/// <summary>
/// Get an object by the provided key.
/// Returns null if no object is found.
/// </summary>
/// <param name="key">Lookup key</param>
/// <returns>T</returns>
public virtual async Task<T> Get<T>(string key) where T : class, IKeyProvider
{
try
{
return await _blobCache.GetObject<T>(key);
}
catch (KeyNotFoundException)
{
return null;
}
}
public async Task LoadInfoAsync(ulong guildId)
{
if (Info != null)
{
return;
}
bool needsReset = false;
try
{
Info = await _blobCache.GetObject <CacheInfo>("info");
if (Info.GuildId != guildId)
{
needsReset = true;
}
}
catch (KeyNotFoundException)
{
needsReset = true;
}
if (needsReset)
{
Info = new CacheInfo()
{
GuildId = guildId, Version = 0
};
await SaveInfoAsync().ConfigureAwait(false);
}
}
public static IObservable <T> CacheApiResult <T>(
this IObservable <T> source,
string cacheKey,
IBlobCache blobCache,
IFullLogger?logger = null,
IScheduler?scheduler = null,
bool forceUpdate = false,
TimeSpan expiration = default)
{
expiration = expiration == TimeSpan.Zero ? Constants.DefaultCacheExpirationTimeOut : expiration;
if (forceUpdate)
{
// TODO: [rlittlesii: July 30, 2020] Add retry and cached
return(source.SelectMany(async value =>
{
await blobCache.InsertObject(cacheKey, value, expiration);
logger?.Debug($"CACHE: Writing {{Value}} to cache with key: {{CacheKey}}", value, cacheKey);
return value;
}));
}
blobCache
.GetObject <T>(cacheKey)
.Subscribe(obj => logger?.Debug("Found: {@Object}", obj));
// TODO: [rlittlesii: July 30, 2020] Add retry and cached
return(blobCache
.GetOrFetchObject(
cacheKey,
() => source.Timeout(Constants.DefaultRequestTimeout), DateTimeOffset.Now.Add(expiration)));
}
/// <summary>
/// Check a file to see if it needs to be re-downloaded.
/// </summary>
/// <param name="file">The file to look at for updates, which must already exist in the blob cache</param>
/// <returns>True once if we need to update again.</returns>
/// <remarks>
/// We use the date from the headers of the file to understand if we need to update. That way we don't have to deal
/// with translating time-zones, and anything funny from indico.
///
/// If something goes wrong (e.g. we are offline), the also return false.
/// If the cache is missing the item, then we need to update.
/// </remarks>
public static IObservable <bool> CheckForUpdate(this IFile file, IBlobCache cache)
{
return(cache.GetObject <string>(file.FileDateKey())
.Zip(file.GetFileDate(), (cacheDate, remoteDate) => cacheDate != remoteDate)
.Catch <bool, KeyNotFoundException>(_ => Observable.Return(true))
.Catch(Observable.Return(false)));
}
/// <summary>
/// This method attempts to returned a cached value, while
/// simultaneously calling a Func to return the latest value. When the
/// latest data comes back, it replaces what was previously in the
/// cache.
///
/// This method is best suited for loading dynamic data from the
/// Internet, while still showing the user earlier data.
///
/// This method returns an IObservable that may return *two* results
/// (first the cached data, then the latest data). Therefore, it's
/// important for UI applications that in your Subscribe method, you
/// write the code to merge the second result when it comes in.
///
/// This also means that await'ing this method is a Bad Idea(tm), always
/// use Subscribe.
/// </summary>
/// <param name="key">The key to store the returned result under.</param>
/// <param name="fetchFunc"></param>
/// <param name="fetchPredicate">An optional Func to determine whether
/// the updated item should be fetched. If the cached version isn't found,
/// this parameter is ignored and the item is always fetched.</param>
/// <param name="absoluteExpiration">An optional expiration date.</param>
/// <param name="shouldInvalidateOnError">If this is true, the cache will
/// be cleared when an exception occurs in fetchFunc</param>
/// <returns>An Observable stream containing either one or two
/// results (possibly a cached version, then the latest version)</returns>
public static IObservable <T> GetAndFetchLatest <T>(this IBlobCache This,
string key,
Func <IObservable <T> > fetchFunc,
Func <DateTimeOffset, bool> fetchPredicate = null,
DateTimeOffset?absoluteExpiration = null,
bool shouldInvalidateOnError = false)
{
var fetch = Observable.Defer(() => This.GetObjectCreatedAt <T>(key))
.Select(x => fetchPredicate == null || x == null || fetchPredicate(x.Value))
.Where(x => x != false)
.SelectMany(_ =>
{
var fetchObs = fetchFunc().Catch <T, Exception>(ex =>
{
var shouldInvalidate = shouldInvalidateOnError ?
