pdfobject/pdfobject.js

/**
 *  PDFObject v2.2.6
 *  https://github.com/pipwerks/PDFObject
 *  @license
 *  Copyright (c) 2008-2021 Philip Hutchison
 *  MIT-style license: http://pipwerks.mit-license.org/
 *  UMD module pattern from https://github.com/umdjs/umd/blob/master/templates/returnExports.js
 */

(function (root, factory) {
    if (typeof define === "function" && define.amd) {
        // AMD. Register as an anonymous module.
        define([], factory);
    } else if (typeof module === "object" && module.exports) {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like environments that support module.exports,
        // like Node.
        module.exports = factory();
    } else {
        // Browser globals (root is window)
        root.PDFObject = factory();
  }
}(this, function () {

    "use strict";

    //PDFObject is designed for client-side (browsers), not server-side (node)
    //Will choke on undefined navigator and window vars when run on server
    //Return boolean false and exit function when running server-side

    if( typeof window === "undefined" || 
        window.navigator === undefined || 
        window.navigator.userAgent === undefined || 
        window.navigator.mimeTypes === undefined){ 
            return false;
    }

    let pdfobjectversion = "2.2.6";
    let nav = window.navigator;
    let ua = window.navigator.userAgent;

    //Time to jump through hoops -- browser vendors do not make it easy to detect PDF support.

    /*
        IE11 still uses ActiveX for Adobe Reader, but IE 11 doesn't expose window.ActiveXObject the same way 
        previous versions of IE did. window.ActiveXObject will evaluate to false in IE 11, but "ActiveXObject" 
        in window evaluates to true.

        MS Edge does not support ActiveX so this test will evaluate false
    */
    let isIE = ("ActiveXObject" in window);

    /*
        There is a coincidental correlation between implementation of window.promises and native PDF support in desktop browsers
        We use this to assume if the browser supports promises it supports embedded PDFs
        Is this fragile? Sort of. But browser vendors removed mimetype detection, so we're left to improvise
    */
    let isModernBrowser = (window.Promise !== undefined);

    //Older browsers still expose the mimeType
    let supportsPdfMimeType = (nav.mimeTypes["application/pdf"] !== undefined);

    //Safari on iPadOS doesn't report as 'mobile' when requesting desktop site, yet still fails to embed PDFs
    let isSafariIOSDesktopMode = (  nav.platform !== undefined && 
                                    nav.platform === "MacIntel" && 
                                    nav.maxTouchPoints !== undefined && 
                                    nav.maxTouchPoints > 1 );

    //Quick test for mobile devices.
    let isMobileDevice = (isSafariIOSDesktopMode || /Mobi|Tablet|Android|iPad|iPhone/.test(ua));

    //Safari desktop requires special handling 
    let isSafariDesktop = ( !isMobileDevice && 
                            nav.vendor !== undefined && 
                            /Apple/.test(nav.vendor) && 
                            /Safari/.test(ua) );
    
    //Firefox started shipping PDF.js in Firefox 19. If this is Firefox 19 or greater, assume PDF.js is available
    let isFirefoxWithPDFJS = (!isMobileDevice && /irefox/.test(ua) && ua.split("rv:").length > 1) ? (parseInt(ua.split("rv:")[1].split(".")[0], 10) > 18) : false;


    /* ----------------------------------------------------
       Supporting functions
       ---------------------------------------------------- */

    let createAXO = function (type){
        var ax;
        try {
            ax = new ActiveXObject(type);
        } catch (e) {
            ax = null; //ensure ax remains null
        }
        return ax;
    };

    //If either ActiveX support for "AcroPDF.PDF" or "PDF.PdfCtrl" are found, return true
    //Constructed as a method (not a prop) to avoid unneccesarry overhead -- will only be evaluated if needed
    let supportsPdfActiveX = function (){ return !!(createAXO("AcroPDF.PDF") || createAXO("PDF.PdfCtrl")); };

    //Determines whether PDF support is available
    let supportsPDFs = (
        //As of Sept 2020 no mobile browsers properly support PDF embeds
        !isMobileDevice && (
            //We're moving into the age of MIME-less browsers. They mostly all support PDF rendering without plugins.
            isModernBrowser ||
            //Modern versions of Firefox come bundled with PDFJS
            isFirefoxWithPDFJS ||
            //Browsers that still support the original MIME type check
            supportsPdfMimeType ||
            //Pity the poor souls still using IE
            (isIE && supportsPdfActiveX())
        )
    );

    //Create a fragment identifier for using PDF Open parameters when embedding PDF
    let buildURLFragmentString = function(pdfParams){

        let string = "";
        let prop;

        if(pdfParams){

            for (prop in pdfParams) {
                if (pdfParams.hasOwnProperty(prop)) {
                    string += encodeURIComponent(prop) + "=" + encodeURIComponent(pdfParams[prop]) + "&";
                }
            }

            //The string will be empty if no PDF Params found
            if(string){

                string = "#" + string;

                //Remove last ampersand
                string = string.slice(0, string.length - 1);

            }

        }

        return string;

    };

    let embedError = function (msg, suppressConsole){
        if(!suppressConsole){
            console.log("[PDFObject] " + msg);
        }
        return false;
    };

    let emptyNodeContents = function (node){
        while(node.firstChild){
            node.removeChild(node.firstChild);
        }
    };

    let getTargetElement = function (targetSelector){

        //Default to body for full-browser PDF
        let targetNode = document.body;

        //If a targetSelector is specified, check to see whether
        //it's passing a selector, jQuery object, or an HTML element

        if(typeof targetSelector === "string"){

            //Is CSS selector
            targetNode = document.querySelector(targetSelector);

        } else if (window.jQuery !== undefined && targetSelector instanceof jQuery && targetSelector.length) {

            //Is jQuery element. Extract HTML node
            targetNode = targetSelector.get(0);

        } else if (targetSelector.nodeType !== undefined && targetSelector.nodeType === 1){

            //Is HTML element
            targetNode = targetSelector;

        }

        return targetNode;

    };

    let generatePDFJSMarkup = function (targetNode, url, pdfOpenFragment, PDFJS_URL, id, omitInlineStyles){

        //Ensure target element is empty first
        emptyNodeContents(targetNode);

        let fullURL = PDFJS_URL + "?file=" + encodeURIComponent(url) + pdfOpenFragment;
        let div = document.createElement("div");
        let iframe = document.createElement("iframe");
        
        iframe.src = fullURL;
        iframe.className = "pdfobject";
        iframe.type = "application/pdf";
        iframe.frameborder = "0";
        iframe.allow = "fullscreen";
        
        if(id){
            iframe.id = id;
        }

        if(!omitInlineStyles){
            div.style.cssText = "position: absolute; top: 0; right: 0; bottom: 0; left: 0;";
            iframe.style.cssText = "border: none; width: 100%; height: 100%;";
            targetNode.style.position = "relative";
            targetNode.style.overflow = "auto";        
        }

        div.appendChild(iframe);
        targetNode.appendChild(div);
        targetNode.classList.add("pdfobject-container");
        
        return targetNode.getElementsByTagName("iframe")[0];

    };

    let generatePDFObjectMarkup = function (embedType, targetNode, targetSelector, url, pdfOpenFragment, width, height, id, title, omitInlineStyles){

        //Ensure target element is empty first
        emptyNodeContents(targetNode);

        let embed = document.createElement(embedType);
        embed.src = url + pdfOpenFragment;
        embed.className = "pdfobject";
        embed.type = "application/pdf";
        embed.title = title;

        if(id){
            embed.id = id;
        }

        if(embedType === "iframe"){
            embed.allow = "fullscreen";
        }

        if(!omitInlineStyles){

            let style = (embedType === "embed") ? "overflow: auto;" : "border: none;";

            if(targetSelector && targetSelector !== document.body){
                style += "width: " + width + "; height: " + height + ";";
            } else {
                style += "position: absolute; top: 0; right: 0; bottom: 0; left: 0; width: 100%; height: 100%;";
            }

            embed.style.cssText = style; 

        }

        targetNode.classList.add("pdfobject-container");
        targetNode.appendChild(embed);

        return targetNode.getElementsByTagName(embedType)[0];

    };

    let embed = function(url, targetSelector, options){

        //If targetSelector is not defined, convert to boolean
        let selector = targetSelector || false;

