Added GET argument to SET command

[jiekun]

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Description of change

Issue: #1411

Added GET argument to SET command, new in Redis 6.2: https://redis.io/commands/set

[jiekun]

To handle this, the read_response() method in connection.py may need to change a little bit.
When redis return '+OK' or '$2' (and a "OK" string value), they will be parsed into b'OK' in read_response().

What do you think @andymccurdy

[andymccurdy]

This looks good. I'd like to wait to merge until Redis 6.2 is released so that we can include it in the unit tests.

[jiekun]

Hmm but it's not working now. There is no way to tell the difference between 'OK' (bool value) and 'OK' (string value, return when ''get'' param is set to True) in client.py.

r.set(1,'OK')     # we got b'OK' response
r.set(1,'foo',get=True)  # we got b'OK' again and will be parsed as bool value

this must be solve if we want to add 'get' argument to the set command. Will take a look tomorrow

[andymccurdy]

This should be pretty easy to solve.

def set(self, ..., get=False):
    options = {}
    ...
    if get:
        pieces.append(b'GET')
        options['get'] = True

    return self.execute_command(*pieces, **options)

Then we make a response callback for SET:

def parse_set(response, **options):
    if options.get('get'):
        # return the string
    # return the boolean

[jiekun]

haha allright. I will deal it in this way. I thought it should be more concise before, without passing any extra argument.

will catch it up tomorrow.

[andymccurdy]

This looks good. Thanks! Tagging this as Redis 6.2 and will merge once the server is released.

[chayim]

Thank you for your contribution @2014BDuck. I just merged, and validated with redis server 6.2.5. Approving, and merging into master.