使用 C# HttpListener 时无法设置 MIME 类型

Posted 2023-03-15

【中文标题】使用 C# HttpListener 时无法设置 MIME 类型

【英文标题】：Can't set MIME types when using C# HttpListener

【发布时间】：2020-11-26 03:27:17

【问题描述】：

我创建了一个 C# HttpListener()。

在请求处理程序中，我执行必要的操作，然后在响应对象上设置标头和 MIME 类型。但是，浏览器报告 MIME 类型始终为空。

private void HandleWebRequest(HttpListenerContext context)

    string path = context.Request.Url.LocalPath.ToLowerInvariant();
    HttpListenerResponse response = context.Response;
    HttpListenerRequest request = context.Request;
        
    try
    
        // Respond to requests here. For ex:
        byte[] displayImage = htmlHelper.GetTextResource(path.Substring(20));
        response.ContentLength64 = displayImage.Length;
        response.OutputStream.Write(displayImage, 0, displayImage.Length);
    
    finally
    
        SetResponseHeaders(path, response);
        response.Close();
    

---

private void SetResponseHeaders(path, response)

    ...
    response.ContentType = MediaTypeNames.Text.Plain;
    response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept, X-Requested-With");
    response.AddHeader("Access-Control-Allow-Methods", "GET,POST");
    response.AddHeader("Access-Control-Allow-Origin", "*");

【参考方案1】：

问题是我在设置 Response.Close(); 时在末尾添加了标头和 MIME 类型；

解决方法是在开头设置标题

private void HandleWebRequest(HttpListenerContext context)

    string path = context.Request.Url.LocalPath.ToLowerInvariant();
    HttpListenerResponse response = context.Response;
    HttpListenerRequest request = context.Request;

    // Set headers here
    SetResponseHeaders(path, response);
        
    try
    
        // Respond to requests here. For ex:
        byte[] displayImage = HtmlHelper.GetTextResource(path.Substring(20));
        response.ContentLength64 = displayImage.Length;
        response.OutputStream.Write(displayImage, 0, displayImage.Length);
    
    finally
    
        response.Close();