JavaScript-Access-Control-Allow-Methods似乎不起作用

我在网络服务器上安装了一个小型Web API应用程序,其中一个GET方法返回3条记录,而POST方法则接受一个对象,然后为其分配ID并返回相同的对象.

我正在从本地Web应用程序进行Ajax调用,并测试了我的CORS实现.到目前为止,几乎所有内容都运行良好.如果我未指定Access-Control-Allow-Origin(现在仅设置为*),则不允许拨打电话(我期望的是),但是我也尝试指定Access-Control-Allow-Methods,但它没有似乎我的输入限制了进行特定的呼叫.

例如,这是我的web.config包含的内容：

<httpProtocol>
  <customHeaders>
    <clear />
    <add name="Access-Control-Allow-Origin" value="*" />
    <add name="Access-Control-Allow-Headers" value="Content-Type, Authorization, Accept, X-Requested-With " />
    <add name="Access-Control-Allow-Methods" value="OPTIONS, GET" />
  </customHeaders>
</httpProtocol>

我只列出了OPTIONS和GET,但是我仍然可以发出POST请求.同样,如果将其设置为“ OPTIONS,POST”,我仍然可以发出GET请求.

编辑

根据下面@geekonaut的回答,我能够按预期看到此功能.我尝试尝试一个PUT请求,而不是GET或POST,但是我收到一个错误,提示不允许OPTIONS(预检)请求.我首先需要在Global.asax.cs文件中添加一个部分来接受该方法,然后,如果我在web.config的Access-Control-Allow-Methods值中切换添加/删除PUT,我看到它只会允许方法(如果已列出).

protected void Application_OnBeginRequest()
{
    if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
    {
        HttpContext.Current.Response.StatusCode = 200;
        HttpContext.Current.Response.End();
    }
}

解决方法:

CORS不会阻止基于其方法的简单(甚至预检)POST请求.

例如,Access-Control-Allow-Methods仅对无法使用简单跨域格式进行的请求有效.

这意味着：GET和POST可以跳过the spec中描述的Access-Control-Allow-Methods：

Simple cross-origin requests generated outside this specification
(such as cross-origin form submissions using GET or POST or
cross-origin GET requests resulting from script elements) typically
include user credentials, so resources conforming to this
specification must always be prepared to expect simple cross-origin
requests with credentials.

Because of this, resources for which simple requests have significance
other than retrieval must protect themselves from Cross-Site Request
Forgery (CSRF) by requiring the inclusion of an unguessable token in
the explicitly provided content of the request.

(强调我的)

标签：ajax,asp-net-web-api2,cors,javascript,jquery
来源： https://codeday.me/bug/20191111/2021160.html