openfoodapi.js

/*
This is just a draft of what a JavaScript consumption of
OpenFood's API could be
*/

var PAGESIZE = 100;

var openfoodapi = openfoodapi || {
    REVISION: "ALPHA",
    IMAGES: "images",
    NUTRIENTS: "nutrients"
};

(function(global) {
    /*
        HELPERS
    */

    // Gets a value or a list of values and a name, and returns a string in the form
    // name=value1&name=value2=name=value3
    function array_to_query(values, name) {
        if (typeof values === "undefined" || values === null || typeof name !== "string") {
            return null;
        }
        if (!Array.isArray(values)) {
            includes = [values];
        }
        return values.map(function(value) {
            return name + "=" + value;
        }).join("&");
    }

    // AJAX helper
    function reach_url(method, url, headers, data, callback) {
        var xhttp = new XMLHttpRequest;
        xhttp.onreadystatechange = function() {
            if (this.readyState === 4) {
                if (typeof callback === "function") {
                    callback(this);
                }
            }
        };

        // Open connection
        xhttp.open(method, url, true);

        // Prepare POST data, if any
        var isPostWithData = method === 'POST' && data;
        if (isPostWithData) {
            xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
            if (typeof data !== 'string') data = JSON.stringify(data);
        }

        // Put headers
        if (Array.isArray(headers)) {
            for (var i = 0, n = headers.length; i < n; i++) {
                var header = headers[i];
                if (Array.isArray(header) && header.length === 2) {
                    xhttp.setRequestHeader(header[0], header[1]);
                }
            }
        }

        // Send request
        xhttp.send(isPostWithData ? data : null);
    }

    // Make a call to the endpoint and handle the response
    function requestURL(method, endpoint, kind, query, post_data, callback) {
        if (!callback) throw new Error('Callback is needed');
        var url = endpoint.host + "/api/v" + endpoint.version + "/" + kind + (query ? "?" + query.join("&") : "");
		console.log(url);
        // Authorization token is sent in the request header
        // Example: Authorization: Token token="582736451287365"
        var headers = [
            ["Authorization", 'Token token="' + endpoint.api_key + '"']
        ];

        function handler(ajax) {
            var me = this;
            var response;
            try {
                response = JSON.parse(ajax.responseText);
                function create_call(name) {
                    return function() {
                        reach_url(method, unescape(response.links[name]),  headers, post_data, me.bind(me));
                    };
                }
                response.next  = create_call('next');
                response.prev  = create_call('prev');
                response.first = create_call('first');
                response.last  = create_call('last');
            } catch (error) {
                response = ajax.responseText;
            }
            callback(response);
        }
        reach_url(method, url, headers, post_data, handler.bind(handler));
    }

    function requestPostURL(endpoint, kind, post_data, callback) {
        requestURL('POST', endpoint, kind, null, post_data, callback);
    }

    function requestProductURL(endpoint, id, includes, page_number, page_size, callback) {
        var query = [];
        includes = array_to_query(includes, "include");
        if (includes)    query.push(includes);
        if (page_number) query.push("page[number]=" + page_number);
        if (page_size)   query.push("page[size]=" + page_size);

        var kind = 'products';
        if (id) kind += "/";

        requestURL('GET', endpoint, kind, query, null, callback);
    }

    function requestSearchURL(endpoint, terms, callback) {
        requestPostURL(endpoint, "products/_search", terms, callback);
    }

    /*
        OpenFood API per se
    */
    var Endpoint = function(api_key, host, version) {
        if (!api_key) {
            console.error("OpenFood endpoints need an API key");
            return null;
        }
        //this.host = host || "https://openfood-staging.herokuapp.com";
        this.host = host || "https://www.openfood.ch";
        this.version = version || 2;
        this.api_key = api_key;
    };

    Endpoint.prototype.product = function(id, includes, callback) {
        requestProductURL(this, id, includes, null, null, function(response) {
            callback(response);
        });
    };

    Endpoint.prototype.products = function(page_number, page_size, callback) {
        requestProductURL(this, null, null, page_number, page_size, function(response) {
            callback(response);
        });
    };

    Endpoint.prototype.products_search= function(terms, pageNumber, callback) {
        var data = {
            _source: true,
			"from" : PAGESIZE*(pageNumber-1), "size" : PAGESIZE,
            query: {
				"dis_max": {
					queries: [
						{"wildcard": {"name_translations.de" : terms}},
						{"wildcard": {"name_translations.it" : terms}},
						{"wildcard": {"name_translations.fr" : terms}},
						{"wildcard": {"name_translations.en" : terms}}
					]
				}
			}
        };
		console.log(data);
        requestSearchURL(this, data, function(response) {
            callback(response);
        });
    };


    global.Endpoint = Endpoint;
})(openfoodapi);