使用Express.js和Angular2進行CORS

Question

我正在嘗試從遠程Express.js服務器將PLY文件下載到Angular / Ionic應用程序。 我現在將Ionic應用程序托管在Amazon AWS上。 這是Ionic應用程序中的打字稿：

//this.currentPlyFile encompasses entire URL
document.getElementById('entity').setAttribute("ply-model", "src: url(" + this.currentPlyFile + ".ply);");

我的Express.js服務器中包含以下內容：

app.use(function(req, res, next) {
        res.header('Access-Control-Allow-Credentials', true);
        res.header('Access-Control-Allow-Origin', '*');
        res.header('Access-Control-Allow-Methods', 'GET,POST');
        res.header('Access-Control-Allow-Headers', 'appid, X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept');
        if ('OPTIONS' == req.method) {
            res.send(200);
        } else {
            next();
        }
    });

但是當請求PLY文件時出現以下錯誤：

XMLHttpRequest cannot load "my url here" No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'my url here' is therefore not allowed access.

這確實令人沮喪，因為我使用Express.js文檔提供的標頭來允許CORS。

Answer 1

預檢->選項-> https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Access_control_CORS- > next()

app.use(function(req, res, next) {
    res.header('Access-Control-Allow-Credentials', true);
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
    res.header('Access-Control-Allow-Headers', 'appid, X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept');
    next();
});

app.get('/', function (req, res) {
  res.send('OK');
});

注意：將這些內容移至configure函數的頂部。

---

或簡單使用表達cors ：

var express = require('express')
var cors = require('cors')
var app = express();

app.use(cors());

app.get('/', function (req, res) {
    res.send('OK');
});