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node-red-nodes/storage/leveldb/67-leveldb.js
2016-11-06 20:26:19 +00:00

82 lines
2.8 KiB
JavaScript

module.exports = function(RED) {
"use strict";
var lvldb = require('level');
function LevelNode(n) {
RED.nodes.createNode(this,n);
this.dbname = n.db;
this.ready = false;
var node = this;
lvldb(this.dbname, function(err, db) {
if (err) { node.error(err); }
node.db = db;
node.db.on('ready', function() { node.ready = true; });
node.db.on('closing', function() { node.ready = false; });
});
node.on('close', function() {
if (node.db) {
node.ready = false;
node.db.close();
}
});
}
RED.nodes.registerType("leveldbase",LevelNode);
function LevelDBNodeIn(n) {
RED.nodes.createNode(this,n);
this.level = n.level;
this.levelConfig = RED.nodes.getNode(this.level);
var node = this;
node.on("input", function(msg) {
if (node.levelConfig && node.levelConfig.ready) {
var key = msg.topic.toString();
if (key && (key.length > 0)) {
node.levelConfig.db.get(msg.topic, function(err, value) {
if (err) {
//node.warn(err);
// for some reason they treat nothing found as an error...
msg.payload = null; // so we should return null
}
else { msg.payload = value; }
node.send(msg);
});
}
else { node.error("Cannot make key string from msg.topic"); }
}
else { node.error("Database not ready",msg); }
});
}
RED.nodes.registerType("leveldb in",LevelDBNodeIn);
function LevelDBNodeOut(n) {
RED.nodes.createNode(this,n);
this.level = n.level;
this.operation = n.operation;
this.levelConfig = RED.nodes.getNode(this.level);
var node = this;
node.on("input", function(msg) {
if (node.levelConfig && node.levelConfig.ready) {
var key = msg.topic.toString();
if (key && (key.length > 0)) {
if (node.operation === "delete") {
node.levelConfig.db.del(msg.topic);
}
else {
node.levelConfig.db.put(msg.topic, msg.payload, function(err) {
if (err) { node.error(err); }
});
}
}
else { node.error("Cannot make key string from msg.topic"); }
}
else { node.error("Database not ready",msg); }
});
}
RED.nodes.registerType("leveldb out",LevelDBNodeOut);
}