SpaceFactoryNetworking

A collection of classes useful for fetching and persisting file data. Built on top of NSURLSession.

Features

Download data directly to disk from an NSURL or NSURLRequest.
Files continue to download when the app is suspended.
Data is automatically moved to persistent storage on disk.
Data can be encrypted using standard iOS disk encryption.
If protected file access is unavailable, data is queued for encryption at a later date.
Specify a disk size limit in bytes. If data on disk exceeds this limit, specific files are chosen and evicted using a combination of the file's last access date and file size.
Specify an identifier when fetching a file. This identifier can be used to check for the existence of a file on disk, or to evict a file.
Specify an optional file group for each file to associate it with other files.
Specify a task priority for a fetch.
Initiate a manual eviction of a file with an identifier and file group, evict all files in a file group, or evict the entire disk cache.
Ignore the results of a currently running fetch operation. This uninstalls the completion handler, but continues downloading the file.
If a fetch is in progress, and another fetch is initiated for the same resource, the second completion handler is installed on the currently running fetch, preventing duplicate data.
Inject existing data to be persisted by the file manager.
Image manager uses a file manager to fetch / persist image data specifically.

Usage

Initialization & Configuration:

self.fileManager = [[SFSFileManager alloc] init];
self.fileManager.usesEncryptionByDefault = YES;
self.fileManager.diskSizeLimit = 512 * 1024 * 1024; // 512 MB

Simplest Fetch:

NSURL *url = [NSURL URLWithString:@"http://placekitten/600/500"];
[self.fileManager fetchFileDataAtURL:url withCompletion:^(NSURL *fileURL, NSError *error) {

    // data fetched using '[url absoluteString]' as the identifier 
    // and 'SFSFileManagerDefaultFileGroup' as the file group
}];

Complex Fetch:

NSURL *url = [NSURL URLWithString:@"http://myapi.com/users"];
NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url];
[request setValue:<#auth string#> forHTTPHeaderField:@"Authorization"];

SFSFileFetchRequest *request = [SFSFileFetchRequest request];
request.urlRequest = urlRequest;
request.identifier = @"12345";
request.fileGroup = @"userDataGroup";
request.encryptionPolicy = SFSFileFetchRequestEncryptionPolicyUseEncryption;
request.taskPriority = SFSFileFetchRequestTaskPriorityHigh;

__typeof__(self) __weak weakSelf = self;
id<SFSTask> task = [self.fileManager fetchFileDataUsingFetchRequest:request withCompletion:^(NSURL *fileURL, NSError *error) {
    
    [weakSelf useFileAtURL:fileURL error:error];
}];

// Some time later...

if ([task isRunning])
{
    [task ignoreResults]; //will cause the above completion block to not be called, but will not cancel the request.
    // or
    [task cancelRequest];
}

Image Manager:

// using 'nil' causes a file manager to be created for you.
self.imageManager = [[SFSImageManager alloc] initWithFileManager:nil]; 

NSURL *url = [NSURL URLWithString:@"http://placekitten/600/500"];

__typeof__(self) __weak weakSelf = self;
[self.imageManager fetchImageAtURL:url withCompletion:^(UIImage *image, NSError *error) {
    
    // completion is executed on the main thread.
    weakSelf.imageView.image = image;
}];

Integration

By far, the easiest way to integrate SpaceFactoryNetworking is using CocoaPods:

# Example Podfile
pod 'SpaceFactoryNetworking'

Otherwise, you can clone this repo, and import files from the 'SpaceFactoryNetworking/Core' folder.

Collaborate

You are welcome to submit pull requests to this project. If you are considering doing so, please reach out to me at daltonclaybrook@gmail.com. I'd like to touch base.

Potential additions:

Unit Tests (much needed)
More screens in the Example app to demonstrate functionality
Callbacks to report progress on a download

Known Issues:

File access may not fail gracefully if the protected file is accessed while the app is in the background and the device is locked.