Fixes #12, Fixes #13: Update data in main thread only once a day

ToyLoadingScreen/ToyLoadingScreen/HGChild.h

@@ -10,12 +10,12 @@
 
 @interface HGChild : NSManagedObject
 
-@property (nonatomic, strong) NSString* name;
-@property (nonatomic, strong) NSString* biography;
-@property (nonatomic, strong) NSString* gender;
-@property (nonatomic, strong) NSDate* birthday;
-@property (nonatomic, strong) NSString* thumbnail;
-@property (nonatomic, strong) NSSet* media;
+@property (nonatomic, strong) NSString *name;
+@property (nonatomic, strong) NSString *biography;
+@property (nonatomic, strong) NSString *gender;
+@property (nonatomic, strong) NSDate *birthday;
+@property (nonatomic, strong) NSString *thumbnail;
+@property (nonatomic, strong) NSSet *media;
 
 + (HGChild *)addChildFromData:(NSDictionary *)data toContext:(NSManagedObjectContext *)context;
 

ToyLoadingScreen/ToyLoadingScreen/HGChildTableViewController.m

@@ -38,9 +38,11 @@ - (void)viewDidLoad {
     self.refreshControl = [[UIRefreshControl alloc] init];
     [self.refreshControl addTarget:self.dataController action:@selector(fetchRemoteData) forControlEvents:UIControlEventValueChanged];
 
-    // Get updates from the web and start the pull to refresh spinner.
-    [self.refreshControl beginRefreshing];
-    [self.dataController fetchRemoteData];
+    // If data is more than a day old, get updates from the web and start the pull to refresh spinner.
+    if ([self.dataController isDataStale]) {
+        [self.refreshControl beginRefreshing];
+        [self.dataController fetchRemoteData];
+    }
 }
 
 // Set the number of sections in the table.

ToyLoadingScreen/ToyLoadingScreen/HGDataController.h

@@ -24,5 +24,6 @@
 
 - (void)fetchLocalData;
 - (void)fetchRemoteData;
+- (BOOL)isDataStale;
 
 @end

ToyLoadingScreen/ToyLoadingScreen/HGDataController.m

@@ -87,6 +87,17 @@ - (BOOL)isNewVersion:(NSString *)version {
     return ![storedVersion.value isEqualToString:version];
 }
 
+// Check if data has not been updated in one day.
+- (BOOL)isDataStale {
+    NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:NSStringFromClass([HGVersion class])];
+    NSArray *versions = [self.managedObjectContext executeFetchRequest:request error:nil];
+    if (versions.count == 0) {
+        return YES;
+    }
+    HGVersion *storedVersion = (HGVersion *)versions[0];
+    return [storedVersion.date timeIntervalSinceNow] < -(60 * 60 * 24);
+}
+
 // Clear all children in the store and replace them with the children in the given JSON object.
 - (void)update:(NSDictionary *)data version:(NSString *)version  {
     // Don't update the store if the version has already been saved.
@@ -95,37 +106,27 @@ - (void)update:(NSDictionary *)data version:(NSString *)version  {
         return;
     }
 
-    NSLog(@"Dispatching a JSON processing thread.");
-    // Create a background thread to store the new data in another managed object context.
-    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
-        NSManagedObjectContext *backgroundContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSConfinementConcurrencyType];
-        backgroundContext.parentContext = self.managedObjectContext;
-
-        // Store data from JSON into the background managed object context.
-        [HGVersion addVersion:version toContext:backgroundContext];
-        for (NSDictionary *childData in data[@"children"]) {
-            HGChild *child = [HGChild addChildFromData:childData toContext:backgroundContext];
-            NSMutableSet *media = [[NSMutableSet alloc] init];
-            for (NSDictionary *mediaItemData in childData[@"media"]) {
-                HGMediaItem *mediaItem = [HGMediaItem addMediaItemFromData:mediaItemData toContext:backgroundContext];
-                [media addObject:mediaItem];
-            }
-            child.media = media;
+    // Remove all children from the store.
+    [self deleteAllEntitiesOfName:NSStringFromClass([HGVersion class])];
+    [self deleteAllEntitiesOfName:NSStringFromClass([HGChild class])];
+
+    // Add children from the web response.
+    [HGVersion addVersion:version toContext:self.managedObjectContext];
+    for (NSDictionary *childData in data[@"children"]) {
+        HGChild *child = [HGChild addChildFromData:childData toContext:self.managedObjectContext];
+        NSMutableSet *media = [[NSMutableSet alloc] init];
+        for (NSDictionary *mediaItemData in childData[@"media"]) {
+            HGMediaItem *mediaItem = [HGMediaItem addMediaItemFromData:mediaItemData toContext:self.managedObjectContext];
+            [media addObject:mediaItem];
         }
-
-        NSLog(@"Saving background context.");
-        NSError *error = nil;
-        if (![backgroundContext save:&error]) {
-            NSLog(@"Background context save failed: %@, %@", error.localizedDescription, error.userInfo);
-        };
+        child.media = media;
+    }
 
