Replace GET handler in TableController - azure-mobile-services

Question

In my table controller, I have:
public IQueryable<MyTable> GetAllMyTable()
I would like to replace the above with my own:
[HttpGet, Route("tables/MyTable")]
public IEnumerable<MyTable> GetAllMyTable()
But I get this response when I call it:
HTTP/1.1 405 Method Not Allowed
Somehow the Web API routing does not reach my method.
Why I'm doing this: the original method produces an inefficient Entity Framework SQL query that takes 3 seconds per call on my local test environment. This is running the query captured from SQL Profiler directly in SQL Mgt Studio. An equivalent query takes less than a second to run. Terrible.
Worse, the inefficient EF queries consumes lots of Azure SQL DTUs, tempting you to up your Azure subscription level if you want a quick fix.
Azure Mobile Apps is wonderful, but the multiple layers of abstraction makes it hard to really see what's going on under the hood, and therefore harder to tune.
Any help would be much appreciated.

Answer 1

HTTP/1.1 405 Method Not Allowed
Per my understanding, the error is obvious. You could send the GET HTTP verb to your endpoint tables/MyTable for retrieving the data. You need to check your request against your mobile app backend via fiddler.
Azure Mobile Apps is wonderful, but the multiple layers of abstraction makes it hard to really see what's going on under the hood, and therefore harder to tune.
For the common table controller, it would look like this:
public IQueryable<Message> GetAllMessage()
{
return Query();
}
The Query() method under EntityDomainManager.cs would equal as follows:
IQueryable<TData> query = this.Context.Set<TData>();
if (!includeDeleted)
{
query = query.Where(item => !item.Deleted);
}
return query;
If it deals with the ODATA queries (e.g. $top, $skip, $filter, etc.), the Nested SQL statement would be generated. We could modify the action to clarify it as follows:
public IEnumerable<Message> GetAllMessage(ODataQueryOptions opt)
{
var message = context.Set<Message>();
var query2=opt.ApplyTo(message, new ODataQuerySettings());
return query2.Cast<Message>().ToList();
}

Answer 2

Here's my rather crude attempt at bypassing the Entity Framework/OData plumbing and using direct SQL. (Wouldn't it be great if Dapper is supported!) This one works well, and is faster than the nested SQL that EF produces. The handling of OData is hacky; I have not had time to investigate using OData to extract the values for UpdatedAt, skip, and top.
I'm only using this approach for one method that needs optimisation. This is the method that the Azure Mobile App client calls when doing a pull.
public IEnumerable<MyTable> GetAllMyTable()
{
var qryValues = HttpUtility.ParseQueryString(Request.RequestUri.Query);
var updatedAtFilter = qryValues["$filter"];
var skip = qryValues["$skip"];
var top = qryValues["$top"];
if (updatedAtFilter != null)
{
var r = new Regex(#"^.+datetimeoffset'(?<time>.+)'.+$", RegexOptions.None);
var m = r.Match(updatedAtFilter);
if (m.Success)
{
var updatedAt = m.Groups["time"].Value.Replace("T", " ");
var sqlString = #"SELECT T0.*
FROM MyTable T0
WHERE T0.UpdatedAt >= #UpdatedAt
ORDER BY UpdatedAt, Id
OFFSET #Skip ROWS
FETCH NEXT #Top ROWS ONLY";
var updatedAtParam = new SqlParameter("UpdatedAt", SqlDbType.DateTimeOffset);
updatedAtParam.Value = updatedAt;
var skipParam = new SqlParameter("Skip", SqlDbType.Int);
skipParam.Value = int.Parse(skip);
var topParam = new SqlParameter("Top", SqlDbType.Int);
topParam.Value = int.Parse(top);
var data = _context.Database.SqlQuery<MyTable>(sqlString, new object[] { updatedAtParam, skipParam, topParam }).AsEnumerable<MyTable>();
return data;
}
}
return null;
}