feat: add required field management in csharp newtonsoft serializer (#2117)

Author: fr-th

docs/languages/Csharp.md

@@ -47,6 +47,7 @@ Requires [System.Text.Json](https://devblogs.microsoft.com/dotnet/try-the-new-sy
 #### Using Newtonsoft/Json.NET
 
 To include functionality that convert the models using the [Newtonsoft/Json.NET](https://www.newtonsoft.com/json) framework, to use this, use the preset `CSHARP_NEWTONSOFT_SERIALIZER_PRESET`.
+You can use the option "enforceRequired" to prevent deserialization if any required field is missing.
 
 Check out this [example for a live demonstration](../../examples/csharp-generate-newtonsoft-serializer).
 

examples/csharp-generate-newtonsoft-serializer/__snapshots__/index.spec.ts.snap

@@ -5,13 +5,20 @@ Array [
   "[JsonConverter(typeof(RootConverter))]
 public partial class Root
 {
-  private string? email;
+  private string email;
+  private string? name;
 
-  public string? Email 
+  public string Email 
   {
     get { return email; }
     set { this.email = value; }
   }
+
+  public string? Name 
+  {
+    get { return name; }
+    set { this.name = value; }
+  }
 }
 
 public class RootConverter : JsonConverter<Root>
@@ -21,8 +28,14 @@ public class RootConverter : JsonConverter<Root>
   JObject jo = JObject.Load(reader);
   Root value = new Root();
 
-  if(jo[\\"email\\"] != null) {
-  value.Email = jo[\\"email\\"].ToObject<string?>(serializer);
+  if(jo[\\"email\\"] is null){
+  throw new JsonSerializationException(\\"Required property 'email' is missing\\");
+}
+
+value.Email = jo[\\"email\\"].ToObject<string>(serializer);
+
+if(jo[\\"name\\"] != null) {
+  value.Name = jo[\\"name\\"].ToObject<string?>(serializer);
 }
 
   
@@ -36,6 +49,10 @@ public class RootConverter : JsonConverter<Root>
 {
   jo.Add(\\"email\\", JToken.FromObject(value.Email, serializer));
 }
+if (value.Name != null)
+{
+  jo.Add(\\"name\\", JToken.FromObject(value.Name, serializer));
+}
   
 
   jo.WriteTo(writer);

examples/csharp-generate-newtonsoft-serializer/index.ts

@@ -4,17 +4,28 @@ import {
 } from '../../src';
 
 const generator = new CSharpGenerator({
-  presets: [CSHARP_NEWTONSOFT_SERIALIZER_PRESET]
+  presets: [
+    {
+      preset: CSHARP_NEWTONSOFT_SERIALIZER_PRESET,
+      options: {
+        enforceRequired: true
+      }
+    }
+  ]
 });
 
 const jsonSchemaDraft7 = {
   $schema: 'http://json-schema.org/draft-07/schema#',
   type: 'object',
   additionalProperties: false,
+  required: ['email'],
   properties: {
     email: {
       type: 'string',
       format: 'email'
+    },
+    name: {
+      type: 'string'
     }
   }
 };

examples/csharp-generate-newtonsoft-serializer/package-lock.json

@@ -46,6 +46,7 @@ export interface CSharpOptions extends CommonGeneratorOptions<CSharpPreset> {
   autoImplementedProperties: boolean;
   modelType: 'class' | 'record';
   handleNullable: boolean;
+  enforceRequired: boolean;
 }
 export type CSharpConstantConstraint = ConstantConstraint<CSharpOptions>;
 export type CSharpEnumKeyConstraint = EnumKeyConstraint<CSharpOptions>;
@@ -77,6 +78,7 @@ export class CSharpGenerator extends AbstractGenerator<
     autoImplementedProperties: false,
     handleNullable: false,
     modelType: 'class',
+    enforceRequired: false,
     // Temporarily set
     dependencyManager: () => {
       return {} as CSharpDependencyManager;

src/generators/csharp/CSharpGenerator.ts

@@ -71,9 +71,11 @@ jo.Add("${prop.unconstrainedPropertyName}", JToken.FromObject(jsonStringComplian
  * Render `deserialize` function based on model
  */
 function renderDeserialize({
-  model
+  model,
+  options
 }: {
   model: ConstrainedObjectModel;
+  options: CSharpOptions;
 }): string {
   const unwrapDictionaryProps = Object.values(model.properties).filter(
     (prop) =>
@@ -96,6 +98,20 @@ function renderDeserialize({
         prop.unconstrainedPropertyName
       }"].ToString())${prop.required ? '.Value' : ''}`;
     }
+
+    if (
+      options?.enforceRequired !== undefined &&
+      options?.enforceRequired &&
+      prop.required
+    ) {
+      return `if(jo["${prop.unconstrainedPropertyName}"] is null){
+  throw new JsonSerializationException("Required property '${prop.unconstrainedPropertyName}' is missing");
+}
+
+value.${propertyAccessor} = ${toValue};
+`;
+    }
+
     return `if(jo["${prop.unconstrainedPropertyName}"] != null) {
   value.${propertyAccessor} = ${toValue};
 }`;
@@ -151,15 +167,15 @@ function renderDeserialize({
 export const CSHARP_NEWTONSOFT_SERIALIZER_PRESET: CSharpPreset<CSharpOptions> =
   {
     class: {
-      self: ({ renderer, content, model }) => {
+      self: ({ renderer, content, model, options }) => {
         renderer.dependencyManager.addDependency('using Newtonsoft.Json;');
         renderer.dependencyManager.addDependency('using Newtonsoft.Json.Linq;');
         renderer.dependencyManager.addDependency(
           'using System.Collections.Generic;'
         );
         renderer.dependencyManager.addDependency('using System.Linq;');
 