-        [self.managedObjectContext performBlock:^{
-            NSError *error = nil;
-            if (![self.managedObjectContext save:&error]) {
-                NSLog(@"Main context save failed: %@, %@", error.localizedDescription, error.userInfo);
-            }
-        }];
-    });
+    // Save the context.
+    NSError *error = nil;
+    if (![self.managedObjectContext save:&error]) {
+        NSLog(@"Context save failed: %@, %@", error.localizedDescription, error.userInfo);
+    };
 }
 
 @end

ToyLoadingScreen/ToyLoadingScreen/HGManagedObjectContext.m

@@ -31,6 +31,7 @@ + (NSManagedObjectModel *)createManagedObjectModel {
 
     // Create the version entity description.
     NSAttributeDescription *versionValueDescription = [[self class] createAttributeDescription:@"value" type:NSStringAttributeType optional:NO indexed:NO];
+    NSAttributeDescription *versionDateDescription = [[self class] createAttributeDescription:@"date" type:NSDateAttributeType optional:NO indexed:NO];
     NSEntityDescription *versionEntity = [[NSEntityDescription alloc] init];
     versionEntity.name = NSStringFromClass([HGVersion class]);
 
@@ -60,7 +61,7 @@ + (NSManagedObjectModel *)createManagedObjectModel {
     childMediaDescription.deleteRule = NSCascadeDeleteRule;
 
     // Add the attribute descriptions to the entity descriptions and the entity descriptions to the managed object context.
-    versionEntity.properties = @[versionValueDescription];
+    versionEntity.properties = @[versionValueDescription, versionDateDescription];
     childEntity.properties = @[childNameDescription, childBiographyDescription, childGenderDescription, childBirthdayDescription, childThumbnailDescription, childMediaDescription];
     mediaEntity.properties = @[mediaUrlDescription, mediaTypeDescription];
     managedObjectModel.entities = @[versionEntity, childEntity, mediaEntity];

ToyLoadingScreen/ToyLoadingScreen/HGMediaItem.h

@@ -10,8 +10,8 @@
 
 @interface HGMediaItem : NSManagedObject
 
-@property (nonatomic, strong) NSString* url;
-@property (nonatomic, strong) NSString* type;
+@property (nonatomic, strong) NSString *url;
+@property (nonatomic, strong) NSString *type;
 
 + (HGMediaItem *)addMediaItemFromData:(NSDictionary *)data toContext:(NSManagedObjectContext *)context;
 

ToyLoadingScreen/ToyLoadingScreen/HGVersion.h

@@ -10,7 +10,8 @@
 
 @interface HGVersion : NSManagedObject
 
-@property (nonatomic, strong) NSString* value;
+@property (nonatomic, strong) NSString *value;
+@property (nonatomic, strong) NSDate *date;
 
 + (HGVersion *)addVersion:(NSString *)value toContext:(NSManagedObjectContext *)context;
 

ToyLoadingScreen/ToyLoadingScreen/HGVersion.m

@@ -11,11 +11,13 @@
 @implementation HGVersion
 
 @dynamic value;
+@dynamic date;
 
 // Add a media item entity to the managed object context and populate it with data from a JSON dictionary.
 + (HGVersion *)addVersion:(NSString *)value toContext:(NSManagedObjectContext *)context {
     HGVersion *version = [NSEntityDescription insertNewObjectForEntityForName:NSStringFromClass([self class]) inManagedObjectContext:context];
     version.value = value;
+    version.date = [NSDate date];
     return version;
 }
 

ToyLoadingScreen/ToyLoadingScreen/main.m

@@ -10,8 +10,7 @@
 
 #import "HGAppDelegate.h"
 
-int main(int argc, char *argv[])
-{
+int main(int argc, char *argv[]) {
     @autoreleasepool {
         return UIApplicationMain(argc, argv, nil, NSStringFromClass([HGAppDelegate class]));
     }