Here is my advise: use _url all the time. Yeah it wastes a few bytes,
but the day you’ll add https support to your site it will save you tons
How would it save headaches in case of https?.
Lets say you have apache in front of your rails server and only apache
is configured for https. And http is disabled in apache.
Now with _url option, the web page gets generated as
<form ... action="http://host/resource/1" ...
And apache passes it along as it as, unless one enables URL rewriting in
apache to replace http with https.
Where as if it is just _path it gets generated as
<form ...action="/resource/1" ...
This form submission works irrespective of how(http or https) apache is
So the earlier recommendation ( i.e., use _path in views _url in
specific use cases) is still a better one compared to use _url in all
cases. (no period )