Refactor to explicit serializer

- Global one can be affected by global settings that can mess things up
- Don't mess with external code when we add contracts/custom serializers etc

Author: mausch

metabase-exporter/ApiObjects.cs

@@ -23,7 +23,7 @@ public class Card
     public ResultMetadata[] ResultMetadata { get; set; }
 
     [JsonProperty("metadata_checksum")]
-    public string MetadataChecksum => GeneralExtensions.MD5Base64(JsonConvert.SerializeObject(ResultMetadata));
+    public string MetadataChecksum => GeneralExtensions.MD5Base64(Program.Serializer.SerializeObject(ResultMetadata));
 
     [JsonProperty("database_id")]
     public DatabaseId DatabaseId { get; set; }

metabase-exporter/GeneralExtensions.cs

@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using Newtonsoft.Json;
 
 namespace metabase_exporter;
 
@@ -40,8 +42,10 @@ public static async Task<IReadOnlyList<TResult>> Sequence<TResult>(this IEnumera
 
     public static string MD5Base64(string x)
     {
-        var md5Value = System.Security.Cryptography.MD5.HashData(Encoding.UTF8.GetBytes(x));
-        return Convert.ToBase64String(md5Value);
+        using (var md5 = System.Security.Cryptography.MD5.Create()) {
+            byte[] md5Value = md5.ComputeHash(Encoding.UTF8.GetBytes(x));
+            return Convert.ToBase64String(md5Value);
+        }            
     }
 
     public static TValue GetOrThrow<TKey, TValue>(this IReadOnlyDictionary<TKey, TValue> dict, TKey key, string error)
@@ -53,4 +57,19 @@ public static TValue GetOrThrow<TKey, TValue>(this IReadOnlyDictionary<TKey, TVa
         throw new KeyNotFoundException($"Key not found: {key}\n{error}");
     }
 
+    public static T DeserializeObject<T>(this JsonSerializer serializer, string rawJson)
+    {
+        using var reader = new StringReader(rawJson);
+        using var jsonReader = new JsonTextReader(reader);
+        return serializer.Deserialize<T>(jsonReader);
+    }
+
+    public static string SerializeObject<T>(this JsonSerializer serializer, T obj)
+    {
+        using var writer = new StringWriter();
+        using var jsonWriter = new JsonTextWriter(writer);
+        serializer.Serialize(jsonWriter, obj);
+        return writer.ToString();
+    }
+
 }

metabase-exporter/MetabaseApi.cs

@@ -32,7 +32,7 @@ HttpRequestMessage request() =>
         var response = await sessionManager.Send(request);
         try
         {
-            return JsonConvert.DeserializeObject<Card>(response);
+            return Program.Serializer.DeserializeObject<Card>(response);
         }
         catch (JsonSerializationException e)
         {
@@ -67,7 +67,7 @@ HttpRequestMessage request() =>
         var response = await sessionManager.Send(request);
         try
         {
-            return JsonConvert.DeserializeObject<Dashboard>(response);
+            return Program.Serializer.DeserializeObject<Dashboard>(response);
         }
         catch (JsonSerializationException e)
         {
@@ -141,7 +141,7 @@ HttpRequestMessage request1() =>
         var response = await sessionManager.Send(request1);
         try
         {
-            return JsonConvert.DeserializeObject<DashboardCard>(response);
+            return Program.Serializer.DeserializeObject<DashboardCard>(response);
         }
         catch (JsonSerializationException e)
         {
@@ -159,7 +159,7 @@ HttpRequestMessage request() =>
         var response = await sessionManager.Send(request);
         try
         {
-            return JsonConvert.DeserializeObject<Collection>(response);
+            return Program.Serializer.DeserializeObject<Collection>(response);
         }
         catch (JsonSerializationException e)
         {
@@ -169,7 +169,7 @@ HttpRequestMessage request() =>
 
