是Mapper.Map在AutoMapper线程安全的？ [英] Is Mapper.Map in AutoMapper thread-safe?

问题描述

我在找了 AutoMapper $ C $现在C（评估它为我的工作项目之一），而且，坦白说，我很惊讶：

I'm looking up AutoMapper code now (evaluating it for one of projects I'm working on), and, frankly speaking, I'm quite surprised:

• 在该库的API是基于一个静态的接入点（映射键入），所以一般它的任何方法必须是线程安全
• 但我没有发现这code的任何证据。

• The library API is based on a single static access point (Mapper type), so generally any of its methods must be thread safe
• But I didn't find ANY evidence of this in code.

所有我能找到是这个问题，但即使是言言似乎有不正确的：如果地图并没有在内部使用线程安全的数据结构，它不能被认为是线程安全的为好，如果我要打电话 CreateMap 在非并发环境，但同时具有地图。

All I was able to find is this issue, but even the statement made there seems incorrect: if Map doesn't use thread-safe data structures internally, it can't be considered as thread-safe as well, if I'm going to call CreateMap in non-concurrent context, but concurrently with Map.

即。 AutoMapper在例如唯一可能的使用模式ASP.NET MVC应用程序是：

I.e. the only possible usage pattern of AutoMapper in e.g. ASP.NET MVC application is:

lock (mapperLock) {
    ... Mapper.AnyMethod(...) ...
}

显然，如果我是正确的，这是一个巨大的缺乏。

Obviously, if I'm correct, that's a huge lack.

所以，我有两个问题：

• 对吗？
• 如果是，什么是AutoMapper的最佳替代品，不存在此问题
？

推荐答案

该链接 的问题或多或少回答你的问题：

The linked issue more or less answers your questions:

Mapper.CreateMap不是线程安全的，也永远是。然而，   Mapper.Map是线程安全的。映射器静态类只是一个薄   包装上的MappingEngine和配置对象之上。

Mapper.CreateMap is not threadsafe, nor will it ever be. However, Mapper.Map is thread-safe. The Mapper static class is just a thin wrapper on top of the MappingEngine and Configuration objects.

因此​​，只有使用 Mapper.CreateMap 如果你做你的配置中的一个集中的地方在一个线程安全的方式。

So only use Mapper.CreateMap if you do your configuration in one central place in a threadsafe manner.

您的评论是：

我问，是因为我想配置automatter就地，   即使用之前。我打算把它配置在非并发   情况下，即〜锁（mapperConfigLock）{Mapper.CreateMap（）......; }，   我担心这是不够的了。

I'm asking this because I'd like to configure automatter in-place, i.e. right before usage. I planned to configure it in non-concurrent context, i.e. ~ lock (mapperConfigLock) { Mapper.CreateMap()....; }, and I fear this is not enough now.

如果你正在做的就地配置只是不使用静态映射类。随着对GitHub的问题上意见建议直接使用映射引擎：

If you are doing in-place configuration just don't use the static Mapper class. As the comment on the github issue suggest use the mapping engine directly:

var config = 
    new ConfigurationStore(new TypeMapFactory(), MapperRegistry.AllMappers());
config.CreateMap<Source, Destination>();
var engine = new MappingEngine(config);

var source = new Source();
var dest = engine.Map(source);

这是更code一点点，但你可以围绕它创建自己的助手。 但一切都在当地一个给定的方法，所以没有共享的状态，无需担心线程安全。

It's a little bit of more code but you can create your own helpers around it. But everything is local in a given method so no shared state no need to worry about thread safety.

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