Javascript Upload and real image refresh/reload - ajax

I need to create, for a specific project, an image manager that works via Ajax (to get the list of images, display them, ...).
The upload of new images, or image modification, is done via an Ajax script (using the new javascript File API).
The upload works fine, but I encounter a problem in case of image modification : the image displayed by the browser after upload is the cached one and not the uploaded one !!
I know it's a classic cache problem, that can be solved via the 'imagesrc?new Date.getTime()' hack, but I can't use it here.
in fact, this hack doesn't really reload the image, it only create a new instance of the image into the cache, associated to the image url 'imagesrc?new Date.getTime()'.
So, if at any moment, into the image manager, I retry to display the image, without adding the '?new Date.getTime()' to the src, it will display again the old image.
And I either cannot add this hack systematically (because, for example, if the image manager needs to display a lot of very heavy images, it's usefull to get them from the browser cache until they are modified).
I searched a way to solve this problem on internet (really replace the cached image after a javascript upload instead of using the above hack), but I found nothing.
Is there a way to do this, or is it totally impossible ?
Any help or suggestion would be greatly appreciated.
Many thanks in advance
Olivier

Configure your server to send ETag-headers for the images.
An ETag is a hash-value of the file that changes when the file is modified. If an ETag is sent, the browser will add an If-None-Match-header containing the last received ETag of that ressource on its next request and the server will respond with 304: not modified to save traffic if nothing has changed or send the new file if there is one.

Related

Is it possible to resize an image when pasted into a rich text field

I am working on an xpages app, where the client wants to restrict the size of images that are pasted into the document. I have restricted docs with the upload component, but not with a pasted image.
Has anyone done anything like this?
Thanks
walt
Yes it is possible, I haven't done this but there are a few ways you could go about it.
Excuse me if you already know this, but it is worth pointing out for anyone who comes across this question in the future, RichText as we knew it from Notes/Domino is not used XPages, it is all MIME. When I started Xpages I knew nothing about MIME so after understanding it all I have written a little summary on my blog to help anyone get used to the idea. If you are going to do anything with the InputRichText control and File Uploads etc. it is worth getting familiar with MIMEEntity's.
http://camerongregor.com/2016/04/21/webmail-ui-you-must-learn-about-mime/
There are 2 ways that images can make it into the 'rich text field', either uploaded using the 'Image' button on the editor toolbar, or alternatively in some web browsers, the image can be pasted from the clipboard. The 2 different methods will include the image in 2 different ways
Uploaded
If the image is uploaded, then the image becomes a multipart/related mime entity of some sort of image/jpeg, image/png etc., related to the text/html. Between the time that the image is uploaded, and the time that the Document is saved, the image file will be located on the server's disk, in the xpages persistence folder associated with the Document e.g.
xsppers_directory/application-id/session-id/document-id/someimage.png
Pasted
When pasted the image is not uploaded as a file to the server's persistence folder, but is instead included within the text/html as a data URI image (as Stephan mentioned in the comment above).
So, if you want a true solution you will need to address both avenues.
Handling Pasted images
I have shared a plugin on my blog which blocks pasted images, so this could be used to eliminate the 'paste' avenue altogether, and force users down the upload avenue.
http://camerongregor.com/2016/11/14/preventing-pasting-of-images-in-ckeditor/
Alternatively, if you are happy with having smaller pasted images, you could just 'restrict' it by modifying the plugin so that it checks the 'length' of the data URI (as Stephan suggested above) and allows the paste if the length is below your predetermined limit.
If even more alternatively, you could find some sort of client side javascript library that will resize images and do it there in the client before the paste.
Or another server-side option is you could process the contents of the 'text/html' MIMEEntity when saving, and find any img tag's that used Data URI's and strip it out, resize the image using some server side library such as ImageMagick and replace it.
Handling Uploaded Images
For uploaded images, an intense solution would be to extend the InputRichText control (similar to how the have demonstrated in the Mastering Xpages 2nd edition) and override the processAjaxRequest event so that it resizes the image during the process of uploading of the image and putting it in the persistence folder. You could resize it there and then using something like ImageMagick.
Or a less intense version would be to process the 'pending' attachments during a before save event. If you get the DominoRichTextItem from the DominoDocument, you should be able to iterate through the Attachments, checking their attachment state, there will be a state which means 'pending/about to upload' and for these ones you can process them while they are in the persistence folder, before they are finally attached to the document.
Finally if you don't want the xpages runtime / persistence directory to be involved, you could do it all after save, just using the backend NotesDocument and MimeEntity processing. Extract the Image MimeEntities to disk, process them with ImageMagick or similar, and then re-attach them.
Someone else may have a simpler solution that I haven't thought of but at least this gives you some idea of what may be involved.

