Handling HttpResponseMessage with persistent connection c #

Question

I am using Httpclient C # .net to connect to a url.

I need to make a GET request. This connection is persistent. The problem is that I need to perform actions according to the notifications that the server sends me.

When executing the HttpResponseMessage, it hangs (being persistent it works and receiving notifications constantly, but it never gives me back control to be able to work according to the notifications of the server) when canceling the execution I can see all notifications by console.

Is there any way to control HttpResponseMessage to be able to work with every response the server sends me?

Should I use another type of technology for this?

This is what I get back by console de "await response.Content.ReadAsStringAsync ();" when I cancel the operation.

<? xml version = "1.0" encoding = "UTF-8" standalone = "yes"?>
<message xmlns = "http://asdasd.com/asd/08/DS/Sync" xmlns: ns2 = "http: // asdadasdasdasd">
<event> KEEPALIVE </ event>
</ message>

<? xml version = "1.0" encoding = "UTF-8" standalone = "yes"?>
<message xmlns = "http://asdasd.com/asd/08/DS/Sync" xmlns: ns2 = "http: // asdadasdasdasd">
<event> KEEPALIVE </ event>
</ message>

<? xml version = "1.0" encoding = "UTF-8" standalone = "yes"?>
<message xmlns = "http://asdasd.com/asd/08/DS/Sync" xmlns: ns2 = "http: // asdadasdasdasd">
<event> KEEPALIVE </ event>
</ message>

every ('message') arrives approximately every 2 minutes I wish that each time I get one I can perform an action I leave the code that ultilizo. Thank you

public async static Task<int> GetRequest(string url)
{
    HttpClient client = new HttpClient();
    HttpResponseMessage response = new HttpResponseMessage();
    response = await client.GetAsync(url, HttpCompletionOption.ResponseHeadersRead);
    Console.WriteLine("STATUS OF CONNECTION");
    Console.WriteLine(response.StatusCode);
    response.EnsureSuccessStatusCode();
    var body = await response.Content.ReadAsStringAsync().ConfigureAwait(continueOnCapturedContext: false); ;

    Console.WriteLine("ANSWER");
    Console.WriteLine(body);
    Console.WriteLine(" \n");
    Console.WriteLine("\n ATTENTION!! Disconnected from the Persistence line \n");

    Console.WriteLine("Connections done");
    int result1 = 1;
    return result1;
}

You need to pause it somehow while still keeping it open https://stackoverflow.com/a/16004845/10634638 — estinamir, Feb 15 '19 at 20:35

score 2 · Accepted Answer · answered Feb 16 '19 at 02:50

You are looking to parse partial HTTP responses, as and when each part is received. The HTTP protocol does not know/understand that you are sending/receiving multiple discrete messages separated by a newline in a single HTTP response.

As far as I know, HttpClient won't be much help to you because it is designed to receive one whole HTTP response. Rick Strahl has a blog on exactly this subject Using .NET HttpClient to capture partial Responses.

You should be able to use HttpWebRequest to manually read bytes from the network stream into a buffer. After appending to the buffer, you will want to check if it contains a complete message (<message> ... </ message>). If so, convert the message to a string and announce it as required: eg raise an event, start a task, call a method, add to a queue. Then clear the buffer and repeat.

TcpClient is probably not the best approach in this scenario, because you may then also need to implement TLS (if your endpoint is HTTPS).

Exact, It is totally what I need. I would have to execute the request get with HttpWebRequest eh go saving the answers in a buffer and from another method consult that buffer and analyze it, I try to do this and I tell them how it goes thank you very much for the answer. — Maximiliano Gustavo Avellaneda, Feb 18 '19 at 15:12

Pavel Anikhouski · Answer 2 · 2021-02-08T20:44:59.973

According MSDN, you don't have to create a new HttpClient per each request

HttpClient is intended to be instantiated once and re-used throughout the life of an application. Instantiating an HttpClient class for every request will exhaust the number of sockets available under heavy loads.

Next, you can specify the default timeout for httpClient or use it per request.

Then, you are using ResponseHeadersRead option, it means

The operation should complete as soon as a response is available and headers are read. The content is not read yet.

Try to switch to ResponseContentRead instead

Handling HttpResponseMessage with persistent connection c #

2 Answers2