tacodb

reusable leveldb server

Synopsis

tacodb wraps leveldbs in a server such that it would be possible to create a hosted service with it, that can be connected to via http and WebSockets.

You database is configured by writing a .js file, which is then bundled (a la browserify) and sent to the tacodb server via http.

Getting Started

start by installing tacodb

more examples

npm install -g tacodb

Then, create an customization file

//db.js
//creat a static http style interface to leveldb.
var static = require('level-static')
module.exports = function (db) {
  db.on('http_connection', static(db))
}

start the server locally.

tacodb local db.js --port 8080

echo hello | curl -sSNT . -X PUT http://localhost:8080/greeting
curl http://localhost:8080/greeting

connecting to tacodb/level via http

Create a database customization file... This will expose an http interface, that can store files inside leveldb.

simple http access

//examples/http/index.js
 
var static = require('level-static')
 
module.exports = function (db) {
  db.on('http_connection', static(db))
}
 

>tacodb local static.js --name static
listening on 8000

This starts a tacodb server running around your db.js file.

#http PUT hi = HELLO 
echo 'HELLO!' | curl -sSNT . localhost:8000/hi
#http GET hi 
curl localhost:8000/hi
HELLO!

Add real time logging

level-static extend the simple http example, so that we can track changes as they occur.

changes http with changes feed.

//examples/changes/index.js
 
var static   = require('level-static')
var through  = require('through')
var route    = require('tiny-route')
var live     = require('level-live-stream')
var stack    = require('stack')
 
module.exports = function (db) {
  //level-static creates a http handling middleware around leveldb.
  db.on('http_connection', stack(
    route.get('/_changes', function (req, res) {
      live(db)
        .pipe(through(function (data) {
          this.queue(JSON.stringify(data) + '\n')
        }))
        .pipe(res)
      req.resume()
    }),
    static(db)
  ))
}
 

start the server...

tacodb local ./index.js --name changes

Then, connect and stream changes like this:

curl localhost:8000/_changes

Then in another terminal:

echo 'Hi!' | curl -sSNT . localhost:8000/hi
echo 'whats up?' | curl -sSNT . localhost:8000/wazzup
echo 'Good Bye!' | curl -sSNT . localhost:8000/bye

connect to tacodb/level over websockets

Create a streaming connection with websockets!

server with websockets & multilevel:

//examples/ws/server.js
 
var multilevel = require('multilevel')
var fs         = require('fs')
var index
try {
  index = fs.readFileSync(__dirname + '/index.html','utf8')
} catch (err) {
  console.error("run `npm run build` to generate the html file")
  throw err
}
module.exports = function (db) {
  db.on('http_connection', function (req, res) {
    req.resume()
    res.end(index)
  })
  db.on('connection', function (stream) {
    console.log('connect')
    stream.pipe(multilevel.server(db)).pipe(stream)
  })
}
 

brower/node client with websockets

//examples/ws/client.js
 
 
var multilevel = require('multilevel')
var reconnect  = require('reconnect/sock')
 
//This client works from both the browser and in node!
//WebSockets everywhere!
 
//use `npm run build` to generate the index.html file.
 
var node = process.title != 'browser'
 
var log = (node ? console.log :
  function () {
    var data = [].slice.call(arguments).map(function (e) {
      return JSON.stringify(e, null, 2)
    }).join(' ')
    var pre = document.createElement('pre')
    pre.innerText = data
    document.body.appendChild(pre)
  })
 
reconnect(function(stream) {
  log('connected!')
  var db = multilevel.client()
  stream.pipe(db).pipe(stream)
 
  setInterval(function () {
    db.put('hi', new Date(), function (err) {
      if(err) return console.error(err)
      db.get('hi', function (err, value) {
        if(err) return console.error(err)
        log('GET', 'hi', value)
      })
    })
  }, 1000)
 
}).connect(node ? 'http://localhost:8000/ws/ws' : '/ws/ws')
//^ on the browser, this assumes you are on the same host as window.location...
 

this client can be used from both the browser and node.js!

running the server & client

start the server

tacodb local server.js --name ws

connect from node:

node client.js

or from the browser

License

MIT