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nano

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Nano

Offical Apache CouchDB library for Node.js.

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

or save nano as a dependency of your project with

npm install --save nano

Table of contents

Getting started

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

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

The URL you supply may also contain authenication credentials e.g. http://admin:mypassword@localhost:5984.

To create a new database:

nano.db.create('alice');

and to use an existing database:

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({ happy: 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.

Promises

Although nano is written using the "callback" style, it is easy enough to switch to a "Promises" style, using the Bluebird library:

var Promise = require('bluebird');
var mydb = require('nano')('http://localhost:5984/animaldb');
 
// create Promise-compatible versions of all functions
Promise.promisifyAll(mydb);
 
// now we have "get" (callback compatible) and "getAsync" (Promise compatible)
animals.getAsync('doc1').then(function(doc) {
  console.log('the doc is', doc);
}).catch(console.error);

Configuration

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

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

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

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

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

You can tell nano to not parse the URL (maybe the server is behind a proxy, is accessed through a rewrite rule or other):

// nano does not parse the URL and return the server api
// "http://localhost:5984/prefix" is the CouchDB server root
var couch = require('nano')(
  { url : "http://localhost:5984/prefix"
    parseUrl : false
  });
var db = couch.use('foo');

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 requestDefaults to false, or adjust the global pool size using:

http.globalAgent.maxSockets = 20;

You can also increase the size in your calling context using requestDefaults 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",
    requestDefaults : { "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 information about the database name:

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

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

Destroys the database name:

nano.db.destroy('alice', function(err, body){
});

nano.db.list([callback])

Lists all the CouchDB databases:

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 to target with options opts. The targetdatabase has to exist, add create_target:true to opts to create it prior to replication:

nano.db.replicate('alice', 'http://admin:password@otherhost.com:5984/alice',
                  { create_target:true }, function(err, body) {
    if (!err)
      console.log(body);
});

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

Enables replication using the new CouchDB api from source to target with options opts. target has to exist, add create_target:true to opts to create it prior to replication. Replication will survive server restarts.

nano.db.replication.enable('alice', 'http://admin:password@otherhost.com:5984/alice',
                  { create_target:true }, function(err, body) {
    if (!err)
      console.log(body);
});

nano.db.replication.query(id, [opts], [callback])

Queries the state of replication using the new CouchDB API. The id comes from the response given by the call to replication.enable:

nano.db.replication.enable('alice', 'http://admin:password@otherhost.com:5984/alice',
                   { create_target:true }, function(err, body) {
    if (!err) {
      nano.db.replication.query(body.id, function(error, reply) {
        if (!err)
          console.log(reply);
      }
    }
});

nano.db.replication.disable(id, [opts], [callback])

Disables replication using the new CouchDB API. The id comes from the response given by the call to replication.enable:

nano.db.replication.enable('alice', 'http://admin:password@otherhost.com:5984/alice',
                   { create_target:true }, function(err, body) {
    if (!err) {
      nano.db.replication.disable(body.id, function(error, reply) {
        if (!err)
          console.log(reply);
      }
    }
});

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.db.info([callback])

Gets database information:

nano.db.info(function(err, body) {
  if (!err) {
    console.log('got database info'', body);
  }
});

nano.use(name)

Returns a database object that allows you to perform operations against that database:

var alice = nano.use('alice');
alice.insert({ happy: 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 custom request to CouchDB. This can be used to create your own HTTP request to the CouchDB server, to perform operations where there is no nano function that encapsulates it. 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.qs – query string parameters, appended after any existing opts.path, opts.doc, or opts.att
  • 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
  • opts.multipart – array of objects for multipart request

nano.relax(opts, [callback])

Alias for nano.request

nano.config

An object containing the nano configurations, possible keys are:

  • url - the CouchDB URL
  • db - the database name

nano.updates([params], [callback])

Listen to db updates, the available params are:

  • params.feed – Type of feed. Can be one of
  • longpoll: Closes the connection after the first event.
  • continuous: Send a line of JSON per event. Keeps the socket open until timeout.
  • eventsource: Like, continuous, but sends the events in EventSource format.
  • params.timeout – Number of seconds until CouchDB closes the connection. Default is 60.
  • params.heartbeat – Whether CouchDB will send a newline character (\n) on timeout. Default is true.

nano.followUpdates([params], [callback])

** changed in version 6 **

Use Follow to create a solid _db_updates feed. Please consult follow documentation for more information as this is a very complete api on it's own

var feed = nano.followUpdates({since: "now"});
feed.on('change', function (change) {
  console.log("change: ", change);
});
feed.follow();
process.nextTick(function () {
  nano.db.create('alice');
});

Document functions

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

Inserts doc in the database with optional params. If params is a string, it's assumed it is the intended document _id. If params is an object, it's passed as query string parameters and docName is checked for defining the document _id:

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

The insert function can also be used with the method signature db.insert(doc,[callback]), where the doc contains the _id field e.g.

