Sincronizzazione di provider di sincronizzazione dei file con altri provider
In questo argomento viene illustrato come creare un'applicazione gestita che consenta a un provider di sincronizzazione dei file di eseguire la sincronizzazione con un altro provider di Sync Framework. In questo caso, l'altro è un provider semplice, ma è comunque possibile utilizzare un provider personalizzato standard. Per ulteriori informazioni sui provider semplici, vedere Implementazione di un provider personalizzato semplice.
Per l'applicazione sono necessari due requisiti principali:
L'applicazione deve implementare IFileDataRetriever come interfaccia di trasferimento dati tra i due provider.
Il provider semplice deve utilizzare lo stesso formato di ID utilizzato dal provider di sincronizzazione dei dati, ovvero un GUID a 16 byte per gli ID replica, un GUID a 16 byte preceduto da un prefisso a 8 byte per gli ID elemento e un Integer a 4 byte per gli ID unità di modifica.
Esempi di codice gestito
Negli esempi inclusi in questa sezione vengono illustrati il codice che riguarda la sincronizzazione di un provider di sincronizzazione dei file e un provider semplice, nonché i requisiti relativi all'ID e all'interfaccia di trasferimento. Per visualizzare il codice nel contesto di un'applicazione completa, vedere l'applicazione "Sync 101 - Synchronizing a File Synchronization Provider with a Simple Provider" disponibile in Code Gallery.
Nell'esempio di codice seguente viene illustrata la corrispondenza della definizione della proprietà IdFormats per il provider semplice con i requisiti indicati in precedenza.
public override SyncIdFormatGroup IdFormats
{
get
{
SyncIdFormatGroup idFormats = new SyncIdFormatGroup();
idFormats.ItemIdFormat.Length = 24;
idFormats.ItemIdFormat.IsVariableLength = false;
idFormats.ReplicaIdFormat.Length = 16;
idFormats.ReplicaIdFormat.IsVariableLength = false;
idFormats.ChangeUnitIdFormat.Length = 4;
idFormats.ChangeUnitIdFormat.IsVariableLength = false;
return idFormats;
}
}
Public Overrides ReadOnly Property IdFormats() As SyncIdFormatGroup
Get
Dim FormatGroup As New SyncIdFormatGroup()
FormatGroup.ItemIdFormat.Length = 24
FormatGroup.ItemIdFormat.IsVariableLength = False
FormatGroup.ReplicaIdFormat.Length = 16
FormatGroup.ReplicaIdFormat.IsVariableLength = False
FormatGroup.ChangeUnitIdFormat.Length = 4
FormatGroup.ChangeUnitIdFormat.IsVariableLength = False
Return FormatGroup
End Get
End Property
Nell'esempio di codice seguente vengono illustrati due dei metodi necessari per i provider semplici, ovvero LoadChangeData e InsertItem. La maggior parte del codice di questi metodi è specifica per l'implementazione di un provider semplice, ma è necessario considerare due aspetti:
LoadChangeData viene utilizzato per caricare i dati enumerati dall'archivio locale (l'archivio gestito dal provider semplice). Questo metodo restituisce i dati sotto forma di oggetto
SimpleFileDataRetriever, che rappresenta l'implementazione dell'esempio di IFileDataRetriever.public override object LoadChangeData(ItemFieldDictionary keyAndExpectedVersion, IEnumerable<SyncId> changeUnitsToLoad, RecoverableErrorReportingContext recoverableErrorReportingContext) { // Figure out which item is being asked for string localRelativePath; long expectedLMT; ParseDictionary(keyAndExpectedVersion, out localRelativePath, out expectedLMT); string localPath = Path.Combine(this.rootFolder, localRelativePath); string currentVersion = File.GetLastWriteTimeUtc(localPath).Ticks.ToString(); // Check if it changed --- race condition! if (File.GetLastWriteTimeUtc(localPath).Ticks != expectedLMT) { recoverableErrorReportingContext.RecordRecoverableErrorForChange( new RecoverableErrorData(null)); return null; } // Return return new SimpleFileDataRetriever(localRelativePath, null, localPath, File.GetAttributes(localPath)); }Public Overrides Function LoadChangeData(ByVal keyAndExpectedVersion As ItemFieldDictionary, ByVal changeUnitsToLoad As IEnumerable(Of SyncId), ByVal recoverableErrorReportingContext As RecoverableErrorReportingContext) As Object ' Figure