Redis Using Python Drivers

Install

The Redis drivers can be installed on the machine by using the python package redis.

pip3 install redis

Start a Redis Container Using Docker

There are many ways to init a Redis database. Docker might be the best one however. To init Redis with a Docker container, run this command:

docker run -p 6379:6379 --name name_of_container -d redis

After opening Docker & running the command above, you should see a docker container running redis.

Using Python to Define Redis Database

Redis stands for Remote Dictionary Service. This definition may make you think of Python dictionaries and in some sense that's true. Remember that Redis databases are defined using key-value pairs, like Python dictionaries.

The main difference between Redis & Python dictionaries are:

• Redis dictionaries support a variety of methods, such as GET, SEL and DEL.
• Python dictionaries don't support these methods, but instead use different ones such as...
  • copy(), clear(), and pop().
• Redis keys are always strings. In Python, keys can be of any datatype

How to Define a Database in Redis

Redis databases can be initialized using the following:

import redis
# Connect
r = redis.Redis(host='localhost', port=6379, db=0)
# Write to DB
t = python_code_to_define_key_value_pairs
r.push('entries', t)

Note that the code above, d=0 inits the database 0. In Redis, by default, there are 16 available databases numbered from 0 ~ 15.

After defining the database and its entries, you may want to read those entries to ensure everything is defined correctly. You can do that with this:

import redis
# Connect
r = redis.Redis(host='localhost', port=6379, db=0)
# Read
for item in r.lrange('items', 0, -1)
    print(item)

Methods in Redis

The table below explains the most common Redis methods that can be used to access and modify database entries.

• GET
  • Use the GET to get the value of a key
  • If the key does not exist, the special value nil is returned.
  • An error is returned if the value stored as key is not a string.
    • This is because GET only handles string values.
• SET
  • Use the SET method to set the key to hold the string value.
  • If a key already holds a value, it is overwritten, regardless of its type.
  • Any previous time to live associated with the key is discarded on successful SET.
• DEL
  • Use the DEL method to remove specified keys.
  • A key is ignored if it does not exist.

References

Web References

• Redis Commands: GET
• Redis Commands: SET
• Redis Commands: DEL
• Redis All Commands Documentation

Note References

• Python
• Redis
• Key-Value Databases
• Docker