Blazor WebAssembly - appsettings.json 在注册服务时作为依赖项
Blazor WebAssembly - appsettings.json as dependency while registering services
我正在尝试将我的自定义 AppSettings class 注册为服务,但它不起作用,我迷路了。我有位于 wwwroot 的 AppSettings class 和相应的 appsettings.json 文件。然后我有另一个 class 取决于 AppSettings class,ctor 看起来像这样:
public GeneratorService(AppSettings appSettings)
{
_appSettings = appSettings;
}
Main 方法如下所示:
public static async Task Main(string[] args)
{
var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("app");
builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });
builder.Services.AddTransient(async sp =>
{
var httpClient = sp.GetRequiredService<HttpClient>();
var response = await httpClient.GetAsync("appsettings.json");
using var json = await response.Content.ReadAsStreamAsync();
return await JsonSerializer.DeserializeAsync<AppSettings>(json);
}
);
builder.Services.AddTransient<GeneratorService>();
await builder.Build().RunAsync();
}
我确信 JsonSerializer 从文件中创建了正确的 AppSettings 实例。我对此很陌生,但据我了解,它应该像这样工作:
- 我正在将 GeneratorService 注入 .razor 页面,因此该页面请求 GeneratorService 实例
- GeneratorService 的构造函数中有 AppSettings,因此它请求 AppSettings 实例
- 服务提供商知道要获取 AppSettings 实例,它必须调用 HttpClient,读取并反序列化 appsettings.json 文件
但是当我尝试加载提到的 .razor 页面时,出现了这个错误:
Unhandled exception rendering component: Unable to resolve service for type 'BP.AppSettings' while attempting to activate 'BP.Services.GeneratorService'.
为什么服务提供者无法创建AppSettings并将其注入GeneratorService?
谢谢你的回答。
示例appsettings.json
{
"ClientConfigurations": {
"AzureAd": {
"Authority": "https://login.microsoftonline.com/001f3bfc-XXXX-XXXX-XXX-17c0e6de3b0f",
"ClientId": "815442365ec-xxxx-xxxx-xxxx-1ce9c3f3429",
"ValidateAuthority": true
}
}
}
添加这些 类。注意匹配的名称。
public class LocalConfigurations
{
public ClientConfigurations ClientConfigurations { get; set; }
}
public class ClientConfigurations
{
public AzureAdConfigurations AzureAd { get; set; }
}
public class AzureAdConfigurations
{
public string Authority { get; set; }
public string ClientId { get; set; }
public bool ValidateAuthority { get; set; }
}
在 program.cs 中它已经加载到 builder.Configuration 中。
这两行应该可以帮助您访问它。
var LocalConfigurations = builder.Configuration.Get<LocalConfigurations>();
builder.Services.AddSingleton(LocalConfigurations.ClientConfigurations);
然后在任何组件中
@page "/"
@inject Models.ClientConfigurations config
@config.AzureAd.ClientId
我是 Blazor 的新手,但是如果你在 root 中有一个 appsettings.json,例如
{
"message": "Hello word"
}
只要在你的服务中注入IConfiguration,所以
public WeatherForecastClient(HttpClient client, IConfiguration Configuration)
{
Console.WriteLine(Configuration["message"]);
this.client = client;
}
在 Dane Vinson's this entry 中,您有另一种方法,它将“appsettings.json”作为嵌入式资源嵌入。
1.-将文件放在 Blazor 客户端项目的根目录下
2.-编辑你的 project.csproj 并添加一些类似的
<ItemGroup>
<EmbeddedResource Include="your-file.json">
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</EmbeddedResource>
</ItemGroup>
3.-创建一个 .json 和一个 class SettingsInfo
4.-在program.cs中添加服务
public static async Task Main(string[] args)
{
//fileName is NameOf your Assembly.your-file.json, e.g.
string fileName = "Blazor1.Client.appsettings.json";
var stream = Assembly.GetExecutingAssembly()
.GetManifestResourceStream(fileName);
var config = new ConfigurationBuilder()
.AddJsonStream(stream)
.Build();
builder.Services.AddTransient(_ =>
{
return config.GetSection("AppSettings")
.Get<SettingsInfo>();
});
....
