An error occurred while sending the request system io ioexception the response ended prematurely



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Thursday, 15 October 2020

Resolving “System.IO.IOException: The response ended prematurely.” in HttpClient Request

Some times a silly mistake can waste lot of time of a developer. The exception “System.IO.IOException: The response ended prematurely.” while making an http client request to call an API from another web app has wasted considerable amount of my time diagnosing the issue. Therefore, thought worth sharing the experience.

The error reported was below when an API request via http client was made from one of the web applications. Strangely the other web application handled the same request with no problems and returned the expected data.

Sending HTTP request GET http://localhost:5001/api/v1/businessTypes/1/ServiceCategories

An unhandled exception has occurred while executing the request.

System.Net.Http.HttpRequestException: An error occurred while sending the request.

—> System.IO.IOException: The response ended prematurely.

at System.Net.Http.HttpConnection.FillAsync(Boolean async)

at System.Net.Http.HttpConnection.ReadNextResponseHeaderLineAsync(Boolean async, Boolean foldedHeadersAllowed)

at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

— End of inner exception stack trace —

This caused me to look at each implementation compared closely and I could not see any difference. Exactly same code patterns were implemented so I was pulling my hair for some time with this one, as it seems something somewhere wrong but was 100% certain it is not the code as there was no difference at all. After spending couple of hours searching for this “The response ended prematurely.” in web there was no proper reasoning could be found.

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Why do I get «The response ended prematurely» when using the HttpClient in C#?

My first code of HTTP Client in .Net Core. The server is running on my PC as well, so I want to send it to localhost.

I’ve added printing of the inner exception after someone recommended it here but it’s not enough for me to understand the problem.

The error I received from the loop inside the catch is:

How can I figure out why can’t I send a message to the server? Does the content of the message can disrupt the connection generation?

I checked the server with another client and it’s working so the problem has to be in my code.

EDIT: The server is using https so I changed my URL to https as well and this is the error I received:

Do I need to add some SSL commands in order to make a secure connection?

Edit2: The new error after adding a command in callURL()

2 Answers 2

System.IO.IOException: The response ended prematurely means the server to which you’re making an HTTP request closed the connection without having sent back a complete response.

It has nothing to do with your client code, as it looks to compile & send content correctly.

Yes, you should be using await client.PostAsync but that isn’t related at all to your question.

Double-check that http://127.0.0.1:5001 is 100% correct — maybe it’s https:// or not on port 5001 .

If it is an endpoint using HTTPS, you may get System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure. as it looks like you’re calling a local endpoint.

.NET does SSL certificate validation by default & will throw an exception if you are trying to call an HTTPS endpoint for which you have no/invalid SSL certificate. You probably have not set up the localhost certificate correctly on your machine.

Initialise your HttpClient like below:

However, please do note allowing all SSL certificates is a security risk if used on anything other than your local dev environment.

Источник

An error occurred while sending the request system io ioexception the response ended prematurely

#c# #http #.net-core #httpclient

Вопрос:

Мой первый код HTTP-клиента в .Net Core. Сервер также работает на моем компьютере, поэтому я хочу отправить его на локальный хост.

Я добавил печать внутреннего исключения после того, как кто-то рекомендовал его здесь, но этого недостаточно, чтобы я понял проблему.

Ошибка, которую я получил из цикла внутри ловушки, состоит в том, что:

Как я могу понять, почему я не могу отправить сообщение на сервер?
Может ли содержимое сообщения нарушить создание соединения?

Я проверил сервер у другого клиента, и он работает, поэтому проблема должна быть в моем коде.

ИЗМЕНИТЬ: Сервер использует https, поэтому я также изменил свой URL на https, и это ошибка, которую я получил:

Нужно ли мне добавлять некоторые команды SSL, чтобы установить безопасное соединение?

Edit2: Новая ошибка после добавления команды в callURL()

Комментарии:

1. Сделайте catch (Exception err) , а затем Console.WriteLine(err.ToString()); — каковы полные сведения об исключении?

2. HttpClient использует асинхронный ввод — поэтому вы должны использовать async методы с await . Вы не должны использовать .Result , потому что это может привести к взаимоблокировкам.

3. @ErmiyaEskandary Значение ошибки: msg: Произошла одна или несколько ошибок. (При отправке запроса произошла ошибка.) источник: Система. Частное. Трассировка ядра: в системе. Нарезание резьбы. Задачи.Задачи. ThrowIfExceptional(логические исключения includeTaskCanceledExceptions) в системе. Нарезание резьбы. Задачи. Задача 1.GetResultCore(Boolean waitCompletionNotification) at System.Threading.Tasks.Task 1.get_Result() в HttpClient. Program.callURL(URL-адрес строки) в C:sourceHTTPClientHTTPClientProgram.cs:line 84

4. Правильно ли 127.0.0.1:5001 на 100%? Работает ли сервер? Ваш код работает так, что бы это ни было, это серверная сторона

5. @ErmiyaEskandary Я только что увидел, что сервер использует https, и я использовал HTTP, поэтому я изменил HTTP на https, и я получил новую ошибку (В сообщении)

Ответ №1:

System.IO.IOException: The response ended prematurely означает, что сервер, на который вы отправляете HTTP-запрос, закрыл соединение, не отправив полный ответ.

Это не имеет никакого отношения к вашему клиентскому коду, так как он правильно компилирует и отправляет контент.

Да, вы должны использовать await client.PostAsync , но это никак не связано с вашим вопросом.

Дважды проверьте, что http://127.0.0.1:5001 это на 100% правильно — возможно, это https:// или нет на порту 5001 .

