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From: Stanislav Lukyanov <stanlukyanov@gmail.com>
Subject: RE: Handling slashes in cache names
Date: Thu, 28 Dec 2017 20:22:31 +0300
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Hi all ,

I=E2=80=99ve implemented an approach of encoding unsafe characters in the c=
ache names for persistent storage directories. You can find it at https://g=
ithub.com/gridgain/apache-ignite/tree/ignite-7264.
How it works now is: 1) all characters outside of the [a-zA-Z0-9_-] class a=
re replaced with their hex value (seems to be the easiest way); 2) a hash o=
f the cache name is added at the end of the name to avoid case-insensitive =
collisions.
There is still a tiny chance of hitting two cache names that are equal igno=
ring case which also have the same hash, but that=E2=80=99s really unlikely=
.

It seems that there are no complications with this approach.
The cache name to directory mapping is like
  mycache -> cache-mycache-f19fd83d
  my/cool/cache -> cache-my2fcool2fcache
  my!@#$%^&()cache -> cache-my21402324255e262829cache-84ba3e99

Turns out the persistence is not the only place that doesn=E2=80=99t like s=
pecial symbols in cache names =E2=80=93 I also got an exception from MBean =
registration when creating a cache with =E2=80=98*=E2=80=99 or =E2=80=98?=
=E2=80=99. Filed https://issues.apache.org/jira/browse/IGNITE-7334 for that=
.

Please let me know if you have any comments.

Thanks,
Stan

From: Stanislav Lukyanov
Sent: 25 =D0=B4=D0=B5=D0=BA=D0=B0=D0=B1=D1=80=D1=8F 2017 =D0=B3. 18:09
To: dev@ignite.apache.org=20
Subject: Handling slashes in cache names

Hi all,

I=E2=80=99m looking into https://issues.apache.org/jira/browse/IGNITE-7264,=
 and I need some guidance on what=E2=80=99s the best way to approach it.

The problem is that cache names are not restricted, but if persistence is e=
nabled the cache needs to have a corresponding directory on the file system=
 (=E2=80=9Ccache-=E2=80=A6=E2=80=9D) which can=E2=80=99t be created if the =
cache name contains certain characters (or a reserved system name).

A straightforward approach would be to check if a cache name is allowed on =
the local system (e.g. via `Paths.get(name)`) and fail to create cache if i=
t isn=E2=80=99t, but I=E2=80=99m a bit concerned with the consistency of th=
e behavior (the same cache name be allowed on one system and not on another=
).
I think a better way would be to replace special characters (say, all non-a=
lphanumeric characters) with underscores in file names (not changing the ca=
che configuration). Would this be OK? Are there any risks I=E2=80=99m not c=
onsidering?

WDYT?

Thanks,
Stan


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