Dekiru.QueryFilter 2.0.2

Dynamic query filter parser

This library provides a parser for a simple query language that can be used to filter data in the form of IQueryable<T>. The main use case is to provide a simple query language for Entity Framework Core and REST APIs.

The library is available as a NuGet package: DynamicQueryParser.

The two main methods are FilterDynamic and IncludeDynamic which can be used to filter and include related entities respectively. The methods are defined as extension methods on IQueryable<T>.

The methods take a string as input which is parsed and converted to an expression tree. The expression tree is then used to filter the data or define the related entities to include. The included entities may also be filtered.

Generally, all methods can be called either as a static method or as a member method. The syntax is either myMethod(SomeCollection) or SomeCollection.myMethod(). There is no functional difference between the two syntaxes, it is just a matter of preference.

The following infix/prefix operators are supported:

• and - SQL AND operator
• or - SQL OR operator
• not - SQL NOT operator
• eq - SQL = operator
• ne - SQL <> operator
• gt - SQL > operator
• ge - SQL >= operator
• lt - SQL < operator
• le - SQL <= operator

The following functions are supported:

• any - SQL EXISTS operator
• any(predicate) - SQL EXISTS operator with a predicate
• all(predicate) - SQL NOT EXISTS operator with a predicate
• startswith - SQL LIKE 'prefix%' operator
• endswith - SQL LIKE '%suffix' operator
• contains - SQL LIKE '%substring%' operator
• substring - SQL SUBSTRING function
• lower - SQL LOWER function
• upper - SQL UPPER function
• trim - SQL TRIM function
• length - SQL LEN function
• now - SQL GETDATE function
• utcnow - SQL GETUTCDATE function
• count - SQL COUNTfunction
• sum - SQL SUM function
• min - SQL MIN function
• max - SQL MAX function
• coalesce - SQL COALESCE function
• empty - SQL = '' operator
• isnull - SQL IS NULL operator
• datepart - SQL DATEPART function

Function names are case-insensitive.

Some sample queries:

Name eq 'John' and not Name eq 'Doe'
Name eq 'John' and Age gt 30
Name eq 'John' or Age gt 30
Name eq 'John' and (Age gt 30 or Age lt 20)

any(Children)
or
Children.any()

any(Children, c: c.Name eq 'Bar')
or
Children.any(c: c.Name eq 'Bar')

Address.Country eq 'Sweden'

startswith(Name, 'J')
or
Name.startswith('J')

endswith(Name, 'n')
or
Name.endswith('n')

Future methods:

• indexof - SQL CHARINDEX function
• replace - SQL REPLACE function
• round - SQL ROUND function
• floor - SQL FLOOR function
• ceiling - SQL CEILING function