我没有在Stackoverflow上找到解决方案后解决了这个问题,所以我在这里分享我的问题和答案中的解决方案.
在使用AddCors的.NET Core Web Api应用程序中启用跨域策略后,它仍无法在浏览器中运行.这是因为浏览器(包括Chrome和Firefox)将首先发送OPTIONS请求,而我的应用程序只响应204 No Content.
解决方法
在项目中添加一个中间件类来处理OPTIONS动词.
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Hosting;
namespace Web.Middlewares
{
public class OptionsMiddleware
{
private readonly RequestDelegate _next;
private IHostingEnvironment _environment;
public OptionsMiddleware(RequestDelegate next,IHostingEnvironment environment)
{
_next = next;
_environment = environment;
}
public async Task Invoke(HttpContext context)
{
this.BeginInvoke(context);
await this._next.Invoke(context);
}
private async void BeginInvoke(HttpContext context)
{
if (context.Request.Method == "OPTIONS")
{
context.Response.Headers.Add("Access-Control-Allow-Origin",new[] { (string)context.Request.Headers["Origin"] });
context.Response.Headers.Add("Access-Control-Allow-Headers",new[] { "Origin,X-Requested-With,Content-Type,Accept" });
context.Response.Headers.Add("Access-Control-Allow-Methods",new[] { "GET,POST,PUT,DELETE,OPTIONS" });
context.Response.Headers.Add("Access-Control-Allow-Credentials",new[] { "true" });
context.Response.StatusCode = 200;
await context.Response.WriteAsync("OK");
}
}
}
public static class OptionsMiddlewareExtensions
{
public static IApplicationBuilder USEOptions(this IApplicationBuilder builder)
{
return builder.UseMiddleware<OptionsMiddleware>();
}
}
}
然后添加app.USEOptions();这是Configure方法中Startup.cs的第一行.
public void Configure(IApplicationBuilder app,IHostingEnvironment env,ILoggerFactory loggerFactory)
{
app.USEOptions();
}
