Chain() — fiber Function Reference

Architecture documentation for the Chain() function in extractors.go from the fiber codebase.

Function go DataBinding Extractors

Entity Profile

DataBinding→ Extractors→ Chain() — fiber Function Reference

Dependency Diagram

graph TD
  1f00988f_0868_50d8_cb7f_d3beb6689f79["Chain()"]
  9369d97d_10d6_c835_81b9_8542715b2822["extractors.go"]
  1f00988f_0868_50d8_cb7f_d3beb6689f79 -->|defined in| 9369d97d_10d6_c835_81b9_8542715b2822
  style 1f00988f_0868_50d8_cb7f_d3beb6689f79 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

extractors/extractors.go lines 462–503

func Chain(extractors ...Extractor) Extractor {
	if len(extractors) == 0 {
		return Extractor{
			Extract: func(fiber.Ctx) (string, error) {
				return "", ErrNotFound
			},
			Source: SourceCustom,
			Key:    "",
			Chain:  []Extractor{},
		}
	}

	// Use the source and key from the first extractor as the primary
	primarySource := extractors[0].Source
	primaryKey := extractors[0].Key

	return Extractor{
		Extract: func(c fiber.Ctx) (string, error) {
			var lastErr error // last error encountered (including ErrNotFound)

			for _, extractor := range extractors {
				if extractor.Extract == nil {
					continue
				}
				v, err := extractor.Extract(c)
				if err == nil && v != "" {
					return v, nil
				}
				if err != nil {
					lastErr = err
				}
			}
			if lastErr != nil {
				return "", lastErr
			}
			return "", ErrNotFound
		},
		Source: primarySource,
		Key:    primaryKey,
		Chain:  append([]Extractor(nil), extractors...), // Defensive copy for introspection
	}
}