带有express的NodeJS :标头未定义

Question

我正在使用Microsoft Flow向我的服务器发送HTTP POST请求。请求正文包含一个名为"Email-To“的自定义标头，它的值是一个字符串。下面是正文：

{
  "$content-type": "multipart/form-data",
  "$multipart": [
    {
      "headers": {
        "Email-To": "test@email.no",
        "Content-Disposition": "form-data; name=\"file\"; filename=901210.xlsx"
      },
      "body": {
        "$content-type": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        "$content": "content"
      }
    }
  ]
}

当请求到达我的NodeJS服务器时，我想从标头中检索值。

app.post('/upload', function(req, res) {
  console.log(req.headers("Email-To"))
  console.log(req.get("Email-To"))
});

两个日志都将始终打印为"undefined“。我尝试通过查看headers下的请求对象本身来进一步调试它。它似乎没有头。

0|server  |   headers:
0|server  |    { host: 'my_ip',
0|server  |      'accept-language': 'en-US',
0|server  |      'user-agent':
0|server  |       'azure-logic-apps/1.0 (workflow aa9d5e05e9b54c478ccebf2412633add; version 08586366094673048593) microsoft-flow/1.0',
0|server  |      'x-ms-execution-location': 'westeurope',
0|server  |      'x-ms-workflow-id': 'aa9d5e05e9b54c478ccebf2412633add',
0|server  |      'x-ms-workflow-version': '08586366094673048593',
0|server  |      'x-ms-workflow-name': '010bf24d-5a56-4053-8a39-e088e727cbf5',
0|server  |      'x-ms-workflow-system-id':
0|server  |       '/locations/westeurope/scaleunits/prod-48/workflows/aa9d5e05e9b54c478ccebf2412633add',
0|server  |      'x-ms-workflow-run-id': '08586365350241297663352938044CU52',
0|server  |      'x-ms-workflow-run-tracking-id': '2eec16eb-2f3f-4a87-a26d-683750ca20f5',
0|server  |      'x-ms-workflow-operation-name': 'HTTP',
0|server  |      'x-ms-workflow-subscription-id': 'b745f25e-91b5-4140-9d73-93b10b1dfb1d',
0|server  |      'x-ms-workflow-resourcegroup-name':
0|server  |       'B5EBEC49F06342E5B0E1F4E04C03D0B7-D8266BA594DC4A5DB55D7F31650FCD73',
0|server  |      'x-ms-tracking-id': 'aa92c109-151a-418c-8d01-754da7bc2c43',
0|server  |      'x-ms-correlation-id': 'aa92c109-151a-418c-8d01-754da7bc2c43',
0|server  |      'x-ms-client-request-id': 'aa92c109-151a-418c-8d01-754da7bc2c43',
0|server  |      'x-ms-client-tracking-id': '08586365350241297663352938044CU52',
0|server  |      'x-ms-action-tracking-id': 'f3a02477-227d-46cf-9105-228fe5c41f8d',
0|server  |      'x-ms-activity-vector': 'IN.0E',
0|server  |      'content-type':
0|server  |       'multipart/form-data; boundary="c859bba4-c9e1-4426-86ce-b3daf6ab74d9"',
0|server  |      'accept-encoding': 'gzip, deflate',
0|server  |      via: '1.1 my_ip (Apache/2.4.18)',
0|server  |      'x-forwarded-for': 'someones_ip',
0|server  |      'x-forwarded-host': 'my_ip',
0|server  |      'x-forwarded-server': 'my_ip',
0|server  |      connection: 'Keep-Alive',
0|server  |      'content-length': '43929' }

在阅读了标题之后，我非常确定任何不与其他标题冲突的键值对都应该工作得很好，但是我的"Email- to“标题似乎不起作用。你知道为什么吗？

编辑: CORS (使用通配符)

Sending POST request to http://my_ip/node/upload

Fired XHR event: loadstart
Fired XHR event: readystatechange
Fired XHR event: error

XHR status: 0
XHR status text: 
Fired XHR event: loadend

编辑2:我尝试使用postman发送POST请求，它工作得很好。我可以像平常一样检索头文件。

编辑3:我像这样添加CORS：

app.post('/upload', function(req, res) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Email-To");

  console.log(req.headers("Email-To"))
  console.log(req.get("Email-To"))
});

Answer 1

尝试使用方括号，它应该可以工作。

app.post('/upload', function(req, res) {
     console.log(req.headers["Email-To"]))
});

Answer 2

请在下面添加行，然后重试。

app.options('/upload', function(req, res) {
  res.setHeader('Access-Control-Allow-Origin','specify your origin');//do not use `*`!
  res.setHeader('Access-Control-Allow-Headers','Email-To');
  res.setHeader('Access-Control-Allow-Methods','POST');
  res.end();
});

Answer 3

尝试使用箭头函数和方括号

app.post('/upload', (req, res) => {
     console.log(req.headers["Email-To"]))
});