Looking at the docs we should be able to create a new source filter like so
new SearchRequest<Project>
{
Source = new SourceFilter
{
Include = Fields<Project>(p => p.Name, prop => prop.StartedOn)
}
}
The issue I'm facing is that Fields isn't typed and doesn't have a constructor.
How do I go about making a Fields for use in sourceFilters, queries etc?
You can find Fields<> method in class Infer, so change example code to
new SearchRequest<Project>
{
Source = new SourceFilter
{
Include = Infer.Fields<Project>(p => p.Name, prop => prop.StartedOn)
}
}
Also you can import this static class in your cs file with using static Nest.Infer;, so you will be able to use this example as it is.
Hope it helps.
Related
I'm using the NEST .NET client (6.3.1), and trying to compose a search query that is based on a number of (optional) parameters.
Here's what i've got so far:
var searchResponse = await _client.SearchAsync<Listing>(s => s
.Query(qq =>
{
var filters = new List<QueryContainer>();
if (filter.CategoryType.HasValue)
{
filters.Add(qq.Term(p => p.CategoryType, filter.CategoryType.Value));
}
if (filter.StatusType.HasValue)
{
filters.Add(qq.Term(p => p.StatusType, filter.StatusType.Value));
}
if (!string.IsNullOrWhiteSpace(filter.Suburb))
{
filters.Add(qq.Term(p => p.Suburb, filter.Suburb));
}
return ?????; // what do i do her?
})
);
filter is an object with a bunch of nullable properties. So, whatever has a value i want to add as a match query.
So, to achieve that i'm trying to build up a list of QueryContainer's (not sure that's the right way), but struggling to figure out how to return that as a list of AND predicates.
Any ideas?
Thanks
Ended up doing it by using the object initialisez method, instead of the Fluent DSL"
var searchRequest = new SearchRequest<Listing>
{
Query = queries
}
queries is a List<QueryContainer>, which i just build up, like this:
queries.Add(new MatchQuery
{
Field = "CategoryType",
Query = filter.CategoryType
}
I feel like there's a better way, and i don't like how i have to hardcode the 'Field' to a string... but it works. Hopefully someone shows me a better way!
I am using the OData sample project at http://www.asp.net/web-api/overview/odata-support-in-aspnet-web-api/working-with-entity-relations. In the Get I want to be able to change the Filter in the QueryOptions of the EntitySetController:
public class ProductsController : EntitySetController<Product, int>
{
ProductsContext _context = new ProductsContext();
[Queryable(AllowedQueryOptions=AllowedQueryOptions.All)]
public override IQueryable<Product> Get()
{
var products = QueryOptions.ApplyTo(_context.Products).Cast<Product>();
return products.AsQueryable();
}
I would like to be able to find properties that are specifically referred to. I can do this by parsing this.QueryOptions.Filter.RawValue for the property names but I cannot update the RawValue as it is read only. I can however create another instance of FilterQueryOption from the modified RawValue but I cannot assign it to this.QueryOptions.Filter as this is read only too.
I guess I could call the new filter's ApplyTo passing it _context.Products, but then I will need to separately call the ApplyTo of the other properties of QueryOptions like Skip and OrderBy. Is there a better solution than this?
Update
I tried the following:
public override IQueryable<Product> Get()
{
IQueryable<Product> encryptedProducts = _context.Products;
var filter = QueryOptions.Filter;
if (filter != null && filter.RawValue.Contains("Name"))
{
var settings = new ODataQuerySettings();
var originalFilter = filter.RawValue;
var newFilter = ParseAndEncyptValue(originalFilter);
filter = new FilterQueryOption(newFilter, QueryOptions.Context);
encryptedProducts = filter.ApplyTo(encryptedProducts, settings).Cast<Product>();
if (QueryOptions.OrderBy != null)
{
QueryOptions.OrderBy.ApplyTo<Product>(encryptedProducts);
}
}
else
{
encryptedProducts = QueryOptions.ApplyTo(encryptedProducts).Cast<Product>();
}
var unencryptedProducts = encryptedProducts.Decrypt().ToList();
return unencryptedProducts.AsQueryable();
}
and it seems to be working up to a point. If I set a breakpoint I can see my products in the unencryptedProducts list, but when the method returns I don't get any items. I tried putting the [Queryable(AllowedQueryOptions=AllowedQueryOptions.All)] back on again but it had no effect. Any ideas why I am not getting an items?
Update 2
I discovered that my query was being applied twice even though I am not using the Queryable attribute. This meant that even though I had items to return the List was being queried with the unencrypted value and therefore no values were being returned.
I tried using an ODataController instead:
public class ODriversController : ODataController
{
//[Authorize()]
//[Queryable(AllowedQueryOptions = AllowedQueryOptions.All)]
public IQueryable<Products> Get(ODataQueryOptions options)
{
and this worked! Does this indicate that there is a bug in EntitySetController?
You would probably need to regenerate ODataQueryOptions to solve your issue. Let's say if you want to modify to add $orderby, you can do this like:
string url = HttpContext.Current.Request.Url.AbsoluteUri;
url += "&$orderby=name";
var request = new HttpRequestMessage(HttpMethod.Get, url);
ODataModelBuilder modelBuilder = new ODataConventionModelBuilder();
modelBuilder.EntitySet<Product>("Product");
var options = new ODataQueryOptions<Product>(new ODataQueryContext(modelBuilder.GetEdmModel(), typeof(Product)), request);
Im trying to use NEST and can´t figure out how to use it together with this class
public class Metric {
public DateTime Timestamp { get; set; }
public Dictionary<string,object> Measurement { get; set; }
}
How do i use the new fluent mapping with a class like this?
