Support TSSLSocket

[laserson]

Currently supported by thrift but not thriftpy.

[amontalenti]

Mentioned by Wes McKinney (author of Pandas) here: https://twitter.com/wesmckinn/status/672638289560539136 (he works on Ibis at Cloudera now)

[lxyu]

Yah we see it, hopefully we'll support it soon.

[lxyu]

SSLSocket supported now, it's actually more difficult than the first glance. The implementation in thriftpy should be better than the upstream apache lib:

1. more secure. it use the latest create_default_context with more secure default options, and has a limited backward compat implementation ported to py26 and py33. For more info refer to the source code of CPython ssl lib, https://github.com/python/cpython/blob/3.5/Lib/ssl.py#L425-L471 , the current apache implementation has none of these.
2. more feature rich. you can customize or persist the SSLContext object to suit your needs.

While on the other hand, security is difficult and I'm not a security expert. I tried to implement the SSL socket based on best practice, there may still have bugs in it.

So you may want to review the code before use, and I'll appricate any feedbacks on the implementation.

[amontalenti]

@lxyu Very cool! I'm going to take a look next week. I also tweeted at Wes to let him know.

[lxyu]

@amontalenti Thanks, I'll make a release as soon as the review finished!

[lxyu]

Close as released in v0.3.3