Linq2CouchBaseLiteExpression

Linq extension to query couchbase lite repository (Linq to Expression)

Writen in .net standard 2.0

IC

How to :

The class Linq2CouchbaseLiteExpression contains a unique method named GenerateFromExpression that generate an couchbase lite IExpression.

This generic method works on objects that are class.

First of all, install the plugin by the nuget package.

Example

/// <summary>
/// Entity object
/// </summary>
public class EntityObject
{
    public string Id { get; set; }

    public string Name { get; set; }

	public int Value { get; set; }
	
	public bool IsHuman { get; set; }
}

// Generate IExpression from a Lambda expression :
var resultFilter = Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => e.Name == "test");

This call will generate a Couchbase lite expression like this :

// Generate manually the IExpression :
Couchbase.Lite.Query.Expression.Property("Name").EqualTo(Couchbase.Lite.Query.Expression.String("test"))

Supported operations

These operations are now supported

Function	Example
>	(e) => e.Value > 10
<	(e) => e.Value < 10
>=	(e) => e.Value >= 10
>=	(e) => e.Value <= 10
==	(e) => e.Name == "test"
!=	(e) => e.Name != "test"
!	(e) => !e.IsHuman
.Equals	(e) => e.Name.Equals("test")
string.IsNullOrEmpty	(e) => string.IsNullOrEmpty(e.Name)

You can also combine conditions :

Function	Example
||	(e) => e.Name == "test" || e.Name == "test 2"
&&	(e) => e.Value > 10 && e.Name == "test 2"

Lambda expression writing

The expression must respect some specific rules :

• You can set field object at left or at right of the operation :

// Valid :
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => e.Name == "test");

// Or :
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => "test" = e.Name );

• You can use call static method withtout parameters only :

// Valid :
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => e.Name == CallToStaticMethod());

// Invalid :
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => e.Name == CallToStaticMethod("Parameter"));

// Invalid :
var customObject = new CustomObject();
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => e.Name ==  customObject.NonPublicMethod());

// Invalid :
var customObject = new CustomObject();
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => e.Name ==  customObject.NonPublicMethodWithParameters("test"));

• Only the methods are now supported : .Equals() or string.IsNullOrEmpty()

// Valid :
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => e.Name.Equals("test"));

// Valid :
Linq2CouchbaseLiteExpression.GenerateFromExpression<EntityObject>((e) => string.IsNullOrEmpty(e.Name);

Contribute

You want more ? Feel free to create an issue or contribute by adding new functionnalities by forking the project and create a pull request.

And if you like this project, don't forget to star it !

You can also support me with a coffee :