nano

nano

minimalistic couchdb driver for node.js

nano features:

• minimalistic - there is only a minimum of abstraction between you and couchdb
• pipes - proxy requests from couchdb directly to your end user
• errors - errors are proxied directly from couchdb: if you know couchdb you already know nano

installation

1. install npm
2. npm install nano

getting started

to use nano you need to connect it to your couchdb install, to do that:

var nano = require('nano')('http://localhost:5984');

to create a new database:

nano.db.create('alice');

and to use it:

var alice = nano.db.use('alice');

in this examples we didn't specify a callback function, the absence of a callback means "do this, ignore what happens". in nano the callback function receives always three arguments:

• err - the error, if any
• body - the http response body from couchdb, if no error. json parsed body, binary for non json responses
• header - the http response header from couchdb, if no error

a simple but complete example using callbacks is:

var nano = require('nano')('http://localhost:5984');

// clean up the database we created previously
nano.db.destroy('alice', function() {
  // create a new database
  nano.db.create('alice', function() {
    // specify the database we are going to use
    var alice = nano.use('alice');
    // and insert a document in it
    alice.insert({ crazy: true }, 'rabbit', function(err, body, header) {
      if (err) {
        console.log('[alice.insert] ', err.message);
        return;
      }
      console.log('you have inserted the rabbit.')
      console.log(body);
    });
  });
});

if you run this example(after starting couchdb) you will see:

you have inserted the rabbit.
{ ok: true,
  id: 'rabbit',
  rev: '1-6e4cb465d49c0368ac3946506d26335d' }

you can also see your document in futon.

configuration

configuring nano to use your database server is as simple as:

var server = require('nano')('http://localhost:5984')
  , db     = server.use('foo')
  ;

however if you don't need to instrument database objects you can simply:

// nano parses the url and knows this is a database
var db = require('nano')('http://localhost:5984/foo');

you can also pass options to the require:

// nano parses the url and knows this is a database
var db = require('nano')('http://localhost:5984/foo');

to specify further configuration options you can pass an object literal instead:

// nano parses the url and knows this is a database
var db = require('nano')(
  { "url"             : "http://localhost:5984/foo"
  , "request_defaults" : { "proxy" : "http://someproxy" }
  , "log"             : function (id, args) { 
      console.log(id, args);
    }
  });

Please check request for more information on the defaults. They support features like cookie jar, proxies, ssl, etc.

pool size and open sockets

a very important configuration parameter if you have a high traffic website and are using nano is setting up the pool.size. by default, the node.js http global agent (client) has a certain size of active connections that can run simultaneously, while others are kept in a queue. pooling can be disabled by setting the agent property in request_defaults to false, or adjust the global pool size using:

http.globalAgent.maxSockets = 20;

you can also increase the size in your calling context using request_defaults if this is problematic. refer to the request documentation and examples for further clarification.

here's an example explicitly using the keep alive agent (installed using npm install agentkeepalive), especially useful to limit your open sockets when doing high-volume access to couchdb on localhost:

var agentkeepalive = require('agentkeepalive');
var myagent = new agentkeepalive({
    maxSockets: 50
  , maxKeepAliveRequests: 0
  , maxKeepAliveTime: 30000
  });

var db = require('nano')(
  { "url"              : "http://localhost:5984/foo"
  , "request_defaults" : { "agent" : myagent }
  });

database functions

nano.db.create(name, [callback])

creates a couchdb database with the given name.

nano.db.create('alice', function(err, body) {
  if (!err) {
    console.log('database alice created!');
  }
});

nano.db.get(name, [callback])

get informations about name.

nano.db.get('alice', function(err, body) {
  if (!err) {
    console.log(body);
  }
});

nano.db.destroy(name, [callback])

destroys name.

nano.db.destroy('alice');

even though this examples looks sync it is an async function.

nano.db.list([callback])

lists all the databases in couchdb

nano.db.list(function(err, body) {
  // body is an array
  body.forEach(function(db) {
    console.log(db);
  });
});

nano.db.compact(name, [designname], [callback])

compacts name, if designname is specified also compacts its views.

nano.db.replicate(source, target, [opts], [callback])

replicates source on target with options opts. target has to exist, add create_target:true to opts to create it prior to replication.

nano.db.replicate('alice', 'http://admin:[e-mail]:5984/alice',
                  { create_target:true }, function(err, body) {
    if (!err) 
      console.log(body);
});

nano.db.changes(name, [params], [callback])

asks for the changes feed of name, params contains additions to the query string.

nano.db.changes('alice', function(err, body) {
  if (!err) {
    console.log(body);
  }
});

nano.db.follow(name, [params], [callback])

uses follow to create a solid changes feed. please consult follow documentation for more information as this is a very complete api on it's own

var feed = db.follow({since: "now"});
feed.on('change', function (change) {
  console.log("change: ", change);
});
feed.follow();
process.nextTick(function () {
  db.insert({"bar": "baz"}, "bar");
});

nano.use(name)

creates a scope where you operate inside name.

var alice = nano.use('alice');
alice.insert({ crazy: true }, 'rabbit', function(err, body) {
  // do something
});

nano.db.use(name)

alias for nano.use

nano.db.scope(name)

alias for nano.use

nano.scope(name)

alias for nano.use

nano.request(opts, [callback])

makes a request to couchdb, the available opts are:

• opts.db – the database name
• opts.method – the http method, defaults to get
• opts.path – the full path of the request, overrides opts.doc and opts.att
• opts.doc – the document name
• opts.att – the attachment name
• opts.content_type – the content type of the request, default to json
• opts.headers – additional http headers, overrides existing ones
• opts.body – the document or attachment body
• opts.encoding – the encoding for attachments

nano.relax(opts, [callback])

alias for nano.request

nano.dinosaur(opts, [callback])

alias for nano.request

                _
              / '_)  WAT U SAY!
     _.----._/  /
    /          /
  _/  (   | ( |
 /__.-|_|--|_l

nano.config

an object containing the nano configurations, possible keys are:

• url - the couchdb url
• db - the database name

document functions

db.insert(doc, [params], [callback])

inserts doc in the database with optional params. if params is a string, its assumed as the intended document name. if params is an object, its passed as query string parameters and doc_name is checked for defining the document name.

var alice = nano.use('alice');
alice.insert({ crazy: true }, 'rabbit', function(err, body) {
  if (!err)
    console.log(body);
});

db.destroy(docname, rev, [callback])

removes revision rev of docname from couchdb.

alice.destroy('alice', '3-66c01cdf99e84c83a9b3fe65b88db8c0', function(err, body) {
  if (!err)
    console.log(body);
});

db.get(docname, [params], [callback])

gets docname from the database with optional query string additions params.

alice.get('rabbit', { revs_info: true }, function(err, body) {
  if (!err)
    console.log(body);
});

db.head(docname, [callback])

same as get but lightweight version that returns headers only.

alice.head('rabbit', function(err, _, headers) {
  if (!err)
    console.log(headers);
});

db.copy(src_doc, dest_doc, opts, [callback])

copy the contents (and attachments) of a document to a new document, or overwrite an existing target document

alice.copy('rabbit', 'rabbit2', { overwrite: true }, function(err, _, headers) {
  if (!err)
    console.log(headers);
});

db.bulk(docs, [params], [callback])

bulk operations(update/delete/insert) on the database, refer to the couchdb doc.

db.list([params], [callback])

list all the docs in the database with optional query string additions params.

alice.list(function(err, body) {
  if (!err) {
    body.rows.forEach(function(doc) {
      console.log(doc);
    });
  }
});

db.fetch(docnames, [params], [callback])

bulk fetch of the database documents, docnames are specified as per couchdb doc. additional query string params can be specified, include_docs is always set to true.

attachments functions

db.attachment.insert(docname, attname, att, contenttype, [params], [callback])

inserts an attachment attname to docname, in most cases params.rev is required. refer to the doc for more details.

var fs = require('fs');

fs.readFile('rabbit.png', function(err, data) {
  if (!err) {
    alice.attachment.insert('rabbit', 'rabbit.png', data, 'image/png',
      { rev: '12-150985a725ec88be471921a54ce91452' }, function(err, body) {
        if (!err)
          console.log(body);
    });
  }
});

or using pipe:

var fs = require('fs');

fs.createReadStream('rabbit.png').pipe(
    alice.attachment.insert('new', 'rab.png', null, 'image/png')
);

db.attachment.get(docname, attname, [params], [callback])

get docname's attachment attname with optional query string additions params.

var fs = require('fs');

alice.attachment.get('rabbit', 'rabbit.png', function(err, body) {
  if (!err) {
    fs.writeFile('rabbit.png', body);
  }
});

or using pipe:

var fs = require('fs');

alice.attachment.get('rabbit', 'rabbit.png').pipe(fs.createWriteStream('rabbit.png'));

db.attachment.destroy(docname, attname, rev, [callback])

destroy attachment attname of docname's revision rev.

