IMPORTANT - This module is no longer maintained

You should probably use cradle instead.

Node.js CouchDB module

A thin node.js idiom based module for CouchDB's REST API that tries to stay close to the metal.

Tutorial

Installation is simple:

$ cd ~/src
$ git clone git://github.com/felixge/node-couchdb.git
$ cd ~/.node_libraries
$ ln -s ~/src/node-couchdb couchdb

To use the library, create a new file called my-couch-adventure.js:

var
  sys = require('sys'),
  couchdb = require('couchdb'),
  client = couchdb.createClient(5984, 'localhost'),
  db = client.db('my-db');

db
  .saveDoc('my-doc', {awesome: 'couch fun'}, function(er, ok) {
    if (er) throw new Error(JSON.stringify(er));
    sys.puts('Saved my first doc to the couch!');
  });

db
  .getDoc('my-doc', function(er, doc) {
    if (er) throw new Error(JSON.stringify(er));
    sys.puts('Fetched my new doc from couch:');
    sys.p(doc);
  });

If you are wondering if there is a race-condition in the above example, the answer is no. Each couchdb.Client uses an internal queue for its requests, just like http.Client. This guarantees ordering. If you want to perform multiple requests at once, use multiple couchdb.Client instances.

API Documentation

Callbacks

All asynchronous functions are performed with callbacks. Callback functions are always the last argument, and always receive one or two arguments. The first argument is an error object or null if an error occurs. The second is the data returned by the function in question, if appropriate.

The callback argument is optional. If not supplied, then errors and return values will be silently ignored.

For example:

client.request('/_uuids', {count: 2}, function (er, data) {
  if (er) {
    // an error occurred.  Attempt to handle it or rethrow, or whatever.
  } else {
    // data is the result of the request.
  }
})

couchdb.toJSON(data)

Identical to JSON.stringify(), except that function values will be converted to strings like this:

couchdb.toJSON({
  foo: 'bar',
  fn: function(a, b) {
    p(a, b);
  }
})
// => {"foo":"bar","fn":"function (a, b) {\n    p(a, b);\n  }"}

node-couchdb uses this function everywhere for JSON serialization, this makes it convenient to embed functions.

couchdb.toQuery(query)

Identical to querystring.stringify(), except that boolean values will be converted to "true" / "false" strings like this:

couchdb.toQuery({
  include_docs: true
})
// => include_docs=true

node-couchdb uses this function everywhere for query serialization, this helps since couchdb expects boolean values in this format.

couchdb.toAttachment(file, cb)

Takes the path of a file and callback receives a JS object suitable for inline document attachment:

couchdb
  .toAttachment(__filename, function(er, r) {
    if (er) throw new Error(JSON.stringify(er));
    // r => {"content_type":"text/javascript","data":"dmFyCiAgs...="}
  });

Check lib/dep/mime.js for a list of recognized file types.

couchdb.createClient([port, host, user, pass])

Creates a new couchdb.Client for a given port (default: 5984) and host (default: 'localhost'). This client will queue all requests that are send through it, so ordering of requests is always guaranteed. Use multiple clients for parallel operations.

If the optional user and pass arguments are supplied, all requests will be made with HTTP Basic Authorization

client.host

The host this client is connecting to. READ-ONLY property

client.port

The port this client is connecting to. READ-ONLY property

client.request(path, [query], cb)

Sends a GET request with a given path and query. Callback receives a result object. Example:

client.request('/_uuids', {count: 2})

client.request(method, [path, query])

Sends a request with a given method, path and query. Callback receives a result object. Example:

client.request('get', '/_uuids', {count: 2})

client.request(options, cb)

Sends a request using the given options and callback receives a result object. Available options are:

• method: The HTTP method (default: 'GET')
• path: The request path (default: '/')
• headers: Additional http headers to send (default: {})
• data: A JS object or string to send as the request body (default: '')
• query: The query options to use (default: {}).
• requestEncoding: The encoding to use for sending the request (default: 'utf8')
• responseEncoding: The encoding to use for sending the request. If set to 'binary', the response is emitted as a string instead of an object and the full option is ignored. (default: 'utf8')
• full: By default the callback receives the parsed JSON as a JS object. If full is set to true, a {headers: ..., json: ...} object is yielded instead. (default: false)

Example:

client.request({
  path: '/_uuids',
  query: {count: 5},
  full: true
}, callback);

client.allDbs()

