Generating and zipping pdf from a visualforce page (salesforce)

README.md

• Tested on Firefox only
• zip_js is a static resource downloaded from https://github.com/gildas-lormeau/zip.js/zipball/master

PdfGenerator.page

<apex:page renderAs="pdf">
PDF Content Goes Here...
</apex:page>

ZipGenerator.page

<apex:page >
    <apex:includeScript value="{!URLFOR($Resource.zip_js,'gildas-lormeau-zip.js-563fe1d/WebContent/zip.js')}"/>
    <a id="download-button" style="display:none;" href="#">Download</a>
    <script>
    //set base path for libraries to static resource
    zip.workerScriptsPath = "{!URLFOR($Resource.zip_js,'gildas-lormeau-zip.js-563fe1d/WebContent/')}";

    //fetch pdf as blob
	var xhr = new XMLHttpRequest();
    xhr.open('GET', '/apex/PdfGenerator', true);
    xhr.responseType = 'blob';
    xhr.onload = function(e) {
        console.log("Ajax Respons=",e);
        console.log("Status=",this);
        
          if (this.status == 200) {
            	var pdfData = this.response;
            
                var blob = new Blob([pdfData], {
                  type : "application/pdf"
                });  
              
              	zipBlob("file.pdf", blob, function(zippedBlob) {
                    console.log("Zip Created");
                    downloadFile(zippedBlob);
                });           
            }
    };
    xhr.send();
	
    //download zipped file 
    function downloadFile(blob){
        var filenameInput = "zippedPDF.zip";
    	var downloadButton = document.getElementById("download-button");
        
        if (typeof navigator.msSaveBlob == "function") {
            navigator.msSaveBlob(blob, filenameInput);
        } else {
            var clickEvent;
            var blobURL = URL.createObjectURL(blob);
            clickEvent = document.createEvent("MouseEvent");
            clickEvent.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
            downloadButton.href = blobURL;
            downloadButton.download = filenameInput;
            downloadButton.dispatchEvent(clickEvent);
        }
    }
    
    function zipBlob(filename, blob, callback) {
            // use a zip.BlobWriter object to write zipped data into a Blob object
            
	    zip.createWriter(new zip.BlobWriter("application/zip"), function(zipWriter) {
            
		    // use a BlobReader object to read the data stored into blob variable
		    zipWriter.add(filename, new zip.BlobReader(blob), function() {
		      // close the writer and calls callback function
		      zipWriter.close(callback);
		    });

	    }, onerror);
    }
    
     function onerror(message) {
        //error handling code goes here
        console.error(message);
    }
    
    </script>
</apex:page>