CSHARP-3748: Versioned API Strict Migration Example for Docs. (#651)

Author: DmitryLukyanov

tests/MongoDB.Driver.Examples/VersionedApiExamples.cs

@@ -13,10 +13,15 @@
 * limitations under the License.
 */
 
+using System;
+using MongoDB.Bson;
+using Xunit;
+
 namespace MongoDB.Driver.Examples
 {
     public class VersionedApiExamples
     {
+        [Fact]
         public void ConfigureServerApi()
         {
             // Start Versioned API Example 1
@@ -28,6 +33,7 @@ public void ConfigureServerApi()
             // End Versioned API Example 1
         }
 
+        [Fact]
         public void ConfigureServerApiStrict()
         {
             // Start Versioned API Example 2
@@ -39,6 +45,7 @@ public void ConfigureServerApiStrict()
             // End Versioned API Example 2
         }
 
+        [Fact]
         public void ConfigureServerApiNonStrict()
         {
             // Start Versioned API Example 3
@@ -50,6 +57,7 @@ public void ConfigureServerApiNonStrict()
             // End Versioned API Example 3
         }
 
+        [Fact]
         public void ConfigureServerApiDeprecationErrors()
         {
             // Start Versioned API Example 4
@@ -60,5 +68,52 @@ public void ConfigureServerApiDeprecationErrors()
             var mongoClient = new MongoClient(mongoClientSettings);
             // End Versioned API Example 4
         }
+
+        [Fact]
+        public void VersionedAPI_Strict_Migration_Example()
+        {
+            var connectionString = "mongodb://localhost";
+            var serverApi = new ServerApi(ServerApiVersion.V1, strict: true);
+            var mongoClientSettings = MongoClientSettings.FromConnectionString(connectionString);
+            mongoClientSettings.ServerApi = serverApi;
+            var mongoClient = new MongoClient(mongoClientSettings);
+            var database = mongoClient.GetDatabase("test");
+            database.DropCollection("coll");
+            var collection = database.GetCollection<BsonDocument>("coll");
+
+            // 1. Populate a test sales collection:
+            collection.InsertMany(
+                new[]
+                {
+                    BsonDocument.Parse(@"{ ""_id"" : 1, ""item"" : ""ab"", ""price"" : 10, ""quantity"" : 2, ""date"" : ISODate(""2021-01-01T08:00:00Z"") }"),
+                    BsonDocument.Parse(@"{ ""_id"" : 2, ""item"" : ""jkl"", ""price"" : 20, ""quantity"" : 1, ""date"" : ISODate(""2021-02-03T09:00:00Z"") }"),
+                    BsonDocument.Parse(@"{ ""_id"" : 3, ""item"" : ""xyz"", ""price"" : 5, ""quantity"" : 5, ""date"" : ISODate(""2021-02-03T09:05:00Z"") }"),
+                    BsonDocument.Parse(@"{ ""_id"" : 4, ""item"" : ""abc"", ""price"" : 10, ""quantity"" : 10, ""date"" : ISODate(""2021-02-15T08:00:00Z"") }"),
+                    BsonDocument.Parse(@"{ ""_id"" : 5, ""item"" : ""xyz"", ""price"" : 5, ""quantity"" : 10, ""date"" : ISODate(""2021-02-15T09:05:00Z"") }"),
+                    BsonDocument.Parse(@"{ ""_id"" : 6, ""item"" : ""xyz"", ""price"" : 5, ""quantity"" : 5, ""date"" : ISODate(""2021-02-15T12:05:10Z"") }"),
+                    BsonDocument.Parse(@"{ ""_id"" : 7, ""item"" : ""xyz"", ""price"" : 5, ""quantity"" : 10, ""date"" : ISODate(""2021-02-15T14:12:12Z"") }"),
+                    BsonDocument.Parse(@"{ ""_id"" : 8, ""item"" : ""abc"", ""price"" : 10, ""quantity"" : 5, ""date"" : ISODate(""2021-03-16T20:20:13Z"") }")
+                });
+
+            // 2. The response from the server when running count using a strict client:
+            try
+            {
+#pragma warning disable CS0618 // Type or member is obsolete
+                collection.Count(FilterDefinition<BsonDocument>.Empty);
+#pragma warning restore CS0618 // Type or member is obsolete
+            }
+            catch (MongoCommandException ex)
+            {
+                Console.WriteLine(ex.Code); // 323
+                Console.WriteLine(ex.CodeName); // APIStrictError
+                Console.WriteLine(ex.Message); // Command count failed: Provided apiStrict:true, but the command count is not in API Version 1. Information on supported commands and migrations in API Version 1 can be found at https://dochub.mongodb.org/core/manual-versioned-api.
+            }
+
+            // 3. An alternative, accepted command to count the number of documents:
+            var count = collection.CountDocuments(FilterDefinition<BsonDocument>.Empty);
+
+            // 4. The output of the above command:
+            Console.WriteLine(count); // 8
+        }
     }
 }