automatically expand the result of an odata function - asp.net-web-api

Question

I defined an odata function to mimic $search which is not supported yet in the recent core release. I want to return the core entity plus an expanded entity which would translate into a js object on each Person in the returned json values array.
I tried odata/People/MyNS.Find(text='john', orderby='CreatedOn')?$expand=CurrentWork where CurrentWork is on People, but that did not work.
Thoughts on how to do this?
// my controller code for the function
[HttpGet]
public ActionResult<ICollection<People>> Find([FromODataUri] string text,
[FromODataUri] string orderBy)
{
if (text == null || text.Length == 0)
return Get().ToList();
if (orderBy == null || orderBy.Length == 0)
orderBy = "CreatedOn";
return _db.People
.Where(p => p.FirstName.Contains(text)
|| p.LastName.Contains(text)
|| p.Nickname.Contains(text))
.OrderBy(orderBy)
.Take(5000)
.ToList();
}
Regular expansion of CurrentWork in a non-function works fine e.g. odata/People?$expand=CurrentWork.

Answer 1

By looking at the Linq query, it's fetching only People data and not any of it's child collections. You should use Include to fetch data for child collections along with parent entity like below. Read more on loading related entities here.
// my controller code for the function
[HttpGet]
public ActionResult<ICollection<People>> Find([FromODataUri] string text,
[FromODataUri] string orderBy)
{
if (text == null || text.Length == 0)
return Get().ToList();
if (orderBy == null || orderBy.Length == 0)
orderBy = "CreatedOn";
return _db.People
.Where(p => p.FirstName.Contains(text)
|| p.LastName.Contains(text)
|| p.Nickname.Contains(text))
.Include(p => p.CurrentWork) // I have added this line
.OrderBy(orderBy)
.Take(5000)
.ToList();
}
Note: You still need to use $expand=CurrentWork as query string. Without this query string, server will remove child collections before sending response to client.

Answer 2

Here's what I came up with in the end. I noticed that the included entities were pulling in alot of data from the database so I reduced down the pull quite a bit by being specific. Include just pulled everything and I could not reduce the Include down directly so I had to use a Select.
[HttpGet]
public IOrderedQueryable Find2([FromODataUri] string text,
[FromODataUri] string orderBy)
{
if (orderBy == null || orderBy.Length == 0)
orderBy = "CreatedOn DESC";
if (text == null || text.Length == 0)
return Get().OrderBy(orderBy);
var r = LikeToRegular(text);
return _db.People
.AsNoTracking() // can't use if using lazy loading
.Select(p => new
{
p.FirstName,
p.LastName,
p.Nickname,
p.CreatedOn,
p.CurrentWork.Title,
p.CurrentWork.Company.CompanyName
})
// Forces local computation, so pulls entire people dataset :-(
.Where(x => Regex.IsMatch(x.LastName ?? "", r)
|| Regex.IsMatch(x.FirstName ?? "", r, RegexOptions.IgnoreCase)
|| Regex.IsMatch(x.Nickname ?? "", r, RegexOptions.IgnoreCase)
|| Regex.IsMatch($"{x.FirstName} {x.LastName}", r,
RegexOptions.IgnoreCase))
.OrderBy(orderBy);
}
// Allow some wildcards in the search...
public static String LikeToRegular(String value)
{
return "^" + Regex.Escape(value)
.Replace("_", ".")
.Replace("%", ".*") + "$";
}