How to configure Swashbuckle to ignore property on model

Question

I'm using Swashbuckle to generate swagger documentation\UI for a webapi2 project. Our models are shared with some legacy interfaces so there are a couple of properties I want to ignore on the models. I can't use JsonIgnore attribute because the legacy interfaces also need to serialize to JSON so I don't want to ignore the properties globally, just in the Swashbuckle configuration.

I found a method of doing this documented here:

https://github.com/domaindrivendev/Swashbuckle/issues/73

But this appears to be out of date with the current Swashbuckle release.

The method recommended for the old version of Swashbuckle is using an IModelFilter implementation as follows:

public class OmitIgnoredProperties : IModelFilter
{
    public void Apply(DataType model, DataTypeRegistry dataTypeRegistry, Type type)
    {
        var ignoredProperties = … // use reflection to find any properties on 
                                  // type decorated with the ignore attributes

        foreach (var prop in ignoredProperties) 
            model.Properties.Remove(prop.Name);

    }
}

SwaggerSpecConfig.Customize(c => c.ModelFilter<OmitIgnoredProperties>());

But I'm unsure how to configure Swashbuckle to use the IModelFilter in the current version? I'm using Swashbuckle 5.5.3.

Answer 1

If you need to do this but without using JsonIgnore (maybe you still need to serialize/deserialize the property) then just create a custom attribute.

[AttributeUsage(AttributeTargets.Property)]
public class SwaggerExcludeAttribute : Attribute
{
}

Then a schema filter similar to Johng's

public class SwaggerExcludeFilter : ISchemaFilter
{
    #region ISchemaFilter Members

    public void Apply(Schema schema, SchemaRegistry schemaRegistry, Type type)
    {
        if (schema?.Properties == null || type == null)
            return;

        var excludedProperties = type.GetProperties()
                                     .Where(t => 
                                            t.GetCustomAttribute<SwaggerExcludeAttribute>() 
                                            != null);

        foreach (var excludedProperty in excludedProperties)
        {
            if (schema.properties.ContainsKey(excludedProperty.Name))
                schema.properties.Remove(excludedProperty.Name);
        }
    }

    #endregion
}

Don't forget to register the filter

c.SchemaFilter<SwaggerExcludeFilter>();

Answer 2

If you mark field/property as internal or protected or private, it will be ignored automatically by swashbuckle in swagger documentation.

Answer 3

The AspNetCore solution looks like:

public class SwaggerExcludeSchemaFilter : ISchemaFilter
{
    public void Apply(Schema schema, SchemaFilterContext context)
    {
        if (schema?.Properties == null)
        {
            return;
        }

        var excludedProperties = context.SystemType.GetProperties().Where(t => t.GetCustomAttribute<SwaggerExcludeAttribute>() != null);
        foreach (PropertyInfo excludedProperty in excludedProperties)
        {
            if (schema.Properties.ContainsKey(excludedProperty.Name))
            {
                schema.Properties.Remove(excludedProperty.Name);
            }
        }
    }
}

Answer 4

Well, with a bit of poking I found a way to do this using ISchemaFilter:

public class ApplyCustomSchemaFilters : ISchemaFilter
{
    public void Apply(Schema schema, SchemaRegistry schemaRegistry, Type type)
    {
        var excludeProperties = new[] {"myProp1", "myProp2", "myProp3"};

        foreach(var prop in excludeProperties)
            if (schema.properties.ContainsKey(prop))
                schema.properties.Remove(prop);
    }
}

then when calling httpConfiguration.EnableSwagger I set the SwaggerDocsConfig to use this SchemaFilter as follows:

c.SchemaFilter<ApplyCustomSchemaFilters>();

Hope this helps someone. I'd still be curious on whether it's possible to use the IModelFilter somehow though.

