ASP .Net Core, Cors Host vs Origin-CodePudding

When I Wanted to add Cors, there were 2 options. Host and Origin.

What is the difference between them?

    builder.Services.AddCors(options =>
    {
        options.AddPolicy("AllowOrigin", builder =>
        {
            builder
                .AllowAnyMethod()
                .AllowAnyHeader()
                .SetIsOriginAllowed(origin => true)
                .AllowCredentials();
            //or
            builder
            .AllowAnyMethod()
            .AllowAnyHeader()
            .SetIsOriginAllowed((host) => true)
            .AllowCredentials();
    
        });
    });

CodePudding user response：

Those are both identical. SetIsOriginAllowed expects a function that takes a string and returns a boolean. Both of those lambdas do that. You can call the parameter "x" and it'll still be the same function.

CodePudding user response：

The method here is .SetIsOriginAllowed(Func<bool,string>).

It's one method that takes a lambda with a string parameter that returns a bool. If you're not familiar with lambdas, they can be thought of as really terse inline functions.

In your question, host and origin are just different names for that string parameter, you could call it TheSpanishInquisition and it would still work identically. If you're not actually using that parameter, I'd suggest using the _ discard operator, so it would be:

builder
  .AllowAnyMethod()
  .AllowAnyHeader()
  .SetIsOriginAllowed(_ => true)
  .AllowCredentials();

The different bracketisation doesn't matter either. Brackets around lambda parameters are optional if there's only a single parameter but are required if there are multiple.