspNETCore'
Ensure the 'From' shows 'ApplicationHost.config' and NOT your web config. (else you will just rewrite it every deploy)
Find environmentVariables about 3 down and click the on value section and the '...'
(Top right of new pane) click 'Add' under 'Collection'
name = ASPNETCORE_ENVIRONMENT value = Development (or whatever environment you want)
(close the screen) Click 'Apply' under 'Actions' at the top right.

I usually refresh the site at this point to make sure it takes and if you did it right, voila now Swagger works. I did this just now in .NET 8 so it works with current versions too.

A_Shah · Accepted Answer · 2024-10-24 14:27:22Z

1

to host on IIS, I added ".." to relative path and also "|| env.IsProduction() " in conditional statement. Wow it worked for me Under "Setup.cs" file, modified "Configure" method in .Net 6.0 API project

answered Oct 24, 2024 at 14:27

A_Shah

236 bronze badges

2 Comments

Frimlik Feb 11 at 11:48

Some strange reason, why publishing to IIS adds another /swagger to the URL...

A_Shah Apr 9 at 7:12

When publishing a .NET Core API with Swagger/OpenAPI to IIS, the /swagger path is added to the URL because that's the default path configured by the Swagger middleware for serving the Swagger UI and JSON endpoint.

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