如何在 express js 中解析多部分/混合请求正文？

Question

How do I parse a request body with content type: multipart/mixed in express?

A simple example of such request is below:

curl -H "Content-Type: multipart/mixed" -F "request=@body.json;type=application/json" -F "file1=@test.xml" -X POST https://mysimpleapi.com

Body.json file is a simple json

[{
    "name": "Test",
    "age": "23"
},
{
    "name": "Best", 
    "age": "24"
}]

and test.xml is just a regular file.

The curl request above looks like this:

{
  "method": "POST",
  "path": "/",
  "query": {},
  "headers": {
    "x-forwarded-for": "163.47.149.248",
    "x-forwarded-proto": "https",
    "x-forwarded-port": "443",
    "host": "mysimpleapi.com",
    "x-amzn-trace-id": "Root=1-618e4f8e-2cc109560ddfb65a7b5822ef",
    "content-length": "428",
    "user-agent": "curl/7.68.0",
    "accept": "*/*",
    "content-type": "multipart/mixed; boundary=------------------------e2d73e2082b30c29"
  },
  "bodyRaw": "--------------------------e2d73e2082b30c29\r\nContent-Disposition: attachment; name=\"request\"; filename=\"body.json\"\r\nContent-Type: application/json\r\n\r\n[{\n    \"name\": \"Test\",\n    \"age\": \"23\"\n},\n{\n    \"name\": \"Best\", \n    \"age\": \"24\"\n}]\n\r\n--------------------------e2d73e2082b30c29\r\nContent-Disposition: attachment; name=\"file1\"; filename=\"test.xml\"\r\nContent-Type: application/xml\r\n\r\n\r\n--------------------------e2d73e2082b30c29--\r\n",
  "body": "--------------------------e2d73e2082b30c29\r\nContent-Disposition: attachment; name=\"request\"; filename=\"body.json\"\r\nContent-Type: application/json\r\n\r\n[{\n    \"name\": \"Test\",\n    \"age\": \"23\"\n},\n{\n    \"name\": \"Best\", \n    \"age\": \"24\"\n}]\n\r\n--------------------------e2d73e2082b30c29\r\nContent-Disposition: attachment; name=\"file1\"; filename=\"test.xml\"\r\nContent-Type: application/xml\r\n\r\n\r\n--------------------------e2d73e2082b30c29--\r\n"
}

I want to get hold of the json object that's in the body of this request.

I was not able to find any documentation on how to parse this type of request. I know how to parse JSON and urlencoded form data from the request, but how do I parse a request like this on express? Is there any package that can do this parsing for me so that the request.body is not an empty object? Or I have to write some kind of parser myself(how do I do this?)?

Answer 1

Answer this myself, dicer for node js can be used to do exactly this. The getting started example on dicer's npm worked just fine for the above example. https://www.npmjs.com/package/dicer