56 lines
3.3 KiB
ReStructuredText
56 lines
3.3 KiB
ReStructuredText
Migrating Configuration
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=======================
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By `Steve Smith`_ and `Scott Addie`_
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In the previous article, we began :doc:`migrating an ASP.NET MVC project to ASP.NET Core MVC <mvc>`. In this article, we migrate configuration.
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.. contents:: Sections:
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:local:
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:depth: 1
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`View or download sample code <https://github.com/aspnet/Docs/tree/master/aspnet/migration/configuration/samples>`__
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Setup Configuration
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-------------------
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ASP.NET Core no longer uses the *Global.asax* and *web.config* files that previous versions of ASP.NET utilized. In earlier versions of ASP.NET, application startup logic was placed in an ``Application_StartUp`` method within *Global.asax*. Later, in ASP.NET MVC, a *Startup.cs* file was included in the root of the project; and, it was called when the application started. ASP.NET Core has adopted this approach completely placing all startup logic in the *Startup.cs* file.
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The *web.config* file has also been replaced in ASP.NET Core. Configuration itself can now be configured, as part of the application startup procedure described in *Startup.cs*. Configuration can still utilize XML files, but typically ASP.NET Core projects will place configuration values in a JSON-formatted file, such as *appsettings.json*. ASP.NET Core's configuration system can also easily access environment variables, which can provide a more secure and robust location for environment-specific values. This is especially true for secrets like connection strings and API keys that should not be checked into source control. See :doc:`/fundamentals/configuration` to learn more about configuration in ASP.NET Core.
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For this article, we are starting with the partially-migrated ASP.NET Core project from :doc:`the previous article <mvc>`. To setup configuration add the following constructor and property to the *Startup.cs* class located in the root of the project:
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.. literalinclude:: configuration/samples/WebApp1/src/WebApp1/Startup.cs
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:language: c#
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:linenos:
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:lines: 15-24
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:dedent: 8
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Note that at this point the *Startup.cs* file will not compile, as we still need to add the following ``using`` statement:
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.. code-block:: c#
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using Microsoft.Extensions.Configuration;
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Add an *appsettings.json* file to the root of the project using the appropriate item template:
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.. image:: configuration/_static/add-appsettings-json.png
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:width: 955px
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Migrate Configuration Settings from web.config
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----------------------------------------------
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Our ASP.NET MVC project included the required database connection string in *web.config*, in the ``<connectionStrings>`` element. In our ASP.NET Core project, we are going to store this information in the *appsettings.json* file. Open *appsettings.json*, and note that it already includes the following:
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.. literalinclude:: configuration/samples/WebApp1/src/WebApp1/appsettings.json
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:language: json
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:emphasize-lines: 4
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:linenos:
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In the highlighted line depicted above, change the name of the database from **_CHANGE_ME** to the name of your database.
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Summary
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-------
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ASP.NET Core places all startup logic for the application in a single file, in which the necessary services and dependencies can be defined and configured. It replaces the *web.config* file with a flexible configuration feature that can leverage a variety of file formats, such as JSON, as well as environment variables.
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