![]() Typed HTTPClient Request using HttpClientFactory This technique has an advantage like you can configure multiple HTTP clients with custom configuration as required like using policy, network credentials, specific headers, or security tokens as needed. Named HTTPClient using IHttpClientFactory in ASP.NET Core – Part 2.I have discussed this technique in detail in the below post, Named HTTPClient Request using HttpClientFactory Once injected HTTpClientFactory from the Constructor, the instance can be used for creating the HTTPClient object as shown below, Public void ConfigureServices(IServiceCollection services) Update ConfigureServices method as below, Required instances can be enabled and disabled as required from the API pipeline as middleware. HTTPClientFactory lets you DI inject the HTTPClient objects using an explicit dependency principle. You create an HTTPClient object using HTTPClientFactory. Let’s look at the basic HttpClient approach where we shall be creating plain HTTPClient using HTTPClientFactory. Let’s get started and see how to effectively use HTTPClientFactory using different techniques.Ĭreate an HTTP request using HTTPClientFactory – Guidelines Automatic management avoids common DNS (Domain Name System) problems that occur when manually managing HTTPClient lifetimes. Solves Stale DNS problems by cycling HTTPMessageHandler instances at regular intervals.Manages the pooling and lifetime of HTTPMessageHandler instances.Solves the Resource exhaustion problems by pooling HTTPMessageHandler.Provides extensions for Polly-based middleware. More control with Delegating handlers.Enable Authentication per request basis if needed.Enable customization of HTTP objects to address specific needs like passing Security Token, NetworkCredentials, specific headers like correlation Ids or other metadata, etc.Enable use of HTTPClient resources as middleware through a factory using explicit DI (Dependency Injection) principles. ![]() Then if needed one can define additional HTTPClient objects with their custom configuration.Ī default HTTPClient can be registered for general access. For example, a client named Account could be registered and configured with specific security to only access the Account details.Centralize the configuration and instantiation of HTTPClient objects.The above common problems can be easily resolved by using HTTPClientfactory introduced recently in. I am not sure if this issue exists in the regular. This is an additional problem that was found in the. NET Core, it was found that Singleton or Static HTTPClient object doesn’t respect the DNS update or change in the. This will result in SocketException errors.Īs discussed above a Singleton or Static HTTPClient object as specified above should help to resolve the most issues.īut in. Especially in server applications, creating a new HttpClient instance for every request will exhaust the number of sockets available under heavy loads. HttpClient is intended to be instantiated once and re-used throughout the life of an application. HTTPClient creating using ‘new’ and ‘using’ block, HTTPClient object doesn’t release the sockets immediately even if it is called using “using” ( IDisposable) block.Example – Async operation with heavy loads. Instantiating HTTPClient objects for each request might exhaust the number of sockets available.Each new HTTPClient object creates a new socket instance.Let’s not forget that socket objects are un-managed resources. So basic understanding is to use ‘ using(.)’ blocks to dispose of the objects but using block doesn’t release the socket immediately when heavy load operations are performed. Please note that the HTTPClient implements IDisposable. This was a commonly known issue while using the HTTPClient objects. Let’s discuss a few issues associated with using HttpClient in the old way. NET Core framework in the form of Stale DNS problems. This was also followed by the realization that one should create Static or Singleton HTTP Client instances but which again ultimately found to be an issue in the recent. Over the years it has been observed a few common issues like resource exhaustion caused by multiple invocations of the HTTP request object. We shall also understand a few approaches to create HTTPClient requests using the below techniques,Īll the above techniques leverage the IHTTPClientFactory interface to DI (Dependency Injection) required client object.ĭI with middleware framework lets API pipeline control the lifetime management of HTTPClient request objects instead of doing it manually. Typed HTTPClient Request using HttpClientFactory.Named HTTPClient Request using HttpClientFactory.Create an HTTP request using HTTPClientFactory – Guidelines.Stale DNS (Domain Name System) problems.
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