Api Platform Filters (Symfony)

Use when

• A collection endpoint needs search, exact match, range, date, boolean, or sort query parameters.
• One query parameter must search across several properties.
• A filter needs custom query logic that the built-in filters do not cover.
• Migrating #[ApiFilter] declarations (deprecated since 4.4) to the Parameters API, by hand or with api:upgrade-filter.

Default workflow

1. Declare parameters with QueryParameter on the operation; keep #[ApiFilter] only in 3.4 code or code not yet migrated.
2. Choose a filter class per parameter, checking the installed version: ExactFilter, PartialSearchFilter, FreeTextQueryFilter, OrFilter, IriFilter (4.2+), ComparisonFilter, SortFilter (4.3+), StartSearchFilter, EndSearchFilter, ChainFilter (4.4+).
3. For a custom filter, implement FilterInterface and read the bound value from $context['parameter'] (AbstractFilter and filterProperty() are deprecated since 4.4: keep them for 4.3 and 3.4 code).
4. Turn on strictQueryParameterValidation so unknown query parameters return 400.
5. Add #[ORM\Index] on filtered columns, then request the endpoint with matching and non-matching values.