Code examples for agent.send() troubleshooting guide.

ack.device.nut

server.settimeoutpolicy(SUSPEND_ON_ERROR, WAIT_FOR_ACK, 10);

// Program does some work...

foreach (count, blob in buffer) {
    // Every send will not return until the server has ACK’d
    // Assume no timeout for this example
    local outcome = agent.send(“process.data”, blob);
    server.log(“Blob %u sent to server”, count + 1);
}

buffer.device.nut

function increaseBuffer(dataToSend) {
    local oldSize = 0;
    local newSize = dataToSend.len();
    if (newSize > 3456) local oldSize = imp.setsendbuffersize(newSize);
    server.log("Buffer increased to " + newSize + " bytes from " + oldSize + " bytes");
}

return.device.nut

server.settimeoutpolicy(RETURN_ON_ERROR, WAIT_TIL_SENT, 10);

dataToSend <- null;
retryTime <- 600;     // Ten minutes

// Code at some point will place the data it needs to send into dataToSend and then call
// transmitter(), a wrapper for agent.send() and related calls, to send it.

function transmitter() {
    // Make sure we have data to send
    if (dataToSend == null) return;
    if (server.isconnected()) {
        // At this point we have WiFi connected so try to add dataToSend to TCP send buffer
        local outcome = agent.send(“message”, dataToSend);
        if (outcome == 0) {
            // Record successful addition of data to impOS buffer by zero-ing dataToSend
            // This can be used to indicate dataToSend is free for more data
            dataToSend = null;
        } else {
            // Couldn’t add dataToSend to the buffer OR
            // WiFi has been lost OR some other failure
            // RETURN_ON_ERROR in force so we need to re-connect before
            // attempting to add dataToSend to the buffer again
            
            // Reschedule transmitter()
            imp.wakeup(retryTime, transmitter);
        }
    } else {
        // WiFi is disconnected, so attempt to reconnect as per RETURN_ON_ERROR
        // Whatever the outcome, we come back to transmitter().
        // We can't schedule transmitter() directly as server.connect()'s
        // callback expects a single parameter to take outcome indicator integer
        server.connect(function(reason) { transmitter(); } );
    }
}