I'd like to download images with the dropbox api and save them in a custom album ("DropBox") in my ALAssetLibrary.
However I don't want to save duplicates. So what is the best way to check if the image is already present in the album.
Is there some sort of hashing within the ALAssetLibrary which I can utilize for this purpose?
I don't mind hashing the NSData of my download images, but doing this for all the images in the album would be way to much.
Maybe storing hashes in meta data someway?
Thank you very much!
akw
I found a solution which works for me so far:
I "misuse" the EXIF user comment tag to save a hash value (in my case, just the dropbox path).
After downloading an image from DropBox, I save it with writeImageDataToSavedPhotosAlbum and store the DropBox path of the image in the kCGImagePropertyExifUserComment.
This way, I only need to scan the ALAssetsGroup for these tags and if present I do not need to download the image at all. Works fine.
Related
I was wondering what the html code was to let users upload their images to my html webpage, I looked at https://www.w3schools.com/php/php_file_upload.asp but when i enter it, it does not work, so if anyone has a code, preferably without a php file required, please share it with me. Thx!
In order for users to be able to upload images to your website, there needs to be a place for those images to be placed. This is the role of the your server. In the example above, they are using a php server to keep track of the image that was uploaded, and serve it back to the user when requested. So, while you may have followed the code in the example, without a server, users cannot upload anything to your site.
Is there a way to disable a user from downloading a file from a URL?
For example I have a link:
wow.mywebsitedomain.com/templates/filename.svg
I want to disable the user from downloading the filename.svg
These svg files are not just an image, they are editable designs that I have spent countless hours on each. No, I do not care if someone does a screenprint or gets a png etc, as those are not scalable, editable, vector files.
When the user clicks on a png thumbnail my actual link opens my online design editor to allow the user to customize these files, then save to my server, then purchase printed media, and they are not allowed to download any files.
I tried putting the actual files into a password protected folder on my server, but they do not open properly, and I do not want the user to have password access to this folder.
Essentially I need the link to be accessible, just not show the actual link for someone to copy and open/save/download etc.
Hopefully there is a simple solution for a non-programmer with basic html skills?
Thanks
Your can do things like "disabling right-click" and stuff - it may prevent some users from downloading your file, BUT basically you cannot prevent a file which is downloaded and interpreted by the browser from being downloaded to a user's hard drive.
This is not only true for SVGs, but also for music, videos, etc.
Instead, you can convert your SVG file to a PNG on server-side, and show only the PNG to the user. Note that you have the possibility to create PNGs of different sizes on the fly - dependent on the request, user's screen resolution, etc. You can also implement caching of the generated PNGs if needed.
On how to create a PNG from SVG in PHP read here:
Convert SVG image to PNG with PHP
You can choose other raster image format, of course.
If they can view it, they can download it. End of story. If you only want them to see a PNG, make a PNG from it and put that up
My understanding is; if you can see it, you can download it,
I'm currently writing an HTML5 WYSIWYG using Google Closure Library and I'm providing users to just drag and drop the image file to contenteditable field with text to add an image.
So I have two ways to store these images:
1. Retrieve the data URL from dropped file, create an IMG tag, set the retrieved data URL as value of attribute SRC of this image and insert this IMG tag into editor's field. When user will submit the form I'll just save all retrieved HTML in my MySQL database and will able render his text with images later.
2. Upload the dropped image to my server and save it as regular file.
Then the server will answer like:
"image saved, its URL is http://example.com/images/uploaded-image.png".
After that I will perform the steps similar to my item 1 (create an IMG tag with attribute src="http://example.com/images/uploaded-image.png" and insert it into editable field).
The first way will load database more because it requires to store an image dataUrl in database field together with text. But it makes image adding more easy and fast, so it improves the user's experience.
The second way will load database less because the images will stored separately (in the file system), but this way requires more requests to the server and some processor time on each image adding into text within the WYSIWYG. Also it will not show an immediate result to user so the user will need to wait when his image will uploaded, what will make user's experience worse.
I need the help to understand which way is more preferable in my case considering all pros and cons.
Another way is to store not only images but complete HTML with images in one file. And use the database for storing a link to the HTML file. Then setup Nginx and get the best performance. IMHO if your application is WYSIWYG then the content should be loaded and laid out completely in the browser before editing.
Is there any way at all to get the meta information about a picture from a link without download the picture it self?
Like i have this url to a picture http://www.abc.com/picture.jpeg, i want to get the meta information such as the dimensions of the picture with out actually downloading the picture it self.
Of course I want to do this by writing a program, because there is large amount of pictures to go through.
I doubt you can get information about an image without downloading it. For example, when you visit a website and it has an image on it, the browser only knows the dimensions of the image after it has downloaded it. This is especially true if you want more advanced metadata such as time picture taken, iso, exposure, etc. The URL carries no information except if you can get some information from the parameters. Ex: http://www.abc.com/picture.jpeg?x=100
Sorry :/.
You might maybe want to look into downloading a thumbnail of the image, or maybe there is a way to not download the image pixel data but only the EXIF metadata which would cut down on download time/costs but still get you that metadata you want. I have no expertise in that subject though.
If all you have is a URL, than all you have is a URL. There's no magic incantation that will extract more data than there is from it. I.e.: No, you'll have to download the image.
If you have control over the server serving the image, you could make an HTTP HEAD request, have the server evaluate the image and output meta information about the image in the HTTP header, essentially creating a custom protocol for this purpose. That's a lot of ifs though and really depends on what you want to do.
I am trying to create a "smart" web browser to load local images. Basically it works as a GUI for an application. I am using QTWebKit to power the browser, the problem is that the images of a given page can be found in different places, some are local files, others are in different resource files.
For example:
an HTML node to load image x.jpg can look like <img src="x.jpg"> and for image y.gif on the same page it can be <img src="y.gif">, now x.jpg is a local file that can be either in the root directory or in some other place. y.gif on the other hand can be in a resource file.
I want the web browser first to set the paths to all possible sources and once the page has been loaded or preferably while the page is loading searches for the images and loads them from their original path.
I considered the option of reading the HTML data first, parse it and search for the resources one by one, then edit the html to include the full path of the image but that would take a long time than what I want and it isn't practical.
Can any one put me on the right direction or does any one have any ideas on how such a design can be implemented.
EDIT: I have manage to delegate the requests by overriding the QNetwrokAccessManager and QNetwrokReply and been able to get the path to the image. The only problem is loading the image into view. I am currently using QHttp to handle the incoming requests but so far I haven't been able to load the image.
been trying to use QHttp's Get() function and passing the path to the jpg image as (file:///path/to/image) and also tried using the local path but nothing is working.
Take a look at How to tell QWebPage not to load specific type of resources?
You need the same approach but instead of dropping request by constructing QNetworkRequest with empty QUrl you need to pass url to the file on the disk.