我曾多次遇到CORS问题,通常可以解决它,但我想通过从MEAN堆栈范式中看到这一点来真正理解。

之前我只是在我的快速服务器中添加了中间件来捕获这些东西,但它看起来像有某种预挂钩,使我的请求出错。

在preflight响应中,Access-Control-Allow-Headers不允许请求报头字段Access-Control-Allow-Headers

我假设我可以这样做:

app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Headers","*")
})

或者等价的,但这似乎不能解决问题。我当然也试过

app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Headers","Access-Control-Allow-Headers")
})

还是不走运。


当前回答

res.setHeader(‘Access-Control-Allow-Headers’,‘*’);

其他回答

res.setHeader(‘Access-Control-Allow-Headers’,‘*’);

这是你需要添加的使它工作。

response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Credentials", "true");
response.setHeader("Access-Control-Allow-Methods", "GET,HEAD,OPTIONS,POST,PUT");
response.setHeader("Access-Control-Allow-Headers", "Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method, Access-Control-Request-Headers");

The browser sends a preflight request (with method type OPTIONS) to check if the service hosted on the server is allowed to be accessed from the browser on a different domain. In response to the preflight request if you inject above headers the browser understands that it is ok to make further calls and i will get a valid response to my actual GET/POST call. you can constraint the domain to which access is granted by using Access-Control-Allow-Origin", "localhost, xvz.com" instead of * . ( * will grant access to all domains)

加上其他的答案。我也有同样的问题,这是我在我的快速服务器中使用的代码,以允许REST调用:

app.all('*', function(req, res, next) {
  res.header('Access-Control-Allow-Origin', 'URLs to trust of allow');
  res.header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
  res.header('Access-Control-Allow-Headers', 'Content-Type');
  if ('OPTIONS' == req.method) {
  res.sendStatus(200);
  } else {
    next();
  }
});

这段代码所做的基本上是拦截所有请求并添加CORS报头,然后继续我的正常路由。当有OPTIONS请求时,它只响应CORS报头。

编辑:我在同一台机器上对两个独立的nodejs express服务器使用此修复。最后,我用一个简单的代理服务器解决了这个问题。

我收到了错误的OP声明使用Django, React和Django -cor -headers库。要用这个堆栈修复它,请执行以下操作:

在settings.py中根据官方文档添加以下内容。

from corsheaders.defaults import default_headers

CORS_ALLOW_HEADERS = default_headers + (
'YOUR_HEADER_NAME',
)

如果您试图在请求标头上添加自定义标头,则必须让服务器知道允许发生特定的标头。在过滤请求的类中执行此操作。在下面的例子中,自定义头名称为"type":

public class CorsFilter implements Filter {
    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin",  request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Methods", "GET,PUT,POST,DELETE,PATCH,OPTIONS");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Accept, X-Requested-With, remember-me, Authorization, type ");
        response.setHeader("Access-Control-Expose-Headers","Authorization");
    }
}