pdfobject.js

/**
 *  PDFObject v2.3.0
 *  https://github.com/pipwerks/PDFObject
 *  @license
 *  Copyright (c) 2008-2024 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){ return false; }

    let pdfobjectversion = "2.3.0";
    let win = window;
    let nav = win.navigator;
    let ua = nav.userAgent;
    let suppressConsole = false;

    //Fallback validation when navigator.pdfViewerEnabled is not supported
    let isModernBrowser = function (){

        /*
           userAgent sniffing is not the ideal path, but most browsers revoked the ability to check navigator.mimeTypes 
           for security purposes. As of 2023, browsers have begun implementing navigator.pdfViewerEnabled, but older versions
           do not have navigator.pdfViewerEnabled or the ability to check navigator.mimeTypes. We're left with basic browser 
           sniffing and assumptions of PDF support based on browser vendor.
        */

        //Chromium has provided native PDF support since 2011.
        //Most modern browsers use Chromium under the hood: Google Chrome, Microsoft Edge, Opera, Brave, Vivaldi, Arc, and more.
        //Chromium uses the PDFium rendering engine, which is based on Foxit's PDF rendering engine.
        //Note that MS Edge opts to use a different PDF rendering engine. As of 2024, Edge uses a version of Adobe's Reader
        let isChromium = (win.chrome !== undefined);

        //Safari on macOS has provided native PDF support since 2009. 
        //This code snippet also detects the DuckDuckGo browser, which uses Safari/Webkit under the hood.
        let isSafari = (win.safari !== undefined || (nav.vendor !== undefined && /Apple/.test(nav.vendor) && /Safari/.test(ua)));

        //Firefox has provided PDF support via PDFJS since 2013.
        let isFirefox = (win.Mozilla !== undefined || /irefox/.test(ua));

        return isChromium || isSafari || isFirefox;  

    };

    /*
       Special handling for Internet Explorer 11.
       Check for ActiveX support, then whether "AcroPDF.PDF" or "PDF.PdfCtrl" are valid.
       IE11 uses ActiveX for Adobe Reader and other PDF plugins, but window.ActiveXObject will evaluate to false. 
       ("ActiveXObject" in window) evaluates to true.
       MS Edge does not support ActiveX so this test will evaluate false for MS Edge.
    */
    let validateAX = function (type){
        var ax = null;
        try {
            ax = new ActiveXObject(type);
        } catch (e) {
            //ensure ax remains null when ActiveXObject attempt fails
            ax = null;
        }
        return !!ax; //convert resulting object to boolean
    };

    let hasActiveXPDFPlugin = function (){ return ("ActiveXObject" in win) && (validateAX("AcroPDF.PDF") || validateAX("PDF.PdfCtrl")) };

    let checkSupport = function (){

        //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);

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

        //As of June 2023, no mobile browsers properly support inline PDFs. If mobile, just say no.
        if(isMobileDevice){ return false; }
        
        //Modern browsers began supporting navigator.pdfViewerEnabled in late 2022 and early 2023.
        let supportsPDFVE = (typeof nav.pdfViewerEnabled === "boolean");

        //If browser supports nav.pdfViewerEnabled and is explicitly saying PDFs are NOT supported (e.g. PDFJS disabled by user in Firefox), respect it.
        if(supportsPDFVE && !nav.pdfViewerEnabled){ return false; }

        return (supportsPDFVE && nav.pdfViewerEnabled) || isModernBrowser() || hasActiveXPDFPlugin();

    };

    //Determines whether PDF support is available
    let supportsPDFs = checkSupport();

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

        let string = "";
        let prop;
        let paramArray = [];
        let fdf = "";
        
        //The comment, viewrect, and highlight parameters require page to be set first. 

        //Check to ensure page is used if comment, viewrect, or highlight are specified
        if(pdfParams.comment || pdfParams.viewrect || pdfParams.highlight){

            if(!pdfParams.page){
                
                //If page is not set, use the first page
                pdfParams.page = 1;
                
                //Inform user that page needs to be set properly
                embedError("The comment, viewrect, and highlight parameters require a page parameter, but none was specified. Defaulting to page 1.");
            
            }

        }

        //Let's go ahead and ensure page is always the first parameter.
        if(pdfParams.page){
            paramArray.push("page=" + encodeURIComponent(pdfParams.page));
            delete pdfParams.page;
        }

        //FDF needs to be the last parameter in the string
        if(pdfParams.fdf){
            fdf = pdfParams.fdf;
            delete pdfParams.fdf;
        }
        
        //Add all other parameters, as needed
        if(pdfParams){

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

            //Add fdf as the last parameter, if needed
            if(fdf){
                paramArray.push("fdf=" + encodeURIComponent(fdf));
            }

            //Join all parameters in the array into a string
            string = paramArray.join("&");

            //The string will be empty if no PDF Parameters were provided
            //Only prepend the hash if the string is not empty
            if(string){
                string = "#" + string;
            }

        }

        return string;

    };

    let embedError = function (msg){
        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 (win.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 convertBase64ToDownloadableLink = function (b64, filename, targetNode, fallbackHTML) {