images inside gmail email not being displayed

I know gmail and hotmail have introduced their own image proxies. I have sent email with simple img tag with src
src="http://www.zong360office.com/assets/images/logo/product-logo.png"
and gmail converts it like this
src="https://ci3.googleusercontent.com/proxy/PCxvUIqBvaJWn_7H8deiQhdJD1QKV_pU5n1JhrPh3xaXMLMzcdSBYCo6-tjs69AYy858H4j5ShIRjw0UrH_VWMtCxC0zIT-Gi4j_dlQv9uRZjzGWFWA=s0-d-e1-ft#http://www.zong360office.com/assets/images/logo/product-logo.png"
Original URL is the direct URL to the image. In the attached image, you can see the request and response headers for this image.
Problem: Please let me know what steps should I take to make this image visible inside gmail.
PS: I am facing the same issue with hotmail as well.
I think I have figured out the GoogleImageProxy issue.
I have answered this in another question as well ( images inside gmail email not being displayed ).
This is something related to CACHING concept. suppose, you have recently deployed your php code on your server but you forgot to upload images. you tested once with your email logic. your system generated an HTML email. When this email will hit the gmail server GoogleImageProxy will try to fetch and store the images from your site to its own proxy server. while fetching the images, GoogleImageProxy found some 404 statuses against your missing images and 403 against some protected images. GoogleImagesProxy has stored these statuses into its own proxy server.
Now tried to open your email, you noticed some 404 statuses against your images. This is something understandable. You immediately realized that you forgot to upload some images, so you uploaded them to your server. and also you have fixed some permissions against protected images.
You are all done now. Now you try to run your php-email script once again. As a result you receive another email in your Gmail or Hotmail inbox. you had fixed all the issues with your images. Now the images must be displayed in your email content. but you are still unable to see the images.
Ah, possibly you forgot to clear your browser's cache. Clear your browser's cache and load the gmail or hotmail page once again. But the result will be still the same. Try to apply dozens of fixes/patches and try to run your php-email script a thousands time. But the result will be still the same. No improvement.
THE REAL PROBLEM
What the hell is going on? Let me explain it to you. Go to your access log and try to find requests from GoogleImageProxy. You'll be surprised to see that there will be only 2 or 3 three requests from GoogleImageProxy depending on the number of different images used in your email. GoogleImageProxy never tried to fetch images Even after you have fixed the issues with your images by uploading missing images and setting permissions for protected images. Why? Clearing your browser's cache has no impact. GoogleImageProxy will never fetch the fresh images even for your newer email because the images are now cached into GoogleImageProxy along with their last status code and not cached in your own browser's.
GoogleImageProxy has set its own expiry date for the images. I think one month. so now the fresh copy of images will be fetch after expiry date. I mean after one month. You can not force GoogleImageProxy to fetch the images. But its important for you to display images in your email. What can be the solution?
THE SOLUTION
Following is the only way to force GoogleImageProxy to fetch your images
Rename your images to something else with png, jpg or gif extensions
only.
Don't use any kind of query string in your image url like "?t=34343"
your image must include png, jpg or gif as an extension.
your image url must be mapped onto your image directly.
If you need to use some proxy url for your protected images then your
response must include the proper header like
"content-type:image/jpeg"
File extension and content-type header must match
Status-code must be 200 instead of 403, 500 etc
IMPORTANT NOTE
Try to repeat the whole process for every run of php-email script. because every time GoogleImageProxy will cache your images and you'll have to repeat the same process for every new try.
Hopefully this will fix the issue for most of the people. In my case this has fixed the issue.
hese are embedded images. You send an image as an attachment and then use it in your img element like: . Gmail transforms the "cid" link to its internal file storage link and that's why it gives element.
This is one of two common ways to have images within email.
The other way is to keep images in your hosting and send img elements with external links: http://yourdomain.com/yourimage.png I strongly recommend to use the second approach especially if you expect to have a lot of images in your email. I had problems with attached images display on Gmail which I couldn't solve.
Make sure your from address is a real valid email and not in the form realname+something#example.com.
I'm using Amazon SES to send emails, and inlining some but not all images as attachments. For me it was the non-attachments that were breaking.
Eventually I realized I was using a 'fake' email for the from field.
My real email is
simon#example.com
To make it easy to filter emails in gmail I used the + syntax to create a 'fake' email for testing purposes.
simon+test#example.com
This works great, except it seems to be changing the behavior of the spam/image filter. My image tags ended up completely stripped of the src attribute.
As soon as I switched back to using the actual email then all the images showed up.

Handling images upload while in other form

Ok, there is a lot of tutorials on the net, how to upload images to express.js servers. But I couldn't find how to upload images while doing other things, e.g:
there is a form, in which I would like to create article. Users fill it with title, some content... after that, he have to upload images. I would like to give him ability to see thumbnails of those images before he create this article. Of course I can just push them through ajax post with jquery, and put them on the screen with javascript, but: when I upload them on to the server, and user closes browser before finishing creating this article, I still have does images on my server, even though no one will use them.
I'm sorry, I couldn't think of simpler explanation of what I want.
So how to handle such a situation?
You can upload image to a temporary folder first and move that image to desired location while actually saving article.
Set up a cron to cleanup the temp folder.

Gmail's new image caching is breaking image links in newsletter

I've got some automatic emails that are sent out upon signup completion for my site.
Until recently, they worked fine. Now Google's new system is rewriting the images and storing them in it's cache (supposedly)
However, Google's new rewriting of my image links are completely breaking them, giving a 500 error and a broken link image.
Lets say my normal image url is:
http://www.mysite.com/images/pic1.jpg
Google is rewriting this to:
https://ci5.googleusercontent.com/proxy/vI79kajdUGm6Wk-fjyicDLjZbCB1w9NfkoZ-zQFOB2OpJ1ILmSvfvHmE56r72us5mIuIXCFiO3V8rgkZOjfhghTH0R07BbcQy5g=s0-d-e1-ft#http://www.mysite.com/images/pic1.jpg
However, there is nothing at that URL.
So, either there is something wrong with the links that are being created by Google or the images are just not being uploaded to the googleusercontent server, but I have no idea how to solve the issue.
Im using PHP, the phpmailer library and a Ubuntu server on Amazon EC2, but Im not sure that is related to the issue.
I think I have figured out the GoogleImageProxy issue.
This is something related to CACHING concept. suppose, you have recently deployed your PHP code on your server but you forgot to upload images. you tested once with your email logic. your system generated an HTML email. When this email will hit the Gmail server GoogleImageProxy will try to fetch and store the images from your site on its own proxy server. while fetching the images, GoogleImageProxy found some 404 statuses against your missing images and 403 against some protected images. GoogleImagesProxy has stored these statuses into its own proxy server.
Now tried to open your email, and you noticed some 404 statuses against your images. This is something understandable. You immediately realized that you forgot to upload some images, so you uploaded them to your server. and also you have fixed some permissions against protected images.
You are all done now. Now you try to run your PHP-email script once again. As a result, you receive another email in your Gmail or Hotmail inbox. you had fixed all the issues with your images. Now the images must be displayed in your email content. but you are still unable to see the images.
Ah, possibly you forgot to clear your browser's cache. Clear your browser's cache and load the Gmail or Hotmail page once again. But the result will be still the same. Try to apply dozens of fixes/patches and try to run your PHP-email script a thousand times. But the result will be still the same. No improvement.
THE REAL PROBLEM
What the hell is going on? Let me explain it to you. Go to your access log and try to find requests from GoogleImageProxy. You'll be surprised to see that there will be only 2 or 3 three requests from GoogleImageProxy depending on the number of different images used in your email. GoogleImageProxy never tried to fetch images Even after you have fixed the issues with your images by uploading missing images and setting permissions for protected images. Why? Clearing your browser's cache has no impact. GoogleImageProxy will never fetch the fresh images even for your newer email because the images are now cached into GoogleImageProxy along with their last status code and not cached in your own browser.
GoogleImageProxy has set its own expiry date for the images. I think one month. so now the fresh copy of images will be fetched after the expiry date. I mean after one month. You can not force GoogleImageProxy to fetch the images. But it is important for you to display images in your email. What can be the solution?
THE SOLUTION
Following is the only way to force GoogleImageProxy to fetch your images
Rename your images to something else with png, jpg, or gif extensions
only.
Don't use any kind of query string in your image URL like ?t=34343
your image must include png, jpg, or gif as an extension.
your image URL must be mapped onto your image directly.
If you need to use some proxy URL for your protected images then your response must include the proper header like
Content-Type: image/jpeg
File extension and content-type header must match
Status-code must be 200 instead of 403, 500, etc
IMPORTANT NOTE
Try to repeat the whole process for every run of PHP-email script. because every time GoogleImageProxy will cache your images and you'll have to repeat the same process for every new try.
Hopefully this will fix the issue for most of the people.
