fmbaucis/Controller/query/links.js

Build scalable REST APIs using the open source tools and standards you already know.

// __Dependencies__
var url = require('url');
var qs = require('querystring');
var deco = require('deco');

// __Module Definition__
var decorator = module.exports = function () {
    var controller = this;

    // Add "Link" header field, with some basic defaults
    controller.query('instance', '*', function (request, response, next) {
        if (controller.relations() === false) return next();

        var originalPath = request.originalUrl.split('?')[0];
        var originalPathParts = originalPath.split('/');
        var linkBase;

        originalPathParts.pop();
        linkBase = originalPathParts.join('/');

        response.links({
            collection: linkBase,
            search: linkBase,
            edit: linkBase + '/' + request.params.id,
            self: originalPath
        });

        next();
    });

    // Add "Link" header field, with some basic defaults (for collection routes)
    controller.query('collection', '*', function (request, response, next) {
        if (controller.relations() === false) return next();

        var originalPath = request.originalUrl.split('?')[0];
        // Used to create a link from current URL with new query string.
        var makeLink = function (query) {
            var newQuery = deco.merge(request.query, query);
            return originalPath + '?' + qs.stringify(newQuery);
        };
        // Response Link header links.
        var links = { search: originalPath, self: makeLink() };
        // Call this function to set response links then move on to next middleware.
        var done = function () { response.links(links), next() };

        // Add paging links unless these conditions are met.
        if (request.method !== 'GET') return done();
        if (!request.query.per_page) return done();

        controller.model().count(request.baucis.conditions, function (error, count) {
            if (error) return next(error);

            var per_page = Number(request.query.per_page);
            var page = Number(request.query.page) || 0;
            var total_pages = Math.ceil(count / per_page);
            links.first = makeLink({ page: 0 });
            links.last = makeLink({ page: Math.max(0, total_pages - 1) });

            if (page > 0) links.previous = makeLink({ page: page - 1 });
            if (page + 1 < total_pages) links.next = makeLink({ page: page + 1 });

            done();
        });
    });
};