Allow restart of a persistent replication

Deleting the _replicator_state property of a replicator document starts a new replication. (This is also supported by CouchDB, but undocumented.) This makes persistent non-continuous replications more useful.
finestructure · Feb 21, 2012 · 56af126 · 56af126
1 parent 20d9fad
commit 56af126
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Showing 4 changed files with 52 additions and 9 deletions.
diff --git a/Source/TDDatabase+Replication.m b/Source/TDDatabase+Replication.m
@@ -67,6 +67,12 @@ - (TDReplicator*) replicatorWithRemoteURL: (NSURL*)remote
 }
 
 
+- (void) stopAndForgetReplicator: (TDReplicator*)repl {
+    [repl databaseClosing];
+    [_activeReplicators removeObjectIdenticalTo: repl];
+}
+
+
 - (void) replicatorDidStop: (NSNotification*)n {
     TDReplicator* repl = n.object;
     if (repl.error)     // Leave it around a while so clients can see the error

diff --git a/Source/TDInternal.h b/Source/TDInternal.h
@@ -54,6 +54,7 @@ extern NSString* const kTDAttachmentBlobKeyProperty;
 @end
 
 @interface TDDatabase (Replication_Internal)
+- (void) stopAndForgetReplicator: (TDReplicator*)repl;
 - (NSString*) lastSequenceWithRemoteURL: (NSURL*)url
                                    push: (BOOL)push;
 - (BOOL) setLastSequence: (NSString*)lastSequence

diff --git a/Source/TDReplicatorManager.m b/Source/TDReplicatorManager.m
@@ -146,10 +146,14 @@ - (BOOL) validateRevision: (TDRevision*)newRev context: (id<TDValidationContext>
     }
 
     // Only certain keys can be changed or removed:
+    NSSet* deletableProperties = [NSSet setWithObjects: @"_replication_state", nil];
     NSSet* mutableProperties = [NSSet setWithObjects: @"filter", @"query_params", nil];
     for (NSString* key in curProperties) {
-        if (![mutableProperties containsObject: key] &&
-                !$equal([curProperties objectForKey: key], [newProperties objectForKey: key])) {
+        id newValue = [newProperties objectForKey: key];
+        if (!newValue && [deletableProperties containsObject: key])
+            ;
+        else if (![mutableProperties containsObject: key] &&
+                !$equal([curProperties objectForKey: key], newValue)) {
             context.errorMessage = $sprintf(@"Cannot modify the '%@' property", key);
             return NO;
         }
@@ -263,8 +267,17 @@ - (void) processInsertion: (TDRevision*)rev {
 
 
 // A replication document has been changed:
-- (void) processUpdate: (TDRevision*)rev ofReplicator: (TDReplicator*)repl {
-    LogTo(Sync, @"ReplicationManager: %@ was updated", rev);
+- (void) processUpdate: (TDRevision*)rev {
+    if (![rev.properties objectForKey: @"_replication_state"]) {
+        // Client deleted the _replication_state property; restart the replicator:
+        LogTo(Sync, @"ReplicatorManager: Restarting replicator for %@", rev);
+        TDReplicator* repl = [_replicatorsByDocID objectForKey: rev.docID];
+        if (repl) {
+            [repl.db stopAndForgetReplicator: repl];
+            [_replicatorsByDocID removeObjectForKey: rev.docID];
+        }
+        [self processInsertion: rev];
+    }
 }
 
 
@@ -280,11 +293,10 @@ - (void) processDeletion: (TDRevision*)rev ofReplicator: (TDReplicator*)repl {
 
 
 - (void) processRevision: (TDRevision*)rev {
-    TDReplicator* repl = [_replicatorsByDocID objectForKey: rev.docID];
-    if (repl)
-        [self processUpdate: rev ofReplicator: repl];
-    else
+    if (rev.generation == 1)
         [self processInsertion: rev];
+    else
+        [self processUpdate: rev];
 }
 
 
@@ -309,6 +321,8 @@ - (void) processAllDocs {
 
 // Notified that a _replicator database document has been created/updated/deleted:
 - (void) dbChanged: (NSNotification*)n {
+    if (_updateInProgress)
+        return;
     TDRevision* rev = [n.userInfo objectForKey: @"rev"];
     LogTo(SyncVerbose, @"ReplicatorManager: %@ %@", n.name, rev);
     NSString* docID = rev.docID;

diff --git a/Source/TDReplicator_Tests.m b/Source/TDReplicator_Tests.m
@@ -205,9 +205,31 @@ static void deleteRemoteDB(void) {
     CAssert(repl);
     CAssertEqual(repl.sessionID, sessionID);
     CAssert(repl.running);
+
+    // Delete the _replication_state property:
+    NSMutableDictionary* updatedProps = [[newRev.properties mutableCopy] autorelease];
+    [updatedProps removeObjectForKey: @"_replication_state"];
+    rev = [TDRevision revisionWithProperties: updatedProps];
+    rev = [replicatorDb putRevision: rev prevRevisionID: rev.revID allowConflict: NO status: &status];
+    CAssertEq(status, 201);
+
+    // Get back the document and verify it's been updated with replicator properties:
+    newRev = [replicatorDb getDocumentWithID: rev.docID revisionID: nil options: 0];
+    Log(@"Updated doc = %@", newRev.properties);
+    sessionID = [newRev.properties objectForKey: @"_replication_id"];
+    CAssert([sessionID length] >= 10);
+    CAssertEqual([newRev.properties objectForKey: @"_replication_state"], @"triggered");
+    CAssert([[newRev.properties objectForKey: @"_replication_state_time"] longLongValue] >= 1000);
+
+    // Check that this restarted the replicator:
+    TDReplicator* newRepl = [sourceDB activeReplicatorWithRemoteURL: remote push: YES];
+    CAssert(newRepl);
+    CAssert(newRepl != repl);
+    CAssertEqual(newRepl.sessionID, sessionID);
+    CAssert(newRepl.running);
 
     // Now delete it:
-    rev = [[[TDRevision alloc] initWithDocID: rev.docID revID: newRev.revID deleted: YES] autorelease];
+    rev = [[[TDRevision alloc] initWithDocID: newRev.docID revID: newRev.revID deleted: YES] autorelease];
     rev = [replicatorDb putRevision: rev prevRevisionID: rev.revID allowConflict: NO status: &status];
     CAssertEq(status, 200);
 }