api-filtering-sorting

SKILL.md

API Filtering & Sorting

Table of Contents

Overview

When to Use

Quick Start

Reference Guides

Best Practices

Overview

Build flexible filtering and sorting systems that handle complex queries efficiently with proper validation, security, and performance optimization.

When to Use

Building search and filter interfaces

Implementing advanced query capabilities

Creating flexible data retrieval endpoints

Optimizing query performance

Validating user input for queries

Supporting complex filtering logic

Quick Start

Minimal working example:

// Node.js filtering implementation
app.get("/api/products", async (req, res) => {
  const filters = {};
  const sortOptions = {};

  // Parse filtering parameters
  const allowedFilters = [
    "category",
    "minPrice",
    "maxPrice",
    "inStock",
    "rating",
  ];
  for (const key of allowedFilters) {
    if (req.query[key]) {
      filters[key] = req.query[key];
    }
  }

  // Build MongoDB query
  const mongoQuery = {};

  if (filters.category) {
    mongoQuery.category = filters.category;
  }
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide
Contents

Query Parameter Filtering
Query Parameter Filtering

Advanced Filter Parser
Advanced Filter Parser

Filter Builder Pattern
Filter Builder Pattern

Python Filtering (SQLAlchemy)
Python Filtering (SQLAlchemy)

Elasticsearch Filtering
Elasticsearch Filtering

Query Validation
Query Validation

Best Practices

✅ DO

Whitelist allowed filter fields

Validate all input parameters

Index fields used for filtering

Support common operators

Provide faceted navigation

Cache filter options

Limit filter complexity

Document filter syntax

Use database-native operators

Optimize queries with indexes

❌ DON'T

Allow arbitrary field filtering

Support unlimited operators

Ignore SQL injection risks

Create complex filter logic

Expose internal field names

Filter on unindexed fields

Allow deeply nested filters

Skip input validation

Combine all filters with OR

Ignore performance impact

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