}
现在您可以在 razor 页面或服务中注入 SettingsInfo
谢谢你们的回答。阅读 Orak 的回答后,我决定将我的 AppSettings 实例注册为单例,现在它可以工作了。所以代替:
builder.Services.AddTransient(async sp =>
{
var httpClient = sp.GetRequiredService<HttpClient>();
var response = await httpClient.GetAsync("appsettings.json");
using var json = await response.Content.ReadAsStreamAsync();
return await JsonSerializer.DeserializeAsync<AppSettings>(json);
}
);
我只有:
var response = await client.GetAsync("appsettings.json");
using var json = await response.Content.ReadAsStreamAsync();
var appSettings = await JsonSerializer.DeserializeAsync<AppSettings>(json);
builder.Services.AddSingleton(appSettings);
我想将 AppSettings 作为单例而不是瞬态更有意义。我仍然不确定为什么我的原始代码不起作用。
编辑:
使用配置也有效:
var appSettings = builder.Configuration.Get<AppSettings>();
builder.Services.AddSingleton(appSettings.NamesLists);
我正在尝试将我的自定义 AppSettings class 注册为服务,但它不起作用,我迷路了。我有位于 wwwroot 的 AppSettings class 和相应的 appsettings.json 文件。然后我有另一个 class 取决于 AppSettings class,ctor 看起来像这样:
public GeneratorService(AppSettings appSettings)
{
_appSettings = appSettings;
}
Main 方法如下所示:
public static async Task Main(string[] args)
{
var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("app");
builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });
builder.Services.AddTransient(async sp =>
{
var httpClient = sp.GetRequiredService<HttpClient>();
var response = await httpClient.GetAsync("appsettings.json");
using var json = await response.Content.ReadAsStreamAsync();
return await JsonSerializer.DeserializeAsync<AppSettings>(json);
}
);
builder.Services.AddTransient<GeneratorService>();
await builder.Build().RunAsync();
}
我确信 JsonSerializer 从文件中创建了正确的 AppSettings 实例。我对此很陌生,但据我了解,它应该像这样工作:
- 我正在将 GeneratorService 注入 .razor 页面,因此该页面请求 GeneratorService 实例
- GeneratorService 的构造函数中有 AppSettings,因此它请求 AppSettings 实例
- 服务提供商知道要获取 AppSettings 实例,它必须调用 HttpClient,读取并反序列化 appsettings.json 文件
但是当我尝试加载提到的 .razor 页面时,出现了这个错误:
Unhandled exception rendering component: Unable to resolve service for type 'BP.AppSettings' while attempting to activate 'BP.Services.GeneratorService'.
为什么服务提供者无法创建AppSettings并将其注入GeneratorService? 谢谢你的回答。
示例appsettings.json
{
"ClientConfigurations": {
"AzureAd": {
"Authority": "https://login.microsoftonline.com/001f3bfc-XXXX-XXXX-XXX-17c0e6de3b0f",
"ClientId": "815442365ec-xxxx-xxxx-xxxx-1ce9c3f3429",
"ValidateAuthority": true
}
}
}
添加这些 类。注意匹配的名称。
public class LocalConfigurations
{
public ClientConfigurations ClientConfigurations { get; set; }
}
public class ClientConfigurations
{
public AzureAdConfigurations AzureAd { get; set; }
}
public class AzureAdConfigurations
{
public string Authority { get; set; }
public string ClientId { get; set; }
public bool ValidateAuthority { get; set; }
}
在 program.cs 中它已经加载到 builder.Configuration 中。 这两行应该可以帮助您访问它。
var LocalConfigurations = builder.Configuration.Get<LocalConfigurations>();
builder.Services.AddSingleton(LocalConfigurations.ClientConfigurations);
然后在任何组件中
@page "/"
@inject Models.ClientConfigurations config
@config.AzureAd.ClientId
我是 Blazor 的新手,但是如果你在 root 中有一个 appsettings.json,例如
{
"message": "Hello word"
}
只要在你的服务中注入IConfiguration,所以
public WeatherForecastClient(HttpClient client, IConfiguration Configuration)
{
Console.WriteLine(Configuration["message"]);
this.client = client;
}
在 Dane Vinson's this entry 中,您有另一种方法,它将“appsettings.json”作为嵌入式资源嵌入。
1.-将文件放在 Blazor 客户端项目的根目录下
2.-编辑你的 project.csproj 并添加一些类似的
<ItemGroup>
<EmbeddedResource Include="your-file.json">
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</EmbeddedResource>
</ItemGroup>
3.-创建一个 .json 和一个 class SettingsInfo
4.-在program.cs中添加服务
public static async Task Main(string[] args)
{
//fileName is NameOf your Assembly.your-file.json, e.g.
string fileName = "Blazor1.Client.appsettings.json";
var stream = Assembly.GetExecutingAssembly()
.GetManifestResourceStream(fileName);
var config = new ConfigurationBuilder()
.AddJsonStream(stream)
.Build();
builder.Services.AddTransient(_ =>
{
return config.GetSection("AppSettings")
.Get<SettingsInfo>();
});
....
}
现在您可以在 razor 页面或服务中注入 SettingsInfo
谢谢你们的回答。阅读 Orak 的回答后,我决定将我的 AppSettings 实例注册为单例,现在它可以工作了。所以代替:
builder.Services.AddTransient(async sp =>
{
var httpClient = sp.GetRequiredService<HttpClient>();
var response = await httpClient.GetAsync("appsettings.json");
using var json = await response.Content.ReadAsStreamAsync();
return await JsonSerializer.DeserializeAsync<AppSettings>(json);
}
);
我只有:
var response = await client.GetAsync("appsettings.json");
using var json = await response.Content.ReadAsStreamAsync();
var appSettings = await JsonSerializer.DeserializeAsync<AppSettings>(json);
builder.Services.AddSingleton(appSettings);
我想将 AppSettings 作为单例而不是瞬态更有意义。我仍然不确定为什么我的原始代码不起作用。
编辑: 使用配置也有效:
var appSettings = builder.Configuration.Get<AppSettings>();
builder.Services.AddSingleton(appSettings.NamesLists);