Use Github raw domain as content source

The domain raw.githubusercontent.com does not impose rate limits. In fact using the regular github.com domain to access a static asset (like a PNG) using cURL redirects to this raw domain:

curl -Is "https://github.com/{ORG}/{REPO}/raw/{BRANCH}/docs/image.png"

HTTP/1.1 302 Found
Server: GitHub.com
Date: Thu, 22 Jun 2017 18:31:55 GMT
Content-Type: text/html; charset=utf-8
Status: 302 Found
Cache-Control: no-cache
Vary: X-PJAX, Accept-Encoding
X-RateLimit-Limit: 100
X-RateLimit-Remaining: 100
Access-Control-Allow-Origin: https://render.githubusercontent.com
Location: https://raw.githubusercontent.com/ORG/REPO/BRANCH/docs/image.png
X-UA-Compatible: IE=Edge,chrome=1
X-Runtime: 0.017536
Strict-Transport-Security: max-age=31536000; includeSubdomains; preload
X-Content-Type-Options: nosniff
X-Frame-Options: deny
X-XSS-Protection: 1; mode=block
X-Runtime-rack: 0.020754
X-Served-By: 7d2a2d05162492046d9960cdbc326796
Age: 0
X-GitHub-Request-Id: D5DB:4C9C:2CFB8EA:4161CAD:594C0D1B

When we request the raw domain content:

curl -Is "https://raw.githubusercontent.com/ORG/REPO/BRANCH/docs/image.png"

HTTP/1.1 200 OK
Content-Security-Policy: default-src 'none'; style-src 'unsafe-inline'
Strict-Transport-Security: max-age=31536000
X-Content-Type-Options: nosniff
X-Frame-Options: deny
X-XSS-Protection: 1; mode=block
ETag: "fd51ed6a84d1ee36c3b0af994dea8c32c785bb29"
Content-Type: image/png
Cache-Control: max-age=300
X-Geo-Block-List:
X-GitHub-Request-Id: AB1E:1776:F1BF31:F95F97:594C0D02
Content-Length: 18411
Accept-Ranges: bytes
Date: Thu, 22 Jun 2017 18:34:09 GMT
Via: 1.1 varnish
Connection: keep-alive
X-Served-By: cache-iad2125-IAD
X-Cache: HIT
X-Cache-Hits: 1
X-Timer: S1498156449.322911,VS0,VE1
Vary: Authorization,Accept-Encoding
Access-Control-Allow-Origin: *
X-Fastly-Request-ID: a440cac380cd0e67b5ebdc40c5d8a4185be58bf1
Expires: Thu, 22 Jun 2017 18:39:09 GMT
Source-Age: 159

Per these HTTP responses we can see there is no rate limit imposed. As we are only targeting public repos it makes sense to switch all our URLs to this domain.

This starts work related to #6 and is a non-breaking change we can implement today.

RadiusNetworks / doc_repo

Use Github raw domain as content source #7