Autofac-通过配置从特定文件夹注册程序集

Question

I register my assemblies by autofac in configuration. I want the autofac load assemblies from another folder, no 'bin' folder.

I try put it 'type' attribute path of asssembly like this:

<component type="Amazon.SQS.AmazonSQSClient, amazonDlls/AWSSDK" service="Amazon.SQS.IAmazonSQS, AWSSDK" />

But I get error of invalid assembly name.

How can I do it - register assembly from specific folder?

by the way: I know it is possible from code but I want from config.

Answer 1

It is not possible to provide a path to the assembly in the fully-qualified type name. It seems it's not even possible to register types from libraries not located in different directory than "bin" folder. Even if you prepare configuration file in the same folder as dll you want to register and read it this way:

builder.RegisterModule(new ConfigurationSettinsgReader("<section-name>", "amazonDlls/app.config"));

you will get the exception of type not found.

Answer 2

As noted in the documentation the names of component types are fully-qualified type names , which is a format defined by the .NET specification. A fully-qualified type name does not include a path.

Specifying a path is not possible with the out-of-the-box configuration format. You have a couple of options.

Option 1: Add a Probing Path

By default, .NET only searches the bin folder of your application for assemblies. You can read about how .NET locates assemblies on MSDN

.NET does allow you to specify additional paths to search via app.config or web.config :

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <probing privatePath="bin;bin\plugins" />
    </assemblyBinding>
  </runtime>
<configuration>

These paths must be subdirectories of the bin folder so that may not work for you.

If it must be outside the bin folder (and not under it in a subdirectory) you can use the <codeBase> element to specify a URL location . If you do that, it looks like the assembly must have a strong name, so keep that in mind. The probingPath mechanism won't require the strong name.

And, of course, there are risks inherent with loading assemblies that are in specified locations outside the GAC and outside your bin folder. Stuff to consider.

Option 2: Create Your Own Configuration Reader

This will be a lot harder. You can grab the Autofac.Configuration source and create your own version of the configuration reader that includes file location support. You'll probably need to look at Assembly.LoadFrom to get that to work, but, again, there are some risks doing that. The Assembly.LoadFrom docs outline the issues.