Swagger authenticate Azure AD B2C redirect url - azure

Question

I could authenticate swagger on Azure AD B2C. It works fine on http://localhost:5078/ . But as soon as I push my website to azure I can not authenticate swagger. It still uses localhost:5078 as redirect URL and not azure website URL.
My code:
builder.Services.AddSwaggerGen(c => {
var OATH2 = "oauth2";
// Enabled OAuth security in Swagger. From here: https://stackoverflow.com/questions/66894523/swagger-not-able-to-authenticate-to-azure-ad-b2c
c.AddSecurityRequirement(new OpenApiSecurityRequirement() {
{
new OpenApiSecurityScheme {
Reference = new OpenApiReference {
Type = ReferenceType.SecurityScheme,
Id = OATH2
}
},
new List<string>()
}
});
c.AddSecurityDefinition(OATH2, new OpenApiSecurityScheme
{
Type = SecuritySchemeType.OAuth2,
Flows = new OpenApiOAuthFlows
{
Implicit = new OpenApiOAuthFlow()
{
AuthorizationUrl = new Uri($"{builder.Configuration["AzureAdB2C:Instance"]}/{builder.Configuration["AzureAdB2C:Domain"]}/{builder.Configuration["AzureAdB2C:SignUpSignInPolicyId"]}/oauth2/v2.0/authorize"),
TokenUrl = new Uri($"{builder.Configuration["AzureAdB2C:Instance"]}/{builder.Configuration["AzureAdB2C:Domain"]}/{builder.Configuration["AzureAdB2C:SignUpSignInPolicyId"]}/oauth2/v2.0/token"),
Scopes = new Dictionary<string, string>() { { builder.Configuration["AzureAdB2C:Scope"], "backend all" } }
}
}
});
});
....
app.UseSwagger();
app.UseSwaggerUI(c => {
c.OAuthClientId(builder.Configuration["AzureAdB2C:SwaggerClientId"]);
c.OAuthScopes(builder.Configuration["AzureAdB2C:Scope"]);
c.OAuthUsePkce();
});
OK on localhost:
Not OK on azure:
https://anna-carat-auth-test.azurewebsites.net/swagger/index.html
Both redirect URLs are registered in app:
How to set a proper redirect URL for swagger?

Answer 1

Created a sample Web Api application.
In Visual Studio click on connected services and add a dependency of Microsoft Identity platform as shown in below snippet.
Once the dependencies are added then in Program.cs file is updated with Azure AD related settings.
builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
.AddMicrosoftIdentityWebApi(builder.Configuration.GetSection("AzureAd"));
// It added the Authentication and Authorization methods.
app.UseAuthentication();
app.UseAuthorization();
In Program.cs file made the code changes as shown below.
builder.Services.AddSwaggerGen(
x =>
{
x.SwaggerDoc("v1", new Microsoft.OpenApi.Models.OpenApiInfo
{
Title = "Swagger Azure AD Demo",
Version = "v1"
});
x.AddSecurityDefinition("oauth2", new Microsoft.OpenApi.Models.OpenApiSecurityScheme
{
Description = "Oauth2.0 which uses AuthorizationCode flow",
Name = "oauth2.0",
Type = SecuritySchemeType.OAuth2,
Flows = new OpenApiOAuthFlows
{
AuthorizationCode = new OpenApiOAuthFlow
{
AuthorizationUrl = new Uri(builder.Configuration["SwaggerAzureAD:AuthorizationUrl"]),
TokenUrl = new Uri(builder.Configuration["SwaggerAzureAD:TokenUrl"]),
Scopes = new Dictionary<string, string>
{
{builder.Configuration["SwaggerAzureAD:Scope"], "Access API as User" }
}
}
}
});
x.AddSecurityRequirement(new OpenApiSecurityRequirement
{
{
new OpenApiSecurityScheme
{
Reference= new OpenApiReference{Type=ReferenceType.SecurityScheme,Id="oauth2"}
},
new[]{builder.Configuration["SwaggerAzureAD:Scope"]}
}
});
});
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI(x=>
{
x.OAuthClientId(builder.Configuration["SwaggerAzureAD:ClientId"]);
x.OAuthUsePkce();
});
}
And the AppSettings.Json
{
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft.AspNetCore": "Warning"
}
},
"AllowedHosts": "*",
"AzureAd": {
"Instance": "https://login.microsoftonline.com/",
"Domain": "Something.onmicrosoft.com",
"TenantId": "TenantID",
"ClientId": "ClientID",
"CallbackPath": "/signin-oidc",
"Scopes": "access_as_user"
},
// These values need to be copied from App registartion
"SwaggerAzureAD": {
"AuthorizationUrl": "",
"TokenUrl": "",
"ClientId": "",
"Scope": ""
}
}
Expose API from App registration.
API Permissions need to be given in the App registrations of Azure.
And has to be copied the value and need to use in the scope attribute of AppSettings.json
And redirection urls to be mentioned and to be used in AppSettings.json form App registration -> Authentication as shown in below snippet.
And able to get the response without any issues.
Response: