I'm getting the thumbnail of a document using file.get API, which is stored the field thumbnailLink in the drive response. But after some time, I get only a broken image.
Could you please let me know the exact expiration time of the thumbnail, which determines the expiration time and how to extend it? We can download the thumbnail image, store it in the cloud and then use it. But since the users are many and the documents are many and the thumbnail varies based on the changes, so I don't think this would be a better approach. I wanted to know whether we have any workaround to fix this issue? Do we have anything to play with the google cache? If so, how to do? will this be a permanent solution
As stated in the documentation
Important: Thumbnails are invalidated each time the content of the file changes. When supplying thumbnails, it is important to upload new thumbnails each time the content is modified. Metadata changes do not invalidate thumbnails.
The google drive thumbnail image link changes the file is changed.
You will need to refresh it if the link is bad by doing a file.get or upload new thumbnail image metadata whenever you change the file.
Related
I want to only allow images that are taken directly with the phone’s camera on my website. Are there any APIs or tricks that could help me tell if an image is authentic and taken with an iPhone or Android camera a few moments ago and not taken from Google Images.
Hi drstuggels they are a few ways to go about this.
WebRTC
To prevent upload from any file, take picture directly on your web interface, via the user webcam.
You would need to
Ask permission to the user to use the webcam.
Open the video stream
Capture on click the frame
Save the frame
This would prevent lambda users from uploading picture "not live".
If this is a solution you are considering, look for WebRTC. Although there are many blog post showcasing demo for this exact use case.
Such as:
https://developer.mozilla.org/en-US/docs/Web/API/WebRTC_API/Taking_still_photos
EXIF validation
As mentioned by iѕєρєня, you could try to access the EXIF metadata of the uploaded picture and run a validation mechanism, for let say freshness but looking for date and time field (if you are looking for a newly taken photo) or the camera model field to make sure it was taken by a camera (phone, DSLR, etc..).
DISCLAIMER:
Nothing will prevent a malicious user from tampering with the js code or file to upload fake picture.
I am making android app that must show a lot of images from my REST API. I want to download images, and the next time check for images' name. If the image exists show them from the phone otherwise download from server.
Now I'm using Retrofit for my network requests and Glide for show images. But I have not good idea for solve this issue.
If needed I can change the network library or image loading library.
Thanks in advance
NOTE: This question might be too broad for the liking of S.O.
What you want to do is make what is known as a cache. The idea is that you have a unique identifier (often refered to as a key) for each object in the cache, such as an md5 sum of the image data, or original name + date of creation.
When you want to display an image, you first check if the image exists in the cache. If it exists simply return with the image from cache. if it does not exist, start the download and upon completion you insert the image into the cache.
Here is an example implementation that does what you want. I cannot vouch for it's quality because I never tried it.
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.
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.
I have some image urls which I want to cache locally and save so that I don't need to make a web request again and again as needed.
Now, I am confused whether there is any significant benefit of using webclient's openreadasync method over bitmap for fetching the image for first time for saving it to IsolatedStorage.
For me, I think bitmap would be a better option as I would be able to get a event for progress.
This post gives good info on various image caching options.
http://blogs.msdn.com/b/swick/archive/2011/04/07/image-tips-for-windows-phone-7.aspx
Matt mentioned the fact that default image caching only works per session. So if you are implementing your own Image caching, then you will have to implement a image downloader for which the WebClient OpenReadAsync provides a way to store file locally
If you were't considering a local cache, UriSource would have been the choice.
If you want to cache images beyond the current application instance lifetime, have a look at http://blogs.msdn.com/b/delay/archive/2010/10/04/there-s-no-substitute-for-customer-feedback-improving-windows-phone-7-application-performance-now-a-bit-easier-with-lowprofileimageloader-and-deferredloadlistbox-updates.aspx which will show a way of saving the images to IsolatedStorage and then display it from there. This means you won't have to get it over the network each time the app is run.
If you're using this for lots of images be sure to manage the images you save as well so you don't fill up the disk with lots of old images you'll never need again.