        //IE-11 safe version. More verbose than modern fetch()
        if (window.Blob && window.URL && window.URL.createObjectURL) {

            var xhr = new XMLHttpRequest();
            xhr.open('GET', b64, true);
            xhr.responseType = 'blob';
            xhr.onload = function() {

                if (xhr.status === 200) {
 
                    var blob = xhr.response;
                    var link = document.createElement('a');
                    link.innerText = "Download PDF";
                    link.href = URL.createObjectURL(blob);
                    link.setAttribute('download', filename);
                    targetNode.innerHTML = fallbackHTML.replace(/\[pdflink\]/g, link.outerHTML);

                }

            };

            xhr.send();
            
        }

    };


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

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

        let source = url;

        if(embedType === "pdfjs"){ 
            //If PDFJS_URL already contains a ?, assume querystring is in place, and use an ampersand to append PDFJS's file parameter
            let connector = (PDFJS_URL.indexOf("?") !== -1) ? "&" : "?"; 
            source = PDFJS_URL + connector + "file=" + encodeURIComponent(url) + pdfOpenFragment;
        } else {
            source += pdfOpenFragment;
        }

        let el = document.createElement("iframe");
        el.className = "pdfobject";
        el.type = "application/pdf";
        el.title = title;
        el.src = source;
        el.allow = "fullscreen";
        el.frameborder = "0";
        if(id){ el.id = id; }

        if(!omitInlineStyles){

            let style = "border: none;";

            if(targetNode !== document.body){
                //assign width and height to target node
                style += "width: " + width + "; height: " + height + ";";
            } else {
                //this is a full-page embed, use CSS to fill the viewport
                style += "position: absolute; top: 0; right: 0; bottom: 0; left: 0; width: 100%; height: 100%;";
            }

            el.style.cssText = style; 

        }

        //Allow developer to insert custom attribute on iframe element, but ensure it does not conflict with attributes used by PDFObject
        let reservedTokens = ["className", "type", "title", "src", "style", "id", "allow", "frameborder"];
        if(customAttribute && customAttribute.key && reservedTokens.indexOf(customAttribute.key) === -1){
            el.setAttribute(customAttribute.key, (typeof customAttribute.value !== "undefined") ? customAttribute.value : "");
        }

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

        return targetNode.getElementsByTagName("iframe")[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
        suppressConsole = (typeof opt.suppressConsole === "boolean") ? opt.suppressConsole : false;
        let id = (typeof opt.id === "string") ? opt.id : "";
        let page = opt.page || false;
        let pdfOpenParams = opt.pdfOpenParams || {};
        let fallbackLink = (typeof opt.fallbackLink === "string" || typeof opt.fallbackLink === "boolean") ? opt.fallbackLink : true;
        let width = opt.width || "100%";
        let height = opt.height || "100%";
        let title = opt.title || "Embedded PDF";
        let forcePDFJS = (typeof opt.forcePDFJS === "boolean") ? opt.forcePDFJS : false;
        let omitInlineStyles = (typeof opt.omitInlineStyles === "boolean") ? opt.omitInlineStyles : false;
        let PDFJS_URL = opt.PDFJS_URL || false;
        let targetNode = getTargetElement(selector);
        let pdfOpenFragment = "";
        let customAttribute = opt.customAttribute || {};
        let fallbackHTML_default = "<p>This browser does not support inline PDFs. Please download the PDF to view it: [pdflink]</p>";

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

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

        //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 generatePDFObjectMarkup("pdfjs", targetNode, url, pdfOpenFragment, width, height, id, title, omitInlineStyles, customAttribute, PDFJS_URL);
        }
 
        // --== Embed attempt #2 ==--

        //Embed PDF if support is detected, or if this is a relatively modern browser 
        if(supportsPDFs){
            return generatePDFObjectMarkup("iframe", targetNode, url, pdfOpenFragment, width, height, id, title, omitInlineStyles, customAttribute);
        }
        
        // --== Embed attempt #3 ==--
        
        //If everything else has failed and a PDFJS fallback is provided, try to use it
        if(PDFJS_URL){
            return generatePDFObjectMarkup("pdfjs", targetNode, url, pdfOpenFragment, width, height, id, title, omitInlineStyles, customAttribute, PDFJS_URL);
        }
        
        // --== PDF embed not supported! Use fallback ==-- 

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

            //If a custom fallback has been provided, handle it now
            if(typeof fallbackLink === "string"){

                //Ensure [url] is set in custom fallback
                targetNode.innerHTML = fallbackLink.replace(/\[url\]/g, url);

            } else {

                //If the PDF is a base64 string, convert it to a downloadable link
                if(url.indexOf("data:application/pdf;base64") !== -1){

                    //Asynchronously append the link to the targetNode
                    convertBase64ToDownloadableLink(url, "file.pdf", targetNode, fallbackHTML_default);
                
                } else {

                    //Use default fallback link
                    let link = "<a href='" + url + "'>Download PDF</a>";
                    targetNode.innerHTML = fallbackHTML_default.replace(/\[pdflink\]/g, link);

                }

            }

        }

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

    };

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

}));