oembed.js

import * as oembedUtils from './oembedUtils.js';
import cheerio from 'cheerio';

import * as entities from 'entities';
import * as URL from 'url';
import * as querystring from 'querystring';

const pxRe = /^([\d\.]+)(?:px)?$/;
const percentRe = /^([\d\.]+)%$/;

function fixOembedIframeAttributes(obj) {
    var result = {};
    for(var key in obj) {
        var value = obj[key];
        if (typeof value === 'string') {
            var m = value.match(pxRe);
            if (m) {
                // Convert string numbers to int.
                value = parseFloat(m[1]);
            } else if (key === 'width' || key === 'height') {
                m = value.match(percentRe);
                if (m) {
                    // Skip % value for width of height.
                    continue;
                }
            }
        }
        result[key] = value;
    }
    return result;
}

function _getOembedIframe(oembed) {

    if (typeof oembed._iframe === 'undefined') {

        var _iframe = null;
        
        if (oembed.html5 || oembed.html) {

            // Allow encoded entities if they start from $lt;
            var html = oembed.html5 || oembed.html; 
            if (/^<$/i.test(html)) {
                html = entities.decodeHTML(html);
            }

            var $container = cheerio('<div>');
            try {
                $container.html(html);
            } catch (ex) {}
            var $iframe = $container.find('iframe');

            if ($iframe.length === 2 && /<iframe>$/i.test(html)) { 
                // Forgive mis-closed iFrame tag
                $iframe = $iframe.first();
            }

            if ($iframe.length === 1) {
                _iframe = fixOembedIframeAttributes($iframe[0].attribs);
                _iframe.placeholder = oembed.thumbnail_url;
            }

        // When oembed is in fact iframe from domain fallbacks on oEmbedError
        } else if (oembed.src) {
            _iframe = oembed;
        }

        if (_iframe && _iframe.src) {
            var src = URL.parse(_iframe.src, true);
            _iframe.host = src.host;
            _iframe.pathname = src.pathname;
            _iframe.path = src.path;
            _iframe.query = src.query;
            _iframe.replaceQuerystring = function(params) {
                var qs = querystring.stringify({..._iframe.query, ...params});
                return _iframe.src.replace(/\?.*$/, '') + (qs ? '?' + qs : '');
            }
            _iframe.assignQuerystring = function(params) {
                var qs = querystring.stringify(params);
                return oembed._iframe.src.replace(/\?.*$/, '') + (qs ? '?' + qs : '');
            }
        } else {
            _iframe = null;
        }

        oembed._iframe = _iframe ? {..._iframe} : null;
    }    

    return oembed._iframe;
}

function getOembedIframe(oembed) {
    return function() {
        return _getOembedIframe(oembed);
    };
}

function getOembedIframeAttr(oembed) {
    return function(attr) {
        var iframe = _getOembedIframe(oembed);
        if (iframe) {
            return iframe[attr];
        }
    };
}

export default {

    provides: ['self', 'oembedError', '__oembedError'],

    getIframe: _getOembedIframe, // available via export for fallbacks as plugins['oembed'].getIframe(obj)

    getData: function(url, oembedLinks, options, cb) {

        var href = oembedLinks[0].href;

        var skip = CONFIG.SKIP_OEMBED_RE_LIST 
                && CONFIG.SKIP_OEMBED_RE_LIST.some(re => re.test(href)), 

            self_endpoint = CONFIG.SKIP_OEMBED_RE_LIST
                         && CONFIG.SKIP_OEMBED_RE_LIST.some(re => re.test(href));


        if (skip || self_endpoint) {
            return cb(null);
        }

        oembedUtils.getOembed(href, options, function(error, oembed) {

            if (error && !oembed) {
                return cb('Oembed error "'+ oembedLinks[0].href + '": ' + error, {
                    oembedError: error,
                    __oembedError: error // To enable fallbacks to optional meta
                });
            } else if (error && oembed) { // via  `options.parseErrorBody = true`
                return cb(null, {
                    oembedError: {
                        code: error, 
                        body: oembed
                    },
                    __oembedError: { // To enable fallbacks to optional meta
                        code: error, 
                        body: oembed
                    },
                });
            }

            var result = {
                oembed: Object.assign({
                    getIframe: getOembedIframe(oembed),
                    getIframeAttr: getOembedIframeAttr(oembed)
                }, oembed),
            };

            // If no oEmbed record for the domain - allow to be whitelisted by the oEmbed endpoint domian record.
            if (options.getWhitelistRecord) {
                var currentWhitelistRecord = options.getWhitelistRecord(url, {disableWildcard: true});
                var oembedWhitelistRecord = options.getWhitelistRecord(href, {exclusiveRel: 'oembed'});

                if (oembedWhitelistRecord 
                    && !oembedWhitelistRecord.isDefault 
                    && (!currentWhitelistRecord 
                        || !currentWhitelistRecord.oembed 
                        || currentWhitelistRecord.isDefault)
                    ) {
                    result.whitelistRecord = oembedWhitelistRecord;
                    result.oembed.domain = oembedWhitelistRecord.domain;
                }
            }

            cb(null, result);
        });
    }
};