var alice = nano.use('alice')
alice.insert({ _id: 'myid', happy: true }, function(err, body) {
  if (!err)
    console.log(body)
})

and also used to update an existing document, by including the _rev token in the document being saved:

var alice = nano.use('alice')
alice.insert({ _id: 'myid', _rev: '1-23202479633c2b380f79507a776743d5', happy: false }, function(err, body) {
  if (!err)
    console.log(body)
})

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

Removes a document from CouchDB whose _id is docname and who's revision is _rev:

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

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

Gets a document from CouchDB whose _id is docname:

alice.get('rabbit', function(err, body) {
  console.log(body);
});

or with optional query string params:

alice.get('rabbit', { revs_info: true }, function(err, body) {
  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])

Copies 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 e.g:

var documents = [
  { a:1, b:2 },
  { _id: 'tiger', striped: true}
];
alice.bulk({docs:documents}, function(err, body) {
  console.log(body);
});

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

List all the docs in the database .

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

or with optional query string additions params:

alice.list({include_docs: true}, function(err, body) {
  if (!err) {
    body.rows.forEach(function(doc) {
      // output eacj document's body
      console.log(doc.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.

var keys = ['tiger', 'zebra', 'donkey'];
alice.fetch({keys: keys}, function(err, data) {
  console.log(data);
});

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

** changed in version 6 **

Bulk fetch of the revisions of the database documents, docnames are specified as per CouchDB doc. additional query string params can be specified, this is the same method as fetch but include_docs is not automatically set to true.

Multipart functions

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

Inserts a doc together with attachments and params. If params is a string, it's assumed as the intended document _id. If params is an object, its passed as query string parameters and docName is checked for defining the _id. Refer to the doc for more details. The attachments parameter must be an array of objects with name, data and content_type properties.

var fs = require('fs');
 
fs.readFile('rabbit.png', function(err, data) {
  if (!err) {
    alice.multipart.insert({ foo: 'bar' }, [{name: 'rabbit.png', data: data, content_type: 'image/png'}], 'mydoc', function(err, body) {
        if (!err)
          console.log(body);
    });
  }
});

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

Get docname together with its attachments via multipart/related request with optional query string additions params. Refer to the doc for more details. The multipart response body is a Buffer.

alice.multipart.get('rabbit', function(err, buffer) {
  if (!err)
    console.log(buffer.toString());
});

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, [params], [callback])

changed in version 6

Destroy attachment attname of docname's revision rev.

alice.attachment.destroy('rabbit', 'rabbit.png',
    {rev: '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 designname with optional query string 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', 'happy_ones', {
  'key': 'Tea Party',
  'include_docs': true
}, function(err, body) {
  if (!err) {
    body.rows.forEach(function(doc) {
      console.log(doc.value);
    });
  }
});

or

alice.view('characters', 'soldiers', {
  'keys': ['Hearts', 'Clubs']
}, function(err, body) {
  if (!err) {
    body.rows.forEach(function(doc) {
      console.log(doc.value);
    });
  }
});

When params is not supplied, or no keys are specified, it will simply return all documents in the view:

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

db.viewWithList(designname, viewname, listname, [params], [callback])

Calls a list function fed by the given view from the specified design document.

alice.viewWithList('characters', 'happy_ones', 'my_list', function(err, body) {
  if (!err) {
    console.log(body);
  }
});

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

Calls a show function from 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");
});

Note that the data is sent in the body of the request. An example update handler follows:

"updates": {
  "in-place" : "function(doc, req) {
      var field = req.form.field;
      var value = req.form.value;
      var message = 'set '+field+' to '+value;
      doc[field] = value;
      return [doc, message];
  }"

db.search(designname, searchname, [params], [callback])

Calls a view of the specified design with optional query string additions params.

alice.search('characters', 'happy_ones', { q: 'cat' }, function(err, doc) {
  if (!err) {
    console.log(doc);
  }
});

Check out the tests for a fully functioning example.

using cookie authentication

Nano supports making requests using CouchDB's cookie authentication functionality. There's an example in coffeescript, 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 to
  if (headers && headers['set-cookie']) {
    auth = headers['set-cookie'];
  }
 
  callback(null, "it worked");
});

Getting current session:

var nano = require('nano')({url: 'http://localhost:5984', cookie: 'AuthSession=' + auth});
 
nano.session(function(err, session) {
  if (err) {
    return console.log('oh noes!')
  }
 
  console.log('user is %s and has these roles: %j',
    session.userCtx.name, session.userCtx.roles);
});

Advanced features

Getting uuids

If your application needs to generate UUIDs, then CouchDB can provide some for you

nano.uuids(3, callback);
// { uuid: [
// '5d1b3ef2bc7eea51f660c091e3dffa23',
// '5d1b3ef2bc7eea51f660c091e3e006ff',
// '5d1b3ef2bc7eea51f660c091e3e007f0',
//]}

The first parameter is the number of uuids to generate. If omitted, it defaults to 1.

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 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, examples in the wild & screencasts

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.

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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.