Im planning to use i like this:
var mesurements = new Dictionary<string, object>();
mesurements["visits"] = 1;
mesurements["url"] = new string[] {"/help", "/about"};
connection.Index(new Metric() {
Timestamp = DateTime.UtcNow,
Measurement = mesurements
});
Will it be possible to write a query against the dictionary? If I wanted to get all Metrics from yesterday with a mesurenemt with a key name "visits", how will that look like ?
You don't have to use mapping, you can rely on elasticsearch's schemaless nature really well in this case.
The json serializer will write that out as:
{
"timestamp" : "[datestring]",
"measurement" : {
"visits" : 1,
"url" : [ "/help", "/about"]
}
}
You can query for the existence of the "measurement.visits" field like so using NEST.
var result = client.Search<Metric>(s=>s
.From(0)
.Size(10)
.Filter(filter=>filter
.Exists("measurement.visits")
)
);
result.Documents now hold the first 10 metrics with a visits key in the Measurement dictionary.
If you do want to explicitly map possible keys in that dictionary using the new fluent mapping:
var result = client.MapFluent<Metric>(m => m
.Properties(props => props
.Object<Dictionary<string,object>>(s => s
.Name(p => p.Measurement)
.Properties(pprops => pprops
.Number(ps => ps
.Name("visits")
.Type(NumberType.#integer)
)
.String(ps => ps
.Name("url")
.Index(FieldIndexOption.not_analyzed))
)
)
)
)
);
Remember that we haven't turned off dynamic mapping using this mapping so you can still inserts other keys into your dictionary without upsetting elasticsearch. Only now elasticsearch will know visits is an actual integer andwe dont want to analyze the url values.
since we are not using any typed accessors (The .Name() call is typed to Metric) .Object<Dictionary<string,object>> could be .Object<object> too.
Hi I have a query like this:
var queryGridData = from question in questions
select new {
i = question.Id,
cell = new List<string>() { question.Id.ToString(), question.Note, question.Topic }
};
The ToString() part needed to convert the int is causing:
LINQ to Entities does not recognize the method 'System.String.ToString()' method, and this method cannot be translated into a store expression.
Hmmmmmmmmmmm. I need it as a string to go into the collection. Any ideas?
I would personally perform just enough of the query in the database to provide the values you want, and do the rest in .NET:
var queryGridData = questions.Select(q => new { q.Id, q.Note, q.Topic })
.AsEnumerable() // Do the rest locally
.Select(q => new { i = q.Id,
cell = new List<string> {
q.Id.ToString(),
q.Note,
q.Topic
} });
(This formatting is horrible, but hopefully it'll be easier to do nicely in an IDE where you've got more space :)
Forgive me if this has been asked already. I've only just started using LINQ. I have the following Expression:
public static Expression<Func<TblCustomer, CustomerSummary>> SelectToSummary()
{
return m => (new CustomerSummary()
{
ID = m.ID,
CustomerName = m.CustomerName,
LastSalesContact = // This is a Person entity, no idea how to create it
});
}
I want to be able to populate LastSalesContact, which is a Person entity.
The details that I wish to populate come from m.LatestPerson, so how can I map over the fields from m.LatestPerson to LastSalesContact. I want the mapping to be re-useable, i.e. I do not want to do this:
LastSalesContact = new Person()
{
// Etc
}
Can I use a static Expression, such as this:
public static Expression<Func<TblUser, User>> SelectToUser()
{
return x => (new User()
{
// Populate
});
}
UPDATE:
This is what I need to do:
return m => (new CustomerSummary()
{
ID = m.ID,
CustomerName = m.CustomerName,
LastSalesContact = new Person()
{
PersonId = m.LatestPerson.PersonId,
PersonName = m.LatestPerson.PersonName,
Company = new Company()
{
CompanyId = m.LatestPerson.Company.CompanyId,
etc
}
}
});
But I will be re-using the Person() creation in about 10-15 different classes, so I don't want exactly the same code duplicated X amount of times. I'd probably also want to do the same for Company.
Can't you just use automapper for that?
public static Expression<Func<TblCustomer, CustomerSummary>> SelectToSummary()
{
return m => Mapper.Map<TblCustomer, CustommerSummary>(m);
}
You'd have to do some bootstrapping, but then it's very reusable.
UPDATE:
I may not be getting something, but what it the purpose of this function? If you just want to map one or collection of Tbl object to other objects, why have the expression?
You could just have something like this:
var customers = _customerRepository.GetAll(); // returns IEnumerable<TblCustomer>
var summaries = Mapper.Map<IEnumerable<TblCustomer>, IEnumerable<CustomerSummary>>(customers);
Or is there something I missed?
I don't think you'll be able to use a lambda expression to do this... you'll need to build up the expression tree by hand using the factory methods in Expression. It's unlikely to be pleasant, to be honest.
My generally preferred way of working out how to build up expression trees is to start with a simple example of what you want to do written as a lambda expression, and then decompile it. That should show you how the expression tree is built - although the C# compiler gets to use the metadata associated with properties more easily than we can (we have to use Type.GetProperty).
This is always assuming I've understood you correctly... it's quite possible that I haven't.
How about this:
public static Person CreatePerson(TblPerson data)
{
// ...
}
public static Expression<Func<TblPerson, Person>> CreatePersonExpression()
{
return d => CreatePerson(d);
}
return m => (new CustomerSummary()
{
ID = m.ID,
CustomerName = m.CustomerName,
LastSalesContact = CreatePerson(m.LatestPerson)
});