Question about Dependency Injection
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Hello guys, I have an issue related to dependency injection in the Program.cs of a .Net 7 application. In this case it's an API, but that does not really matter. Before calling the line: var app = builder.Build(); I am adding a few singletons normally with :
builder.Services.AddSingleton();
builder.Services.AddSingleton();My issue is that the HTTP client singleton requires info from the config singleton, and it's not a simple case of injecting the former into the latter. We can't use appsettings.json to manage our configuration, that would be too easy, and because the second one is an HTTP client, I have this code :
builder.Services.AddSingleton();
builder.Services.AddHttpClient(client =>
{
client.BaseAddress = new Uri(myConfig.myURI);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));}).ConfigurePrimaryHttpMessageHandler(() =>
{
return new HttpClientHandler()
{
UseDefaultCredentials = true
};
});.. all this still before I call builder.Build(); I have already googled and chatGPT'd the problem, but the solutions I get are for .Net 6 at best, and do not apply. My current solution is to use builder.Services.BuildServiceProvider().GetService() to get an instance of myConfig, but then the builder is called twice, so this instance is lost, and after the builder.Build(), I have to read my config again. Technically, this works, but it's ugly and triggers my OCD. If there's any DI god out there, what am I missing ? :) Thanks in advance Fred
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Hello guys, I have an issue related to dependency injection in the Program.cs of a .Net 7 application. In this case it's an API, but that does not really matter. Before calling the line: var app = builder.Build(); I am adding a few singletons normally with :
builder.Services.AddSingleton();
builder.Services.AddSingleton();My issue is that the HTTP client singleton requires info from the config singleton, and it's not a simple case of injecting the former into the latter. We can't use appsettings.json to manage our configuration, that would be too easy, and because the second one is an HTTP client, I have this code :
builder.Services.AddSingleton();
builder.Services.AddHttpClient(client =>
{
client.BaseAddress = new Uri(myConfig.myURI);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));}).ConfigurePrimaryHttpMessageHandler(() =>
{
return new HttpClientHandler()
{
UseDefaultCredentials = true
};
});.. all this still before I call builder.Build(); I have already googled and chatGPT'd the problem, but the solutions I get are for .Net 6 at best, and do not apply. My current solution is to use builder.Services.BuildServiceProvider().GetService() to get an instance of myConfig, but then the builder is called twice, so this instance is lost, and after the builder.Build(), I have to read my config again. Technically, this works, but it's ugly and triggers my OCD. If there's any DI god out there, what am I missing ? :) Thanks in advance Fred
If you're "stuck" with a given framework, count yourself lucky if you get something to work. When it does, move on instead of thinking about "ugly"; it's a waste of time.
"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I
-
Hello guys, I have an issue related to dependency injection in the Program.cs of a .Net 7 application. In this case it's an API, but that does not really matter. Before calling the line: var app = builder.Build(); I am adding a few singletons normally with :
builder.Services.AddSingleton();
builder.Services.AddSingleton();My issue is that the HTTP client singleton requires info from the config singleton, and it's not a simple case of injecting the former into the latter. We can't use appsettings.json to manage our configuration, that would be too easy, and because the second one is an HTTP client, I have this code :
builder.Services.AddSingleton();
builder.Services.AddHttpClient(client =>
{
client.BaseAddress = new Uri(myConfig.myURI);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));}).ConfigurePrimaryHttpMessageHandler(() =>
{
return new HttpClientHandler()
{
UseDefaultCredentials = true
};
});.. all this still before I call builder.Build(); I have already googled and chatGPT'd the problem, but the solutions I get are for .Net 6 at best, and do not apply. My current solution is to use builder.Services.BuildServiceProvider().GetService() to get an instance of myConfig, but then the builder is called twice, so this instance is lost, and after the builder.Build(), I have to read my config again. Technically, this works, but it's ugly and triggers my OCD. If there's any DI god out there, what am I missing ? :) Thanks in advance Fred
If you want a singleton then you have to inject it into a thread flow that does not depend on requests but rather something like the start up method. But as with the other reply, the point it to deliver something. And you need to have a realistic view about what might actually need to be easily replaced in the future. So does it actually need to be injected. Configuration might be it but you can do that with a standard factory idiom also.
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Hello guys, I have an issue related to dependency injection in the Program.cs of a .Net 7 application. In this case it's an API, but that does not really matter. Before calling the line: var app = builder.Build(); I am adding a few singletons normally with :
builder.Services.AddSingleton();
builder.Services.AddSingleton();My issue is that the HTTP client singleton requires info from the config singleton, and it's not a simple case of injecting the former into the latter. We can't use appsettings.json to manage our configuration, that would be too easy, and because the second one is an HTTP client, I have this code :
builder.Services.AddSingleton();
builder.Services.AddHttpClient(client =>
{
client.BaseAddress = new Uri(myConfig.myURI);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));}).ConfigurePrimaryHttpMessageHandler(() =>
{
return new HttpClientHandler()
{
UseDefaultCredentials = true
};
});.. all this still before I call builder.Build(); I have already googled and chatGPT'd the problem, but the solutions I get are for .Net 6 at best, and do not apply. My current solution is to use builder.Services.BuildServiceProvider().GetService() to get an instance of myConfig, but then the builder is called twice, so this instance is lost, and after the builder.Build(), I have to read my config again. Technically, this works, but it's ugly and triggers my OCD. If there's any DI god out there, what am I missing ? :) Thanks in advance Fred
I'm not sure why you do things exactly this way but it seems to me that you're struggling because you're doing something you're not supposed to do with HTTP clients. Here are some nice reads about
IHttpClientFactory. I think they'll help you to instantiate your HttpClient in a more robust way. Use the IHttpClientFactory - .NET | Microsoft Learn[^] Use IHttpClientFactory to implement resilient HTTP requests | Microsoft Learn[^] -
If you're "stuck" with a given framework, count yourself lucky if you get something to work. When it does, move on instead of thinking about "ugly"; it's a waste of time.
"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I
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Hello guys, I have an issue related to dependency injection in the Program.cs of a .Net 7 application. In this case it's an API, but that does not really matter. Before calling the line: var app = builder.Build(); I am adding a few singletons normally with :
builder.Services.AddSingleton();
builder.Services.AddSingleton();My issue is that the HTTP client singleton requires info from the config singleton, and it's not a simple case of injecting the former into the latter. We can't use appsettings.json to manage our configuration, that would be too easy, and because the second one is an HTTP client, I have this code :
builder.Services.AddSingleton();
builder.Services.AddHttpClient(client =>
{
client.BaseAddress = new Uri(myConfig.myURI);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));}).ConfigurePrimaryHttpMessageHandler(() =>
{
return new HttpClientHandler()
{
UseDefaultCredentials = true
};
});.. all this still before I call builder.Build(); I have already googled and chatGPT'd the problem, but the solutions I get are for .Net 6 at best, and do not apply. My current solution is to use builder.Services.BuildServiceProvider().GetService() to get an instance of myConfig, but then the builder is called twice, so this instance is lost, and after the builder.Build(), I have to read my config again. Technically, this works, but it's ugly and triggers my OCD. If there's any DI god out there, what am I missing ? :) Thanks in advance Fred
Ok, a few months late admittedly. I'm not a fan of all this functional style boostrapping in ASP.NET core. I find the whole thing obfuscated and difficult to work with and often grapple just to do something simple like config or logging. Anyway, I have this in my code:
services.AddHttpClient((serviceProvider, httpClient) =>
{
var opts = serviceProvider.GetRequiredService>();
httpClient.BaseAddress = opts.Value.BaseUrl;
})So, if you just want to get access to config, I think you can just retrieve it from the service provider given as the second parameter to the lambda, no BuildServiceProvider() required.
Regards, Rob Philpott.