This.InvalidateObject <T>(key) :
Observable.Return(Unit.Default);
return(shouldInvalidate.SelectMany(__ => Observable.Throw <T>(ex)));
});
return(fetchObs
.SelectMany(x => This.InvalidateObject <T>(key).Select(__ => x))
.SelectMany(x => This.InsertObject <T>(key, x, absoluteExpiration).Select(__ => x)));
});
var result = This.GetObject <T>(key).Select(x => new Tuple <T, bool>(x, true))
.Catch(Observable.Return(new Tuple <T, bool>(default(T), false)));
return(result.SelectMany(x =>
{
return x.Item2 ?
Observable.Return(x.Item1) :
Observable.Empty <T>();
}).Concat(fetch).Multicast(new ReplaySubject <T>()).RefCount());
}
/// <summary>
/// This method attempts to returned a cached value, and fetch one from
/// the web. Optionally, it can continue to query to see if an update is required.
///
/// If the cached value exists, it is returned. Then the predicate is queried to see
/// if the remote value should be refreshed.
///
/// If there is no cached value, then the value is fetched.
///
/// Once the above is done, as the retrySequence comes in, the predicate will
/// be called to see if a refresh is needed. If so, the data will be re-fetched.
///
/// In all cases any remotely fetched data is cached.
///
/// This also means that await'ing this method is a Bad Idea(tm), always
/// use Subscribe. 1-infinity values can be returned depending on the arguments.
/// </summary>
/// <param name="key">The key to store the returned result under.</param>
/// <param name="fetchFunc">A sequence that will return the new values of the data</param>
/// <param name="fetchPredicate">A Func to determine whether
/// the updated item should be fetched. Only called once a cached version exists.</param>
/// <param name="retrySequence">Sequence that will trigger a predicate call followed by
/// a fetch call if the predicate indicates so.</param>
/// <param name="This">The blob cache against which we operate</param>
/// <returns>An Observable stream containing one or more
/// results (possibly a cached version, then the latest version(s))</returns>
public static IObservable <T> GetAndFetchLatest <T>(this IBlobCache This,
string key,
Func <IObservable <T> > fetchFunc,
Func <DateTimeOffset, IObservable <bool> > fetchPredicate,
IObservable <Unit> retrySequence = null,
DateTimeOffset?absoluteExpiration = null
)
{
if (fetchPredicate == null)
{
throw new ArgumentException("fetchPredicate");
}
if (fetchFunc == null)
{
throw new ArgumentException("fetchFunc");
}
// We are going to get the cache value if we can. And then we will run updates after that.
// If we have nothing cached, then we will run the fetch directly. Otherwise we will run the
// fetch sequence.
var getOldKey = This.GetObjectCreatedAt <T>(key);
var refetchIfNeeded = getOldKey
.Where(dt => dt != null && dt.HasValue && dt.Value != null)
.SelectMany(dt => fetchPredicate(dt.Value))
.Where(doit => doit == true)
.Select(_ => default(Unit));
var fetchRequired = getOldKey
.Where(dt => dt == null || !dt.HasValue || dt.Value == null)
.Select(_ => default(Unit));
// Next, get the item...
var fetchFromCache = Observable.Defer(() => This.GetObject <T>(key))
.Catch <T, KeyNotFoundException>(_ => Observable.Empty <T>());
var fetchFromRemote = fetchRequired.Concat(refetchIfNeeded)
.SelectMany(_ => fetchFunc())
.SelectMany(x => This.InsertObject <T>(key, x, absoluteExpiration).Select(_ => x));
var items = fetchFromCache.Concat(fetchFromRemote);
// Once we have these, we also have to kick off a second set of fetches for our retry sequence.
