Deal with Cross-Origin Issues

This article explains how to deal with cross-origin issues (CORS).

CORS issues occur in the following scenario: your application runs on your local dev machine https://localhost:3000 or on your production domain, but you need it to call the GoodData APIs from https://secure.gooddata.com/gdc/.

Modern browsers do not permit this because of the security measure known as the same-origin-policy.

You have to overcome the CORS restriction before you can develop or deploy your application. To do so, use the following methods:

• Use a proxy (recommended for a local dev machine)
• Enable CORS (recommended for a production domain)

Use a proxy

You can set up a proxy to bypass the CORS restriction on a local dev machine, because making a cross-origin request from a trusted application is safe. The proxy will make the GoodData API accessible under the same hostname and port as your web application, that is, https://localhost:3000/gdc/.

To set up a proxy, in your project's /src directory, create the setupProxy.js file with the following content:

const proxy = require("http-proxy-middleware");

module.exports = function (app) {
     app.use(proxy("/gdc", {
         "changeOrigin": true,
         "cookieDomainRewrite": "localhost",
         "secure": false,
         "target": "https://secure.gooddata.com",
         "headers": {
             "host": "secure.gooddata.com",
             "origin": null
         },
         "onProxyReq": function(proxyReq, req, res) {
             proxyReq.setHeader("accept-encoding", "identity")
         }
     }));
     app.use(proxy("/*.html", {
         "changeOrigin": true,
         "secure": false,
         "target": "https://secure.gooddata.com"
     }));
     app.use(proxy("/packages/*.{js,css}", {
         "changeOrigin": true,
         "secure": false,
         "target": "https://secure.gooddata.com"
     }));
 };

NOTE: If you are using Microsoft Edge or Microsoft Explorer browsers on a Windows machine, set cookieDomainRewrite to the IP address on which your local web server runs. You can get your IP address from the console output after the server started. For example:

"cookieDomainRewrite": "127.0.0.1"

The /gdc prefix refers to the GoodData APIs as they are hosted under https://secure.gooddata.com/gdc. The "secure: false" section allows you to set up a proxy against your localhost server that may use a self-signed certificate.

If you want to connect to the live examples, set all the target properties to https://developer.na.gooddata.com. The workspaceId of the demo workspace is xms7ga4tf3g3nzucd8380o2bev8oeknp.

In addition, proxying the /*.html pages allows you to easily establish a user session by logging in using the GoodData login page (account.html) and possibly invoke other GoodData actions that you may need during the development.

Enable CORS

Setting up CORS allows you to develop and run web applications that can communicate directly with the GoodData APIs.

This section does not address authentication. The easiest way to make sure that your API requests to the GoodData platform are authenticated is to be logged into your white-labeled domain in the same browser you are using for your local development.

Step 1. Get a white-labeled GoodData domain.

By default, you access the GoodData Portal via https://secure.gooddata.com. If you white-label the GoodData Portal URL, you can have it at, for example, https://analytics.example.com.

In general, a white-labeled domain enables you to remove branding elements from the GoodData Portal and optionally replace them with branding from your enterprise. For more information, see White Label Your Domain.

White-labeling is done by the GoodData Support specialists per request submitted via the GoodData Support Portal.

You can white-label a brand new domain or an existing domain.

Step 2. Configure CORS.

The domains from which you want to enable API calls must be listed as allowed origins for your white-labeled domain. To make those domains allowed origins, use the API for adding domains allowed for CORS access.

• An allowed origin URL must start with https:// and must end with a top-level domain (such as .com, .org, and so on).
• You can add a port number to an allowed origin URL (for example, https://www.example.com:8080).
• You can use a wildcard (*, **) to represent a domain of the third and consecutive levels.

NOTE: If you followed the instructions from the tutorial Create Your First Application from Scratch, you can now remove the setupProxy.js file because it is not required anymore.