CODEWITHSUNDEEP
azureazure-functions
Joe Eng
Joe Eng

Reputation: 1214

HttpClient gets disposed w/Azure Functions Dependency Injection

When you add HttpClient using DI in Azure Functions it seems that anything that has a dependency on it must be a singleton, or the HttpClient will get disposed once the lifetime of the dependent class ends.

I'm adding HttpClient w/default settings:

builder.Services.AddHttpClient();

Here's the error I see in the logs when I attempt to re-run the function:

Cannot access a disposed object.
Object name: 'System.Net.Http.HttpClient'.

Can anyone confirm? If so, is this expected behavior?

Upvotes: 2

Views: 2500

Answers (1)

Thiago Custodio
Thiago Custodio

Reputation: 18387

I am not sure if you had checked the official doc but here's how you should inject the http client factory into your code:

//registering

using System;
using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Http;
using Microsoft.Extensions.Logging;

[assembly: FunctionsStartup(typeof(MyNamespace.Startup))]

namespace MyNamespace
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddHttpClient();

            builder.Services.AddSingleton((s) => {
                return new MyService();
            });

            builder.Services.AddSingleton<ILoggerProvider, MyLoggerProvider>();
        }
    }
}

//azure function

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace MyNamespace
{
    public class HttpTrigger
    {
        private readonly IMyService _service;
        private readonly HttpClient _client;

        public HttpTrigger(IMyService service, IHttpClientFactory httpClientFactory)
        {
            _service = service;
            _client = httpClientFactory.CreateClient();
        }

        [FunctionName("GetPosts")]
        public async Task<IActionResult> Get(
            [HttpTrigger(AuthorizationLevel.Function, "get", Route = "posts")] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");
            var res = await _client.GetAsync("https://microsoft.com");
            await _service.AddResponse(res);

            return new OkResult();
        }
    }
}

https://learn.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection

Upvotes: 4

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