-        const deserialize = renderDeserialize({ model });
+        const deserialize = renderDeserialize({ model, options });
         const serialize = renderSerialize({ model });
 
         return `[JsonConverter(typeof(${model.name}Converter))]

src/generators/csharp/presets/NewtonsoftSerializerPreset.ts

@@ -9,6 +9,7 @@ const doc = {
   required: ['string prop'],
   properties: {
     'string prop': { type: 'string' },
+    notRequiredStringProp: { type: 'string' },
     numberProp: { type: 'number' },
     enumProp: {
       $id: 'EnumTest',
@@ -29,7 +30,14 @@ const doc = {
 describe('Newtonsoft JSON serializer preset', () => {
   test('should render serialize and deserialize converters', async () => {
     const generator = new CSharpGenerator({
-      presets: [CSHARP_NEWTONSOFT_SERIALIZER_PRESET]
+      presets: [
+        {
+          preset: CSHARP_NEWTONSOFT_SERIALIZER_PRESET,
+          options: {
+            enforceRequired: true
+          }
+        }
+      ]
     });
 
     const outputModels = await generator.generate(doc);

test/generators/csharp/presets/NewtonsoftSerializerPreset.spec.ts

@@ -5,6 +5,7 @@ exports[`Newtonsoft JSON serializer preset should render serialize and deseriali
 public partial class Test
 {
   private string stringProp;
+  private string? notRequiredStringProp;
   private double? numberProp;
   private EnumTest? enumProp;
   private NestedTest? objectProp;
@@ -16,6 +17,12 @@ public partial class Test
     set { this.stringProp = value; }
   }
 
+  public string? NotRequiredStringProp 
+  {
+    get { return notRequiredStringProp; }
+    set { this.notRequiredStringProp = value; }
+  }
+
   public double? NumberProp 
   {
     get { return numberProp; }
@@ -48,8 +55,14 @@ public class TestConverter : JsonConverter<Test>
   JObject jo = JObject.Load(reader);
   Test value = new Test();
 
-  if(jo[\\"string prop\\"] != null) {
-  value.StringProp = jo[\\"string prop\\"].ToObject<string>(serializer);
+  if(jo[\\"string prop\\"] is null){
+  throw new JsonSerializationException(\\"Required property 'string prop' is missing\\");
+}
+
+value.StringProp = jo[\\"string prop\\"].ToObject<string>(serializer);
+
+if(jo[\\"notRequiredStringProp\\"] != null) {
+  value.NotRequiredStringProp = jo[\\"notRequiredStringProp\\"].ToObject<string?>(serializer);
 }
 if(jo[\\"numberProp\\"] != null) {
   value.NumberProp = jo[\\"numberProp\\"].ToObject<double?>(serializer);
@@ -61,7 +74,7 @@ if(jo[\\"objectProp\\"] != null) {
   value.ObjectProp = jo[\\"objectProp\\"].ToObject<NestedTest?>(serializer);
 }
 
-  var additionalProperties = jo.Properties().Where((prop) => prop.Name != \\"string prop\\" || prop.Name != \\"numberProp\\" || prop.Name != \\"enumProp\\" || prop.Name != \\"objectProp\\");
+  var additionalProperties = jo.Properties().Where((prop) => prop.Name != \\"string prop\\" || prop.Name != \\"notRequiredStringProp\\" || prop.Name != \\"numberProp\\" || prop.Name != \\"enumProp\\" || prop.Name != \\"objectProp\\");
   value.AdditionalProperties = new Dictionary<string, dynamic>();
 
   foreach (var additionalProperty in additionalProperties)
@@ -78,6 +91,10 @@ if(jo[\\"objectProp\\"] != null) {
 {
   jo.Add(\\"string prop\\", JToken.FromObject(value.StringProp, serializer));
 }
+if (value.NotRequiredStringProp != null)
+{
+  jo.Add(\\"notRequiredStringProp\\", JToken.FromObject(value.NotRequiredStringProp, serializer));
+}
 if (value.NumberProp != null)
 {
   jo.Add(\\"numberProp\\", JToken.FromObject(value.NumberProp, serializer));