if (retrySequence == null)
{
return(items);
}
var getAfter = retrySequence
.SelectMany(_ => This.GetObjectCreatedAt <T>(key))
.SelectMany(dt => fetchPredicate(dt.Value))
.Where(doit => doit == true)
.SelectMany(_ => fetchFunc())
.SelectMany(x => This.InsertObject <T>(key, x, absoluteExpiration).Select(_ => x));
return(items.Concat(getAfter));
}
public async Task <T> GetFromCache <T>(string cacheName)
{
try
{
T t = await _cache.GetObject <T>(cacheName);
return(t);
}
catch (KeyNotFoundException)
{
return(default);
private async Task <T> GetFromCacheAsync <T>(string cacheKey)
{
try
{
return(await cache.GetObject <T>(cacheKey));
}
catch (KeyNotFoundException)
{
return(default(T));
}
}
public async Task <List <IPage> > FetchPages(string id)
{
Cache = BlobCache.LocalMachine;
List <IPage> getPagesTask = await GetPagesAsync(id);
await Cache.InsertObject("pages", getPagesTask, DateTimeOffset.Now.AddHours(2));
List <IPage> pages = await Cache.GetObject <List <IPage> >("pages");
return(pages);
}
public async Task <UserDto> GetUser()
{
try
{
return(await _blobCache.GetObject <UserDto>($"current_user").ToTask());
}
catch (Exception)
{
return(null);
}
}
public IObservable <T> GetObject <T>(string key)
{
try
{
return(blob.GetObject <T>(key));
}
catch (KeyNotFoundException)
{
return(Observable.Return(default(T)));
}
}
//These methods are the ones we call from courseViewModel and ChapterViewModel
public async Task <List <ChapterLevel> > FetchChapterLevels(string id)
{
Cache = BlobCache.LocalMachine;
List <Chapter> getChaptersTask = await GetChaptersAsync(id);
List <ChapterLevel> chapterLevels = FetchSortedLevels(getChaptersTask);
await Cache.InsertObject("chapters", chapterLevels, DateTimeOffset.Now.AddHours(2));
List <ChapterLevel> chapters = await Cache.GetObject <List <ChapterLevel> >("chapters");
return(chapters);
}
partial void BtnRestoreData_TouchUpInside(UIButton sender)
{
_encryptionProvider.SetPassword(txtPassword.Text);
_encryptedBlobCache
.GetObject <SomeData>("key")
.Do(data => InvokeOnMainThread(() => lblResult.Text = $"Data Restored: {data.SomeName}"))
.Catch((Exception exc) =>
{
InvokeOnMainThread(() => lblResult.Text = $"{exc}");
return(Observable.Empty <SomeData>());
})
.Subscribe();
}
/// <summary>
/// Attempt to return an object from the cache. If the item doesn't
/// exist or returns an error, call a Func to return the latest
/// version of an object and insert the result in the cache.
///
/// For most Internet applications, this method is the best method to
/// call to fetch static data (i.e. images) from the network.
/// </summary>
/// <param name="key">The key to associate with the object.</param>
/// <param name="fetchFunc">A Func which will asynchronously return
/// the latest value for the object should the cache not contain the
/// key.
///
/// Observable.Start is the most straightforward way (though not the
/// most efficient!) to implement this Func.</param>
/// <param name="absoluteExpiration">An optional expiration date.</param>
/// <returns>A Future result representing the deserialized object from
/// the cache.</returns>
public static IObservable <T> GetOrFetchObject <T>(this IBlobCache This, string key, Func <IObservable <T> > fetchFunc, DateTimeOffset?absoluteExpiration = null)
{
return(This.GetObject <T>(key).Catch <T, Exception>(_ =>
{
object dontcare;
var prefixedKey = This.GetHashCode().ToString() + key;
var result = Observable.Defer(() => fetchFunc())
.Do(x => This.InsertObject(key, x, absoluteExpiration))
.Finally(() => inflightFetchRequests.TryRemove(prefixedKey, out dontcare))
.Multicast(new AsyncSubject <T>()).RefCount();
return (IObservable <T>)inflightFetchRequests.GetOrAdd(prefixedKey, result);
}));
}
public T GetObject <T>(string key)
{
try
{
return(_cache.GetObject <T>(key).ToTask().Result);
}
catch (AggregateException ex)
{
if (ex.InnerExceptions.Count == 1 && ex.InnerExceptions[0] is KeyNotFoundException)
{
return(default(T));
}
throw ex;
}
}
/// <summary>
/// Получаем кэш по ключу,
/// если кэша нет взять данные из переданной функции и записать в кэш.
