Can someone explain the general idea behind providing ... Abstraction packages?
As an example, when I search for the word "hosting" in VS NuGet package manager, in the list of findings there are:
Microsoft.Extensions.Hosting
Microsoft.Extensions.Hosting.Abstractions
Microsoft.AspNetCore.Hosting.Server.Abstraction
Microsoft.AspNetCore.Hosting.Abstractions
Microsoft.AspNetCore.Hosting
Microsoft.Extensions.Hosting.WindowsServices
Are these all related? Some seem to be platform dependent (AspNetCore) while others are not? Is there a general rule that tells me when to choose which?
Suppose I want to implement BackgroundService in a .NET5 class library, which of these NuGets shall I install? (It seems that Microsoft.Extensions.Hosting.Abstractions works fine for me, but I had to try that out.)
Thanks
The idea is that a library or package that you provide would only reference the Abstraction packages for easier compatibility.
E.g. if you ship a company-wide NuGet package with some business logic in it or a custom client, you may want to use ILogger / ILogger<T> for logging but not actually depend on any implementation for logging (both the built-in loggers or Serilog etc.), so you can reference the logging abstractions for these interfaces.
We have recently upgraded our API's (using Forms Authentication) Servicestack version 4.0.40 to latest stable version of Servicestack (V5.1.0). We use Autofac Ioc registration using InstancePerHttpRequest for API's (this is using Autofac.Integration.Mvc from Autofac.Mvc4 package).
Below code does not work anymore after servicestack upgrade.
this.UseAutofac(afcBuilder.Build());
Error CS0012 The type 'ServiceStackHost' is defined in an assembly
that is not referenced. You must add a reference to assembly
'ServiceStack, Version=4.0.48.0, Culture=neutral,
PublicKeyToken=null'.
So we have tried alternate ways to make it work using InstancePerDependency but that is causing missing "ASP.NET_SessionId" cookie value after API authentication.
Please suggest code to get actual "InstancePerHttpRequest" work with latest ServiceStack version.
I've already answered this question in ServiceStack Customer Forums but for anyone else's benefit with similar issues I'll include it below:
The issue isn't with ServiceStack or AutoFac it's with one of your dependencies which still has a binary reference to an old v4.0.48 of ServiceStack (highlighted in the Exception). You can't mix and match ServiceStack .dlls from different versions so you would need to re-compile whichever assembly has the old binary ServiceStack reference to use the version of ServiceStack you're using.
Autofac wouldn't have a dependency to ServiceStack, it would be one of your dependencies that is registered with Autofac. You can either use an Assembly inspector like JetBrains dotpeek and inspect the .dll references of each dll reference in your project or comment out registrations until you find the one with the dependency.
Basically you're unlikely to get anywhere focusing on ServiceStack or Autofac .dll's, you need to find the .dll that has a reference to ServiceStack v4.0.48 and re-compile it to use the version of ServiceStack you've upgraded to.
If you look at the dependency of Autofac.Mvc4, you'll see it only has a dependency to Autofac. Autofac's not going to have a dependency to ServiceStack v4.0.48, one of your own .dll's is going to have the old binary reference that's causing the issue.
Suppose I have a class library which I want to target netstandard1.3, but also use BigInteger. Here's a trivial example - the sole source file is Adder.cs:
using System;
using System.Numerics;
namespace Calculator
{
public class Adder
{
public static BigInteger Add(int x, int y)
=> new BigInteger(x) + new BigInteger(y);
}
}
Back in the world of project.json, I would target netstandard1.3 in the frameworks section, and have an explicit dependency on System.Runtime.Numerics, e.g. version 4.0.1. The nuget package I create will list just that dependency.
In the brave new world of csproj-based dotnet tooling (I'm using v1.0.1 of the command-line tools) there's an implicit metapackage package reference to NETStandard.Library 1.6.1 when targeting netstandard1.3. This means that my project file is really small, because it doesn't need the explicit dependency:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netstandard1.3</TargetFramework>
</PropertyGroup>
</Project>
... but the nuget package produced has a dependency on NETStandard.Library, which suggests that in order to use my small library, you need everything there.
