public virtual void Add <T>(T instance) where T : class
{
if (instance == null)
{
throw new ArgumentNullException(nameof(instance));
}
var type = typeof(T);
var value = _idAccessor.GetId(instance);
var key = _idManager.GetFromId(typeof(T), value);
if (key == null)
{
key = _idManager.GenerateId(type);
_idAccessor.SetId(instance, key.Id);
}
var entry = new SessionEntry()
{
Action = ActionType.Add,
Instance = instance,
Key = key
};
_sessionCache.Attach(entry);
}
public ITransaction Setup(IEnumerable <object> items)
{
var txnEntries = items.Select(x =>
{
var type = x.GetType().Name;
var id = _idAccessor.GetId(x)?.ToString();
var rev = _revisionAccessor.GetRevision(x)?.ToString();
var txn = new TransactionEntry()
{
DateTime = DateTime.UtcNow,
Id = $"{id}-{type}",
ActualId = id,
ActualRev = rev,
Type = type
};
return(txn);
});
var transaction = new Transaction(_couchDb, _idAccessor, _revisionAccessor);
try
{
transaction.Init(txnEntries);
}
catch (Exception e)
{
transaction.Rollback(e);
throw;
}
return(transaction);
}
public Task <IEnumerable <LoadContext> > Execute(QueryContext context,
Next <QueryContext, IEnumerable <LoadContext> > next)
{
var ctx = context;
var q = ctx.Query;
var query = new MongoQueryRequest
{
Selector = q.Selector,
Limit = q.Limit,
Skip = q.Skip,
Sort = q.Sort
};
var allDocs = _couchDb.MongoQuery(query);
//using the loaded docs, update the context entries.
var results =
(from entity in allDocs.Docs
let id = _idAccessor.GetId(entity)
let key = _idManager.GetFromId(entity.GetType(), id)
select new LoadContext()
{
Entity = entity,
Key = key,
Type = entity.GetType()
}).ToList();
return(Task.FromResult((IEnumerable <LoadContext>)results));
}
public Task Execute(IEnumerable <LoadContext> context, Next <IEnumerable <LoadContext> > next)
{
var items = context.ToList(); //ensure 1 iteration over list. (tasks to run once)
//we do not want to load items which have been loaded from the cache
var toLoad = items.Where(x => !x.LoadedFromCache).ToDictionary(loadContext => loadContext.Key.CouchDbId);
var allDocs = _couchDb.LoadAllEntities(new AllDocsRequest()
{
Keys = toLoad.Keys
});
//using the loaded docs, update the context entries.
foreach (var entity in allDocs.Rows.Select(x => x.Doc))
{
var id = _idAccessor.GetId(entity);
var key = _idManager.GetFromId(entity.GetType(), id);
toLoad[key.CouchDbId].Entity = entity;
}
return(Task.CompletedTask);
}
public void Init(IEnumerable <TransactionEntry> txnEntries)
{
_txnEntries = new Dictionary <string, TransactionEntry>();
foreach (var txnEntry in txnEntries)
{
txnEntry.TransactionId = _id;
_txnEntries.Add(txnEntry.ActualId, txnEntry);
}
var now = DateTime.UtcNow;
bool HasExpired(DateTime time) => new TimeSpan(now.Ticks - time.Ticks).TotalSeconds > 5;
var existingTransactionEntries = _couchDb
.LoadAllEntities(
new AllDocsRequest()
{
Keys = _txnEntries.Values.Select(x => x.Id) //checking against transaction key for documents
})
.Rows
.Select(x => x.Doc)
.Cast <TransactionEntry>()
.ToList();
var hasTransactionLockConflict = existingTransactionEntries.Any(x => HasExpired(x.DateTime));
if (hasTransactionLockConflict)
{
throw new TransactionException(existingTransactionEntries.Select(x => x.Id).ToList());
}
var payload = new BulkDocsRequest()
{
Docs = _txnEntries.Values.Select(
txn => new BulkDocRequest()
{
Id = txn.Id,
Content = txn
})
};
_results = _couchDb.BulkApplyChanges(payload).ToList();
//now we have a txn (lock) we confirm the target docs are still on the same rev
var conflictingDocs = _couchDb.LoadAllEntities(
new AllDocsRequest()
{
Keys = _txnEntries.Values.Select(x => x.ActualId)
})
.Rows
.Select(x => x.Doc)
.Select(x => new
{
Id = _idAccessor.GetId(x).ToString(),
Rev = _revisionAccessor.GetRevision(x)?.ToString()
})
.Where(x =>
{
if (!_txnEntries.TryGetValue(x.Id, out var entry))
{
return(false);
}
return(entry.ActualRev != x.Rev);
})
.ToList();
if (conflictingDocs.Any())
{
throw new AggregateException(conflictingDocs.Select(x => new ConflictException(x.Id, x.Rev, "conflict", "stale reference")));
}
}