alice.attachment.destroy('rabbit', 'rabbit.png',
    '1-4701d73a08ce5c2f2983bf7c9ffd3320', function(err, body) {
      if (!err)
        console.log(body);
});

views and design functions

db.view(designname, viewname, [params], [callback])

calls a view of the specified design with optional query string additions params. if you're looking to filter the view results by key(s) pass an array of keys, e.g { keys: ['key1', 'key2', 'key_n'] }, as params.

alice.view('characters', 'crazy_ones', function(err, body) {
  if (!err) {
    body.rows.forEach(function(doc) {
      console.log(doc.value);
    });
  }
});

db.show(designname, showname, doc_id, [params], [callback])

calls a show function of the specified design for the document specified by doc_id with optional query string additions params.

alice.show('characters', 'format_doc', '3621898430' function(err, doc) {
  if (!err) {
    console.log(doc);
  }
});

take a look at the couchdb wiki for possible query paramaters and more information on show functions.

db.atomic(designname, updatename, docname, [body], [callback])

calls the design's update function with the specified doc in input.

db.atomic("update", "inplace", "foobar", 
{field: "foo", value: "bar"}, function (error, response) {
  assert.equal(error, undefined, "failed to update");
  assert.equal(response.foo, "bar", "update worked");
});

check out the tests for a fully functioning example.

using cookie authentication

nano supports making requests using couchdb's cookie authentication functionality. there's a step-by-step guide here, but essentially you just:

var nano     = require('nano')('http://localhost:5984')
  , username = 'user'
  , userpass = 'pass'
  , callback = console.log // this would normally be some callback
  , cookies  = {} // store cookies, normally redis or something
  ;

nano.auth(username, userpass, function (err, body, headers) {
  if (err) { 
    return callback(err);
  }

  if (headers && headers['set-cookie']) {
    cookies[user] = headers['set-cookie'];
  }

  callback(null, "it worked");
});

reusing a cookie:

var auth = "some stored cookie"
  , callback = console.log // this would normally be some callback
  , alice = require('nano')(
    { url : 'http://localhost:5984/alice', cookie: 'AuthSession=' + auth });
  ;

alice.insert(doc, function (err, body, headers) {
  if (err) {
    return callback(err);
  }

  // change the cookie if couchdb tells us too
  if (headers && headers['set-cookie']) {
    auth = headers['set-cookie'];
  }

  callback(null, "it worked");
});

advanced features

extending nano

nano is minimalistic but you can add your own features with nano.request(opts, callback)

for example, to create a function to retrieve a specific revision of the rabbit document:

function getrabbitrev(rev, callback) {
  nano.request({ db: 'alice',
                 doc: 'rabbit',
                 method: 'get',
                 params: { rev: rev }
               }, callback);
}

getrabbitrev('4-2e6cdc4c7e26b745c2881a24e0eeece2', function(err, body) {
  if (!err) {
    console.log(body);
  }
});

pipes

you can pipe in nano like in any other stream.
for example if our rabbit document has an attachment with name picture.png (with a picture of our white rabbit, of course!) you can pipe it to a writable stream

var fs = require('fs'),
    nano = require('nano')('http://127.0.0.1:5984/');
var alice = nano.use('alice');
alice.attachment.get('rabbit', 'picture.png').pipe(fs.createWriteStream('/tmp/rabbit.png'));

then open /tmp/rabbit.png and you will see the rabbit picture.

tutorials & screencasts

• screencast: couchdb and nano
• article: nano - a minimalistic couchdb client for nodejs
• article: getting started with node.js and couchdb
• article: document update handler support
• article: nano 3
• article: securing a site with couchdb cookie authentication using node.js and nano
• article: adding copy to nano
• article: how to update a document with nano
• article: thoughts on development using couchdb with node.js

roadmap

check issues

tests

to run (and configure) the test suite simply:

cd nano
npm install
npm test

after adding a new test you can run it individually (with verbose output) using:

nano_env=testing node tests/doc/list.js list_doc_params

where list_doc_params is the test name.

meta

                _
              / _) roar! i'm a vegan!
       .-^^^-/ /
    __/       /
   /__.|_|-|_|     cannes est superb

• code: git clone git://github.com/dscape/nano.git
• home: http://github.com/dscape/nano
• bugs: http://github.com/dscape/nano/issues
• build:

(oo)--',- in caos

license

copyright 2011 nuno job <nunojob.com> (oo)--',--

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.html

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.