HTML files: getting around CORS (cross-origin)

General
1

I used an older version of CasparCG a few years ago for some graphic outputs for some game streams. I don’t have access to the computer that handled that, but I currently have code that’s not loading due to cross-origin issues, which is common for accessing local files. I’m not sure how I worked around it last time, so I’d like to know if anyone knows of the solution.

The specific code that’s throwing the cross-origin error is this:
xhr.open('GET', "streamcontrol.JSON?test="+cacheBuster,true);

2

did you figure this out?

i have a project that is giving me the same issue.
for testing i am using a local json file.
on deployment it will be an ajax call.

3

It’s not the CasparCG issue:

security aside, you can simply add header on server side (that’s where your JSON is generated):
Access-Control-Allow-Origin: *

4

Yes, if your webpage is opened via the file:// protocol, any request is cross-origin.

If you really need to load JSON files over the file:// protocol, you have three options:

  • Disable the browser setting for CORS protection. For example for Firefox this is: security.fileuri.strict_origin_policy in about:config, which I obviously don’t recommend, or
  • Load your JSON files via JSONP, or
  • Start a local web server with Python or Node.js to server your files over http://localhost thus not doing cross-origin requests.