Answer 5

The code below is very much based on @Richard's answer, but I am including it as a new answer because it has three completely new, useful features which I have added:

• Runs on .NET Core on the latest version of Swashbuckle (v5)
• Allows the SwaggerIgnore attribute to be applied to fields not just to properties
• Handles the fact that property and field names may have been overridden using the JsonProperty attribute
• EDIT: Now correctly handles camelCasing of originally TitleCased fields or properties (prompted by @mattruma's answer)

So the revised code is:

[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
public class SwaggerIgnoreAttribute : Attribute
{
}

internal static class StringExtensions
{
    internal static string ToCamelCase(this string value)
    {
        if (string.IsNullOrEmpty(value)) return value;
        return char.ToLowerInvariant(value[0]) + value.Substring(1);
    }
}

public class SwaggerIgnoreFilter : ISchemaFilter
{
    public void Apply(OpenApiSchema schema, SchemaFilterContext schemaFilterContext)
    {
        if (schema.Properties.Count == 0)
            return;

        const BindingFlags bindingFlags = BindingFlags.Public |
                                          BindingFlags.NonPublic |
                                          BindingFlags.Instance;
        var memberList = schemaFilterContext.SystemType
                            .GetFields(bindingFlags).Cast<MemberInfo>()
                            .Concat(schemaFilterContext.SystemType
                            .GetProperties(bindingFlags));

        var excludedList = memberList.Where(m =>
                                            m.GetCustomAttribute<SwaggerIgnoreAttribute>()
                                            != null)
                                     .Select(m =>
                                         (m.GetCustomAttribute<JsonPropertyAttribute>()
                                          ?.PropertyName
                                          ?? m.Name.ToCamelCase()));

        foreach (var excludedName in excludedList)
        {
            if (schema.Properties.ContainsKey(excludedName))
                schema.Properties.Remove(excludedName);
        }
    }
}

and in Startup.cs:

services.AddSwaggerGen(c =>
{
    ...
    c.SchemaFilter<SwaggerIgnoreFilter>();
    ...
});

Answer 6

(Based on mutex's answer.)

I added another line to not have problems with NullReferenceException.

public void Apply(Schema schema, SchemaRegistry schemaRegistry, Type type)
{
  var excludeProperties = new[] { "myProp1", "myProp2, myProp3"};

   foreach (var prop in excludeProperties)
     if(schema.properties != null) // This line
       if (schema.properties.ContainsKey(prop))
        schema.properties.Remove(prop);        
}

If you want to delete all schemas

public void Apply(Schema schema, SchemaRegistry schemaRegistry, Type type)
{
  schema.properties = null;       
} 

Answer 7

Here is what I used with Newtonsoft.Json.JsonIgnoreAttribute:

internal class ApplySchemaVendorExtensions : Swashbuckle.Swagger.ISchemaFilter
{
    public void Apply(Schema schema, SchemaRegistry schemaRegistry, Type type)
    {
        foreach (var prop in type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance)
                                 .Where(p => p.GetCustomAttributes(typeof(Newtonsoft.Json.JsonIgnoreAttribute), true)?.Any() == true))
            if (schema?.properties?.ContainsKey(prop.Name) == true)
                schema?.properties?.Remove(prop.Name);
    }
}

Answer 8

For people like me who are using .Net Core and are using the build in app.UseSwaggerUi3WithApiExplorer()

Use [JsonIgnore] tag using Newtonsoft.Json;

public class Project
{
    [Required]
    public string ProjectName { get; set; }

    [JsonIgnore]
    public string SomeValueYouWantToIgnore { get; set; }
}

It will be excluded from your documentation.

Answer 9

Based on Stef Heyenrath's answer.

Attribute to mark properties to exclude from the Swagger documentation.

[AttributeUsage(AttributeTargets.Property)]
public class SwaggerExcludeAttribute : Attribute
{
}

The filter to exclude the properties from the Swagger documentation.

public class SwaggerExcludeSchemaFilter : ISchemaFilter
{
    public void Apply(Schema schema, SchemaFilterContext context)
    {
        if (schema?.Properties == null)
        {
            return;
        }

        var excludedProperties = 
            context.SystemType.GetProperties().Where(
                t => t.GetCustomAttribute<SwaggerExcludeAttribute>() != null);

        foreach (var excludedProperty in excludedProperties)
        {
            var propertyToRemove =
                schema.Properties.Keys.SingleOrDefault(
                    x => x.ToLower() == excludedProperty.Name.ToLower());

            if (propertyToRemove != null)
            {
                schema.Properties.Remove(propertyToRemove);
            }
        }
    }
}

The schema.Properties.Keys are camelCase, while the properties themselves are PascalCase. Tweaked the method to convert both to lower case and compare to see what should be excluded.