        //Ensure options object is not undefined -- enables easier error checking below
        let opt = options || {};

        //Get passed options, or set reasonable defaults
        let id = (typeof opt.id === "string") ? opt.id : "";
        let page = opt.page || false;
        let pdfOpenParams = opt.pdfOpenParams || {};
        let fallbackLink = opt.fallbackLink || true;
        let width = opt.width || "100%";
        let height = opt.height || "100%";
        let title = opt.title || "Embedded PDF";
        let assumptionMode = (typeof opt.assumptionMode === "boolean") ? opt.assumptionMode : true;
        let forcePDFJS = (typeof opt.forcePDFJS === "boolean") ? opt.forcePDFJS : false;
        let supportRedirect = (typeof opt.supportRedirect === "boolean") ? opt.supportRedirect : false;
        let omitInlineStyles = (typeof opt.omitInlineStyles === "boolean") ? opt.omitInlineStyles : false;
        let suppressConsole = (typeof opt.suppressConsole === "boolean") ? opt.suppressConsole : false;
        let forceIframe = (typeof opt.forceIframe === "boolean") ? opt.forceIframe : false;
        let PDFJS_URL = opt.PDFJS_URL || false;
        let targetNode = getTargetElement(selector);
        let fallbackHTML = "";
        let pdfOpenFragment = "";
        let fallbackHTML_default = "<p>This browser does not support inline PDFs. Please download the PDF to view it: <a href='[url]'>Download PDF</a></p>";

        //Ensure URL is available. If not, exit now.
        if(typeof url !== "string"){ return embedError("URL is not valid", suppressConsole); }

        //If target element is specified but is not valid, exit without doing anything
        if(!targetNode){ return embedError("Target element cannot be determined", suppressConsole); }

        //page option overrides pdfOpenParams, if found
        if(page){ pdfOpenParams.page = page; }

        //Stringify optional Adobe params for opening document (as fragment identifier)
        pdfOpenFragment = buildURLFragmentString(pdfOpenParams);


        // --== Do the dance: Embed attempt #1 ==--

        //If the forcePDFJS option is invoked, skip everything else and embed as directed
        if(forcePDFJS && PDFJS_URL){
            return generatePDFJSMarkup(targetNode, url, pdfOpenFragment, PDFJS_URL, id, omitInlineStyles);
        }
 
        // --== Embed attempt #2 ==--

        //Embed PDF if traditional support is provided, or if this developer is willing to roll with assumption
        //that modern desktop (not mobile) browsers natively support PDFs 
        if(supportsPDFs || (assumptionMode && !isMobileDevice)){
            
            //Should we use <embed> or <iframe>? In most cases <embed>. 
            //Allow developer to force <iframe>, if desired
            //There is an edge case where Safari does not respect 302 redirect requests for PDF files when using <embed> element.
            //Redirect appears to work fine when using <iframe> instead of <embed> (Addresses issue #210)
            //Forcing Safari desktop to use iframe due to freezing bug in macOS 11 (Big Sur)
            let embedtype = (forceIframe || supportRedirect || isSafariDesktop) ? "iframe" : "embed";
            
            return generatePDFObjectMarkup(embedtype, targetNode, targetSelector, url, pdfOpenFragment, width, height, id, title, omitInlineStyles);

        }
        
        // --== Embed attempt #3 ==--
        
        //If everything else has failed and a PDFJS fallback is provided, try to use it
        if(PDFJS_URL){
            return generatePDFJSMarkup(targetNode, url, pdfOpenFragment, PDFJS_URL, id, omitInlineStyles);
        }
        
        // --== PDF embed not supported! Use fallback ==-- 

        //Display the fallback link if available
        if(fallbackLink){

            fallbackHTML = (typeof fallbackLink === "string") ? fallbackLink : fallbackHTML_default;
            targetNode.innerHTML = fallbackHTML.replace(/\[url\]/g, url);

        }

        return embedError("This browser does not support embedded PDFs", suppressConsole);

    };

    return {
        embed: function (a,b,c){ return embed(a,b,c); },
        pdfobjectversion: (function () { return pdfobjectversion; })(),
        supportsPDFs: (function (){ return supportsPDFs; })()
    };

}));