.NET HttpClient: How to set the request method dynamically?

Question

How can one use HttpClient and set the method dynamically without having to do something like:

    public async Task<HttpResponseMessage> DoRequest(string url, HttpContent content, string method)
    {
        HttpResponseMessage response;

        using (var client = new HttpClient())
        {
            switch (method.ToUpper())
            {
                case "POST":
                    response = await client.PostAsync(url, content);
                    break;
                case "GET":
                    response = await client.GetAsync(url);
                    break;
                default:
                    response = null;
                    // Unsupported method exception etc.
                    break;
            }
        }

        return response;
    }

At the moment it looks like you would have to use:

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.Method = "POST";

You can httprequestmessage and set the method, url and content. Then use send method of httpclient — Nkosi
– Nkosi, Commented Dec 9, 2016 at 17:47
Note that you should not new HttpClient() per request, or you can exhaust your socket pool at scale. Use a single static instance. — Matt Johnson-Pint
– Matt Johnson-Pint, Commented Jul 11, 2017 at 18:30

CodeFuller · Accepted Answer · 2016-12-09 18:15:57Z

9

HttpRequestMessage contains constructor taking instance of HttpMethod but there is no ready constructor that converts HTTP method string to HttpMethod, so you can't avoid that switch (in one form or another).

However you should not have duplicated code under different switch cases, so implementation would be something like this:

private HttpMethod CreateHttpMethod(string method)
{
    switch (method.ToUpper())
    {
        case "POST":
            return HttpMethod.Post;
        case "GET":
            return HttpMethod.Get;
        default:
            throw new NotImplementedException();
    }
}

public async Task<HttpResponseMessage> DoRequest(string url, HttpContent content, string method)
{
    var request = new HttpRequestMessage(CreateHttpMethod(method), url)
    {
        Content = content
    };

    return await client.SendAsync(request);
}

If you don't like that switch you could avoid it using Dictionary with method string as a key, however such solution will not be simpler or faster.

edited Dec 9, 2016 at 18:15

answered Dec 9, 2016 at 18:01

CodeFuller

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1 Comment

Ed Harrod Over a year ago

You can also pass in HttpMethod httpMethod as a parameter, and then do new HttpRequestMessage(httpMethod, url)

Tsahi Asher · Accepted Answer · 2018-07-09 14:01:11Z

9

but there is no ready constructor that converts HTTP method string to HttpMethod

Well that's not true any longer...¹

public HttpMethod(string method);

Can be used like this:

var httpMethod = new HttpMethod(method.ToUpper());

Here is working code.

using System.Collections.Generic;
using System.Net.Http;
using System.Text;

namespace MyNamespace.HttpClient
{
public static class HttpClient
{
    private static readonly System.Net.Http.HttpClient NetHttpClient = new System.Net.Http.HttpClient();
    static HttpClient()
    {}

    public static async System.Threading.Tasks.Task<string> ExecuteMethod(string targetAbsoluteUrl, string methodName, List<KeyValuePair<string, string>> headers = null, string content = null, string contentType = null)
    {
        var httpMethod = new HttpMethod(methodName.ToUpper());

        var requestMessage = new HttpRequestMessage(httpMethod, targetAbsoluteUrl);

        if (!string.IsNullOrWhiteSpace(content) || !string.IsNullOrWhiteSpace(contentType))
        {
            var contentBytes = Encoding.UTF8.GetBytes(content);
            requestMessage.Content = new ByteArrayContent(contentBytes);

            headers = new List<KeyValuePair<string, string>>
            {
                new KeyValuePair<string, string>("Content-type", contentType)
            };
        }

        headers?.ForEach(kvp => { requestMessage.Headers.Add(kvp.Key, kvp.Value); });

        var response = await NetHttpClient.SendAsync(requestMessage);

        return await response.Content.ReadAsStringAsync();

    }
}
}

edited Jul 9, 2018 at 14:01

Tsahi Asher

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answered Jul 11, 2017 at 18:23

Mark D.

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2 Comments

sky91 Over a year ago

the msdn link is not accessible now. Please change to the learn.microsoft.com/en-us/dotnet/api/…

Mark D. Over a year ago

@ Tsahi Ahser - thanks for editing the resource link!

user2397863 · Accepted Answer · 2018-08-07 17:27:09Z

1

.Net Core

var hc = _hcAccessor.HttpContext;

var hm = new HttpMethod(hc.Request.Method.ToUpper());
var hrm = new HttpRequestMessage(hm, 'url');

answered Aug 7, 2018 at 17:27

user2397863

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Comments

Robert · Accepted Answer · 2022-03-31 15:10:41Z

0

.NET Core later versions:

HttpClient client = new HttpClient();

// Add headers etc...

// Post
response = await client.PostAsync(uri, content);

// Get
response = await client.GetAsync(uri);

answered Mar 31, 2022 at 15:10

Robert

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