Retrieves a pending PostgreSQL LISTEN/NOTIFY notification from a database connection.
Before using it, identify which data, connection or runtime state the operation reads or changes. This avoids examples that appear to work but apply to a different context.
What Is pg_get_notify() in PHP?
Retrieves a pending PostgreSQL LISTEN/NOTIFY notification from a database connection.
Syntax:
<?php
// Signature for reference only
pg_get_notify(...)
Parameters and Return Value
Required arguments and available parameters depend on the installed extension and PHP version. Check the actual API signature for the deployment target before adapting these examples.
The result depends on the installed extension and the surrounding runtime.
Example 1: Basic Usage
<?php
$databaseConnection = pg_connect("host=localhost dbname=app user=appuser password=example");
pg_query($databaseConnection, "LISTEN app_updates");
var_dump(pg_get_notify($databaseConnection, PGSQL_ASSOC));Retrieves a pending PostgreSQL LISTEN/NOTIFY notification from a database connection.
Example 2: Another Case
<?php
$databaseConnection = pg_connect("host=localhost dbname=app user=appuser password=example");
pg_query($databaseConnection, "LISTEN job_events");
var_dump(pg_get_notify($databaseConnection, PGSQL_NUM));The second sample illustrates a different way to inspect or handle this operation. Configure the underlying session, socket, key material or connection first.
Practical Example
<?php
$databaseConnection = pg_connect("host=localhost dbname=app user=appuser password=example");
pg_query($databaseConnection, "LISTEN app_updates");
pg_consume_input($databaseConnection);
$notification = pg_get_notify($databaseConnection, PGSQL_ASSOC);
if ($notification !== false) { echo $notification["message"]; }The practical example is a teaching scenario. Change sample configuration and credentials before using a similar design in an application.
Important Behavior and Edge Cases
- A valid pgsql connection is required and results may be absent until asynchronous messages are consumed.
- Relevant PHP environment: Extension-specific. Ensure the required extension and operating-system capabilities are present.
- Check results and release resources where necessary; successful syntax alone does not guarantee a successful operation.
Comparison With Related Functions
| Option | When to Use It |
|---|---|
pg_get_notify | Retrieves a pending PostgreSQL LISTEN/NOTIFY notification from a database connection. |
pg_get_result | Use this related operation for its different responsibilities; do not assume identical inputs or return values. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Reading a result before the command completes | Consume input and wait for the appropriate async query result state. |
| Treating a false return as an empty result set | Distinguish missing, pending and failed results. |
| Embedding user input into SQL strings | Use prepared statements and bound values. |
Key Takeaways
- Retrieves a pending PostgreSQL LISTEN/NOTIFY notification from a database connection.
- A valid pgsql connection is required and results may be absent until asynchronous messages are consumed.
- Validate inputs and handle failure conditions before integrating this operation into a production workflow.
Retrieves a pending PostgreSQL LISTEN/NOTIFY notification from a database connection. Use the appropriate runtime and treat any environment-dependent output as an example, not a guaranteed result.