kataras/iris · error

iris: rewrite: decode:

Error message

iris: rewrite: decode: 

What it means

After opening the rules file, rewrite.LoadOptions decodes it with the yaml or json decoder chosen by extension; a decode error is re-panicked prefixed with 'iris: rewrite: decode: '. The file was found and the extension was valid, but its contents do not parse as the corresponding format or do not fit the Options structure.

Solutions

1. Validate the file with a YAML/JSON parser and fix the reported syntax error (line/column is in the panic message).
2. Check that the document structure matches rewrite.Options (primary ROOT redirection plus list of redirect match rules).
3. Test parsing in a unit test with yaml.Unmarshal/json.Unmarshal on the same file so failures surface with full error detail.

Example fix

// before (redirects.yml)
redirects:
	- /old /new   # tab indentation -> decode error
// after (redirects.yml)
redirects:
  - /old /new

data, err := os.ReadFile(rulesPath)
if err != nil { return err }
switch strings.ToLower(filepath.Ext(rulesPath)) {
case ".yaml", ".yml":
    var v any
    if err := yaml.Unmarshal(data, &v); err != nil {
        return fmt.Errorf("invalid rewrite yaml: %w", err)
    }
case ".json":
    if !json.Valid(data) {
        return errors.New("invalid rewrite json")
    }
}

defer func() {
    if r := recover(); r != nil {
        log.Fatalf("rewrite rules decode failed: %v", r)
    }
}()
engine := rewrite.Load(rulesPath)

When it happens

Trigger: Loading a .yml file with YAML syntax errors (bad indentation, tabs), or a .json file with trailing commas/comments, or content whose types don't match rewrite.Options fields (e.g. a string where a list of RedirectMatch objects is expected).

Common situations: Hand-edited YAML using tabs instead of spaces; JSON file exported with comments; redirect rules defined in a shape the Options struct doesn't recognize; merge artifacts (<<<<<<< markers) left in the file.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• iris: rewrite: unexpected file extension:
• err
• iris: rewrite:
• malformed document file:
• parse yaml

AI-assisted analysis of kataras/iris@7bedaf55a0 (2026-08-30). Data as JSON: /api/errors/53ad9ebd01fcdb3b. Report an issue: GitHub.

Appendix: source

Thrown at middleware/rewrite/rewrite.go:60

	}

	f, err := os.Open(filename)
	if err != nil {
		panic("iris: rewrite: " + err.Error())
	}
	defer f.Close()

	switch ext {
	case ".yaml", ".yml":
		err = yaml.NewDecoder(f).Decode(&opts)
	case ".json":
		err = json.NewDecoder(f).Decode(&opts)
	default:
		panic("iris: rewrite: unexpected file extension: " + filename)
	}

	if err != nil {
		panic("iris: rewrite: decode: " + err.Error())
	}

	return
}

// Rewrite is a struct that represents a rewrite engine for Iris web framework.
// It contains a slice of redirect rules, an options struct, a logger, and a domain validator function.
// It provides methods to create, configure, and apply rewrite rules to HTTP requests and responses.
//
// Navigate through _examples/routing/rewrite for more.
type Engine struct {
	redirects []*redirectMatch
	options   Options

	logger          *golog.Logger
	domainValidator func(string) bool
}

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