DigitalInfinity/ESP32-PaxCounter
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

node red server by cyberman with seq no in payload, not in port, and timezone (diff minimized)

Browse Source
This commit is contained in:
Marius Gripp 2019-10-01 17:28:54 +02:00
parent ba732012b9
commit 5fcb33d03d
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/Timeserver/Nodered-Timeserver.json
View File

@ -187,7 +187,7 @@
"type": "function", "type": "function",
"z": "449c1517.e25f4c", "z": "449c1517.e25f4c",
"name": "Timeserver Logic", "name": "Timeserver Logic",
"func": "/* LoRaWAN Timeserver\n\nconstruct 5 byte timesync_answer from gateway timestamp and node's time_sync_req\n\nbyte meaning\n1..4 current second (from epoch time 1970)\n5 1/250ths fractions of current second\n\nFPort = sequence number (taken from node's time_sync_req)\n\n*/\n\nfunction timecompare(a, b) {\n \n const timeA = a.time;\n const timeB = b.time;\n\n let comparison = 0;\n if (timeA > timeB) {\n comparison = 1;\n } else if (timeA < timeB) {\n comparison = -1;\n }\n return comparison;\n}\n\nlet confidence = 2000; // max millisecond diff gateway time to server time\n\n// guess if we have received a valid time_sync_req command\nif (msg.payload.payload_raw.length != 1)\n return;\n\nvar deviceMsg = { payload: msg.payload.dev_id };\nvar seqNo = msg.payload.payload_raw[0];\nvar seqNoMsg = { payload: seqNo };\nvar gateway_list = msg.payload.metadata.gateways;\n\n// filter all gateway timestamps that have milliseconds part (which we assume have a \".\")\nvar gateways = gateway_list.filter(function (element) {\n return (element.time.includes(\".\"));\n});\n\nvar gateway_time = gateways.map(gw => {\n return {\n time: new Date(gw.time),\n eui: gw.gtw_id,\n }\n });\nvar server_time = new Date(msg.payload.metadata.time);\n\n// validate all gateway timestamps against lorawan server_time (which is assumed to be recent)\nvar gw_timestamps = gateway_time.filter(function (element) {\n return ((element.time > (server_time - confidence) && element.time <= server_time));\n});\n\n// if no timestamp left, we have no valid one and exit\nif (gw_timestamps.length === 0) {\n var notavailMsg = { payload: \"n/a\" };\n var notimeMsg = { payload: 0xff }; \n var buf2 = Buffer.alloc(1);\n msg.payload = new Buffer(buf2.fill(0xff));\n return [notavailMsg, notavailMsg, deviceMsg, seqNoMsg, msg];}\n\n// sort time array in ascending order to find most recent timestamp for time answer\ngw_timestamps.sort(timecompare);\n\nvar timestamp = gw_timestamps[0].time;\nvar eui = gw_timestamps[0].eui;\nvar offset = server_time - timestamp;\n\nvar seconds = Math.floor(timestamp/1000);\nvar fractions = (timestamp % 1000) / 4;\n\nlet buf = new ArrayBuffer(5);\nnew DataView(buf).setUint32(0, seconds);\nnew DataView(buf).setUint8(4, fractions);\n\nmsg.payload = new Buffer(new Uint8Array(buf));\nmsg.port = seqNo;\nvar euiMsg = { payload: eui };\nvar offsetMsg = { payload: offset };\n\nreturn [euiMsg, offsetMsg, deviceMsg, seqNoMsg, msg];", "func": "/* LoRaWAN Timeserver\n\nconstruct 5 byte timesync_answer from gateway timestamp and node's time_sync_req\n\nbyte meaning\n1..4 current second (from epoch time 1970)\n5 1/250ths fractions of current second\n\nFPort = sequence number (taken from node's time_sync_req)\n\n*/\n\nfunction timecompare(a, b) {\n \n const timeA = a.time;\n const timeB = b.time;\n\n let comparison = 0;\n if (timeA > timeB) {\n comparison = 1;\n } else if (timeA < timeB) {\n comparison = -1;\n }\n return comparison;\n}\n\nlet confidence = 2000; // max millisecond diff gateway time to server time\n\n// guess if we have received a valid time_sync_req command\nif (msg.payload.payload_raw.length != 1)\n return;\n\nvar deviceMsg = { payload: msg.payload.dev_id };\nvar seqNo = msg.payload[0];\nvar seqNoMsg = { payload: seqNo };\nvar gateway_list = msg.payload.metadata.gateways;\n\n// filter all gateway timestamps that have milliseconds part (which we assume have a \".\")\nvar gateways = gateway_list.filter(function (element) {\n return (element.time.includes(\".\"));\n});\n\nvar gateway_time = gateways.map(gw => {\n return {\n time: new Date(gw.time),\n eui: gw.gtw_id,\n }\n });\nvar server_time = new Date(msg.payload.metadata.time);\n\n// validate all gateway timestamps against lorawan server_time (which is assumed to be recent)\nvar gw_timestamps = gateway_time.filter(function (element) {\n return ((element.time > (server_time - confidence) && element.time <= server_time));\n});\n\n// if no timestamp left, we have no valid one and exit\nif (gw_timestamps.length === 0) {\n var notavailMsg = { payload: \"n/a\" };\n var notimeMsg = { payload: 0xff }; \n var buf2 = Buffer.alloc(1);\n msg.payload = new Buffer(buf2.fill(0xff));\n return [notavailMsg, notavailMsg, deviceMsg, seqNoMsg, msg];}\n\n// sort time array in ascending order to find most recent timestamp for time answer\ngw_timestamps.sort(timecompare);\n\nvar timestamp = gw_timestamps[0].time;\nvar eui = gw_timestamps[0].eui;\nvar offset = server_time - timestamp;\n\nvar seconds = Math.floor(timestamp/1000);\nvar fractions = (timestamp % 1000) / 4;\n\nlet buf = new ArrayBuffer(7);\nnew DataView(buf).setUint8(0, seqNo);\n// Timezone (in 15min steps)\nvar timezone = 8; // CET = UTC+2h\nnew DataView(buf).setUint8(1, timezone);\nnew DataView(buf).setUint32(2, seconds);\nnew DataView(buf).setUint8(6, fractions);\n\nmsg.payload = new Buffer(new Uint8Array(buf));\nmsg.port = 9;\nvar euiMsg = { payload: eui };\nvar offsetMsg = { payload: offset };\n\nreturn [euiMsg, offsetMsg, deviceMsg, seqNoMsg, msg];",
"outputs": 5, "outputs": 5,
"noerr": 0, "noerr": 0,
"x": 350, "x": 350,
@ -384,4 +384,4 @@
"disabled": false, "disabled": false,
"hidden": false "hidden": false
} }
] ]