Based on your example, it looks like you are using traditional extensions (.jpg, .png, .gif). Some folks on this thread, describing the same issues you are facing, have stated that using those extensions solves the problem.
Other possible solutions:
Image links broken in Gmail because of google's Image proxy
Doubtful, but maybe a cookie problem
Image URL proxy whitelist setting - this has turned out to be the solution for a few users who are under Google Apps. Via Gmail is not showing image when image url is getting appended with https://ci4.googleusercontent.com/proxy
I was having a similar issue, but it was caused by the length of the URL. Google generates the following URL when caching an image from gmail:
https://ci4.googleusercontent.com/proxy/[hash]#[url])
The hash generated is based on the URL of the image, but the size will vary based on characters used. I ran several tests with different sized URLs, and found the cached image would fail to load consistently (400/Invalid Request) if the hash exceeds 2076 characters in length (close to 2048 bytes + meta? not sure).
Again, the image URL could generate a hash that exceeds this many characters at ~1000 special characters, or 1500+ simple characters. If the hash exceeds 2076 characters in length, the request fails.
I realize this is an old post, but hopefully this helps other devs scouring Google
I know this is an old question but the same thing happened to me. When I checked my access logs this is what I found -
www.example.ca 66.249.85.50 - - [10/Apr/2014:17:57:18 -0400] "GET /newsletters/Apr10_2014/cad/cad2.jpg HTTP/1.1" 403 457 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7 (via ggpht.com GoogleImageProxy)"
You can see that my server was blocking the GOOGLEIMAGEPROXY giving it a 403 Forbidden reply. I decided to check my .htaccess and sure enough I was blocking the term PROXY. After removing the term, the images appear just fine now on Gmail. Hope that helps.
I just tried ,
after replacing the image (without changing image name)
Open email in new browser , it shows new image
Ctrl+f5 (forces a cache refresh) in the chrome (my default browser) ,
also shows new image
use .png or .jpg
otherwise image will not render
url add auto
https://ci3.googleusercontent.com/proxy/jTpYlM6RUv7Wi8Hxjha4fzExKFy9mjyh133MKKfo3FuV3toLToG6zJcA0IAdIMEW75pY6pkEd2aOSVhWIn0A82q-24YaAd-_k00wIMHwIuUBiy9vEGrMpAW73HaHQmViuESP7A=s0-d-e1-ft#
HTTPS image locations do cache. Several of our production environments have no problems with gmail proxying image locations using a HTTPS uri. I could see gmail ignoring your content if the SSL certificate is invalid in some way.
Check that the content-type returned for the image file by your server is correct.
You can check this using Fiddler.
In my case the size of file was the problem, it was 22 Mb (i know right?), and after we reduced the size everything started working like a charm.
Check file size and if it's too big, compress it.
I know this is an old question but I've met this problem. In my case images are stored at Google Cloud Storage. What is interesting is that link
https://storage.cloud.google.com/{bla_bla}/logo.png
returns 307 (temporary redirect) and Location header containing something like
https://{xxx}-apidata.googleusercontent.com/{bla-bla_bla}/logo.png?{zzz}
Seems like GoogleImageProxy does not process 307 correctly
I have a perfect solution of this problem, which worked for me if you are using PHPMailer then you just have to add another option in PHPMailer for attaching image like this
$mail = new PHPMailer();
$mail->AddEmbeddedImage('../absolutepath/image/image.jpg', 'logoimg', '../absolutepath/image/image.jpg');
Here we have given absolute path of image and give it a name call 'logoimg' or whatever you want.
Now you can add this logoimg to wherever in your HTML Body like this
$mail->Body = "
<h1>Test of PHPMailer html body with image</h1>
<p>This is a test picture: <img src=\"cid:logoimg\" /></p>";
$mail->send();
That's All.
I had this issue when I was sending gifs. I found that the file size matters to Googles Proxy server. I suggest making the files as small as possible and see if that works. You can use your Gmail account and add a photo from a URL to test. If the gif shows up when you are composing your email it will be receivable.
happy coding.
Is it working from Outook/hotmail? It should then we can isolate it as google issue. In your case it is not.
Size of the image can be a problem. Try to reduce it and see
www.mysite.com this site might be accessible from your system. But
is it also accessible from google server?
Try changing extension.. this is the trick: You might have tried several things but it would still fetch from cache(which invalidates your efforts) but when the extension changes, it fetches again and all the work you did before comes into play and if it works you might think it is the 'extension' that did the trick!! (like many of those who speaks about extensions)
In my case of running into this issue, the problem was that accidentally the path to the image in the email template had triple slashes in the URL, e.g. https:///content.example.org/image.png. This was hard to spot, and while it was working in other email clients who could successfully resolve the URL, Google's image proxy wasn't able to handle it and resulted in a 404 for the proxied image address.
It's March 6 and you've probably already figured this out, but thought I'd chime in to help others. I discovered that JPGs don't work in gmail. The PNG format works great. Sorry I can't explain why, but sometimes it's better not to ask why. Use PNG!

Logging image downloads

I'm trying to find a way of finding out who is downloading what image from an image gallery. Users can download using a button beside the thumbnail or right click and use the "save link as" Is it possible to relate a user session or ID to a "save link as" action from all browsers using either PHP or JavaScript.
Yes, my preferred way of doing this would be via PHP. You'd have to set up a script which would load up the file and send it to the user browser. This script would also be able to log the download somewhere (e.g. your database).
For example - in very rough pseudo-code:
download.php
$file = $_GET['file'];
updateFileCount($file);
header('Content-Type: image/jpeg');
sendFile($file);
Then, you just have your download link point to download.php instead of the actual file. (Note that updateFileCount and sendFile are functions that you would have to provide, of course - this script is an example of a download script which you could use)
Note: I highly recommend avoiding the use of $_GET['file'] to get the whole filename - malicious users could use it to retrieve sensitive files from your web server. But the safe use of PHP downloads is a topic for another question.
You need a gateway script, like ImageDownload.php?picture=me.jpg, or something like that.
That page whould return the image bytes, as well as logging that the image is downloaded.
Because the images being saved are on their computer locally there would be no way to get that kind of information as they have already retrieved the image from your system. Even with javascript the best I know that you could do is to log each time a user presses the second mousebutton using some kind of ajax'y stuff.
I don't really like the idea, but if you wanted to log everytime someone downloaded an image you could host the images inside a flash or java app that made it a requirement to click a download image button. That way the only way for them to get the image without doing that would be to either capture packets as they came into their side or take a screenshot.
Your server access logs should already have the request for the non-thumbnailed version of the file, so you just need to modify the log format to include the sessionid, which I presume you can map back to a user.
I agree strongly with the suggestion put forward by Phill Sacre. For what you are looking for this is the way to go.
It also has the benefit of being potentially able to keep the tracked files out of the direct web path so that they can't be direct linked to.
I use this method in a client site where the images are paid content so must be restricted access.

Resources