Filtery

Filtery help you to build the query using a syntax which is similar to Mongo

Installation

Add filtery to your list of dependencies in mix.exs:

def deps do
  [
    {:filtery, "~> 0.1.0"}
  ]
end

Documentation is published here https://hexdocs.pm/filtery.

Usage

Filtery help you to build the query using a similar syntax with MongoDB like this:

filter = %{
    status: "active",
    email: %{not: nil},
    role: ["admin", "moderator"]
}
Filtery.apply(User, filter)

The result is a query like this:

from(u in User, where: u.status == "active" and not is_nil(u.email) and u.role in ["admin", "moderator"])

Syntax

You can use <field>: <value> expressions to specify the equality condition and query operator expressions.

%{
  <field1>: <value1>,
  <field2>: { <operator>, <value> },
  ...
}

Notes: all operator belows are reserved keywords and cannot be used as field name

Supported operator

1. Comparition operator

:eq	Matches values that are equal to a specified value.
:gt	Matches values that are greater than a specified value.
:gte	Matches values that are greater than or equal to a specified value.
:in	Matches any of the values specified in an array.
:lt	Matches values that are less than a specified value.
:lte	Matches values that are less than or equal to a specified value.
:ne	Matches all values that are not equal to a specified value.
:nin	Matches none of the values specified in an array.

2. Logical operator

Name	Description
:and	Joins query clauses with a logical AND returns all documents that match the conditions of both clauses.
:not	Inverts the effect of a query expression and returns documents that do not match the query expression.
:or	Joins query clauses with a logical OR returns all documents that match the conditions of either clause.

AND operator

By default, if a map or keyword list is given, Filtery will join all field condition of that map using AND

Filtery.apply(User, %{status: "active", age: {:gt, 20}})

# same with
Filtery.apply(User, %{and:
                      %{status: "active", age: {:gt, 20}}
                      })

# same with
Filtery.apply(User, %{and:
                      [status: "active", age: {:gt, 20]}
                     })
                     
# same with
from(u in User, where: u.status == "active" and u.age > 20)

OR operator

The :or operator performs a logical OR operation on an array of two or more <expressions>

Filtery.apply(Product, %{or: %{
                           price: {:gt, 20},
                           category: "sport"
                         }})

NOT operator

Performs a logical NOT operation on the specified <operator-expression>

Syntax: %{ field: %{ not: <operator-expression> } }

Filtery.apply(Product, %{or: %{
                           price: {:gt, 20},
                           category: {:not: "sport"}
                         }})

Filtery.apply(Product, %{or: %{
                           price: {:not, {:gt, 20}},
                           category: "sport"
                         }})

3. Extra operator

Filtery provides some more useful operators to work with text and range.

Name	Description
:between	Matches values > lower bound and < upper bound
:ibetween	Matches values >= lower bound and <=upper bound
like, contains	Match values which contains specific value
ilike, icontains	Case insensitive version of like
has	For array type column, Matches array which has specific value

Syntax

• between | ibetween

  Syntax: field: {:between, [lower_value, upper_value]}

Check NULL and skip nil filter

By default is a value in the filter is nil, Filtery applies is_nil to check NULL value. You can tell Filtery to ignore all nil field by passing skip_nil: true to the options

Filtery.apply(query, filter, skip_nil: true)

In that case, if you want to check field which is NULL or NOT NULL you use :is_nil instead of nil when passing value to the filter:

Filter.apply(query, %{email: :is_nil}, skip_nil: true)

Define your operators

You can extend Filtery and define your own operator. For example, here I define a new operatory equal

defmodule MyFiltery do
    use Filtery.Base
    
    def filter(column, {:equal, value}) do
    dynamic([q], field(q, ^column) == ^value)
    end
end

To support a filter, you must follow this spec

@spec filter(column::atom(), {operator::atom(), value::any()}) :: Ecto.Query.dynamic()

Within the body of filter/2 function using dynamic to compose your condtion and return a dynamic