Merge pull request OData#529 from OData/robertmclaws-modelproducerfix

Fix ModelProducer to handle multiple APIs with different DbContexts
chinadragon0515 · Dec 27, 2016 · fbe309c · fbe309c
2 parents ae7167a + d1e5944
commit fbe309c
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Showing 3 changed files with 48 additions and 4 deletions.
diff --git a/src/Microsoft.Restier.Providers.EntityFramework/Model/ModelProducer.cs b/src/Microsoft.Restier.Providers.EntityFramework/Model/ModelProducer.cs
@@ -62,7 +62,27 @@ public Task<IEdmModel> GetModelAsync(ModelContext context, CancellationToken can
             var dbContext = context.GetApiService<DbContext>();
 
             var efModel = (dbContext as IObjectContextAdapter).ObjectContext.MetadataWorkspace;
-            var efEntityContainer = efModel.GetItems<EntityContainer>(DataSpace.CSpace).Single();
+            // @robertmclaws: The query below actually returns all registered Containers across all registered DbContexts.
+            //                 It is likely a bug in some other part of OData. But we can roll with it.
+            var efEntityContainers = efModel.GetItems<EntityContainer>(DataSpace.CSpace);
+            // @robertmclaws: Because of the bug above, we should not make any assumptions about what is returned, and get 
+            //                the specific container we want to use. Even if the bug gets fixed, the next line should still 
+            //                continue to work.
+            var efEntityContainer = efEntityContainers.FirstOrDefault(c => c.Name == dbContext.GetType().Name);
+            // @robertmclaws: Now that we're doing a proper FirstOrDefault() instead of a Single(), we wont' crash if more
+            //                than one is returned, and we can check for null and inform the user specifically what happened.
+            if (efEntityContainer == null)
+            {
+                if (efEntityContainers.Count > 1)
+                {
+                    // @robertmclaws: In this case, we have multiple DbContexts available, but none of them match up.
+                    //                Tell the user what we have, and what we were expecting, so they can fix it.
+                    var containerNames = efEntityContainers.Aggregate("", (current, next) => next.Name + ", ");
+                    throw new Exception(string.Format(Resources.MultipleDbContextsExpectedException, containerNames.Substring(0, containerNames.Length - 2), efEntityContainer.Name));
+                }
+                // @robertmclaws: In this case, we only had one DbContext available, and if wasn't thw right one.
+                throw new Exception(string.Format(Resources.DbContextCouldNotBeFoundException, dbContext.GetType().Name, efEntityContainer.Name));
+            }
             var itemCollection = (ObjectItemCollection)efModel.GetItemCollection(DataSpace.OSpace);
 
             foreach (var efEntitySet in efEntityContainer.EntitySets)

diff --git a/src/Microsoft.Restier.Providers.EntityFramework/Properties/Resources.Designer.cs b/src/Microsoft.Restier.Providers.EntityFramework/Properties/Resources.Designer.cs
diff --git a/src/Microsoft.Restier.Providers.EntityFramework/Properties/Resources.resx b/src/Microsoft.Restier.Providers.EntityFramework/Properties/Resources.resx
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <root>
   <!-- 
     Microsoft ResX Schema 
@@ -120,12 +120,18 @@
   <data name="DataModificationMustBeCUD" xml:space="preserve">
     <value>A DataModificationEntry must be either New, Update or Delete.</value>
   </data>
+  <data name="DbContextCouldNotBeFoundException" xml:space="preserve">
+    <value>Could not find the correct DbContext instance for this EntityFrameworkApi. \r\n The Context name was '{0}' but the Container expects '{1}'.</value>
+  </data>
   <data name="InvalidLineStringGeographyType" xml:space="preserve">
     <value>Need 'LineString type', while input is {0}.</value>
   </data>
   <data name="InvalidPointGeographyType" xml:space="preserve">
     <value>Need 'Point type', while input is {0}.</value>
   </data>
+  <data name="MultipleDbContextsExpectedException" xml:space="preserve">
+    <value>This project has multiple EntityFrameworkApis using different DbContexts, and the correct context could not be loaded. \r\n The contexts available are '{0}' but the Container expects '{1}'.</value>
+  </data>
   <data name="PreconditionCheckFailed" xml:space="preserve">
     <value>The precondition check for request {0} on resource {1} is failed.</value>
   </data>
@@ -136,4 +142,4 @@
   <data name="UnsupportedPropertyType" xml:space="preserve">
     <value>Unsupported type for property: {0}.</value>
   </data>
-</root>
+</root>