fiber/middleware/cors/utils.go

86 lines
2.8 KiB
Go

package cors
import (
"net/url"
"strings"
)
// matchScheme compares the scheme of the domain and pattern
func matchScheme(domain, pattern string) bool {
didx := strings.Index(domain, ":")
pidx := strings.Index(pattern, ":")
return didx != -1 && pidx != -1 && domain[:didx] == pattern[:pidx]
}
// validateDomain checks if the domain matches the pattern
func validateDomain(domain, pattern string) bool {
// Directly compare the domain and pattern for an exact match.
if domain == pattern {
return true
}
// Normalize domain and pattern to exclude schemes and ports for matching purposes
normalizedDomain := normalizeDomain(domain)
normalizedPattern := normalizeDomain(pattern)
// Handling the case where pattern is a wildcard subdomain pattern.
if strings.HasPrefix(normalizedPattern, "*.") {
// Trim leading "*." from pattern for comparison.
trimmedPattern := normalizedPattern[2:]
// Check if the domain ends with the trimmed pattern.
if strings.HasSuffix(normalizedDomain, trimmedPattern) {
// Ensure that the domain is not exactly the base domain.
if normalizedDomain != trimmedPattern {
// Special handling to prevent "example.com" matching "*.example.com".
if strings.TrimSuffix(normalizedDomain, trimmedPattern) != "" {
return true
}
}
}
}
return false
}
// normalizeDomain removes the scheme and port from the input domain
func normalizeDomain(input string) string {
// Remove scheme
input = strings.TrimPrefix(strings.TrimPrefix(input, "http://"), "https://")
// Find and remove port, if present
if len(input) > 0 && input[0] != '[' {
if portIndex := strings.Index(input, ":"); portIndex != -1 {
input = input[:portIndex]
}
}
return input
}
// normalizeOrigin checks if the provided origin is in a correct format
// and normalizes it by removing any path or trailing slash.
// It returns a boolean indicating whether the origin is valid
// and the normalized origin.
func normalizeOrigin(origin string) (bool, string) {
parsedOrigin, err := url.Parse(origin)
if err != nil {
return false, ""
}
// Validate the scheme is either http or https
if parsedOrigin.Scheme != "http" && parsedOrigin.Scheme != "https" {
return false, ""
}
// Validate there is a host present. The presence of a path, query, or fragment components
// is checked, but a trailing "/" (indicative of the root) is allowed for the path and will be normalized
if parsedOrigin.Host == "" || (parsedOrigin.Path != "" && parsedOrigin.Path != "/") || parsedOrigin.RawQuery != "" || parsedOrigin.Fragment != "" {
return false, ""
}
// Normalize the origin by constructing it from the scheme and host.
// The path or trailing slash is not included in the normalized origin.
return true, strings.ToLower(parsedOrigin.Scheme + "://" + parsedOrigin.Host)
}