Add possibility to establish SSL connection with SSL_VERIFY_NONE

[mtuleika-appcast]

This PR adds possibility to establish SSL connection to Redis with SSL_VERIFY_NONE(in my case to ElastiCache).

What was done:

• hiredis submodule was bumped to version 1.0.0
• C extension in hiredis-rb was extended to support SSL connection without certification

require 'hiredis'

conn = Hiredis::Connection.new
conn.connect_ssl('<host>', 6379)

conn.write %w[AUTH <password>]
puts conn.read
conn.write %w[SET speed awesome]
puts conn.read
conn.write %w[GET speed]
puts conn.read

[ssinghi]

I think first PR #69 can be merged and then the ssl support added.

[milieu]

Well PR #69 has been merged...

[ayoul3]

hey @ssinghi and team, would love for this to be merged if/when possible !

[stanhu]

I don't think we can assume that OpenSSL is here. We may want to use pkg_config to determine the LDFLAGS and CFLAGS.

[stanhu]

I don't think SSL_VERIFY_NONE should be the default. I'd say that the default should be verify is enabled, but you may pass a verify option.

[engwan]

@stanhu I also saw https://github.com/michael-grunder/hiredis-rb/commits/ssl-support which is also an attempt to add SSL support.

I saw it has some code to conditionally link OpenSSL: michael-grunder@a9897ec#diff-573a6b1ffeebb872ab4255105affc087786e9e64b583ebcf28bca619c0a1227aR48-R49

[stanhu]

This is a bit of an ugly hack since it's reaching inside the hiredis internals to get this information.

I think we're better off modifying hiredis to support the setting of verify mode: redis/hiredis#1085

[YegorZdanovich]

@stanhu @ssinghi
@mtuleika-appcast doesn't work on ruby projects anymore, maybe someone can continue this PR