lib/couchdb.js

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 *
 * 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.
 */

/* jshint node: true */

"use strict";

var request = require('request');
var follow = require('follow');

var DEFAULT_COUCHDB_URI = "http://localhost";

var couchdbURI = DEFAULT_COUCHDB_URI;

function init(uri) {
    couchdbURI = uri;
}

// Generic interface + convenience functions for working with couch dbs
function db(name) {
    this.name = name;
    this.db_url = couchdbURI + '/' + this.name;
    this.is_following = false;
}

db.prototype = {
    get:function(id, callback) {
        // Gets a specific document by id

        var url = this.db_url + '/' + id;
        request.get(url, function(error, response, body) {
            if (error) {
                callback(error);
            } else {
                if (response.statusCode === 200) {
                    callback(false, JSON.parse(body));
                } else if (response.statusCode === 404) {
                    callback(true, 404);
                } else {
                    callback(true, response.statusCode);
                }
            }
        });
    },
    query_view:function(design, view, callback) {
        // Queries a view.

        var url = this.db_url + '/_design/' + design + '/_view/' + view;
        request.get(url, function(error, response, body) {
            if (error) {
                callback(error);
            } else {
                if (response.statusCode === 200) {
                    callback(false, JSON.parse(body));
                } else if (response.statusCode === 404) {
                    callback(true, 404);
                } else {
                    callback(true, response.statusCode);
                }
            }
        });
    },
    clobber:function(id, document, callback) {
        // Overwrites a document
        var url = this.db_url + '/' + id;

        request.put({
            url:url,
            json:document
        }, function(error, response, body) {
            if (error || response.statusCode === 404) {
                console.error('Request failed: ' + url);
                callback(true, JSON.stringify(body));
                return;
            }

            var status = response.statusCode;
            if (status === 201) {
                callback(false, body);
            } else if (status === 409) {
                request.get(url, function(err, resp, bod) {
                    if (err) {
                        callback(err);
                    } else {
                        if (resp.statusCode === 200) {
                            var existing = JSON.parse(bod);
                            var rev = existing._rev;
                            request.del({
                                url:url + '?rev=' + rev,
                            }, function(er, res, boday) {
                                if (er) {
                                    callback(er);
                                }  else {
                                    if (res.statusCode === 200) {
                                        request.put({
                                            url:url,
                                            json:document
                                        }, function(argh, r, bodee) {
                                            if (argh) {
                                                callback(argh);
                                            } else {
                                                if (r) {
                                                    if (r.statusCode === 201) {
                                                        callback(false, bodee);
                                                    } else {
                                                        callback(true, r.statusCode);
                                                    }
                                                } else {
                                                    callback(true,"URL failed?");
                                                }
                                            }
                                        });
                                    } else {
                                        callback(true, res.statusCode);
                                    }
                                }
                            });
                        } else {
                            callback(true, resp.statusCode);
                        }
                    }
                });
            } else {
                callback(true, response.statusCode);
            }

        });
    },
    follow:function(callback) {
        if (!this.is_following) {
            this.is_following = true;
            follow({
                db:this.db_url,
                since:'now',
                include_docs:true
            }, function(err, change) {
                if (!err) {
                    callback(false, change);
                } else {
                    callback(err);
                }
            });
            return true;
        } else {
            return false;
        }
    }
};

module.exports = {
    init: init,
    db:   db,
};