mmm: A JavaScript repository from docyes

//MMM... Minimal Metal Models for JavaScript

//Usage example of an MMM model
var geobit = new Geobit({longitude: 90, latitude: 70});
geobit.save(
    function(model){
        if(model.error.message){
            alert('big douche!');
        }else{
            alert('big success!');
        }
    }
);

//Implementation of a sample Model
function Geobit(options){
    mmm.Model.call(options);
    this.addField('longitude');
    this.addField('latitude');
    this.addField('raw');
    this.addField('acl_token');
}
Geobit.prototype = new mmm.Model;
Geobit.constructor = Geobit;
//not all REST api's are equal
Geobit.prototype.save = function(success, failure){
    var that = this;
    var method;
    var url;
    var fields;
    var body = {};
    if(this.getField('id')===undefined){
        method = 'POST';
        url = '/api/1.0/geobits';
        fields = ['raw', 'longitude', 'latitude', 'parent_id'];
        for(var postField in postFields){
            var field = this.getField(postField);
            if(field!==undefined){
                body[postField] = field;
            }
        }
    }else{
        method = 'PUT';
        url = '/api/1.0/geobits/' + this.getField('id');
        fields = ['raw', 'longitude', 'latitude', 'parent_id', 'acl_token']
        for(var putField in putFields){
            var field = this.getField(putField);
            if(field!==undefined){
                body[putField] = field;
            }
        }
    }
    GeobaconRESTAdapter.request(url, method, 
        function(response){
            Geobit.setFieldsFromResponse(model, response);
        }, 
        {body: body}
    );
};
//static helper for popluting model objects from a pre-formatted response
Geobit.setFieldsFromResponse = function(model, response){
    if('error' in response){
        model.error = response.error;
        return;
    }
    if(response.id){
        model.setField('id', response.id);
    }
    var properties = response.properties;
    if(properties){
        model.setField('raw', properties.raw);
        model.setField('parent_id', properties.parent_id);
        model.setField('acl_token', properties.acl_token);
    }
    var geometry = response.geometry;
    if(geometry && geometry.coordinates){
        var coordinates = geometry.coordinates;
        model.setField('longitude', coordinates[0]);
        model.setField('latitude', coordinates[1]);
    }
};
//retrieve a single item
Geobit.get = function(id, longitude, latitude, distance, callback){
    var url;
    var getParams;
    var path = '/api/1.0/geobits' + id;
    var params = {
        longitude: longitude,
        latitude: latitude,
        distance: distance
    };
    var model = new Geobit();
    for(var param in params){
        getParams += (getParams) ? '&' : '';
        getParams += encodeURIComponent(param) + '=' + encodeURIComponent(params[param]);
    }
    url = path + '?' + getParams;
    GeobaconRestAdapter.request(url, 'GET', function(response){
        Geobit.setFieldsFromResponse(model, response);
        callback(model);
    });
};
//simple adapater for making XHR requests and handling responses
var GeobaconRESTAdapter = {
    hostname: 'http://geobacon.com',
    request: function(url, method, callback, options){
        var body = {};
        var options = options || {};
        var url = this.hostname + path;
        if(options.body && (method=='POST' || method=='PUT')){
            body = options.body;
        }
        var xhr = $.ajax(url, {
            type: method, 
            data: body, 
            complete: function(xhr){
                GeobaconRESTAdapter.response(xhr, callback);
            }
        });
    },
    response: function(xhr, callback){
        var envelope = {};
        try {
            envelope = JSON.parse(xhr.responseText);
        }catch(e){
            envelope = {error: {message: 'Could not process request', params: []}};
        }
        callback(envelope);
    }
};
docyes/mmm
