As a quick aside before I begin, multiple people were involved in this research. I thank them all at the end, but I wanted to be sure folks know this was definitely something I got a lot of help on.
Earlier this week a user reported an odd issue to me. He was using CFHTTP to hit the Google Places API and noticed that code he had in ColdFusion 10 worked, but in ColdFusion 11 the same code returned a 404 error. I was able to quickly confirm the issue and began my investigation.
The first thing I noticed was that the URL in question also worked fine in the browser. I seemed to remember an API a few years ago that blocked the default user agent used with CFHTTP so the first thing I attempted was a simple change to that value. I got my own user agent and supplied it to the tag, but it didn't help.
Next - I was curious if there was some particular change to the headers being sent by CFHTTP between versions. To test this, I wrote a new CFM that dumped the headers:
When I did so, I noticed two changes. First, ColdFusion 11 was sending Accept-Encoding with gzip, deflate. Secondly, the host value recorded was localhost:80 compared to localhost on ColdFusion 10. I assumed the second change wasn't relevant. My CF11 box was localhost:8511 and since I was hitting localhost/test.cfm, I figured it was just noting the different port. As to the first change, I added that header to the ColdFusion 10 server test and after confirming the headers matched, switched back to hitting Google and was not able to replicate the bug.
So - here is where things get interesting. Turns out, the change with the port number was important. Rupesh from the ColdFusion team confirmed that the HttpClient library used in ColdFusion 11 always adds the port to the URL, even when you don't put it there. While a host of foo should be the exact same as foo:80, Google, for whatever reasons, doesn't like the port and returns a 404. (Dan Switzer made the argument, though, that for OAuth 1 calls every part of the URL is significant, and the port would make a difference there.)
So - Rupesh has filed a bug report with Apache in regards to HttpClient, which is good, and he has stated that they will try to make a workaround for this in ColdFusion itself. To be clear, you do not need to worry about this for - I'd guess - a majority of your cfhttp calls. But you definitely want to be aware of it.
Luckily, there is a fix. A super easy fix. I only found this after I wrote a fix in Java, and kicked myself for missing this email from David Boyer. Just add a Host header and everything works:
<cfhttpparam name="Host" value="maps.googleapis.com" type="header">
Thanks to David Boyer, Dan Switzer, Mark Kruger, Rupesh, Wil Genovese, and anyone else I forgot.