private static void CacheFcnt(FCnt serverFCnt, IDatabase cache, string cacheKey)
{
cache.StringSet(cacheKey, JsonConvert.SerializeObject(serverFCnt), new TimeSpan(30, 0, 0, 0), When.Always, CommandFlags.DemandMaster);
}
public static IActionResult Run(HttpRequest req, ILogger log, ExecutionContext context, ApiVersion currentApiVersion)
{
// set the current version in the response header
req.HttpContext.Response.Headers.Add(ApiVersion.HttpHeaderName, currentApiVersion.Version);
var requestedVersion = req.GetRequestedVersion();
if (requestedVersion == null || !currentApiVersion.SupportsVersion(requestedVersion))
{
return(new BadRequestObjectResult($"Incompatible versions (requested: '{requestedVersion.Name ?? string.Empty}', current: '{currentApiVersion.Name}')"));
}
FCnt serverFCnt;
string devEUI = req.Query["DevEUI"];
string fCntDown = req.Query["FCntDown"];
string fCntUp = req.Query["FCntUp"];
string gatewayId = req.Query["GatewayId"];
string abpFcntCacheReset = req.Query["ABPFcntCacheReset"];
int newFCntDown = 0;
if (redisCache == null)
{
lock (typeof(FCntCacheCheck))
{
if (redisCache == null)
{
var config = new ConfigurationBuilder()
.SetBasePath(context.FunctionAppDirectory)
.AddJsonFile("local.settings.json", optional: true, reloadOnChange: true)
.AddEnvironmentVariables()
.Build();
var redisConnectionString = config.GetConnectionString("RedisConnectionString");
if (string.IsNullOrEmpty(redisConnectionString))
{
string errorMsg = "Missing RedisConnectionString in settings";
throw new Exception(errorMsg);
}
var redis = ConnectionMultiplexer.Connect(redisConnectionString);
redisCache = redis.GetDatabase();
}
}
}
if (!string.IsNullOrEmpty(abpFcntCacheReset))
{
redisCache.KeyDelete(devEUI);
return((ActionResult) new OkObjectResult(null));
}
if (!string.IsNullOrEmpty(devEUI) && !string.IsNullOrEmpty(fCntDown) && !string.IsNullOrEmpty(fCntUp) && !string.IsNullOrEmpty(gatewayId))
{
int clientFCntDown = int.Parse(fCntDown);
int clientFCntUp = int.Parse(fCntUp);
string cacheKey = devEUI;
try
{
if (redisCache.LockTake(cacheKey + "msglock", gatewayId, new TimeSpan(0, 0, 10)))
{
string cachedFCnt = redisCache.StringGet(cacheKey, CommandFlags.DemandMaster);
// we have it cached
if (!string.IsNullOrEmpty(cachedFCnt))
{
serverFCnt = (FCnt)JsonConvert.DeserializeObject(cachedFCnt, typeof(FCnt));
// it is a new message coming up by the first gateway
if (clientFCntUp > serverFCnt.FCntUp)
{
if (clientFCntDown >= serverFCnt.FCntDown)
{
newFCntDown = (int)(clientFCntDown + 1);
}
else
{
newFCntDown = (int)(serverFCnt.FCntDown + 1);
}
serverFCnt.FCntUp = clientFCntUp;
serverFCnt.FCntDown = newFCntDown;
serverFCnt.GatewayId = gatewayId;
CacheFcnt(serverFCnt, redisCache, cacheKey);
}
// it is a retry message coming up by the same first gateway
else if (clientFCntUp == serverFCnt.FCntUp && gatewayId == serverFCnt.GatewayId)
{
newFCntDown = serverFCnt.FCntDown + 1;
serverFCnt.FCntDown = newFCntDown;
CacheFcnt(serverFCnt, redisCache, cacheKey);
}
else
{
// we tell not to send any ack or downstream msg
newFCntDown = 0;
}
}
// it is the first message from this device
else
{
newFCntDown = clientFCntDown + 1;
serverFCnt = new FCnt();
serverFCnt.FCntDown = newFCntDown;
serverFCnt.FCntUp = clientFCntUp;
