This PR introduces a new secure media setting. When enabled, it prevent unathorized access to media uploads (files of type image, video and audio). When the `login_required` setting is enabled, then all media uploads will be protected from unauthorized (anonymous) access. When `login_required`is disabled, only media in private messages will be protected from unauthorized access.
A few notes:
- the `prevent_anons_from_downloading_files` setting no longer applies to audio and video uploads
- the `secure_media` setting can only be enabled if S3 uploads are already enabled and configured
- upload records have a new column, `secure`, which is a boolean `true/false` of the upload's secure status
- when creating a public post with an upload that has already been uploaded and is marked as secure, the post creator will raise an error
- when enabling or disabling the setting on a site with existing uploads, the rake task `uploads:ensure_correct_acl` should be used to update all uploads' secure status and their ACL on S3
This also corrects FileHelper.download so it supports "follow_redirect"
correctly (it used to always follow 1 redirect) and adds a `validate_url`
param that will bypass all uri validation if set to false (default is true)
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
Previously, we would initialize an ImageOptim object each time we resize.
This object init is mega expensive (170ms on a VERY fast machine):
```
[1] pry(main)> Benchmark.measure { FileHelper.image_optim }
=> #<Benchmark::Tms:0x00007f55440c1de0
@cstime=0.055742,
@cutime=0.141031,
@label="",
@real=0.17165619300794788,
@stime=0.0002750000000000252,
@total=0.19890400000000008,
@utime=0.0018560000000000798>
```
This happens cause during init it hunts for all the right binaries and sets
up internals.
We now memoize this object to avoid a huge amount of pointless work.
This feature ensures optimized images run via pngquant, this results extreme amounts of savings for resized images. Effectively the only impact is that the color palette on small resized images is reduced to 256.
To ensure safety we only apply this optimisation to images smaller than 500k.
This commit also makes a bunch of image specs less fragile.
