node-red/nodes/core/storage/28-tail.js

70 lines
2.1 KiB
JavaScript

/**
* Copyright 2013, 2014 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
**/
module.exports = function(RED) {
"use strict";
var spawn = require('child_process').spawn;
var plat = require('os').platform();
if (plat.match(/^win/)) {
throw "Info : Currently not supported on Windows.";
}
function TailNode(n) {
RED.nodes.createNode(this,n);
this.filename = n.filename;
this.split = n.split;
var node = this;
var err = "";
// TODO: rewrite to use node-tail
var tail = spawn("tail", ["-F", "-n", "0", this.filename]);
tail.stdout.on("data", function (data) {
if (node.split) {
// TODO: allow customisation of the line break - as we do elsewhere
var strings = data.toString().split("\n");
for (var s in strings) {
//TODO: should we really filter blanks? Is that expected?
if (strings[s] !== "") {
node.send({
topic: node.filename,
payload: strings[s]
});
}
}
}
else {
var msg = {
topic:node.filename,
payload: data.toString()
};
node.send(msg);
}
});
tail.stderr.on("data", function(data) {
node.error(data.toString());
});
this.on("close", function() {
if (tail) { tail.kill(); }
});
}
RED.nodes.registerType("tail",TailNode);
}