我如何重写耙任务自定义数据库适配器？ [英] How do I override rake tasks for a custom database adapter?

问题描述

我写了一个自定义数据库适配器，当一个护栏服务器正在运行工作正常，有效。现在我想补充平时rake任务定义，创建，删除和迁移的数据库。

I've written a custom database adapter that works correctly and effectively when a rails server is running. I would now like to add the usual rake task definitions for creating, dropping and migrating the database.

我想实现：

db:[drop|create|migrate]

我如何用我的gem包这些定义，让他们替代默认的值的人谁使用的宝石？

How do I package these definitions with my gem so that they override the default ones for anyone who uses the gem?

我看了看，通过其它适配器，但所有的耙任务逻辑的来源似乎是烤成active_record本身，每个任务只接通适配器名称。

I looked through the source of other adapters but all the rake task logic appears to be baked into active_record itself, each task just switches on the adapter name.

推荐答案

这样做的正确的方法是使用一个新的rake任务和更新您的通话code！

The correct way of doing this is to use a new rake task and update your calling code!

猴补丁默认任务是一个可怕的概念，希望有一个更好的挂钩点的地方自定义的适配器。这里有一个方法来覆盖rake任务，如果你没有选择，只能低着头这条道路（你可能做到这意思吗！）：

Monkey-patching default tasks is a scary concept, hopefully there's a nicer hook point somewhere for custom adapters. Here's a way to override a rake task if you have no choice (which you probably do! just sayin') but to head down that path:

# somewhere in your gem's tasks
tasks = Rake.application.instance_variable_get '@tasks'
tasks.delete 'db:create'
namespace 'db' do
  task 'create' do
    # ...
  end
end

此技术也可以修改，以包裹耙任务。

This technique can also be modified to wrap rake tasks.

如果你想的添加的任务，以现有的rake任务，使用增强。

If you want to add tasks to an existing rake task, use enhance.

Rake::Task['db:create'].enhance do
  Rake::Task['db:after_create'].invoke
end

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