DocumentServer-v-9.2.0/web-apps/apps/common/checkExtendedPDF.js

/*
 * (c) Copyright Ascensio System SIA 2010-2024
 *
 * This program is a free software product. You can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License (AGPL)
 * version 3 as published by the Free Software Foundation. In accordance with
 * Section 7(a) of the GNU AGPL its Section 15 shall be amended to the effect
 * that Ascensio System SIA expressly excludes the warranty of non-infringement
 * of any third-party rights.
 *
 * This program is distributed WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For
 * details, see the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
 *
 * You can contact Ascensio System SIA at 20A-6 Ernesta Birznieka-Upish
 * street, Riga, Latvia, EU, LV-1050.
 *
 * The  interactive user interfaces in modified source and object code versions
 * of the Program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU AGPL version 3.
 *
 * Pursuant to Section 7(b) of the License you must retain the original Product
 * logo when distributing the program. Pursuant to Section 7(e) we decline to
 * grant you any rights under trademark law for use of our trademarks.
 *
 * All the Product's GUI elements, including illustrations and icon sets, as
 * well as technical writing content are licensed under the terms of the
 * Creative Commons Attribution-ShareAlike 4.0 International. See the License
 * terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode
 *
 */
function checkExtendedPDF(directUrl, key, url, token, callback) {
    //110 is not enough for the new PDF form    
    var limit = 300;
    if (directUrl) {
        downloadPartialy(directUrl, limit, null, function(text) {
            callback(isExtendedPDFFile(text))
        });
    } else {
        let postData = JSON.stringify({
            'url': url,
            "token": token
        });
        var handlerUrl = "../../../../downloadfile/"+encodeURIComponent(key);
        downloadPartialy(handlerUrl, limit, postData, function(text) {
            callback(isExtendedPDFFile(text))
        });
    }
}
function isExtendedPDFFile(text) {
    if (!text) {
        return false;
    }
    const indexFirst = text.indexOf('%\xCD\xCA\xD2\xA9\x0D');
    if (indexFirst === -1) {
        return false;
    }

    let pFirst = text.substring(indexFirst + 6);

    if (!(pFirst.lastIndexOf('1 0 obj\x0A<<\x0A', 0) === 0)) {
        return false;
    }

    pFirst = pFirst.substring(11);

    let signature = 'ONLYOFFICEFORM';
    const indexStream = pFirst.indexOf('stream\x0D\x0A');
    const indexMeta = pFirst.indexOf(signature);

    if (indexStream === -1 || indexMeta === -1 || indexStream < indexMeta) {
        return false;
    }

    let pMeta = pFirst.substring(indexMeta);
    pMeta = pMeta.substring(signature.length + 3);

    let indexMetaLast = pMeta.indexOf(' ');
    if (indexMetaLast === -1) {
        return false;
    }

    pMeta = pMeta.substring(indexMetaLast + 1);

    indexMetaLast = pMeta.indexOf(' ');
    if (indexMetaLast === -1) {
        return false;
    }

    return true;
}
function downloadPartialy(url, limit, postData, callback) {
    var callbackCalled = false;
    var xhr = new XMLHttpRequest();
    //value of responseText always has the current content received from the server, even if it's incomplete
    // xhr.responseType = "json"; it raises an IE error. bug 66160
    xhr.overrideMimeType('text/plain; charset=iso-8859-1');
    xhr.onreadystatechange = function () {
        if (callbackCalled) {
            return;
        }
        if (xhr.readyState === 4) {
            callbackCalled = true;
            callback(xhr.responseText);
        } else if (xhr.readyState === 3 && xhr.responseText.length >= limit) {
            callbackCalled = true;
            var res = xhr.responseText;
            xhr.abort();
            callback(res);
        }
    };
    let method = postData ? 'POST' : 'GET';
    xhr.open(method, url, true);
    xhr.setRequestHeader('Range', 'bytes=0-' + limit); // the bytes (incl.) you request
    xhr.send(postData);
}

var startCallback;
var eventFn = function(msg) {
    if (msg.origin !== window.parentOrigin && msg.origin !== window.location.origin && !(msg.origin==="null" && (window.parentOrigin==="file://" || window.location.origin==="file://"))) return;

    var data = msg.data;
    if (Object.prototype.toString.apply(data) !== '[object String]' || !window.JSON) {
        return;
    }
    try {
        data = window.JSON.parse(data)
    } catch(e) {
        data = '';
    }

    if (data && data.command==="checkParams") {
        data = data.data || {};
        checkExtendedPDF(data.directUrl, data.key, data.url, data.token, startCallback);
        _unbindWindowEvents();
    }
};

var _bindWindowEvents = function() {
    if (window.addEventListener) {
        window.addEventListener("message", eventFn, false)
    } else if (window.attachEvent) {
        window.attachEvent("onmessage", eventFn);
    }
};

var _unbindWindowEvents = function() {
    if (window.removeEventListener) {
        window.removeEventListener("message", eventFn)
    } else if (window.detachEvent) {
        window.detachEvent("onmessage", eventFn);
    }
};

function listenApiMsg(callback) {
    startCallback = callback;
    _bindWindowEvents();
}