Если это конечная точка, использующая HTTPS, вы можете получить System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure. , как это выглядит, если вы вызываете локальную конечную точку.

.NET по умолчанию выполняет проверку SSL-сертификата и создаст исключение, если вы пытаетесь вызвать конечную точку HTTPS, для которой у вас нет/недействительного SSL-сертификата. Возможно, вы неправильно настроили сертификат localhost на своем компьютере.

Инициализируйте ваше HttpClient подобное ниже:

Однако, пожалуйста, обратите внимание, что разрешение всех SSL-сертификатов представляет угрозу безопасности, если они используются в чем-либо, кроме вашей локальной среды разработки.

Комментарии:

1. Теперь это работает. Очень странно.. Большое спасибо!

2. @RoyAncri Не пропускайте проверку сертификации в производстве, однако для разработки это будет нормально. Установка правильного SSL — сертификата на производственном сервере позволит вам удалить приведенный выше код, который представляет угрозу безопасности, если оставить его в таком виде на чем-либо, кроме сборок разработчиков-надеюсь, это поможет!

3. @ErmiyaEskandary Да, я прочитаю, как это сделать для производственного проекта. Еще раз спасибо

Источник

Exception while calling an external API from .NET Core 3.1 — HttpClient #51077

Comments

joshymonmc commented Apr 11, 2021 •

System.Net.Http.HttpRequestException: An error occurred while sending the request. System.IO.IOException: The response ended prematurely.

We are trying to access an external REST API (runs on Java 8, hosted on Solaris linux, Tomcat) from an application on a Windows machine,.NET Core 3.1, using HTTPClient. We try with a PostAsync request.

What we observe is when we make the call first time, if fails with an exception. And the next time, if we make the request within 15 second, the request becomes successful.

And the same API request works fine with Postman, irrespective of whether its first request or second request.

Part of Code

Note : The external apiURL is https and the API server is behind a load balancer.

Part of Exception details:

The exception occurs after 30 seconds, from the request is made.

What we tried so far:

1. Changed the Async Post call to sync, no change in the result.
2. Suggested several options mentioned in the internet like
   a. setting TLS verions to 1, 1.1, 1.2 for the request
   b. made DefaultRequestHeaders.ConnectionClose = true
   c. tried with UseCookies = false
   d. Used .NET Framework 4.8 instead of .NET Core

but no luck so far.

1. We are not able to make any changes on the API hosted on Solaris server, since its within our client’s corporate network.

Looking forward to the support to resolve the issue at the earliest. Appreciate an early response!

To Reproduce

Exceptions (if any)

Further technical details

• ASP.NET Core version 3.1
• The IDE VS Code on Windows

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System.Net.Http.HttpRequestException: An error occurred while sending the request. System.IO.IOException: The response ended prematurely.

We are trying to access an external REST API (runs on Java 8, hosted on Solaris linux, Tomcat) from an application on a Windows machine,.NET Core 3.1, using HTTPClient. We try with a PostAsync request.

What we observe is when we make the call first time, if fails with an exception. And the next time, if we make the request within 15 second, the request becomes successful.

And the same API request works fine with Postman, irrespective of whether its first request or second request.

Part of Code

HttpResponseMessage response = client.PostAsync(
apiUrl, new StringContent(postData, Encoding.UTF8,
«application/json»)).Result;
apiResponse = response.Content.ReadAsStringAsync().Result;

Note : The external apiURL is https and the API server is behind a load balancer.

Part of Exception details:

The exception occurs after 30 seconds, from the request is made.

System.Net.Http.HttpRequestException: An error occurred while sending the request.
—> System.IO.IOException: The response ended prematurely.
at System.Net.Http.HttpConnection.FillAsync()
at System.Net.Http.HttpConnection.ReadNextResponseHeaderLineAsync(Boolean foldedHeadersAllowed)
at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
— End of inner exception stack trace —
at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)

What we tried so far:

1. Changed the Async Post call to sync, no change in the result.
2. Suggested several options mentioned in the internet like
   a. setting TLS verions to 1, 1.1, 1.2 for the request
   b. made DefaultRequestHeaders.ConnectionClose = true
   c. tried with UseCookies = false
   d. Used .NET Framework 4.8 instead of .NET Core

but no luck so far.

1. We are not able to make any changes on the API hosted on Solaris server, since its within our client’s corporate network.

Looking forward to the support to resolve the issue at the earliest. Appreciate an early response!

Источник

What I Broke – Programming and Web Development

Let’s take a look at what I’ve broken today

Http gRPC with .NET Core and Docker – Error starting gRPC call. System.Net.Http.HttpRequestException: An error occurred while sending the request. —> System.IO.IOException: The response ended prematurely.

I’ve been mucking around with gRPC today while using .NET Core and Docker. I have two Microservices in the setup, one server and one client. Because these services will only be communicating internally I intended to use HTTP instead of HTTPS. Unfortunately, I hit the following error while attempting to set this up:

According Microsoft’s eshoponcontainers documentation there are a few extra steps for getting this to work:

Using gRPC without TLS
gRPC works with HTTP/2 only. Usually when a client connects to a server, the connection is done using HTTP1.1 and promoted to HTTP/2 only if both, server and client, support HTTP/2. This promotion is performed using a protocol negotiation, usually implemented using ALPN protocol which requires TLS.

In order to get it to work you need to add the following to your server :

.ConfigureKestrel(options =>
<
options.Listen(IPAddress.Any, 5001, listenOptions =>
<
listenOptions.Protocols = HttpProtocols.Http2;
>);
>);
>);

You then need to explicitly allow HTTP/2 without TLS when creating the client:

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