如何在使用PostUrlEncodedAsync时从Content-Type中移除Charset=UTF-8

Question

flurlClient.ConfigureHttpClient(c => c.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/x-www-form-urlencoded"));

Answer 1

我没有使用Flurl，而是尝试用HttpClient实现同样的目标。这样做不起作用，所以我为Flurl创建了一个扩展方法。

https://stackoverflow.com/a/44543016/915414建议使用StringContent更改内容类型：

var jobInJson = JsonConvert.SerializeObject(job);
var json = new StringContent(jobInJson, Encoding.UTF8);
json.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json; odata=verbose");

var flurClient = GetBaseUrlForOperations("Jobs");

return await flurClient.PostAsync(json).ReceiveJson<Job>();

尽管这确实改变了Content-Type，但charset=UTF-8仍然存在。

我对System.net.http.StringContent进行了反编译，看看它是如何工作的。它默认为一个字符集：

this.Headers.ContentType = new MediaTypeHeaderValue(mediaType == null ? "text/plain" : mediaType)
{
     CharSet = encoding == null ? HttpContent.DefaultStringEncoding.WebName : encoding.WebName
};

你猜怎么着...PostUrlEncodedAsync的核心是使用StringContent。

因此，我为Flurl创建了一个扩展方法，它使用了类似的StringContent实现，其中CharSet=“”；

public static class HttpExtensions
{
    public static Task<HttpResponseMessage> PostUrlEncodedAsyncWithoutCharset(this IFlurlClient client, object data, CancellationToken cancellationToken = default(CancellationToken), HttpCompletionOption completionOption = HttpCompletionOption.ResponseContentRead)
    {
        CapturedUrlContentCustom urlEncodedContent = new CapturedUrlContentCustom(client.Settings.UrlEncodedSerializer.Serialize(data));
        return client.SendAsync(HttpMethod.Post, (HttpContent)urlEncodedContent, new CancellationToken?(cancellationToken), completionOption);
    }
}

public class CapturedUrlContentCustom : CapturedStringContentCustom
{
    public CapturedUrlContentCustom(string data)
    : base(data, (Encoding) null, "application/x-www-form-urlencoded")
    {
    }
}

CaptureDStringContentCustom：

public class CapturedStringContentCustom : CustomStringContent
{
    public string Content { get; }
    public CapturedStringContentCustom(string content, Encoding encoding = null, string mediaType = null)
        : base(content, encoding, mediaType)
    {
        this.Content = content;
    }
}

CustomStringContent：

public class CustomStringContent : ByteArrayContent
    {
        private const string defaultMediaType = "application/x-www-form-urlencoded";


        public CustomStringContent(string content)
      : this(content, (Encoding)null, (string)null)
        {
        }


        public CustomStringContent(string content, Encoding encoding)
      : this(content, encoding, (string)null)
        {
        }


        public CustomStringContent(string content, Encoding encoding, string mediaType)
      : base(CustomStringContent.GetContentByteArray(content, encoding))
        {
            this.Headers.ContentType = new MediaTypeHeaderValue(mediaType == null ? "application/x-www-form-urlencoded" : mediaType)
            {
                CharSet = ""
            };
        }

        private static byte[] GetContentByteArray(string content, Encoding encoding)
        {
            if (content == null)
                throw new ArgumentNullException(nameof(content));
            if (encoding == null)
                encoding = Encoding.UTF8;
            return encoding.GetBytes(content);
        }
    }

现在，您可以调用PostUrlEncodedAsyncWithoutCharset并且Charset=UTF-8将不会出现。