CODEWITHSUNDEEP
javascriptpdfjszip
quantum_leap
quantum_leap

Reputation: 11

Compress PDFs that reside on a server with JSZip

Seems like it's not possible at the moment. Has anyone done it? I just have a few PDF files that I would like to add to a zip folder!

Upvotes: 0

Views: 2386

Answers (1)

David Duponchel
David Duponchel

Reputation: 4069

Sorry for the lack of links in this post : this is my first post on stackoverflow and as the error message says, "[I] need at least 10 reputation to post more than 2 links."

To download a pdf (or any binary file), you can use xhr.responseType = "arraybuffer" to get the raw content (warning : this won't work in IE 6-9, more on that below). You can't use jQuery to do that (yet, see github.com/jquery/jquery/pull/1525) but a raw xhr query or any ajax library handling binary data will work. For example jszip-utils at github.com/Stuk/jszip-utils (disclaimer : I'm a contributor on this library).

I recently worked (github.com/Stuk/jszip/pull/114) on the JSZip documentation and I added an example of what you're trying to do. The pull request is still pending so here is the temporary url : http://dduponchel.github.io/temp-jszip-documentation/documentation/examples/downloader.html

It should be at http://stuk.github.io/jszip/documentation/examples/downloader.html after the merge.

Here is the code :

This function uses JSZipUtils and wrap the result into a jQuery.Deferred but any library that can return an ArrayBuffer or a Uint8Array will work.

/**
 * Fetch the content, add it to the JSZip object
 * and use a jQuery deferred to hold the result.
 * @param {String} url the url of the content to fetch.
 * @param {String} filename the filename to use in the JSZip object.
 * @param {JSZip} zip the JSZip instance.
 * @return {jQuery.Deferred} the deferred containing the data.
 */
function deferredAddZip(url, filename, zip) {
    var deferred = $.Deferred();
    JSZipUtils.getBinaryContent(url, function (err, data) {
        if(err) {
            deferred.reject(err);
        } else {
            zip.file(filename, data, {binary:true});
            deferred.resolve(data);
        }
    });
    return deferred;
}

This is the main function, it uses FileSaver.js as a polyfill for saveAs :

var $form = $("#download_form").on("submit", function () {

    var zip = new JSZip();
    var deferreds = [];

    // find every checked item
    $(this).find(":checked").each(function () {
        var url = $(this).data("url");
        var filename = url.replace(/.*\//g, "");
        deferreds.push(deferredAddZip(url, filename, zip));
    });

    // when everything has been downloaded, we can trigger the dl
    $.when.apply($, deferreds).done(function () {
        var blob = zip.generate({type:"blob"});

        // see FileSaver.js
        saveAs(blob, "example.zip");
    }).fail(function (err) {
        // handle the error here
    });
    return false;
});

Note on IE 6-9 : jszip and jszip-utils support IE 6-9 but without ArrayBuffer/Uint8Array, you will get poor performances.

EDIT: Link JSZip Utils GitHub: https://github.com/Stuk/jszip-utils

Upvotes: 2

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