在 Asp.Net Core 中使用 POST 方法重定向到 URL

Question

我有简单的 url 重写器：

    private static void RedirectToAPI(RewriteContext context)
    {
        var request = context.HttpContext.Request;
        if (request.Path.Value.StartsWith("/apiendpoint", StringComparison.OrdinalIgnoreCase))
        {           
            var json = JsonConvert.SerializeObject(request.Path.Value
                .Split(new char[] { '/' }, StringSplitOptions.RemoveEmptyEntries)
                .Skip(1));
            var response = context.HttpContext.Response;

            response.Headers[HeaderNames.Location] = $"/custom";
            response.StatusCode = StatusCodes.Status301MovedPermanently;
            context.Result = RuleResult.EndResponse;
            using (var bodyWriter = new StreamWriter(response.Body))
            {
                bodyWriter.Write(json);
                bodyWriter.Flush();
            }
        }
    }

问题是，当它重定向到/custom url 时，请求有方法 GET，而这个方法需要 POST。

例如，发送GET请求到url /apiendpoint/first/second/third ，然后rewriter响应redirect，相应地，下面的请求必须是POST方法，但现在是GET。

如何更改请求方法，即在 url 重写器响应之后？

Answer 1

这是一个示例代码

public class ConvertGetToPostHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        // Add your logic here to decide if the request Method needs to be changed
        // Caution: This works only if you're redirecting internally
        request.Method = HttpMethod.Post;
        return await base.SendAsync(request, cancellationToken);
    }
}

您必须将处理程序添加到处理程序管道中

config.MessageHandlers.Add(new ConvertGetToPostHandler());

此外，请通读此文档以深入了解其目的和用法。

Answer 2

你能把@juunas 的答案设置为正确答案吗，正如你在我的示例代码中看到的那样，他的答案为我解决了这个问题。

internal class RedirectCultureRule : IRule
{
    private const string CultureKey = "culture";

    public void ApplyRule(RewriteContext context)
    {
        HttpRequest httpRequest = context.HttpContext.Request;
        httpRequest.Query.TryGetValue(CultureKey, out StringValues cultureValues);
        string culture = cultureValues;

        if (cultureValues.Count > 0 && culture.IsCultureMatch())
        {
            context.Result = RuleResult.ContinueRules;
            return;
        }

        Dictionary<string, string> queryParts = new Dictionary<string, string>();
        NameValueCollection queryString = HttpUtility.ParseQueryString(httpRequest.QueryString.ToString());

        foreach (string key in queryString)
        {
            queryParts[key.Trim()] = queryString[key].Trim();
        }

        if (!queryParts.ContainsKey(CultureKey))
        {
            queryParts[CultureKey] = CultureInfo.CurrentCulture.Name;
        }

        string query = $"?{string.Join("&", queryParts.Select(qp => $"{qp.Key}={qp.Value}"))}";

        if (query.Length > 1)
        {
            httpRequest.QueryString = new QueryString(query);
        }

        string url = UriHelper.GetDisplayUrl(httpRequest);

        HttpResponse httpResponse = context.HttpContext.Response;
        httpResponse.StatusCode = 308;
        httpResponse.Headers[HeaderNames.Location] = url;

        using (StreamReader requestReader = new StreamReader(httpRequest.Body))
        {
            using (StreamWriter responseWriter = new StreamWriter(httpResponse.Body))
            {
                string body = requestReader.ReadToEnd();
                responseWriter.Write(body);
                responseWriter.Flush();
            }
        }

        context.Result = RuleResult.EndResponse;
    }
}

Answer 3

如果使用 ASP.NET Core 2.0，则有 RedirectPermanentPreserveMethod，您可以在此处阅读。 如果不支持此方法，您可以尝试手动执行。

Answer 4

编辑：啊，刚刚检查了评论。 如果初始请求是 GET，那么这也不起作用，您不能告诉浏览器进行 POST。 不是没有返回一个使用 JavaScript 自动执行表单的视图。

您需要返回 308，而不是 301。

这是更改后的代码：

private static void RedirectToAPI(RewriteContext context)
{
    var request = context.HttpContext.Request;
    if (request.Path.Value.StartsWith("/apiendpoint", StringComparison.OrdinalIgnoreCase))
    {           
        var json = JsonConvert.SerializeObject(request.Path.Value
            .Split(new char[] { '/' }, StringSplitOptions.RemoveEmptyEntries)
            .Skip(1));
        var response = context.HttpContext.Response;

        response.Headers[HeaderNames.Location] = $"/custom";
        response.StatusCode = 308;
        context.Result = RuleResult.EndResponse;
        using (var bodyWriter = new StreamWriter(response.Body))
        {
            bodyWriter.Write(json);
            bodyWriter.Flush();
        }
    }
}

308 是永久重定向，需要浏览器保留该方法。 https://httpstatuses.com/308

临时版本是 307。

这些重定向的便捷方法在 MVC Core 2.0.0-preview1 中可用。