Implementacao de Shaping Data

CourseLibrary.API/Controllers/AuthorsController.cs

@@ -19,21 +19,27 @@ public class AuthorsController : ControllerBase
  private readonly ICourseLibraryRepository _courseLibraryRepository;
  private readonly IMapper _mapper;
  private readonly IPropertyMappingService _propertyMappingService;
+ private readonly IPropertyCheckerService _propertyCheckerService;
 
  public AuthorsController(ICourseLibraryRepository courseLibraryRepository,
- IMapper mapper , IPropertyMappingService propertyMappingService)
+ IMapper mapper , IPropertyMappingService propertyMappingService,
+ IPropertyCheckerService propertyCheckerService
+ )
  {
  _courseLibraryRepository = courseLibraryRepository ??
  throw new ArgumentNullException(nameof(courseLibraryRepository));
  _mapper = mapper ??
  throw new ArgumentNullException(nameof(mapper));
  _propertyMappingService = propertyMappingService ??
  throw new ArgumentNullException(nameof(propertyMappingService));
+
+ _propertyCheckerService = propertyCheckerService ??
+ throw new ArgumentNullException(nameof(propertyCheckerService));
  }
 
  [HttpGet(Name = "GetAuthors")]
  [HttpHead]
- public ActionResult<IEnumerable<AuthorDto>> GetAuthors(
+ public IActionResult GetAuthors(
  [FromQuery] AuthorsResourceParameters authorsResourceParameters)
  {
  if (!_propertyMappingService.ValidMappingExistsFor<AuthorDto, Entities.Author>
@@ -42,6 +48,12 @@ public class AuthorsController : ControllerBase
  return BadRequest();
  }
 
+ if (!_propertyCheckerService.TypeHasProperties<AuthorDto>
+ (authorsResourceParameters.Fields))
+ {
+ return BadRequest();
+ }
+
  var authorsFromRepo = _courseLibraryRepository.GetAuthors(authorsResourceParameters);
 
  var previousPageLink = authorsFromRepo.HasPrevious ?
@@ -65,20 +77,26 @@ public class AuthorsController : ControllerBase
  Response.Headers.Add("X-Pagination",
  JsonSerializer.Serialize(paginationMetadata));
 
- return Ok(_mapper.Map<IEnumerable<AuthorDto>>(authorsFromRepo));
+ return Ok(_mapper.Map<IEnumerable<AuthorDto>>(authorsFromRepo)
+ .ShapeData(authorsResourceParameters.Fields));
  }
 
  [HttpGet("{authorId}", Name = "GetAuthor")]
- public IActionResult GetAuthor(Guid authorId)
+ public IActionResult GetAuthor(Guid authorId, string fields)
  {
+ if (!_propertyCheckerService.TypeHasProperties<AuthorDto>
+ (fields))
+ {
+ return BadRequest();
+ }
  var authorFromRepo = _courseLibraryRepository.GetAuthor(authorId);
 
  if (authorFromRepo == null)
  {
  return NotFound();
  }
 
- return Ok(_mapper.Map<AuthorDto>(authorFromRepo));
+ return Ok(_mapper.Map<AuthorDto>(authorFromRepo).ShapeData(fields));
  }
 
  [HttpPost]
@@ -127,6 +145,7 @@ public ActionResult DeleteAuthor(Guid authorId)
  return Url.Link("GetAuthors",
  new
  {
+ fields = authorsResourceParameters.Fields,
  orderBy = authorsResourceParameters.OrderBy,
  pageNumber = authorsResourceParameters.PageNumber - 1,
  pageSize = authorsResourceParameters.PageSize,
@@ -137,6 +156,7 @@ public ActionResult DeleteAuthor(Guid authorId)
  return Url.Link("GetAuthors",
  new
  {
+ fields = authorsResourceParameters.Fields,
  orderBy = authorsResourceParameters.OrderBy,
  pageNumber = authorsResourceParameters.PageNumber + 1,
  pageSize = authorsResourceParameters.PageSize,
@@ -148,6 +168,7 @@ public ActionResult DeleteAuthor(Guid authorId)
  return Url.Link("GetAuthors",
  new
  {
+ fields = authorsResourceParameters.Fields,
  orderBy = authorsResourceParameters.OrderBy,
  pageNumber = authorsResourceParameters.PageNumber,
  pageSize = authorsResourceParameters.PageSize,

