std.db.redis
The std.db.redis module provides functions for interacting with Redis databases, including direct command execution and pipeline operations.
Core Functions
cmd(command: string, ...args: any)
Executes a Redis command and returns the result.
Parameters:
command: The Redis command string (e.g., "SET mykey value")args: Optional additional arguments for the command
Return Type: any (depends on Redis command)
Example:
use std.db.redis;
// Set a key
redis.cmd("SET mykey somevalue");
// Get a key
let value = redis.cmd("GET mykey");
print(value); // "somevalue"
// Get list elements
let lists = redis.cmd("LRANGE mylist 0 -1");
print(lists); // Array of list elements
pipeline()
Creates a new Redis pipeline for executing multiple commands atomically.
Return Type: Pipeline object
Pipeline Methods:
cmd(command: string, ...args: any) - Adds a command to the pipelineexec() - Executes all commands in the pipelinediscard() - Discards the pipeline without executing
Example:
use std.db.redis;
// Create pipeline
let p = redis.pipeline();
// Add commands
p.cmd("SET k1 v1");
p.cmd("SET k2 v2");
p.cmd("GET k1");
// Execute pipeline
let results = p.exec();
print(results); // ["OK", "OK", "v1"]
// Alternatively, discard pipeline
// p.discard();
Usage Examples
Basic Key Operations
use std.db.redis;
// Set and get values
redis.cmd("SET username alice");
let name = redis.cmd("GET username");
print(name); // "alice"
// Increment counter
redis.cmd("INCR counter");
let count = redis.cmd("GET counter");
print(count); // "1"
List Operations
use std.db.redis;
// Push to list
redis.cmd("RPUSH mylist item1");
redis.cmd("RPUSH mylist item2");
// Get all list items
let items = redis.cmd("LRANGE mylist 0 -1");
print(items); // ["item1", "item2"]
Hash Operations
use std.db.redis;
// Set hash fields
redis.cmd("HSET user:1000 name Alice age 30");
// Get hash field
let name = redis.cmd("HGET user:1000 name");
print(name); // "Alice"
// Get all hash fields
let user = redis.cmd("HGETALL user:1000");
print(user); // {"name": "Alice", "age": "30"}
Set Operations
use std.db.redis;
// Add to set
redis.cmd("SADD myset item1");
redis.cmd("SADD myset item2");
// Get set members
let members = redis.cmd("SMEMBERS myset");
print(members); // ["item1", "item2"]
Pipeline Example
use std.db.redis;
// Create pipeline
let p = redis.pipeline();
// Add multiple commands
p.cmd("SET user:1:name Alice");
p.cmd("SET user:1:age 30");
p.cmd("GET user:1:name");
// Execute and get results
let results = p.exec();
print(results); // ["OK", "OK", "Alice"]
Error Handling
use std.db.redis;
try {
// Attempt invalid command
redis.cmd("INVALIDCOMMAND");
} catch (e) {
print(`Redis error: ${e.message}`);
}
Transaction Example
use std.db.redis;
// Start transaction
redis.cmd("MULTI");
// Add commands
redis.cmd("SET key1 value1");
redis.cmd("SET key2 value2");
// Execute transaction
let results = redis.cmd("EXEC");
print(results); // ["OK", "OK"]
Expiration Example
use std.db.redis;
// Set key with expiration
redis.cmd("SET mykey value EX 60"); // Expires in 60 seconds
// Check TTL
let ttl = redis.cmd("TTL mykey");
print(ttl); // 60 (or less, depending on when checked)
Complex Pipeline
use std.db.redis;
// Create pipeline for user registration
let p = redis.pipeline();
// Add user data
p.cmd("HSET user:1000 name Alice age 30 email alice@example.com");
// Add to users set
p.cmd("SADD users 1000");
// Get all user data
p.cmd("HGETALL user:1000");
// Execute pipeline
let results = p.exec();
print(results); // [1, 1, {"name": "Alice", "age": "30", "email": "alice@example.com"}]
Sorted Set Operations
use std.db.redis;
// Add to sorted set
redis.cmd("ZADD myzset 1 item1");
redis.cmd("ZADD myzset 2 item2");
// Get sorted set members
let members = redis.cmd("ZRANGE myzset 0 -1");
print(members); // ["item1", "item2"]
Pub/Sub Example
use std.db.redis;
// Publish message
redis.cmd("PUBLISH mychannel 'Hello World'");
// Note: Subscribe would be handled in a separate process
// redis.cmd("SUBSCRIBE mychannel");
