IIS 中的 ASP.NET Core，(ICollection/List/Array) appsettings.json -> web.config

Question

Using the Options pattern I created a class with an ICollection<string> allowedHosts property. Inside the appsettings.json I've added [ "google.nl", "bing.com" ] and when the app is running in Development mode everything is fine.

However, in production, we use IIS and by using the Configuration Editor of IIS to define the environmentVariables , and this gets saved as web.config and will somewhat look like this:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <aspNetCore>
            <environmentVariables>
                <environmentVariable name="ASPNETCORE_ENVIRONMENT" value="Production" />
                <environmentVariable name="AllowedHosts" value="How to format?" />
            </environmentVariables>
        </aspNetCore>
    </system.webServer>
</configuration>

My problem is: how can I convert this JSON from the appsettings.json :

{
  "allowedHosts": [ "google.com", "bing.com" ]
}

To XML for the web.config file? I tried using ["google.com"] , "google.com" but none is working.

Edit: I've used a bad property name, in this case the AllowedHosts has a different use and I should change the property name.

Answer 1

The AllowedHosts is a special configuration that accepts a semicolon-delimited list of host names without port numbers. For more details, see Host filtering .

If you need allow multiple hosts, you could configure it as below :

<aspNetCore processPath="dotnet" arguments=".\abc.dll" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" hostingModel="InProcess">
    <environmentVariables>
        <environmentVariable name="AllowedHosts" value="google.com;bing.com" />
    </environmentVariables>
</aspNetCore>

---

If you would like to get array from Web.Config configuration, you could change the key name to be :

<key-name>:<index>

eg :

<environmentVariables>
    <environmentVariable name="AllowedHosts:0" value="google.com" />
    <environmentVariable name="AllowedHosts:1" value="bing.com" />
</environmentVariables>

To get the array in ASP.NET Core :

var allowed =  _config.GetSection("AllowedHosts").AsEnumerable();

/* output :
[  
   {  
      "key":"AllowedHosts",
      "value":"*"
   },
   {  
      "key":"AllowedHosts:1",
      "value":"bing.com"
   },
   {  
      "key":"AllowedHosts:0",
      "value":"google.com"
   }
]
*/

Answer 2

Wouldn't you set that up in your Startup class? https://docs.microsoft.com/en-us/aspnet/core/security/cors?view=aspnetcore-2.2