CourseLibrary.API/Helpers/IEnumerableExtensions.cs

@@ -0,0 +1,92 @@
+using System;
+using System.Collections.Generic;
+using System.Dynamic;
+using System.Linq;
+using System.Reflection;
+using System.Threading.Tasks;
+
+namespace CourseLibrary.API.Helpers
+{
+ public static class IEnumerableExtensions
+ {
+ public static IEnumerable<ExpandoObject> ShapeData<TSource>( this IEnumerable<TSource> source, string fields)
+ {
+ if (source == null)
+ {
+ throw new ArgumentNullException(nameof(source));
+ }
+ // create a list to hold our ExpandoObjects
+ var expandoObjectList = new List<ExpandoObject>();
+
+ // create a list with PropertyInfo objects on TSource. Reflection is 
+ // expensive, so rather than doing if for each object in the list, we do
+ // it once and reuse the results. After all, part of the reflection is on the
+ // type of the object (TSource), not on the instance
+ var propertyInfoList = new List<PropertyInfo>();
+
+ if (string.IsNullOrWhiteSpace(fields))
+ {
+ // all public properties should be in the ExpandoObject
+ var propertyInfos = typeof(TSource)
+ .GetProperties(BindingFlags.Public | BindingFlags.Instance);
+
+ propertyInfoList.AddRange(propertyInfos);
+ }
+ else
+ {
+ // the field are separated by ",", so we split it.
+ var fieldsAfterSplit = fields.Split(',');
+
+ foreach (var field in fieldsAfterSplit)
+ {
+ // trim each field, as it might contain leading 
+ // or trailing spaces. Can't trim the var in foreach,
+ // so use another var.
+ var propertyName = field.Trim();
+
+ // use reflection to get the property on the source object
+ // we need to include public and instance, b/c specifying a binding 
+ // flag overwrites the already-existing binding flags.
+ var propertyInfo = typeof(TSource)
+ .GetProperty(propertyName, BindingFlags.IgnoreCase |
+ BindingFlags.Public | BindingFlags.Instance);
+
+ if (propertyInfo == null)
+ {
+ throw new Exception($"Property {propertyName} wasn't found on" +
+ $" {typeof(TSource)}");
+ }
+
+ // add propertyInfo to list 
+ propertyInfoList.Add(propertyInfo);
+ }
+ }
+
+ // run through the source objects
+ foreach (TSource sourceObject in source)
+ {
+ // create an ExpandoObject that will hold the 
+ // selected properties & values
+ var dataShapedObject = new ExpandoObject();
+
+ // Get the value of each property we have to return. For that,
+ // we run through the list
+ foreach (var propertyInfo in propertyInfoList)
+ {
+ // GetValue returns the value of the property on the source object
+ var propertyValue = propertyInfo.GetValue(sourceObject);
+
+ // add the field to the ExpandoObject
+ ((IDictionary<string, object>)dataShapedObject)
+ .Add(propertyInfo.Name, propertyValue);
+ }
+
+ // add the ExpandoObject to the list
+ expandoObjectList.Add(dataShapedObject);
+ }
+
+ // return the list
+ return expandoObjectList;
+ }
+ }
+}

