api-filtering-sorting

Builds flexible API filtering and sorting systems with query parameter parsing, validation, and security. Use when implementing search endpoints, building data grids, or creating dynamic query APIs.

Stars 163

Forks 31

Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/skills/other/api-filtering-sorting

SKILL.md

API Filtering & Sorting

Build flexible filtering and sorting systems that handle complex queries efficiently.

Query Parameter Syntax

GET /products?category=electronics&price[gte]=100&price[lte]=500&sort=-price,name

Implementation (Node.js)

javascript

const allowedFilters = ['category', 'status', 'price', 'createdAt'];
const allowedSorts = ['name', 'price', 'createdAt'];

app.get('/products', async (req, res) => {
  const filter = {};
  const sort = {};

  // Parse filters
  for (const [key, value] of Object.entries(req.query)) {
    if (key === 'sort') continue;

    const match = key.match(/^(\w+)\[(\w+)\]$/);
    if (match) {
      const [, field, operator] = match;
      if (!allowedFilters.includes(field)) continue;
      filter[field] = { [`$${operator}`]: parseValue(value) };
    } else if (allowedFilters.includes(key)) {
      filter[key] = value;
    }
  }

  // Parse sort
  if (req.query.sort) {
    for (const field of req.query.sort.split(',')) {
      const direction = field.startsWith('-') ? -1 : 1;
      const name = field.replace(/^-/, '');
      if (allowedSorts.includes(name)) sort[name] = direction;
    }
  }

  const products = await Product.find(filter).sort(sort);
  res.json({ data: products });
});

function parseValue(value) {
  if (value === 'true') return true;
  if (value === 'false') return false;
  if (!isNaN(value)) return Number(value);
  return value;
}

Filter Operators

Operator	Meaning	Example
eq	Equals	`?status=active`
ne	Not equals	`?status[ne]=deleted`
gt/gte	Greater than	`?price[gte]=100`
lt/lte	Less than	`?price[lte]=500`
in	In array	`?status[in]=active,pending`
like	Contains	`?name[like]=phone`

Security

Whitelist allowed filter fields
Validate input types per field
Index frequently-filtered columns
Limit query complexity
Prevent SQL/NoSQL injection

Best Practices

Support common operators
Cache filter option lists
Monitor query performance
Provide sensible defaults