/// </summary>
/// <typeparam name="T">Тип данных получаемых из кеша.</typeparam>
/// <param name="key">Ключ кеша.</param>
/// <param name="fetchFunc">Функция получения данных.Вывозится в случаи если данных нет в кеше.</param>
/// <returns>Данные из кеша</returns>
public static T GetOrPutCached <T>(string key, Func <T> fetchFunc)
{
try
{
T result = Cache.GetObject <T>(key).Wait();
if (result == null)
{
return(PutCache(key, fetchFunc.Invoke()));
}
return(result);
}
catch (KeyNotFoundException)
{
return(PutCache(key, fetchFunc.Invoke()));
}
}
/// <summary>
/// Gets a dictionary filled with the specified keys with their corresponding values.
/// </summary>
/// <typeparam name="T">The type of item to get.</typeparam>
/// <param name="blobCache">The blob cache to extract the values from.</param>
/// <param name="keys">The keys to get the values for.</param>
/// <returns>A observable with the specified values.</returns>
public static IObservable <IDictionary <string, T> > GetObjects <T>(this IBlobCache blobCache, IEnumerable <string> keys)
{
if (blobCache is IObjectBulkBlobCache bulkCache)
{
return(bulkCache.GetObjects <T>(keys));
}
return(keys.ToObservable()
.SelectMany(x =>
{
return blobCache.GetObject <T>(x)
.Select(y => new KeyValuePair <string, T>(x, y))
.Catch <KeyValuePair <string, T>, KeyNotFoundException>(_ => Observable.Empty <KeyValuePair <string, T> >());
})
.ToDictionary(k => k.Key, v => v.Value));
}
public async Task DirectAuth(string login, string password)
{
_currentUserName = login;
_gitHub.Credentials = new Credentials(login, password);
await _gitHub.User.Current();
var persistentId = Id.ToString();
var model = await _blobCache.GetObject <ProviderModel>(persistentId);
model.Token = password;
model.User = login;
await _blobCache.InsertObject(persistentId, model);
_isAuthenticated.OnNext(true);
}
public async Task <T> Get <T> (string key)
{
T u = default(T);
try
{
string res = await cache.GetObject <string>(key);
u = (T)JsonConvert.DeserializeObject(res, typeof(T), settings);
}
catch (KeyNotFoundException ex)
{
Debug.WriteLine(ex.Message);
}
return(u);
}
public static IObservable <T> GetAndRequestFetch <T>(this IBlobCache This,
string key,
Func <IObservable <T> > fetchFunc,
Func <DateTimeOffset?, IObservable <bool> > fetchPredicate,
IObservable <Unit> requestSequence = null,
DateTimeOffset?absoluteExpiration = null
)
{
if (fetchPredicate == null)
{
throw new ArgumentException("fetchPredicate");
}
if (fetchFunc == null)
{
throw new ArgumentException("fetchFunc");
}
// We are going to get the cache value if we can. And then we will run updates after that.
// If we have nothing cached, then we will run the fetch directly. Otherwise we will run the
// fetch sequence.
var getOldKey = This.GetObjectCreatedAt <T>(key);
// Next, get the item...
var fetchFromCache = Observable.Defer(() => This.GetObject <T>(key))
.Catch <T, KeyNotFoundException>(_ => Observable.Empty <T>());
var items = fetchFromCache;
// Once we have these, we also have to kick off a second set of fetches for our retry sequence.
if (requestSequence == null)
{
return(items);
}
// TODO: How can we make this atomic. THe problem is that fetchPredicate may depend on the object having been
// inserted, but because they are on different threads we may get race conditions. So there must be a way...
