New base64encode and sha256 filters

[silviuvergoti]

Adding new filters.
Fixes issues #573 and #572.

[ogrammer]

Perhaps base64 is common enough to be in the core, but if SHA256 gets added then suddenly we could end up with MD5, SHA-1, SHA-2, SHA-3 and more. I feel like there are too many hashing functions for any of them to be included in the core.

Just curious, what's the use for having a hashing filter?

And base64encode sounds too long, maybe just base64?

[silviuvergoti]

Sure, I'll shorten it. I thought that a simple base64 would not be clear enough if it concerns encoding or decoding.
Regarding the hashing filters, there are a lot of web services requiring hashing of PII (emails, ids, phones). If someone needs it, the filter could be changed to something like {{ originalstring | hash('SHA-256') }} and it could support many more hash algorithms.

[ebussieres]

Should we provide a base64 decoder too ?

[silviuvergoti]

@ebussieres, decoding a base64 string will return a byte array. If it's a binary object, reconstructing it might not be feasible. Do you suggest a return value type of byte[]? The encoder was mainly targeted to strings with special characters.

[ebussieres]

byte[] decodedBytes = Base64.getDecoder().decode(encodedString);
String decodedString = new String(decodedBytes);

[ogrammer]

What's the use case? I mean base64 encoding can be useful for putting in a link or showing a raw image but decoding seems pretty useless, if it's data from another server I'd expect it to be decoded before being provided to the template. Besides, new String(...) is loose and will probably cause problems on Windows machines, StandardCharsets.UTF_8 should be supplied.

[silviuvergoti]

I'll add the decoder and it will try to return an UTF-8 String. If there's an exception, we'll throw it. No object casting will be done.

[ebussieres]

Can you add some documentation for the new filters too ?

https://github.com/PebbleTemplates/pebble/tree/master/docs/src/orchid/resources

[silviuvergoti]

Sure.