CourseLibrary.API/Helpers/ObjectExtensions.cs

@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using System.Dynamic;
+using System.Linq;
+using System.Reflection;
+using System.Threading.Tasks;
+
+namespace CourseLibrary.API.Helpers
+{
+ public static class ObjectExtensions
+ {
+ public static ExpandoObject ShapeData<TSource>(this TSource source,
+ string fields)
+ {
+ if (source == null)
+ {
+ throw new ArgumentNullException(nameof(source));
+ }
+
+ var dataShapedObject = new ExpandoObject();
+
+ if (string.IsNullOrWhiteSpace(fields))
+ {
+ // all public properties should be in the ExpandoObject 
+ var propertyInfos = typeof(TSource)
+ .GetProperties(BindingFlags.IgnoreCase |
+ BindingFlags.Public | BindingFlags.Instance);
+
+ foreach (var propertyInfo in propertyInfos)
+ {
+ // get the value of the property on the source object
+ var propertyValue = propertyInfo.GetValue(source);
+
+ // add the field to the ExpandoObject
+ ((IDictionary<string, object>)dataShapedObject)
+ .Add(propertyInfo.Name, propertyValue);
+ }
+
+ return dataShapedObject;
+ }
+
+ // the field are separated by ",", so we split it.
+ var fieldsAfterSplit = fields.Split(',');
+
+ foreach (var field in fieldsAfterSplit)
+ {
+ // trim each field, as it might contain leading 
+ // or trailing spaces. Can't trim the var in foreach,
+ // so use another var.
+ var propertyName = field.Trim();
+
+ // use reflection to get the property on the source object
+ // we need to include public and instance, b/c specifying a 
+ // binding flag overwrites the already-existing binding flags.
+ var propertyInfo = typeof(TSource)
+ .GetProperty(propertyName,
+ BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
+
+ if (propertyInfo == null)
+ {
+ throw new Exception($"Property {propertyName} wasn't found " +
+ $"on {typeof(TSource)}");
+ }
+
+ // get the value of the property on the source object
+ var propertyValue = propertyInfo.GetValue(source);
+
+ // add the field to the ExpandoObject
+ ((IDictionary<string, object>)dataShapedObject)
+ .Add(propertyInfo.Name, propertyValue);
+ }
+
+ // return the list
+ return dataShapedObject;
+ }
+ }
+}

CourseLibrary.API/ResourcesParameters/AuthorsResourceParameters.cs

@@ -17,5 +17,6 @@ public class AuthorsResourceParameters
  set => _pageSize = (value > maxPageSize) ? maxPageSize : value; 
  }
  public string OrderBy { get; set; } = "Name";
+ public string Fields { get; set; }
  }
 }

CourseLibrary.API/Services/IPropertyCheckerService.cs

@@ -0,0 +1,7 @@
+namespace CourseLibrary.API.Services
+{
+ public interface IPropertyCheckerService
+ {
+ bool TypeHasProperties<T>(string fields);
+ }
+}

CourseLibrary.API/Services/PropertyCheckerService.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Threading.Tasks;
+
+namespace CourseLibrary.API.Services
+{
+ public class PropertyCheckerService : IPropertyCheckerService
+ {
+ public bool TypeHasProperties<T>(string fields)
+ {
+ if (string.IsNullOrWhiteSpace(fields))
+ {
+ return true;
+ }
+
+ // the field are separated by ",", so we split it.
+ var fieldsAfterSplit = fields.Split(',');
+
+ // check if the requested fields exist on source
+ foreach (var field in fieldsAfterSplit)
+ {
+ // trim each field, as it might contain leading 
+ // or trailing spaces. Can't trim the var in foreach,
+ // so use another var.
+ var propertyName = field.Trim();
+
+ // use reflection to check if the property can be
+ // found on T. 
+ var propertyInfo = typeof(T)
+ .GetProperty(propertyName,
+ BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
+
+ // it can't be found, return false
+ if (propertyInfo == null)
+ {
+ return false;
+ }
+ }
+
+ // all checks out, return true
+ return true;
+ }
+
+ }
+}

CourseLibrary.API/Startup.cs

@@ -82,6 +82,7 @@ public void ConfigureServices(IServiceCollection services)
  });
 
  services.AddTransient<IPropertyMappingService,PropertyMappingService>();
+ services.AddTransient<IPropertyCheckerService, PropertyCheckerService>();
  services.AddAutoMapper(AppDomain.CurrentDomain.GetAssemblies());
 
  services.AddScoped<ICourseLibraryRepository, CourseLibraryRepository>();