'Access-Control-Allow-Origin ' Missing. What should be my next step?

Question

I want to pull yield curve data from here:

http://www.treasury.gov/resource-center/data-chart-center/interest-rates/pages/XmlView.aspx?data=yieldyear&year=2015

The below get request returns a 200 (OK) status code but also a console note saying Cross-Origin Request Blocked because CORS header 'Access-Control-Allow-Origin' missing.

$.get('http://www.treasury.gov/resource-center/data-chart-center/interest-rates/pages/XmlView.aspx?data=yieldyear&year=2015', function (data) {
$(data).find("entry").each(function () { // or "item" or whatever suits your feed
    var el = $(this);

    console.log("------------------------");
    console.log("d:NEW_DATE      : " + el.find("d:NEW_DATE").text());
    console.log("d:BC_1MONTH     : " + el.find("d:BC_1MONTH").text());
    console.log("d:BC_3MONTH     : " + el.find("d:BC_3MONTH").text());
});

});

Are there clear rules/laws on accessing data if Access-Control-Allow-Origin is not set to '*' (public)?

What is the consensus when hitting these issues? The data is clearly publicly available; do I ask the US department of treasury to change their Access-Control-Allow-Origin setting to include my domain? (Access-Control-Allow-Origin Multiple Origin Domains?).

It is also clear that there were work arounds before CORS (https://www.nczonline.net/blog/2010/05/25/cross-domain-ajax-with-cross-origin-resource-sharing/). Are they appropriate/legal in this situation? Please could someone suggest concise resource for learning about them if so?

Perhaps I should give up and find a new data source?

Answer 1

I resolved this issue with PHP, it was possible to pull the XML from the server side as opposed to the client side javascript attempt that was causing the 'Access-Control-Allow-Origin' issue. Code here:

$url = "http://www.treasury.gov/resource-center/data-chart-center/interest-rates/pages/XmlView.aspx?data=yieldyear&year=2015";
$xml = simplexml_load_file($url);
echo $xml->asXML();

In my research I went down the wrong track for a little while; the treasury yield curve data I was looking for is part of the government's data.gov project. They have a site for developers here.

My initial thought was to use the CKAN API but it seems that they only store metadata in CKAN, not the actual data.