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Libcurl: perform a REST HTTP PUT

The libcurl library does not provide a clear example on how to issue HTTP PUT operations in a REST context; the examples are mainly about file transfers . For my proxy application this is not really what I need: I want to perform a REST HTTP PUT, keep it simple, meaning without using the "Expect" and "Transfer-Encoding" that libcurl adds by default. After some struggling I discovered that this behavior can be changed by using the following code: CURL * pCurl; struct curl_slist *headers = NULL; headers = curl_slist_append(headers, "Content-Type: application/json "); headers = curl_slist_append(headers, "Content-Length: 12345 "); headers = curl_slist_append(headers, "Expect:"); headers = curl_slist_append(headers, "Transfer-Encoding:"); pCurl = curl_easy_init(); curl_easy_setopt(pCurl, CURLOPT_VERBOSE, 1); curl_easy_setopt(pCurl, CURLOPT_PUT, 1); curl_easy_setopt(pCurl, CURLOPT_URL, " https://your-server.app...
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ZWay: most interesting data for a binary sensor

In order to be able to refresh the persisted state of my binary sensors on my little web application, I extended my "Z-Wave proxy" to send some information when it initially starts. It retrieves data from a few "data holders": The current level (if the sensor is triggered or not). The configured wake-up interval. The last sleep time. The last wake-up time. The battery level. The following code can be used to do so. const ZWBYTE COMMAND_CLASS_ALARM = 113; const ZWBYTE COMMAND_CLASS_BATTERY = 128; const ZWBYTE COMMAND_CLASS_SENSOR_BINARY = 48; const ZWBYTE COMMAND_CLASS_WAKE_UP = 132; [...] bool level = findInstanceDataAsBoolean(aZWay, COMMAND_CLASS_SENSOR_BINARY, "level"); int wakeUpInterval = findInstanceDataAsInt(aZWay, COMMAND_CLASS_WAKE_UP, "interval"); int lastSleepTime = findInstanceDataAsInt(aZWay, COMMAND_CLASS_WAKE_UP, "lastSleep"); int lastWakeUpTime = findInstanceDataAsInt(aZWay, COMMAND_CLASS_WAKE_UP,...
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ZWay: notification on wake-up events

Z-Wave battery powered devices implement a periodic "wake-up" where it contacts the controller; for the door sensors I am using, I configured the wake-up to happen every 5 minutes. Now, how to capture this in the ZWay library? It is again the same as for other events: register a callback on a certain "data holder". Here this data holder is found on: device instance level; command class: 132 (wake up); path: "lastWakeup" (there is also another one "lastSleep", so far it is not clear to me which one is the best to use). Here is a sample code registering a call-back for this event: zway_data_acquire_lock(aZWay); ZDataHolder dataHolder = zway_find_device_instance_cc_data(aZWay, mDeviceId, 0, COMMAND_CLASS_WAKE_UP, "lastWakeup"); if (dataHolder != NULL) { zway_data_add_callback_ex(aZWay, dataHolder, &aliveCallback, TRUE, this); } else { cerr << "No data holder for deviceId=" << (int) mDeviceId...
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From Z-Wave to my phone!

Now that I know a bit better how to use the ZWay library, and that I refreshed a bit my C/C++ knowledge, I can finally complete the first use-case of my home security system: getting notified of an event on my phone (my good "old" HTC Legend running Android 2.2). For a long time I have been wondering and hesitating about the "server" part of my system. The Raspberry Pi could of course play this role, but it would not be "safe" since cutting the home power or un-plugging it would void the "security system". Yes of course I could put the Raspberry Pi on battery, hide it somewhere in the house and use WiFi to connect to others networks in case my home Internet connection would drop, but then again, cutting the power of the whole neighborhood would still kill my system. So it had to be something external. Looking at prices for getting my own Linux private server, that would be something like 5-15 Euros a month. That sounds rather stupid since for...
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ZWay: notification on event (continued)

After getting your hand on a Z-Wave data holder in the ZWay library, the next step is to register a listener for getting notified when a change occurs on this data. The ZWay library provides the following methods for managing data holder listeners: zway_data_add_callback() zway_data_remove_callback() zway_data_add_callback_ex() zway_data_remove_callback_ex() zway_data_acquire_lock(aZWay); ZDataHolder dataHolder = zway_find_device_instance_cc_data(aZWay, 2, 0, COMMAND_CLASS_SENSOR_BINARY, "level"); if (dataHolder != NULL) { zway_data_add_callback_ex(aZWay, dataHolder, &dataChangeCallback, TRUE, this); } else { cerr << "No data holder for deviceId=" << (int) mDeviceId << endl; } zway_data_release_lock(aZWay); The following code will register the following "dataChangeCallback" function in the ZWay stack and make sure it is invoked when the Z-Wave binary sensor with node ID 2 gets triggered. void dataChangeCallba...
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ZWay: notification on event

Having now my sensors now installed "properly" (well, the sensors are hell to mount on PVC) on the door and windows at home, it is time to set-up my little ZWay application to get notified when these sensors are generating some events. More precisely, when a window or door gets open... The ZWay API provides the possibility to install some callbacks when "data holder" are changed. Therefore the first thing to investigate is the data holder. There are a few functions to get a hand on a data holder: zway_find_data(...) That one requires a data holder as argument, so that's not the one we need. zway_find_controller_data zway_find_device_data zway_find_device_instance_data zway_find_device_instance_cc_data These are the functions to use; to get the "root" of the data holder, you can simply provide an empty string as parameter e.g. ZDataHolder dataHolder = zway_find_device_instance_cc_data(theZWay, 2, 0, 48, ""); Given a bit o...
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ZWay: getting the device list.

Back after a while... and a son! Here is a piece of code that can be used with the latest version of the ZWay library. It makes it possible to retrieve the Z-Wave device list and display the device names and associated XML file (each recognized device can be associated to an XML that contains a bunch of meta-data: name, description etc.). int main(int argc, char ** argv) { ZWay theZWay; ZWError result; memset(&theZWay, 0, sizeof(theZWay)); result = zway_init(&theZWay, "/dev/ttyAMA0", "/home/pi/src/razberry-proxy/config", "/home/pi/src/razberry-proxy/translations", "/home/pi/src/razberry-proxy/ZDDX", stdout, Warning); if (result == NoError) { result = zway_start(theZWay, &terminationCb); if (result == NoError) { printf("Discovering...\n"); result = zway_discover(theZW...
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