out which item is being asked for Dim localRelativePath As String = "" Dim expectedLMT As Long ParseDictionary(keyAndExpectedVersion, localRelativePath, expectedLMT) Dim localPath As String = Path.Combine(Me.rootFolder, localRelativePath) Dim currentVersion As String = File.GetLastWriteTimeUtc(localPath).Ticks.ToString() ' Check if it changed --- race condition! If File.GetLastWriteTimeUtc(localPath).Ticks <> expectedLMT Then recoverableErrorReportingContext.RecordRecoverableErrorForChange(Nothing) Return Nothing End If ' Return Return New SimpleFileDataRetriever(localRelativePath, Nothing, localPath, File.GetAttributes(localPath)) End FunctionInsertItem viene utilizzato per inserire i dati nell'archivio locale dall'archivio remoto (l'archivio gestito dal provider di sincronizzazione dei file). Questo metodo esegue il cast dei dati dell'elemento ricevuti in un oggetto IFileDataRetriever. Anche il metodo InsertItem esegue il cast dei dati.
public override void InsertItem(object itemData, IEnumerable<SyncId> changeUnitsToCreate, RecoverableErrorReportingContext recoverableErrorReportingContext, out ItemFieldDictionary keyAndUpdatedVersion, out bool commitKnowledgeAfterThisItem) { // Figure out where to create it IFileDataRetriever fileData = (IFileDataRetriever)itemData; string localPath = Path.Combine(this.rootFolder, Path.Combine(fileData.RelativeDirectoryPath, fileData.FileData.Name)); // Check if it is already there --- name collision if (File.Exists(localPath)) { recoverableErrorReportingContext.RecordConstraintError( ConstructDictionary(Path.Combine(fileData.RelativeDirectoryPath, fileData.FileData.Name))); keyAndUpdatedVersion = null; commitKnowledgeAfterThisItem = false; return; } // Create it File.Copy(fileData.AbsoluteSourceFilePath, localPath); // Return particulars to Simple Provider framework keyAndUpdatedVersion = ConstructDictionary( Path.Combine(fileData.RelativeDirectoryPath, fileData.FileData.Name), File.GetLastWriteTimeUtc(localPath).Ticks); commitKnowledgeAfterThisItem = false; }Public Overrides Sub InsertItem(ByVal itemData As Object, ByVal changeUnitsToCreate As IEnumerable(Of SyncId), ByVal recoverableErrorReportingContext As RecoverableErrorReportingContext, ByRef keyAndUpdatedVersion As ItemFieldDictionary, ByRef commitKnowledgeAfterThisItem As Boolean) ' Figure out where to create it Dim fileData As IFileDataRetriever = DirectCast(itemData, IFileDataRetriever) Dim localPath As String = Path.Combine(Me.rootFolder, Path.Combine(fileData.RelativeDirectoryPath, fileData.FileData.Name)) ' Check if it is already there --- name collision If File.Exists(localPath) Then recoverableErrorReportingContext.RecordConstraintError(ConstructDictionary(Path.Combine(fileData.RelativeDirectoryPath, fileData.FileData.Name))) keyAndUpdatedVersion = Nothing commitKnowledgeAfterThisItem = False Exit Sub End If ' Create it File.Copy(fileData.AbsoluteSourceFilePath, localPath) ' Return particulars to Simple Provider framework keyAndUpdatedVersion = ConstructDictionary(Path.Combine(fileData.RelativeDirectoryPath, fileData.FileData.Name), File.GetLastWriteTimeUtc(localPath).Ticks) commitKnowledgeAfterThisItem = False End Sub
Nell'esempio di codice seguente viene creata la classe SimpleFileDataRetriever, che utilizza AbsoluteSourceFilePath e RelativeDirectoryPath per identificare i percorsi dei file e FileData e FileStream per trasferire i dati effettivi.
class SimpleFileDataRetriever : IFileDataRetriever, IDisposable
{
private string _relativeLocalFilePath;
private Stream _sourceStream;
private string _absoluteSourceFilePath;
private FileAttributes _attributes;
public SimpleFileDataRetriever(string relativeLocalFilePath, Stream sourceStream, string absoluteSourceFilePath, FileAttributes attributes)
{
this._relativeLocalFilePath = relativeLocalFilePath;
this._sourceStream = sourceStream;
this._attributes = attributes;
this._absoluteSourceFilePath = absoluteSourceFilePath;
}
#region IFileDataRetriever Members
// If the local store has no concept of absolute file path then return a NotImplementedException here.