It turns out I can disable that functionality using DisableImplicitFrameworkReferences, then add in the dependency manually again:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netstandard1.3</TargetFramework>
<DisableImplicitFrameworkReferences>true</DisableImplicitFrameworkReferences>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="System.Runtime.Numerics" Version="4.0.1" />
</ItemGroup>
</Project>
Now my NuGet package says exactly what it depends on. Intuitively, this feels like a "leaner" package.
So what's the exact difference for a consumer of my library? If someone tries to use it in a UWP application, does the second, "trimmed" form of dependencies mean that the resulting application will be smaller?
By not documenting DisableImplicitFrameworkReferences clearly (as far as I've seen; I read about it in an issue) and by making the implicit dependency the default when creating a project, Microsoft are encouraging users to just depend on the metapackage - but how can I be sure that doesn't have disadvantages when I'm producing a class library package?
In the past, we've given developers the recommendation to not reference the meta
package (NETStandard.Library) from NuGet packages but instead reference
individual packages, like System.Runtime and System.Collections. The
rationale was that we thought of the meta package as a shorthand for a bunch of
packages that were the actual atomic building blocks of the .NET platform. The
assumption was: we might end up creating another .NET platform that only
supports some of these atomic blocks but not all of them. Hence, the fewer packages you reference, the more portable you'd be. There were also concerns regarding how our tooling deals with large package graphs.
Moving forward, we'll simplify this:
.NET Standard is an atomic building block. In other words, new platforms
aren't allowed to subset .NET Standard -- they have to implement all of it.
We're moving away from using packages to describe our platforms,
including .NET Standard.
This means, you'll not have to reference any NuGet packages for .NET Standard
anymore. You expressed your dependency with the lib folder, which is exactly how
it has worked for all other .NET platforms, in particular .NET Framework.
However, right now our tooling will still burn in the reference to
NETStandard.Library. There is no harm in that either, it will just become
redundant moving forward.
I'll update the FAQ on the .NET Standard repo to include this question.
Update: This question is now part of the FAQ.
The team used to recommend figuring out what the slimmest package set was. They no longer do this, and recommend people just bring in NETStandard.Library instead (in the case of an SDK-style project, this will be done automatically for you).
I've never gotten a totally straight forward answer as to why that was, so allow me to make some educated guesses.
The primary reason is likely to be that it allows them to hide the differences in versions of the dependent libraries that you would otherwise be required to track yourself when changing target frameworks. It's also a much more user friendly system with the SDK-based project files, because you frankly don't need any references to get a decent chunk of the platform (just like you used to with the default references in Desktop-land, especially mscorlib).
By pushing the meta-definition of what it means to be a netstandard library, or a netcoreapp application into the appropriate NuGet package, they don't have to build any special knowledge into the definition of those things as Visual Studio (or dotnet new) sees them.
Static analysis could be used during publishing to limit the shipped DLLs, which is something they do today when doing native compilation for UWP (albeit with some caveats). They don't do that today for .NET Core, but I presume it's an optimization they've considered (as well as supporting native code).
There's nothing stopping you from being very selective, if you so choose. I believe you'll find that you're nearly the only one doing it, which also defeats the purpose (since it'll be assumed everybody is bringing in NETStandard.Library or Microsoft.NETCore.App).
You shouldn't need to disable the implicit reference. All platforms that the library will be able to run on will already have the assemblies that the NETStandard.Library dependency would require.
The .NET Standard Library is a specification, a set of reference assemblies that you compile against that provides a set of APIs that are guaranteed to exist on a know set of platforms and versions of platforms, such as .NET Core or the .NET Framework. It is not an implementation of these assemblies, just enough of the API shape to allow the compiler to successfully build your code.
The implementation for these APIs are provided by a target platform, such as .NET Core, Mono or .NET Framework. They ship with the platform, because they are an essential part of the platform. So there is no need to specify a smaller dependency set - everything's already there, you won't change that.
The NETStandard.Library package provides these reference assemblies. One point of confusion is the version number - the package is version 1.6.1, but this does not mean ".NET Standard 1.6". It's just the version of the package.
The version of the .NET Standard you're targeting comes from the target framework you specify in your project.