     static (StringContent HttpContent, string Json) ToJsonContent(object o)
     {
-        var json = JsonConvert.SerializeObject(o);
+        var json = Program.Serializer.SerializeObject(o);
         var content = new StringContent(json, Encoding.UTF8, "application/json");
         return (content, json);
     }
@@ -191,7 +191,7 @@ public async Task<IReadOnlyList<Card>> GetAllCards()
         HttpRequestMessage request() => new HttpRequestMessage(HttpMethod.Get, new Uri("/api/card", UriKind.Relative));
         var response = await sessionManager.Send(request);
         try {
-            return JsonConvert.DeserializeObject<Card[]>(response);
+            return Program.Serializer.DeserializeObject<Card[]>(response);
         } catch (JsonReaderException e) {
             throw new MetabaseApiException($"Error parsing response for {nameof(Card)} from:\n{response}", e);
         }
@@ -204,7 +204,7 @@ public async Task<IReadOnlyList<Collection>> GetAllCollections()
         response = response.Replace("\"id\":\"root\"", "\"id\":\"0\"");
         try
         {
-            return JsonConvert.DeserializeObject<Collection[]>(response);
+            return Program.Serializer.DeserializeObject<Collection[]>(response);
         }
         catch (JsonSerializationException e)
         {
@@ -217,7 +217,7 @@ public async Task<IReadOnlyList<Dashboard>> GetAllDashboards()
         HttpRequestMessage request() => new HttpRequestMessage(HttpMethod.Get, new Uri("/api/dashboard", UriKind.Relative));
         var response = await sessionManager.Send(request);
         try {
-            var dashboards = JsonConvert.DeserializeObject<Dashboard[]>(response);
+            var dashboards = Program.Serializer.DeserializeObject<Dashboard[]>(response);
             // the endpoint that returns all dashboards does not include all detail for each dashboard
             return await dashboards.Traverse(async dashboard => await GetDashboard(dashboard.Id));
         }
@@ -233,7 +233,7 @@ public async Task<Dashboard> GetDashboard(DashboardId dashboardId)
         var response = await sessionManager.Send(request);
         try
         {
-            return JsonConvert.DeserializeObject<Dashboard>(response);
+            return Program.Serializer.DeserializeObject<Dashboard>(response);
         }
         catch (JsonSerializationException e)
         {
@@ -247,7 +247,7 @@ public async Task<IReadOnlyList<DatabaseId>> GetAllDatabaseIds()
         var response = await sessionManager.Send(request);
         try
         {
-            var databases = JsonConvert.DeserializeObject<JObject>(response)["data"];
+            var databases = Program.Serializer.DeserializeObject<JObject>(response)["data"];
             return databases.Select(d => new DatabaseId((int) d["id"])).ToImmutableList();
         }
         catch (JsonSerializationException e)
@@ -262,7 +262,7 @@ public async Task<RunCardResult> RunCard(CardId card)
         var response = await sessionManager.Send(request);
         try
         {
-            return JsonConvert.DeserializeObject<RunCardResult>(response);
+            return Program.Serializer.DeserializeObject<RunCardResult>(response);
         }
         catch (JsonSerializationException e)
         {

metabase-exporter/Program.cs

@@ -24,25 +24,40 @@ public static async Task Main(string[] args)
 
         var rawConfig = builder.Build();
         var config = ParseConfig(rawConfig);
+            
+        _serializer = JsonSerializer.Create(new JsonSerializerSettings
+        {
+            //Formatting = Formatting.Indented // don't set this, it will mess checksums
+        });
+        _indentedSerializer = JsonSerializer.Create(new JsonSerializerSettings
+        {
+            Formatting = Formatting.Indented,
+        });
+            
         var api = await InitApi(config.MetabaseApiSettings);
         await config.Switch(
             export: api.Export, 
             import: api.Import, 
             testQuestions: _ => api.TestQuestions());
     }
 
+    static JsonSerializer _serializer;
+    public static JsonSerializer Serializer => _serializer;
+
+    static JsonSerializer _indentedSerializer;
+
     static async Task Export(this MetabaseApi api, Config.Export export)
     {
         var state = await api.Export(export.ExcludePersonalCollections);
-        var stateJson = JsonConvert.SerializeObject(state, Formatting.Indented);
+        var stateJson = _indentedSerializer.SerializeObject(state);
         File.WriteAllText(path: export.OutputFilename, contents: stateJson);
         Console.WriteLine($"Exported current state for {export.MetabaseApiSettings.MetabaseApiUrl} to {export.OutputFilename}");
     }
 
     static async Task Import(this MetabaseApi api, Config.Import import)
     {
         var rawState = File.ReadAllText(import.InputFilename);
-        var state = JsonConvert.DeserializeObject<MetabaseState>(rawState);
+        var state = Program.Serializer.DeserializeObject<MetabaseState>(rawState);
         await api.Import(state, import.DatabaseMapping, import.IgnoredDatabases);
         Console.WriteLine($"Done importing from {import.InputFilename} into {import.MetabaseApiSettings.MetabaseApiUrl}");
     }