Question

我正在尝试连接客户端服务器和其他api服务器。我在后端使用角度js，在后端使用loopback。

在lb-services.js上我将基本网址更改为：

  var urlBase = 'http://localhost:3000/api';

我的角度js在端口4000上运行。但是当我向其余的api发帖时，我在浏览器上收到此错误：

XMLHttpRequest cannot load http://localhost:3000/api/People. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:4000' is therefore not allowed access. The response had HTTP status code 404.

无论如何我可以代理连接或使两台服务器一起正常工作吗？

这是我的gulp / server.js：

'use strict';

var path = require('path');
var gulp = require('gulp');
var conf = require('./conf');

var browserSync = require('browser-sync');
var browserSyncSpa = require('browser-sync-spa');

var util = require('util');

var proxyMiddleware = require('http-proxy-middleware');

function browserSyncInit(baseDir, browser) {
  browser = browser === undefined ? 'default' : browser;

  var routes = null;
  if(baseDir === conf.paths.src || (util.isArray(baseDir) && baseDir.indexOf(conf.paths.src) !== -1)) {
    routes = {
      '/bower_components': 'bower_components'
    };
  }

  var server = {
    baseDir: baseDir,
    routes: routes
  };

  /*
   * You can add a proxy to your backend by uncommenting the line below.
   * You just have to configure a context which will we redirected and the target url.
   * Example: $http.get('/users') requests will be automatically proxified.
   *
   * For more details and option, https://github.com/chimurai/http-proxy-middleware/blob/v0.9.0/README.md
   */
   server.middleware = proxyMiddleware('/api', {
     target: 'http://localhost:3000/api',
     changeOrigin: true

   });

  browserSync.instance = browserSync.init({
    startPath: '/',
    server: server,
    browser: browser,
    port:4000
  });
}

browserSync.use(browserSyncSpa({
  selector: '[ng-app]'// Only needed for angular apps
}));

gulp.task('serve', ['watch'], function () {
  browserSyncInit([path.join(conf.paths.tmp, '/serve'), conf.paths.src]);
});

gulp.task('serve:dist', ['build'], function () {
  browserSyncInit(conf.paths.dist);
});

gulp.task('serve:e2e', ['inject'], function () {
  browserSyncInit([conf.paths.tmp + '/serve', conf.paths.src], []);
});

gulp.task('serve:e2e-dist', ['build'], function () {
  browserSyncInit(conf.paths.dist, []);
});

Answer 1

无论如何，我可以代理连接或使两台服务器都能正常工作在一起吗？

令人惊讶的是，您收到此错误，因为环回默认启用CORS。值得查看loopback服务器中的middleware.json文件，看看cors.params.origin是否为true。 Here是供您参考的文档链接。

我不确定您是如何更改urlBase以访问其余api的。我使用here描述的角度模块配置完成了它。

Answer 2

您可以为LoopBack API添加CORS支持：

https://docs.strongloop.com/display/public/LB/Security+considerations#Securityconsiderations-CORS

Changin是loopback lb-services.js的基本URL

2 个答案: