Requests connection maintenance such as keepalive probes for a configured easy handle. This guide demonstrates its use in PHP code and explains when the result or side effect needs extra checks.
What It Does
Requests connection maintenance such as keepalive probes for a configured easy handle.
Syntax and Parameters
The examples below show a real call to curl_upkeep with suitable arguments. Read the function call in context: its connection, handle, input data or other prerequisites are created before use.
Requirements: cURL extension; HTTP client and transfer-handling tools.
Example 1: Core Behavior
The first case demonstrates the precise handle or result type.
<?php
$ch = curl_init('https://api.example.test/health');
curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 3, CURLOPT_CONNECTTIMEOUT => 2]);
$result = curl_upkeep($ch);
echo $result ? "Maintenance requested" : "Unsupported or failed";Observe the returned value or changed resource state. A successful function call can still require additional checks before a higher-level operation is considered successful.
Example 2: Alternative or Failure Case
The second case checks behavior under a different configuration or request.
<?php
$ch = curl_init('https://api.example.test/products');
curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 4, CURLOPT_CONNECTTIMEOUT => 2]);
$result = curl_upkeep($ch);
echo $result ? "Maintenance requested" : "Unsupported or failed";Compare the different inputs, environment assumptions or result checks. Do not use a transport-level success value as proof that all business-level requirements were met.
Practical Example: Applying the Rule
The practical case shows how to inspect the operation outcome instead of assuming success.
<?php
$ch = curl_init('https://api.example.test/orders');
curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 5, CURLOPT_CONNECTTIMEOUT => 2]);
$result = curl_upkeep($ch);
echo $result ? "Maintenance requested" : "Unsupported or failed";In an application, convert low-level failures into controlled responses and log only non-sensitive diagnostic context.
Important Behavior and Edge Cases
This is not an HTTP request and does not guarantee the connection remains alive; support depends on libcurl.
TLS validation, bounded timeouts and a destination allowlist are essential for network requests involving potentially untrusted targets.
Comparison with Related Functions or Patterns
| Approach | When it differs |
|---|---|
| curl_upkeep | Requests connection maintenance such as keepalive probes for a configured easy handle. |
| Related API or pattern | curl_exec transfers response data, rather than maintaining a connection. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Forgetting destination validation, timeouts or TLS verification during a transfer | This is not an HTTP request and does not guarantee the connection remains alive; support depends on libcurl. |
| Substituting a related API without checking its semantics | curl_exec transfers response data, rather than maintaining a connection. |
Key Takeaways
- Requests connection maintenance such as keepalive probes for a configured easy handle.
- This is not an HTTP request and does not guarantee the connection remains alive; support depends on libcurl.
- curl_exec transfers response data, rather than maintaining a connection.
Select this API or pattern based on its documented behavior and the trust boundaries in your own application, and test all external integrations against their actual deployments.