serverFCnt.GatewayId = gatewayId;
CacheFcnt(serverFCnt, redisCache, cacheKey);
}
}
}
finally
{
redisCache.LockRelease(cacheKey + "msglock", gatewayId);
}
}
else
{
string errorMsg = "Missing DevEUI or FCntDown or FCntUp or GatewayId";
throw new Exception(errorMsg);
}
return((ActionResult) new OkObjectResult(newFCntDown));
}
public static async Task <IActionResult> Run([HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req, ILogger log, ExecutionContext context)
{
FCnt serverFCnt;
string devEUI = req.Query["DevEUI"];
string fCntDown = req.Query["FCntDown"];
string fCntUp = req.Query["FCntUp"];
string gatewayId = req.Query["GatewayId"];
string ABPFcntCacheReset = req.Query["ABPFcntCacheReset"];
int newFCntDown = 0;
if (redisCache == null)
{
lock (typeof(FCntCacheChechk))
{
if (redisCache == null)
{
var config = new ConfigurationBuilder()
.SetBasePath(context.FunctionAppDirectory)
.AddJsonFile("local.settings.json", optional: true, reloadOnChange: true)
.AddEnvironmentVariables()
.Build();
var redisConnectionString = config.GetConnectionString("RedisConnectionString");
if (string.IsNullOrEmpty(redisConnectionString))
{
string errorMsg = "Missing RedisConnectionString in settings";
throw new Exception(errorMsg);
}
var redis = ConnectionMultiplexer.Connect(redisConnectionString);
redisCache = redis.GetDatabase();
}
}
}
if (!string.IsNullOrEmpty(ABPFcntCacheReset))
{
redisCache.KeyDelete(devEUI);
return((ActionResult) new OkObjectResult(null));
}
if (!String.IsNullOrEmpty(devEUI) && !String.IsNullOrEmpty(fCntDown) && !String.IsNullOrEmpty(fCntUp) && !String.IsNullOrEmpty(gatewayId))
{
int clientFCntDown = int.Parse(fCntDown);
int clientFCntUp = int.Parse(fCntUp);
string cacheKey = devEUI;
try
{
if (redisCache.LockTake(cacheKey + "msglock", gatewayId, new TimeSpan(0, 0, 10)))
{
string cachedFCnt = redisCache.StringGet(cacheKey, CommandFlags.DemandMaster);
//we have it cached
if (!string.IsNullOrEmpty(cachedFCnt))
{
serverFCnt = (FCnt)JsonConvert.DeserializeObject(cachedFCnt, typeof(FCnt));
//it is a new message coming up by the first gateway
if (clientFCntUp > serverFCnt.FCntUp)
{
if (clientFCntDown >= serverFCnt.FCntDown)
{
newFCntDown = (int)(clientFCntDown + 1);
}
else
{
newFCntDown = (int)(serverFCnt.FCntDown + 1);
}
serverFCnt.FCntUp = clientFCntUp;
serverFCnt.FCntDown = newFCntDown;
serverFCnt.GatewayId = gatewayId;
CacheFcnt(serverFCnt, redisCache, cacheKey);
}
//it is a retry message coming up by the same first gateway
else if (clientFCntUp == serverFCnt.FCntUp && gatewayId == serverFCnt.GatewayId)
{
newFCntDown = serverFCnt.FCntDown + 1;
serverFCnt.FCntDown = newFCntDown;
CacheFcnt(serverFCnt, redisCache, cacheKey);
}
else
{
//we tell not to send any ack or downstream msg
newFCntDown = 0;
}
}
//it is the first message from this device
else
{
newFCntDown = clientFCntDown + 1;
serverFCnt = new FCnt();
serverFCnt.FCntDown = newFCntDown;
serverFCnt.FCntUp = clientFCntUp;
serverFCnt.GatewayId = gatewayId;
CacheFcnt(serverFCnt, redisCache, cacheKey);
}
}
}
finally
{
redisCache.LockRelease(cacheKey + "msglock", gatewayId);
}
}
else
{
string errorMsg = "Missing DevEUI or FCntDown or FCntUp or GatewayId";
throw new Exception(errorMsg);
}
return((ActionResult) new OkObjectResult(newFCntDown));
}