If you're creating a library and want it to run on .NET Standard 1.3, you'd reference the NETStandard.Library package, currently at version 1.6.1. But more importantly, your project file would target netstandard1.3.
The NETStandard.Library package will give you a different set of reference assemblies depending on your target framework moniker (I'm simplifying for brevity, but think lib\netstandard1.0, lib\netstandard1.1 and dependency groups). So if your project targets netstandard1.3, you'll get the 1.3 reference assemblies. If you target netstandard1.6, you'll get the 1.6 reference assemblies.
If you're creating an application, you can't target the .NET Standard. It doesn't make sense - you can't run on a specification. Instead, you target concrete platforms, such as net452 or netcoreapp1.1. NuGet knows the mapping between these platforms and the netstandard target framework monikers, so knows which lib\netstandardX.X folders are compatible with your target platform. It also knows that the dependencies of NETStandard.Library are satisfied by the target platform, so won't pull in any other assemblies.
Similarly, when creating a standalone .NET Core app, the .NET Standard implementation assemblies are copied with your app. The reference to NETStandard.Library does not bring in any other new apps.
Note that dotnet publish will create a standalone application, but it won't doesn't currently do trimming, and will publish all assemblies. This will be handled automatically by tooling, so again, trimming dependencies in your library won't help here.
The only place I can imagine where it might help to remove the NETStandard.Library reference is if you are targeting a platform that doesn't support the .NET Standard, and you can find a package from the .NET Standard where all of the transitive dependencies can run on your target platform. I suspect there aren't many packages that would fit that bill.
When using EF Code First, It appears WCF RIA Services Wizard (that runs when adding a new DomainService) in VS 2012 does not recognize the DbContexts defined in the project (it only recognizes the ObjectContext).
This means that when Adding a New Item in VS2012 and choosing Add DomainServiceClass, the wizard is not able to detect available context classes * combo list is empty *
Please see the attached image
Any idea what could be happening here?
Thanks,
-Sumit
This is a known issue with Visual Studio 2012, WCF RIA Services and Entity Framework, cause the Wizard to create new Domain Services doesn´t know the DbContext types.
The simple solution is to continue using Visual Studio 2010 to create Entity Models. Although using RIAServices.EntityFramework NuGet package won´t work, cause it doesn´t support current Versions of Entity Framework.
Another solution is to change the type of your Context from DbContext to ObjectContext.
Theres also a KB article for that specific scenario.
Update:
An update to WCF Ria Services was released to support EF 5 and the usage of DbContext. More information can be found here.
I believe that the wizard don't find your class due to the fact that WCF ria is older than EF 5. Try to redirect the assembly binding to
<runtime>
<legacyUnhandledExceptionPolicy enabled="1" />
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="EntityFramework" publicKeyToken="b77a5c561934e089" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>
...
let us know if it works
This is now possible with the 4.2 release of WCF RIA Services.
If you create a WCF RIA project and get prompted to select a Windows Phone version, this is a reported issue you need remove Windows Phone 8.0 & 7.1 SDK.
If then you get an error to do with project templates perform a repair on WCF RIA 1.0 SP2 which you should have already installed.
I have been playing around with the new StateMachine workflow that has been added to Windows Workflow as part of Platform Update 1 (see also). I now want to look at installing what I've created and therefore need to make sure my bootstrapper is up-to-date. In the future, I will be moving to WIX but right now, for the purposes of prototyping, I'm just using a regular Setup and Deployment project and its bootstrap support.
The list of standard pre-requisites does not include the PU1 as an option. Therefore, how can I add support for it?
Update
I found this answer on StackOverflow regarding custom prerequisites, which led me to this article on MSDN, which led me to creating my own pre-requisite. However, I got a new error about mismatched framework requirements. I suspect I need to pick apart the multi-targeting support and the existing .NET framework prerequisite package to see how to make a new prerequisite that will work correctly.
I've had a stab at creating my own bootstrapper packages for this. The results are here to download. Note that these are entirely untested and provided as-is - use at your own risk. However, feedback is welcome. Hopefully Microsoft will provide an official solution.
See How to detect if the .NET Framework Platform Update 1 is installed
is the Microsoft .NET Framework 4 Platform Update 1 - Runtime Update (KB2478063) what you are looking for? See here for the download.