dart-server/angulardart 和 CORS 的问题 [英] problems with dart-server/angulardart and CORS

问题描述

我在我的服务器上使用 dart，而 angulardart 作为我的客户端.我可以通过服务器上的 http.get 请求数据，这工作正常 - 但我无法让 POST 工作.

I am using dart on my server and angulardart as my client. I can request data via http.get on my server, that is working fine - but I can't get POST to work.

服务器:(服务器使用开始"https://github.com/lvivski/start)

Server: (the server makes use of "Start" https://github.com/lvivski/start)

//runs at 127.0.0.1:4040:
server.post("/rest/qr").listen((request) {
  addCorsHeaders(request.response);
  request.payload().then((map) {
    print(map);
  }).then((_) {
    request.response.send("ok");
  });
});

客户端(角度):

// runs at http://127.0.0.1:3030
final String _codesUrl = "http://127.0.0.1:4040/rest/qr";
_http.post(_codesUrl, JSON.encode(temp.toMap())).then((HttpResponse response) {
  print(response.status);
});

addCorsHeaders:

addCorsHeaders:

void addCorsHeaders(Response res) {
    res.header("Access-Control-Allow-Origin", "*, ");
    res.header("Access-Control-Allow-Methods", "POST, GET, OPTIONS");
    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");}

这是我的代码.正如我已经说过的，从 angular 到我的服务器的 http.get 确实有效.通过 angular http-service 失败发布到我的服务器:请求的资源上不存在 'Access-Control-Allow-Origin' 标头.因此，不允许访问 Origin '127.0.0.1:3030'."

This is my code. As I already said, http.get from angular to my server does work. Post to my server via the angular http-service fail : "No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '127.0.0.1:3030' is therefore not allowed access."

我还尝试了 Google Chrome 中的高级 rest 插件来向该 URL 发出 POST 请求.这些请求确实有效.我是否错过了 angulardart POST 请求中的某些内容?服务器和客户端运行在不同的端口上.

I also tried the advanced rest plugin in Google Chrome to make POST-request to that URL.These requests do work. Do I miss something on the angulardart POST-requests? Server and Client run on different ports.

推荐答案

我自己也遇到过这个问题.事实证明，某些 CORS 请求需要预检请求".GET 没有，但 POST 有.以下文章详细解释了所有这些:

I've run into this issue myself. Turns out that some CORS requests require a "preflight request". GET does not, but POST does. The following article explains all of this in detail:

http://www.html5rocks.com/en/tutorials/cors/#toc-adding-cors-support-to-the-server

要点是对于 POST CORS 请求，客户端将首先向服务器发送OPTIONS"请求，询问 CORS POST 是否正常.这就是我之前提到的预检请求".在获得 POST 之前，您需要捕获它并回复它.

The gist is that for a POST CORS request, the client will first send an "OPTIONS" request to the server, asking if a CORS POST is OK or not. This is the "preflight request" I mentioned previously. You need to catch it and respond back to it before you will get the POST.

我不确定如何使用 Start 框架回答 OPTIONS 请求，但 dartlang 网站上有一个教程，介绍如何使用 vanilla dart 解决确切问题:

I'm not sure how to answer OPTIONS requests with the Start framework, but the dartlang website has a tutorial on how to solve the exact problem with vanilla dart:

https://www.dartlang.org/docs/tutorials/forms/#handling-options-requests

处理 OPTION 请求的代码(摘自上述文章):

The code to handle the OPTION requests (cribbed from the above article):

void handleOptions(HttpRequest req) {
  HttpResponse res = req.response;
  addCorsHeaders(res);
  print('${req.method}: ${req.uri.path}');
  res.statusCode = HttpStatus.NO_CONTENT;
  res.close();
 }

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