var getAfter = requestSequence
.SelectMany(_ => This.GetObjectCreatedAt <T>(key))
.SelectMany(dt => fetchPredicate(dt))
.Where(doit => doit == true)
.SelectMany(_ => fetchFunc())
.SelectMany(x => This.InsertObject <T>(key, x, absoluteExpiration).Select(_ => x));
return(items.Concat(getAfter));
}
public Task <T> Get <T>(string key)
{
var t = Task.Run(async() =>
{
try
{
return(await cache.GetObject <T>(key));
}
catch (KeyNotFoundException)
{
return(default(T));
}
});
t.ConfigureAwait(false);
return(t);
}
public static IObservable <IDictionary <string, T> > GetObjects <T>(this IBlobCache This, IEnumerable <string> keys, bool noTypePrefix = false)
{
var bulkCache = This as IObjectBulkBlobCache;
if (bulkCache != null)
{
return(bulkCache.GetObjects <T>(keys));
}
return(keys.ToObservable()
.SelectMany(x =>
{
return This.GetObject <T>(x)
.Select(y => new KeyValuePair <string, T>(x, y))
.Catch <KeyValuePair <string, T>, KeyNotFoundException>(_ => Observable.Empty <KeyValuePair <string, T> >());
})
.ToDictionary(k => k.Key, v => v.Value));
}
/// <summary>
/// Return all objects of a specific Type in the cache.
/// </summary>
/// <param name="blobCache">The cache to get the items.</param>
/// <typeparam name="T">The type of item to get.</typeparam>
/// <returns>A Future result representing all objects in the cache
/// with the specified Type.</returns>
public static IObservable <IEnumerable <T> > GetAllObjects <T>(this IBlobCache blobCache)
{
if (blobCache is IObjectBlobCache objCache)
{
return(objCache.GetAllObjects <T>());
}
// NB: This isn't exactly thread-safe, but it's Close Enough(tm)
// We make up for the fact that the keys could get kicked out
// from under us via the Catch below
return(blobCache.GetAllKeys()
.SelectMany(x => x
.Where(y =>
y.StartsWith(GetTypePrefixedKey(string.Empty, typeof(T)), StringComparison.InvariantCulture))
.ToObservable())
.SelectMany(x => blobCache.GetObject <T>(x)
.Catch(Observable.Empty <T>()))
.ToList());
}
public SettingsService(ILogger logger = null, ISecureBlobCache secureBlobCache = null, IBlobCache localMachineCache = null)
{
_logger = logger ?? Locator.Current.GetService <ILogger>();
_secureBlobCache = secureBlobCache ?? Locator.Current.GetService <ISecureBlobCache>();
_localMachineCache = localMachineCache ?? Locator.Current.GetService <IBlobCache>();
BaseApiUrl = @"http://test.test.no/api";
var log = _logger.ForContext <SettingsService>();
log.Information($"Instantiated: {nameof(SettingsService)}");
// Check and set access token
GetToken()
.ToObservable()
.LogException(log, "Unable to get access token")
.Subscribe();
_localMachineCache.GetObject <bool>(IsNewUserKey)
.Catch <bool, Exception>(ex => Observable.Return(true))
.Subscribe(newUser => IsNewUser = newUser);
}
/// <summary>
/// Return all objects of a specific Type in the cache.
/// </summary>
/// <returns>A Future result representing all objects in the cache
/// with the specified Type.</returns>
public static IObservable <IEnumerable <T> > GetAllObjects <T>(this IBlobCache This)
{
var objCache = This as IObjectBlobCache;
if (objCache != null)
{
return(objCache.GetAllObjects <T>());
}
// NB: This isn't exactly thread-safe, but it's Close Enough(tm)
// We make up for the fact that the keys could get kicked out
// from under us via the Catch below
return(This.GetAllKeys()
.SelectMany(x => x
.Where(y =>
y.StartsWith(GetTypePrefixedKey("", typeof(T))))
.ToObservable())
.SelectMany(x => This.GetObject <T>(x)
.Catch(Observable.Empty <T>()))
.ToList());
}
public object Get(string key, Type t)
{
return(_internalCache.GetObject <object>(key));
}
public Task <T> Get <T>(int id) where T : BaseModel, new()
{
return(Task.FromResult(localBlobCache.GetObject <T>(typeof(T).Name).FirstOrDefault(x => x.Id == id)));
}
public IObservable <IEnumerable <GitHubRepository> > GetRepositories() => _blob.GetObject <IEnumerable <GitHubRepository> >(nameof(GitHubRepository));
private async void RecoverObjects()
{
var animal = (await localData.GetObject <Animal>("Animals").ToTask());
Settings.Name = "JoseMontero";
}
public IObservable <List <PuzzleGroup> > GetPuzzles()
{
IObservable <List <PuzzleGroup> > observableResult = _blobCache.GetObject <List <PuzzleGroup> >("kross");
return(observableResult);
}
