Could not create instance of type (My implementation of FilterUrlExtensions) No matching constructor was found

Question

I'm using Sitecore 9.0.2.

I am implementing Sitecore.Pipelines.PreprocessRequest.FilterUrlExtensions, that in Sitecore 9.0.2 has a constructor with the following signature:

public FilterUrlExtensions(string allowed, string blocked, string streamFiles, string doNotStreamFiles);

And my own class looks like this:

public class CustomPreprocessor : Sitecore.Pipelines.PreprocessRequest.FilterUrlExtensions
{ 
    public CustomPreprocessor(string allowed, string blocked, string streamFiles, string doNotStreamFiles) : base(allowed, blocked, streamFiles, doNotStreamFiles)
    {
    }

    public override void Process(PreprocessRequestArgs args)
    {
        base.Process(args);
    }
}

Yet I'm still getting this error: Could not create instance of type: eSundhedWeb.Foundation.Permissions.Pipelines.CustomPreprocessor. No matching constructor was found.

What can be the cause for this?

The reason why I'm trying to override the preprocessor is because I serve media files they don't seem to enter into the HttpRequest pipeline where I'm doing some authentication. I read somewhere that the preprocessor might be sending it straight to MVC because media is served as .ashx. If you've got a better idea I'm grateful for clues.

EDIT: I'm registering the processor as such in a config file:

<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <pipelines>
      <initialize>
        <processor type="eSundhedWeb.Foundation.Permissions.Pipelines.CustomPreprocessor, eSundhedWeb.Foundation.Permissions" patch:instead="processor[@type='Sitecore.Pipelines.PreprocessRequest.FilterUrlExtensions, Sitecore.Kernel']" />
      </initialize>
    </pipelines>
  </sitecore>
</configuration>

Answer 1

Try to modify your patch config the following way:

<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <pipelines>
      <initialize>
        <processor type="eSundhedWeb.Foundation.Permissions.Pipelines.CustomPreprocessor, eSundhedWeb.Foundation.Permissions" patch:instead="processor[@type='Sitecore.Pipelines.PreprocessRequest.FilterUrlExtensions, Sitecore.Kernel']">
          <param desc="Allowed extensions (comma separated)">aspx, ashx, asmx</param>
          <param desc="Blocked extensions (comma separated)">*</param>
          <param desc="Blocked extensions that stream files (comma separated)">*</param>
          <param desc="Blocked extensions that do not stream files (comma separated)"/>
        </processor>
      </initialize>
    </pipelines>
  </sitecore>
</configuration>

An even better solution would be to patch the configuration like this, then you don't need to copy the default values:

<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:set="http://www.sitecore.net/xmlconfig/set/">
  <sitecore>
    <pipelines>
      <initialize>
        <processor type="Sitecore.Pipelines.PreprocessRequest.FilterUrlExtensions, Sitecore.Kernel" set:type="eSundhedWeb.Foundation.Permissions.Pipelines.CustomPreprocessor, eSundhedWeb.Foundation.Permissions" />
      </initialize>
    </pipelines>
  </sitecore>
</configuration>

Answer 2

You shall use resolve=true to initialize parametrized constructor in Sitecore

For Example here cache key is been overridden and need to use the parameterized constructor