CoreKit.DataFilter.Linq 1.0.0

CoreKit.DataFilter.Linq

This library allows you to apply dynamic filtering (FilterRequest) to IQueryable<T> in LINQ/EF Core using expression trees. It supports:

• Filtering with dynamic conditions
• Sorting with Dynamic LINQ
• Pagination using Skip/Take

🔧 Key Component

GenericLinqFilterProcessor<T>

Builds a Func<T, bool> expression tree based on a FilterRequest and applies it to a LINQ query.

✅ Usage

With ApplyFilter(...)

var processor = new GenericLinqFilterProcessor<Product>();
var query = processor.ApplyFilter(_dbContext.Products, request);

With extension method:

var result = _dbContext.Products
    .AsQueryable()
    .ApplyFilterRequest(request)
    .ToList();

Requires reference to CoreKit.DataFilter.Linq.Extensions

📦 Supported Features

• All FilterOperatorEnum operators
• Nested groups with AND / OR
• IN, NULL, NOT NULL support
• Sorting via System.Linq.Dynamic.Core

📦 NuGet Requirements

dotnet add package System.Linq.Dynamic.Core

🎯 How to receive filters in your Controller

You can support both GET and POST methods in your controller for filtering, but they have different behaviors:

✅ Option 1: POST (Recommended for complex filters)

[HttpPost("search")]
public IActionResult Search([FromBody] FilterRequest request)
{
    var result = _dbContext.Products
        .AsQueryable()
        .ApplyFilterRequest(request)
        .ToList();

    return Ok(result);
}

⚠️ Option 2: GET (Limited support)

[HttpGet("search")]
public IActionResult Search([FromQuery] SimpleQueryRequest query)
{
    var request = query.ToFilterRequest();

    var result = _dbContext.Products
        .AsQueryable()
        .ApplyFilterRequest(request)
        .ToList();

    return Ok(result);
}

⚠️ Limitations of GET filtering

🧮 How to use SimpleQueryRequest in a GET

📌 Query string parameters

🧪 Example GET request

GET /api/products/search
  ?filterQuery=status:eq:active;price:gt:100
  &sort=createdAt
  &sortDir=desc
  &page=2
  &pageSize=10

🧾 Syntax for filterQuery

Each filter is composed of:

field:operator:value

• Use ; to separate multiple rules.
• To use OR logic, prefix each rule with or:.

✅ Supported operators in filterQuery

🧠 Important Notes

• Values in in must be comma-separated and not quoted.

• Use or: prefix for logical OR:

  or:category:eq:Books;or:category:eq:Stationery
  

• Nested groups and complex logical combinations (AND + OR) are not supported in GET.

🔧 Controller example

[HttpGet("search")]
public IActionResult Search([FromQuery] SimpleQueryRequest query)
{
    var request = query.ToFilterRequest();
    var result = _dbContext.Products
        .AsQueryable()
        .ApplyFilterRequest(request)
        .ToList();

    return Ok(result);
}

📬 How to use FilterRequest in a POST

Use POST when you need full filtering capabilities including:

• Grouped filters (AND / OR)
• Operators like IN, NULL, NOT NULL
• Large payloads not suitable for query strings

📦 Example JSON body

{
  "filter": {
    "logic": "and",
    "rules": [
      { "field": "status", "operator": "Equals", "value": "active" },
      { "field": "price", "operator": "GreaterThan", "value": "100" }
    ],
    "groups": [
      {
        "logic": "or",
        "rules": [
          { "field": "category", "operator": "Equals", "value": "Books" },
          { "field": "category", "operator": "Equals", "value": "Stationery" }
        ]
      }
    ]
  },
  "sort": [
    { "field": "createdAt", "direction": "desc" }
  ],
  "pagination": {
    "page": 1,
    "pageSize": 20
  }
}

🔧 Controller example

[HttpPost("search")]
public IActionResult Search([FromBody] FilterRequest request)
{
    var result = _dbContext.Products
        .AsQueryable()
        .ApplyFilterRequest(request)
        .ToList();

    return Ok(result);
}