Google Docs Viewer occasionally failing to load content in iframe

问题

I'm having an issue with the Google Docs viewer that is causing a nightmare to solve because it only happens intermittently. I'm looking for guidance on how to make the content in the iframe load everytime without issue as it should.

Steps to reproduce 1) This page is a basic HTML page with a h1 tag and an iframe containing a link to a PDF on the same server

http://bit.ly/1mqbuf7

2) When you load the page, the pdf document will load in the iframe 60% of the time.

3) If you hit refresh 10 or so times, at least once it will fail to appear. Google returns a 307 first (Which it also does when it works) and then returns a 204 - no content. When it works, it returns a 200, with the content you see in the viewer.

I'm struggling to understand why it only does this some of the time with no visible errors. This has been tested and failed on Google Chrome v 48.0.2564.103 (PC) and Internet Explorer Edge v25.10586 (PC) with the same results and frequency of failure.

Any guidance would be greatly appreciated.

回答1:

Here's a "hack" that will ensure a proper loading every time (albeit with some delay, due to potential failed attempts - it's Google's fault, don't shoot the messenger!). The 2s interval duration can be modified to best fit the time expected for a successful effort to start loading the iFrame.

HTML:

<div id="test-id-1" style="text-align: center; width: 100%; height: 1150px" class="embed-pdf" data-url="{insert_pdf_link_here}"><span class="loader">Please wait...</span></div>

JS:

$(document).ready(function() {

    let embed_pdfs = {};

    $('.embed-pdf').each(function() {
        var $pdfViewer = $('<iframe src="https://docs.google.com/viewer?url=' + $(this).data('url') + '&embedded=true" style="width: 100%; height: 100%" frameborder="0" scrolling="no"></iframe>');
        $pdfViewer.appendTo($(this));
        console.log($(this).attr('id') + " created");
        embed_pdfs[$(this).attr('id')] = 'created';
    });

    $(document).find('.embed-pdf iframe').load(function(){
        embed_pdfs[$(this).parents('.embed-pdf').attr('id')] = 'loaded';
        $(this).siblings('.loader').remove();
        console.log($(this).parents('.embed-pdf').attr('id') + " loaded");
    });

    let embed_pdf_check = setInterval(function() {
        let remaining_embeds = 0;
        $.each(embed_pdfs, function(key, value) {
            try {
                if ($($('#' + key)).find('iframe').contents().find("body").contents().length == 0) {
                    remaining_embeds++;
                    console.log(key + " resetting");
                    $($('#' + key)).find('iframe').attr('src', src='https://docs.google.com/viewer?url=' + $('#' + key).data('url') + '&embedded=true');
                }
            }
            catch(err) {
                console.log(key + " reloading");
            }
        });
    
        if (!remaining_embeds) {
            clearInterval(embed_pdf_check);
        }
    }, 2000);
});

回答2:

This is not fixing your problem per se, but since I had the same problem and I eventually managed to find an acceptable solution, I thought I'd share it.

var $docViewer = $(`<iframe src="${newValue}" height="100%" width="100%"></iframe>`);
//If using modern browser, use and embed object
if (window.chrome || typeof (window.mozInnerScreenX) != "undefined")
  $docViewer = $(`<object width="100%" height="100%" data="${newValue}" type="application/pdf">
                    <embed src="${newValue}" type="application/pdf">
                        <p>This browser does not support PDFs.Please download the PDF to view it: <a href="${newValue}">Download PDF</a>.</p>
                    </embed>
                </object>`);
//Add the new viewer
$docViewer.appendTo($("#invoicePreview"));

Basically, use an embed if modern browser, and the gviewer if not. The embed object behaves identically to the google doc viewer, it works in 100% of cases (no failed loads), but since it's not supported for IE and/or low-end mobile devices, use the google doc viewer for that... Progressive Enhancements I guess.

来源：https://stackoverflow.com/questions/35298724/google-docs-viewer-occasionally-failing-to-load-content-in-iframe

标签

html

iframe

google-docs