HttpClient on .Net Standard 2.0

Unity Engine
1

Hi there,

I’m working on a library for Unity where we can use the System.Net.Http.HttpClient in Unity targeting .Net Standard 2.0.
This works perfectly in a test project in Visual Studio, separate from Unity, but when used in Unity, the following code throws an exception:

        public static HttpClient Create(TimeSpan timeout = default(TimeSpan), ICredentials credentials = null, string proxy = null)
        {
            var useProxy = !string.IsNullOrEmpty(proxy);
            var config = new HttpClientHandler
            {
                UseProxy = useProxy,
                Proxy = useProxy ? new WebProxy(proxy) : null
            };
            if (useProxy)
                config.DefaultProxyCredentials = credentials;
            if (credentials != null)
            {
                config.UseDefaultCredentials = false;
                config.Credentials = credentials;
            }
            var client = new HttpClient(config);

            if (!timeout.Equals(default(TimeSpan)))
                client.Timeout = timeout;
            return client;
        }

The error thrown is InvalidOperationException:
Operation is not valid due to the current state of the object. at System.Net.Http.HttpClientHandler.set_Proxy (System.Net.IWebProxy value) [0x0000e] in <20a8f293e89843148f03a963627efba4>:0,
this references line 7 in the code above.

My question is: has anyone here encountered the same problem? Is the HttpClient class not fully supported when targeting .Net Standard 2.0? I’m at a loss here, the code compiles perfectly, but at runtime it seems it behaves quite differently in Unity vs. a normal .Net project.

2

It took me some time to get it right but httpClient is supported by Unity out of the box on .NET 2.0 standard targets. This is the code I ended up with to access a REST api:

public static async Task<Resource> GetResource()
        {
            using (var httpClient = new HttpClient())
            {
                httpClient.BaseAddress = new Uri(URL);
                httpClient.DefaultRequestHeaders.Accept.Clear();
                httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                var response = await httpClient.GetAsync("api/session");
                if (response.StatusCode != HttpStatusCode.OK)
                    return null;
                var resourceJson = await response.Content.ReadAsStringAsync();
                return JsonUtility.FromJson<Resource>(resourceJson);
            }
        }
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