Wrapper for GET /_all_dbs.

client.config()

Wrapper for GET /_config.

client.uuids([count])

Wrapper for GET /_uuids. count is the number of uuid's you would like CouchDB to generate for you.

client.replicate(source, target, [options])

Wrapper for POST /_replicate. source and target are references to the databases you want to synchronize, options can include additional keys such as {create_target:true}.

client.stats([group, key])

Wrapper for GET /_stats. group and key can be used to limit the stats to fetch.

client.activeTasks()

Wrapper for GET /_active_tasks.

client.db(name)

Creates a new couchdb.Db instance for a database with the given name.

db.name

The name of the db this instance is tied to. READ-ONLY property

db.client

A reference to the couchdb.Client this instance is tied to. READ-ONLY property

db.request(options)

Same as client.request, but the path option gets automatically prefixed by '/db-name'.

db.exists(cb)

Callback called with a boolean indicating whether this db exists or not.

db.info(cb)

Wrapper for GET /db-name.

db.create(cb)

Wrapper for PUT /db-name.

db.remove()

Wrapper for DELETE /db-name.

db.getDoc(id)

Wrapper for GET /db-name/doc-id. Fetches a document with a given id from the database.

db.saveDoc(id, doc)

Wrapper for PUT /db-name/doc-id. Saves a json doc with a given id.

db.saveDoc(doc)

Same as the above, but the id can either a property of doc, or omitted to let CouchDB generate a uuid for this new document.

db.removeDoc(id, rev)

Deletes document id with rev from the db.

db.copyDoc(srcId, destId, [destRev])

Copies document srcId to destId. If destId already exists, you need to supply destRev to overwrite it.

db.bulkDocs(data)

Wrapper for POST /db-name/_bulk_docs.

db.saveDesign(design, doc)

A convenience wrapper for saveDoc() that prefixes the document id with '_design/'+design. Useful for storing views like this:

db
  .saveDesign('my-design', {
    views: {
      "my-view": {
        map: function() {
          emit(null, null)
        }
      }
    }
  })

db.saveAttachment(file, docId, options)

Attaches a file to a given docId. Available options:

• name: The name of the attachment. (default: path.basename(file))
• contentType: The content type to associate with this attachment (default: see lib/dep/mime.js)
• rev: If the docId already exists, you have to supply its current revision.

db.removeAttachment(docId, attachmentId, docRev)

Delete attachment attachmentId from doc docId with docRev.

db.getAttachment(docId, attachmentId, cb)

Loads the attachment attachmentId from docId. The callback receivesthe binary content of the attachment. There is no streaming, don't use this with large files.

db.allDocs(query)

Wrapper for GET /db-name/_all_docs. query allows to specify options for this view.

db.allDocsBySeq(query)

Wrapper for GET /db-name/_all_docs_by_seq.

db.compact([design])

Wrapper for POST /db-name/_compact/design-name. design provides the name of the design to invoke compact for, otherwise the whole db is used.

db.tempView(data, query)

Wrapper for POST /db-name/_temp_view.

db.viewCleanup(data, query)

Wrapper for POST /db-name/_view_cleanup.

db.view(design, view, [query], [cb])

Wrapper for GET /db-name/_design/design-name/_view/view-name. Fetches all documents for the given design and view with the specified query options.

db.list(design, list, view, [query], [cb])

Wrapper for GET /db-name/_design/design-name/_list/list-name/view-name. Fetches all documents for the given design and view with the specified query options.

db.changes([query])

Wrapper for GET /db-name/_changes. This can be used for long-polling or one-time retrieval from the changes feed. If you want to get a continuous stream of changes, use the db.changesStream() function instead.

db.changesStream([query])

Returns an events.EventEmitter stream that emits the following events:

• data(change): Emitted for each change line in the stream. The change parameter holds the change object.
• heartbeat: Emitted for each heartbeat send by CouchDB, no need to check this for most stuff.
• end(hadError): Emitted if the stream ends. This should not happen unless you manually invoke stream.end().

See the CouchDB docs for available query parameters.

Important: This function uses its own http client for making requests, so unlike all other functions it does not go through the internal request queue.

Todo

• http status, message and parsed body for errors
• db.saveAttachment(file, docId, options) take file descriptor
• Implement Authentication

Limitations

• Streaming attachments is not supported at this point (patches welcome)
• Etags are only available via client.request({full: true})