Connection pool exhausted error in Ti.Network.HTTPClient

To resolve connection pool exhaustion in Ti.Network.HTTPClient, developers must explicitly call `client.close()` once a request is complete. Relying on garbage collection (GC) to clean up instances is unreliable because the timing of GC-based resource release varies significantly between iOS and Android runtimes, leading to leaked sockets that exhaust the pool.

The Root Cause

The framework maintains a keep-alive connection pool that defaults to five connections per host. When a client is instantiated but not closed, the underlying socket remains active or tied to the pool until the runtime reclaims the object. Because rapid requests can instantiate new clients faster than the GC can trigger, the pool quickly reaches its limit, causing subsequent requests to hang or fail with exhaustion errors.

Recommended Strategy: Explicit Management

The only supported approach is to manage the lifecycle of the client explicitly. This ensures the socket is returned to the pool or terminated immediately regardless of whether the request succeeds or fails.

• Use a finally block or ensure client.close() is called in both onload and onerror handlers.
• If making sequential requests, consider reusing a single HTTPClient instance rather than creating a new one per request.

Implementation Example

var client = new Ti.Network.HTTPClient();
client.get('https://api.example.com/data', function(response) {
    // Handle response
    client.close();
}, function(error) {
    // Handle error
    client.close();
});

Verification and Workarounds

While you could disable keep-alive via headers (Connection: close) as a workaround, this introduces significant overhead due to repeated TCP/TLS handshakes. To verify the fix, use a network proxy like Charles or mitmproxy to observe that connections are closed immediately after the callback execution.

Note: To provide more specific tuning parameters, please specify the SDK version you are using, as internal pool behavior can vary between versions.