// The FSP will instead use the stream for file copying.
// If implemented, return absolute local path including file name.
public string AbsoluteSourceFilePath
{
get
{
return this._absoluteSourceFilePath;
}
}
public FileData FileData
{
get
{
FileInfo fi = new FileInfo(_absoluteSourceFilePath);
//For the relative path on FileData, provide relative path including file name
return new FileData(
_relativeLocalFilePath,
_attributes,
fi.CreationTimeUtc,
fi.LastAccessTimeUtc,
fi.LastWriteTimeUtc,
fi.Length);
}
}
public System.IO.Stream FileStream
{
get
{
if (this._sourceStream == null)
{
this._sourceStream = new FileStream(this._absoluteSourceFilePath, FileMode.Open);
}
return _sourceStream;
}
}
// Must return the relative path without the filename
public string RelativeDirectoryPath
{
get
{
return Path.GetDirectoryName(_relativeLocalFilePath);
}
}
#endregion
#region IDisposable Members
public void Dispose()
{
if (this._sourceStream != null)
{
this._sourceStream.Close();
}
}
#endregion
}
Class SimpleFileDataRetriever
Implements IFileDataRetriever
' Implements IDisposable
Private _relativeLocalFilePath As String
Private _sourceStream As Stream
Private _absoluteSourceFilePath As String
Private _attributes As FileAttributes
Public Sub New(ByVal relativeLocalFilePath As String, ByVal sourceStream As Stream, ByVal absoluteSourceFilePath As String, ByVal attributes As FileAttributes)
Me._relativeLocalFilePath = relativeLocalFilePath
Me._sourceStream = sourceStream
Me._attributes = attributes
Me._absoluteSourceFilePath = absoluteSourceFilePath
End Sub
#Region "IFileDataRetriever Members"
' If the local store has no concept of absolute file path then return a NotImplementedException here.
' The FSP will instead use the stream for file copying.
' If implemented, return absolute local path including file name.
Public ReadOnly Property AbsoluteSourceFilePath() As String Implements IFileDataRetriever.AbsoluteSourceFilePath
Get
Return Me._absoluteSourceFilePath
End Get
End Property
Public ReadOnly Property FileData() As FileData Implements IFileDataRetriever.FileData
Get
Dim fi As New FileInfo(_absoluteSourceFilePath)
'For the relative path on FileData, provide relative path including file name
Return New FileData(_relativeLocalFilePath, _attributes, fi.CreationTimeUtc, fi.LastAccessTimeUtc, fi.LastWriteTimeUtc, fi.Length)
End Get
End Property
Public ReadOnly Property FileStream() As System.IO.Stream Implements IFileDataRetriever.FileStream
Get
If Me._sourceStream Is Nothing Then
Me._sourceStream = New FileStream(Me._absoluteSourceFilePath, FileMode.Open)
End If
Return _sourceStream
End Get
End Property
' Must return the relative path without the filename
Public ReadOnly Property RelativeDirectoryPath() As String Implements IFileDataRetriever.RelativeDirectoryPath
Get
Return Path.GetDirectoryName(_relativeLocalFilePath)
End Get
End Property
#End Region
#Region "IDisposable Members"
Public Sub Dispose()
If Me._sourceStream IsNot Nothing Then
Me._sourceStream.Close()
End If
End Sub
#End Region
End Class
Nell'esempio di codice seguente vengono sincronizzati i due provider. Il processo di sincronizzazione è identico sia che si esegua la sincronizzazione di due provider di sincronizzazione dei file o di due provider semplici. L'implementazione dell'interfaccia IFileDataRetriever e l'utilizzo dei formati di ID appropriati garantiscono che i dati vengano trasferiti nel modo corretto.
static void DoBidirectionalSync(string pathA, Guid replicaA, string pathB, Guid replicaB)
{
SyncOperationStatistics stats;
MySimpleFileProvider providerA = new MySimpleFileProvider(replicaA, pathA);
FileSyncProvider providerB = new FileSyncProvider(replicaB, pathB);
//Set the custom provider's conflict resolution policy to custom in order to show
//how to perform complex resolution actions.
providerA.Configuration.ConflictResolutionPolicy = ConflictResolutionPolicy.ApplicationDefined;
//Register callbacks so that we can handle conflicts if they are detected, and other events.
RegisterCallbacks(providerA);
RegisterCallbacks(providerB);
//Synchronize the two providers that are specified.
Console.WriteLine("Sync {0} and {1}...", pathA, pathB);
SyncOrchestrator agent = new SyncOrchestrator();
//To avoid writing conflict resolution logic in your matching provider it is good practice to always sync from custom provider
//to FSP provider first. That way the FSP will handle all the conflicts itself. Here we do the opposite to show our custom
//constraint conflict resolution.
agent.Direction = SyncDirectionOrder.UploadAndDownload;
agent.LocalProvider = providerB;
agent.RemoteProvider = providerA;
stats = agent.Synchronize();
//Display the statistics from the SyncOperationStatistics object that is returned
//by Synchronize().
Console.WriteLine("Download Applied:\t {0}", stats.DownloadChangesApplied);
Console.WriteLine("Download Failed:\t {0}", stats.DownloadChangesFailed);
Console.WriteLine("Download Total:\t\t {0}", stats.DownloadChangesTotal);
Console.WriteLine("Upload Total:\t\t {0}", stats.UploadChangesApplied);
Console.WriteLine("Upload Total:\t\t {0}", stats.UploadChangesFailed);
Console.WriteLine("Upload Total:\t\t {0}", stats.UploadChangesTotal);
}
Private Shared Sub DoBidirectionalSync(ByVal pathA As String, ByVal replicaA As Guid, ByVal pathB As String, ByVal replicaB As Guid)
Dim stats As SyncOperationStatistics
Dim providerA As New MySimpleFileProvider(replicaA, pathA)
Dim providerB As New FileSyncProvider(replicaB, pathB)
'Set the custom provider's conflict resolution policy to custom in order to show
'how to perform complex resolution actions.
providerA.Configuration.ConflictResolutionPolicy = ConflictResolutionPolicy.ApplicationDefined
'Register callbacks so that we can handle conflicts if they are detected, and other events.
RegisterCallbacks(providerA)
RegisterCallbacks(providerB)
'Synchronize the two providers that are specified.
Console.WriteLine("Sync {0} and {1}...", pathA, pathB)
Dim agent As New SyncOrchestrator()
'To avoid writing conflict resolution logic in your matching provider it is good practice to always sync from custom provider
'to FSP provider first. That way the FSP will handle all the conflicts itself. Here we do the opposite to show our custom
'constraint conflict resolution.
agent.Direction = SyncDirectionOrder.UploadAndDownload
agent.LocalProvider = providerB
agent.RemoteProvider = providerA
stats = agent.Synchronize()
'Display the statistics from the SyncOperationStatistics object that is returned
'by Synchronize().
Console.WriteLine("Download Applied:" & vbTab & " {0}", stats.DownloadChangesApplied)
Console.WriteLine("Download Failed:" & vbTab & " {0}", stats.DownloadChangesFailed)
Console.WriteLine("Download Total:" & vbTab & vbTab & " {0}", stats.DownloadChangesTotal)
Console.WriteLine("Upload Total:" & vbTab & vbTab & " {0}", stats.UploadChangesApplied)
Console.WriteLine("Upload Total:" & vbTab & vbTab & " {0}", stats.UploadChangesFailed)
Console.WriteLine("Upload Total:" & vbTab & vbTab & " {0}", stats.UploadChangesTotal)
End Sub
Vedere anche
Concetti
Implementazione di un provider personalizzato semplice
Integrazione di dati da provider diversi
Sincronizzazione di file