ASP. NET CORE Study02

asp.net core Profile load priority

By default , Under the project Of launchSettings.json Configuration files have the highest priority ,appsettings.Development.json Priority level is second ,appsettings.json Profile priority last .
Pay attention to is , stay appsettings.json You can create more than one settings.json , Such as development.json ,productionsetting.json etc. json The configuration file , Each is different json File can be used for different configuration information , Not only can it be configured independently for the development environment , In more complex business scenarios, you can also extract some configurations , such as connectionsetting.json Special configuration for various connections .

because launchsettings The configuration file is the configuration loaded when the project is started , It must be loaded first , Of course, the highest priority , and appsettings The configuration information is the information that the project runs and loads , Priority is certainly lower than launchsetting The configuration file .

asp.net core Read custom json Configuration information

Mode one ：

Use IConfiguration How to interface .

1. Create and write custom json The configuration file .
2. stay program Class ConfigureAppConfiguration Method to specify the configuration provider for the application , namely Will customize the configuration json File is added to the application's configuration file collection .

3. controller Call in , Use Constructor injection , from asp.net core The built-in container injects a IConfiguration Object of interface type .

In this way, you can get the customization json Profile information .

Mode two

Use IOptions How to interface

1. Create and write custom json The configuration file .
2. stay program In the program startup class json Configuration file added to asp.net core In the configuration file collection of the program , One by one with the way .
3. New entity class , The class name should be consistent with the node name , namely In the custom json In profile The node name of the specific node information to be read bring into correspondence with . Properties of type The data type of the node information that needs to be read must be consistent , Among them, under the node key The value should be the attribute name of the entity class .
4. stay startup Medium ConfigureService Registration service .

5. stay controller Call in , Constructor injection is also used , Into a Defined entity class , Get the node data from the injected entity class .

In this way, you can also get json Configuration information .

asp.net core Read appsettings.json Configuration information

Mode one ：

Use IConfiguration How to interface

1. appsettings.json The configuration file has defined the required node information , Of course not necessarily appsettings.json Documents can also be appsettings.Production.json or appsettings.Development.json file . for example Read database connection string .
2. First, in the statup Medium configureService Method ,

Use services.AddSingleton(COnfiguration); register .

3. And then in controller Call in , Use constructor Injection , One IConfiguration Object of interface type , use .GetSection(“ConnectionStrings”)[“DeefaultConnection”] Get the required node information in a similar way .

Mode two ：

Use IOptions How to interface

1. Write the corresponding appsettings.json The configuration file .
2. Define an entity class , The class name should be consistent with the name of the node , The attributes of entity classes are also recommended and json The node names of are consistent , Data types need to be consistent .
3. stay startup Of configureservice Method registration , Use

services.Configure<ConnectionStrings>(Configuration.GetSection("ConnectionStrings"));

// todo
The registration method here and Read custom... Above json Mode 2 in the configuration file Of

ConnectionStrings option = new ConnectionStrings();
Configuration.GetSection("ConnectionStrings").Bind(option);
services.AddSingleton(option);

The function is consistent .

4. stay controller Call in , Inject through the constructor , Into a IOptions Object of type , stay IOptions Of T In the middle of Defined entity class . Use is the way to access attributes through objects .