首先，我不会直接使用HttpClient。犯错太容易了——尤其是在头球方面。 DefaultHeadersCollection 不是不可变的，也不是线程安全的，因为应用程序的其他部分可以更改您的标题。最好在拨打电话时设置标题。如果您正在使用抽象，并且建议这样做，因为该区域中的类有点混乱，您可能希望有一个标题集合，并在发送之前将它们放在您的 HttpRequestMessage 上。您需要确保将内容标题放在内容上，而不是消息上。
Code Reference
foreach (var headerName in request.Headers.Names)
{
//"Content-Type"
if (string.Compare(headerName, HeadersExtensions.ContentTypeHeaderName, StringComparison.OrdinalIgnoreCase) == 0)
{
//Note: not sure why this is necessary...
//The HttpClient class seems to differentiate between content headers and request message headers, but this distinction doesn't exist in the real world...
//TODO: Other Content headers
httpContent?.Headers.Add(HeadersExtensions.ContentTypeHeaderName, request.Headers[headerName]);
}
else
{
httpRequestMessage.Headers.Add(headerName, request.Headers[headerName]);
}
}
这是一个可用于发送包含标头的请求的数据结构。
Code Reference
public interface IRequest
{
CancellationToken CancellationToken { get; }
string? CustomHttpRequestMethod { get; }
IHeadersCollection Headers { get; }
HttpRequestMethod HttpRequestMethod { get; }
AbsoluteUrl Uri { get; }
}
public interface IRequest<TBody> : IRequest
{
TBody? BodyData { get; }
}
还有一个标题集合：
Code Reference
public sealed class HeadersCollection : IHeadersCollection
{
#region Fields
private readonly IDictionary<string, IEnumerable<string>> dictionary;
#endregion
#region Public Constructors
public HeadersCollection(IDictionary<string, IEnumerable<string>> dictionary) => this.dictionary = dictionary;
public HeadersCollection(string key, string value) : this(ImmutableDictionary.CreateRange(
new List<KeyValuePair<string, IEnumerable<string>>>
{
new(key, ImmutableList.Create(value))
}
))
{
}
#endregion Public Constructors
#region Public Properties
public static HeadersCollection Empty { get; } = new HeadersCollection(ImmutableDictionary.Create<string, IEnumerable<string>>());
public IEnumerable<string> Names => dictionary.Keys;
IEnumerable<string> IHeadersCollection.this[string name] => dictionary[name];
#endregion Public Properties
#region Public Methods
public bool Contains(string name) => dictionary.ContainsKey(name);
public IEnumerator<KeyValuePair<string, IEnumerable<string>>> GetEnumerator() => dictionary.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => dictionary.GetEnumerator();
public override string ToString() => string.Join("\r\n", dictionary.Select(kvp => $"{kvp.Key}: {string.Join(", ", kvp.Value)}\r\n"));
#endregion
}
查看所有工作代码和示例here。