I'm using NSURLSessionDownloadTask to download some .mov files from a web and storing them in my app.
Now what I'd like to achieve is to
download ALL files of certain type (in this case .mov) available on the page, without having to specify every file URL
download files ONLY if they are not already stored in my app.
Is there any way to achieve this?
You would have to scrape that html page to get all the urls (.mov) you are looking for. Either you can use NSXMLParser if you want to write your own or you can google some library.
When you download a file, persist some metadata (eg. name or some unique identifier) either in SQLite or CoreData, so that you can check if the file has already been downloaded.
Related
I have a Rails application which is suppose to upload images from a Dropbox URL pointed to a folder. The folder contains the images. Application is suppose to upload all images present in folder.
The URL is somewhat like this
https://www.dropbox.com/sh/17fsm6bsnac1g4q/AADJ7B2L0OIrkSrc7YcG-OO9a?dl=0
I can see the images but how can I get the list of all images URL. I have tried parsing the URL by appending dl=1 which downloads the images.
URI.parse('https://www.dropbox.com/sh/17fsm6bsnac1g4q/AADJ7B2L0OIrkSrc7YcG-OO9a?dl=1).
How can I get the URL of all images. If I can not get URL of images then how can i download all images and them upload them.
If you are okay with just downloading everything, you can make a GET request to the dl=1 version of the link you have. This URL parameter is documented here. This will give you a zipped version of the folder which you can then unzip and use as necessary.
Dropbox doesn't offer a way to get links for each of the files in the linked folder, but you can use the Dropbox API to list the files and then download them individually. You can use the /2/files/list_folder endpoint and pass the shared link in as the shared_link parameter. That will give you a list of the items in the folder.
You can then use /2/sharing/get_shared_link_file to download any desired file(s), by passing in the shared link as the url parameter, and the relative path for the file as the path parameter.
In order to be able to access iCloud Drive from the application,
I think that we want to use UIDocumentPickerViewController from the application.
but i found following problems when i use UIDocumentPickerViewController.
Cannot upload multiple files at once.
Cannot Download multiple files at once.
When pushViewController from navigationController then display
become strange.
I want to avoid above problems, So is there any another way to get files information from iCloudDrive without using UIDocumentPickerViewController?
like Send some request or query.
I have searched lot and didn't find any query or request to get Files ,Upload files and download files from iCloudDrive.
if you have any idea about this please tell me.
Thanks,
I don't think there's any straightforward alternative, but you could think of...
...using iCloud directly (not iCloud Drive), but then users will only have access to their files from your application
...using Google Drive's sharing extension which supports uploading multiple files at once (the Dropbox SDK probably supports that, too, but their sharing extension doesn't)
...zipping all files before uploading them
...changing the file format so that it's a bundle of multiple files, if you are in control of the file format
...file a radar/feature request, and possibly wait forever ;)
Not sure if that helps, but I don't think you have much of a choice here.
I am developing an iOS app that uses a large amount of images that are needed for animations for short videos. I want to save my application assets as static files in cloud and once they are needed download them using secure API call (either JSON, XML or any other alternative for that matter).
What is the best option for that. I have checked Parse, Dropbox, iCloud, Google Drive, but I am puzzled since I see only instructions for dynamic data that lets users access content they have created and not static assets.
What would be best option for that?
If you just want an easy way to serve static files I would take a look at Amazon S3. You can just upload files through the online console and then get the public URL to those files to use in your app. You can also use the S3 API to upload files through your web service or iOS app.
Hope this helps!
I'd go for Parse (basically because it is fast to learn and develop), you can create a table with the images and change the writing permissions if you are afraid somebody could modify the table.
Another option that you can check it's the special Config table so you can upload custom files (zip files i.e.) and download them in demand.
Is the only way to download a file through Google Drive through the download_url that is provided? I have the file_id and would like to make one simple call to download the file. Right now it looks like you have to make one call to fetch the file metadata and retrieve the download_url, then another to actually download the file. Is this the only way?
Also, the download_url is described as a "short lived url". How long will this url be available for?
Thanks
Using the download_url is the correct way to download a file from Drive. I'd strongly advise against trying to build the download urls yourself as the resulting code will be likely to break.
A download_url is usually available for hours, but instead of relying on that you should always retrieve the updated file before downloading a file from Drive. More information at this other question: How long does the Google Drive SDK "short lived" download URL exist for?
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.