Reads multiple named fields from a Redis hash.
The objective is to understand the behavior and operational limits, not only the method name.
What It Does
Reads multiple named fields from a Redis hash.
Syntax and Return Value
Redis::hMGet(...)The return value and exceptional cases depend on the call described here: Missing fields are represented by false under phpredis defaults; handle them explicitly.
Requirements: install and enable the corresponding PHP driver or extension and configure the service before running the examples.
Example 1: Basic Use
Requires the phpredis extension and a running Redis server. Keys use a guide-specific prefix; clean up example keys after experimenting.
<?php
$redis = new Redis();
$redis->connect(getenv('REDIS_HOST') ?: '127.0.0.1', (int) (getenv('REDIS_PORT') ?: 6379), 2.0);
$redis->hMSet('guide:hmget:1',["name"=>'draft',"visits"=>3]);
echo json_encode($redis->hMGet('guide:hmget:1',["name","visits","missing"]));Example 2: A Second Scenario
Requires the phpredis extension and a running Redis server. Keys use a guide-specific prefix; clean up example keys after experimenting.
<?php
$redis = new Redis();
$redis->connect(getenv('REDIS_HOST') ?: '127.0.0.1', (int) (getenv('REDIS_PORT') ?: 6379), 2.0);
$redis->hMSet('guide:hmget:2',["name"=>'review',"visits"=>4]);
echo json_encode($redis->hMGet('guide:hmget:2',["name","visits","missing"]));Example 3: Practical Checks
Requires the phpredis extension and a running Redis server. Keys use a guide-specific prefix; clean up example keys after experimenting.
<?php
$redis = new Redis();
$redis->connect(getenv('REDIS_HOST') ?: '127.0.0.1', (int) (getenv('REDIS_PORT') ?: 6379), 2.0);
$redis->hMSet('guide:hmget:3',["name"=>'published',"visits"=>5]);
echo json_encode($redis->hMGet('guide:hmget:3',["name","visits","missing"]));Important Behavior and Edge Cases
Missing fields are represented by false under phpredis defaults; handle them explicitly.
For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.
Comparison with Related Approaches
| Approach | Important distinction |
|---|---|
| Redis::hMGet | Reads multiple named fields from a Redis hash. |
| Related API / pattern | hGet reads one field; hGetAll reads every field. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Assuming the happy path covers edge cases | Missing fields are represented by false under phpredis defaults; handle them explicitly. |
| Using a related API interchangeably | hGet reads one field; hGetAll reads every field. |
Key Takeaways
- Reads multiple named fields from a Redis hash.
- Missing fields are represented by false under phpredis defaults; handle them explicitly.
- hGet reads one field; hGetAll reads every field.
Choose this API or pattern when its exact semantics match your task, and verify the result against the database driver and runtime used by your application.