I'd like to allow user to select a directory (in which I parse some text files) and store the result(List<File>) in a PERSISTENT storage on the same client so that when the user returns, there is no need to select the same directory again.
During the session selecting the directory (via <input webkitdirectory="..." />) and then accessing the directory and parsing the file already works fine, but I've no idea on what kind of data I shall save in order to retrieve it later. I've tried by using window.webkitResolveLocalFileSystemURL() but wasn't successful so far... any idea?
Ok, so you're using something like:
<input type="file" id="file-input" webkitdirectory="" directory="">
This lets the user upload a directory. Roughly speaking, here's the code to get the list of files uploaded:
query("#file-input").on.change.add((e) {
print(e.target.files);
});
It sounds like you already figured that part out.
Really, you just get a list of files. I looked at e.target, and I don't think there's anything in there related to the directory itself. For instance, I don't see anything about the directory name, and it's not as if you suddenly have write access to that directory. You also can't upload files from that directory the next time the user loads the page without him selecting the directory again.
However, what you can do is upload files from that directory and save a copy of those files locally using local file storage.
See also:
"Using the HTML5 Filesystem API" p. 20-21
https://github.com/dart-lang/dart-html5-samples/tree/master/web/file
How do I use Google Chrome 11's Upload Folder feature in my own code?
By the way, I know I wasn't able to achieve exactly what you wanted, but if you approve of my answer, please accept it. My boss promised to buy me a puppy if I answer 100 questions on Stack Overflow ;)
Related
I'm developing a MVC5 web app, hosted through azure, that lets you manage your movies (it's just for myself at the moment). I'm trying to find a way to scan a local folder on the users pc for a list of file names. I do realise the security/permissions issues I might run into. I do not need the file uploaded, only the full file name.
It would work by the user being able to select a folder where they store their movies and it will take in all the file names, including the ones in any sub directories.
I tried a multiple file upload form but quickly ran into issues with the max request limit which I tried messing around with but it proved redundant in the end. I can settle for the user selecting multiple files but would rather it done the directory way.
I know this might prove impossible in the end but any help would be greatly appreciated.
I developed an Ipad app which download different kind of files, but after a week or some days the downloaded files are removed and the app that open the file can find it anymore.
Could anybody help me, Where should I save downloaded files in my app to avoid that the file came automatically deleted?. IOS usually remove downloaded files after certain time?.
I already read this apple documentation
I know that maybe is not something complicated but I can't figure out why the file is removed If anybody can help me I'll appreciate that.
Put data cache files in the /Library/Caches
directory. Examples of files you should put in this directory include
(but are not limited to) database cache files and downloadable
content, such as that used by magazine, newspaper, and map apps. Your
app should be able to gracefully handle situations where cached data
is deleted by the system to free up disk space.
Most probably you are using caches/temp directory which the system can clear contents of in case of low space. To avoid deletion use Documents Directory.
If you are already storing in documents directory, then the file can appear missing if you are storing its hardcoded path , which can change during app update. Try storing relative path and log the contents of your documents directory to see what files exist.
save the files in your local sqlite db, data core or if you can serialize them with the standard user defaults
In my app I want users to be able to associate a file(s) they have on their desktop/DropBox with a specific item, but I don't want/need them to be able to actually attach the file...I just want to get the file name and location and save that in my database. Then when I display the item I'll hyperlink to the location captured. Can someone point me to an example(s) of how to accomplish this? I looked at the JQuery File Upload (http://blueimp.github.com/jQuery-File-Upload/) but as I mentioned don't actually need to upload the file...so this should be something super easy.
Thanks for your time and assistance.
You can try and get value of file input, but you'll fail.
See this jsfiddle.
All I'm getting is the fake path
C:\fakepath\134.png
And there's certainly no C:\ drive on Mac OSX. :)
I guess, this is because of security restrictions. You shouldn't know (or care) about user's filesystem in a web app.
I need to upload multiple files on my website.
But I need not just a form for uploading multiple files, I need to upload whole directories.
How's this possible for the minimalist?
Yours, Joern.
According to my somewhat limited knowledge this is not possible, only file transfer is possible, not directories.
Here are some workarounds, based on discussion on Velocity Reviews and another discussion:
upload a zip, which you unzip at the server side
upload directories over ftp (web page can be a front end to this)
upload files one by one
I would go either for zip or ftp. Note: someone might have produced a gem that enables uploading directories (I know nothing of such thing, but I will be happy to find out, if there is).
Adding another option to the list provided by Sorrow:
upload via REST/JSON
OK, this is a partial solution, but it does give you the opportunity to write a script that reads your directory and POSTS to your website.
I have a website that shows galleries. Users can upload their own content from the web (by entering a URL) or by uploading a picture from their computer.
I am storing the URL in the database which works fine for the first use case but I need to figure out where to store the actual images if a user does a upload from their computer.
Is there any recommendation here or best practice on where I should store these?
Should I save them in the appdata or content folders? Should they not be stored with the website at all because it's user content?
You should NOT store the user uploads anywhere they can be directly accessed by a known URL within your site structure. This is a security risk as users could upload .htm file and .js files. Even a file with the correct extension can contain malicious code that can be executed in the context of your site by an authenticated user allowing server-side or client-side attacks.
See for example http://www.acunetix.com/websitesecurity/upload-forms-threat.htm and What security issues appear when users can upload their own files? which mention some of the issues you need to be aware of before you allow users to upload files and then present them for download within your site.
Don't put the files within your normal web site directory structure
Don't use the original file name the user gave you. You can add a content disposition header with the original file name so they can download it again as the same file name but the path and file name on the server shouldn't be something the user can influence.
Don't trust image files - resize them and offer only the resized version for subsequent download
Don't trust mime types or file extensions, open the file and manipulate it to make sure it's what it claims to be.
Limit the upload size and time.
Depending on the resources you have to implement something like this, it is extremely beneficial to store all this stuff in Amazon S3.
Once you get the upload you simply push it over to Amazon and pop the URL in your database as you're doing with the other images. As mentioned above it would probably be wise to open up the image and resize it before sending it over. This both checks it is actually an image and makes sure you don't accidentally present a full camera resolution image to an end user.
Doing this now will make it much, much easier if you ever have to migrate/failover your site and don't want to sync gigabytes of image assets.
One way is to store the image in a database table with a varbinary field.
Another way would be to store the image in the App_Data folder, and create a subfolder for each user (~/App_Data/[userid]/myImage.png).
For both approaches you'd need to create a separate action method that makes it possible to access the images.
While uploading images you need to verify the content of the file before uploading it. The file extension method is not trustable.
Use magic number method to verify the file content which will be an easy way.
See the stackoverflow post and see the list of magic numbers
One way of saving the file is converting it to binary format and save in our database and next method is using App_Data folder.
The storage option is based on your requirement. See this post also
Set upload limit by setting maxRequestLength property to Web.Config like this, where the size of file is specified in KB
<httpRuntime maxRequestLength="51200" executionTimeout="3600" />
You can save your trusted data just in parallel of htdocs/www folder so that any user can not access that folder. Also you can add .htaccess authentication on your trusted data (for .htaccess you should kept your .htpasswd file in parallel of htdocs/www folder) if you are using apache.