postgres log outputter

pgrecon.js

var fs    = require("fs"),
    spawn = require('child_process').spawn;
    
var filename = process.ARGV[2];

if (!filename)
  return console.log("Usage: node <pgrecon.js> <filename>");

var tail = spawn("tail", ["-f", filename]);
console.log("start tailing");

var state = {
  line: [],
  part: '',
  quoted: false,
  slice_from: 0,
  capture: function(data,index) {
    if (this.quoted) return(false);
    // capture slice without surrounding quotes
    if (data[this.slice_from]==34) this.slice_from++;
    this.part += data.slice(this.slice_from,data[index-1] == 34 ? index-1 : index).toString();
    this.line.push(this.part);
    this.part = '';
    this.slice_from = index+1;
    return(true);
  },
  line_complete: function() {
    tail.emit('line',this.line);
    this.line = [];
    this.part = '';
    this.quoted = false;
  }
}

tail.on("line", function (line) {
  console.log(line);
});

tail.stdout.on("data", function (data) {
  state.slice_from = 0;
  for (var i=0,len=data.length;i<len;i++) {
    switch(data[i]) {
      case 10: //line feed
        if (state.capture(data,i)) state.line_complete();
        break;
      case 44: //comma
        state.capture(data,i);
        break;
      case 34: //quote
       state.quoted = !state.quoted;
       break;
    }
  }
});