83 lines
2.0 KiB
Go
83 lines
2.0 KiB
Go
package imgcache
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import (
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"net/url"
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"strings"
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)
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// HostWhitelist implements the Whitelist interface for checking allowed source hosts.
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type HostWhitelist struct {
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// exactHosts contains hosts that must match exactly (e.g., "cdn.example.com")
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exactHosts map[string]struct{}
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// suffixHosts contains domain suffixes to match (e.g., ".example.com" matches "cdn.example.com")
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suffixHosts []string
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}
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// NewHostWhitelist creates a whitelist from a list of host patterns.
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// Patterns starting with "." are treated as suffix matches.
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// Examples:
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// - "cdn.example.com" - exact match only
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// - ".example.com" - matches cdn.example.com, images.example.com, etc.
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func NewHostWhitelist(patterns []string) *HostWhitelist {
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w := &HostWhitelist{
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exactHosts: make(map[string]struct{}),
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suffixHosts: make([]string, 0),
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}
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for _, pattern := range patterns {
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pattern = strings.ToLower(strings.TrimSpace(pattern))
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if pattern == "" {
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continue
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}
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if strings.HasPrefix(pattern, ".") {
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w.suffixHosts = append(w.suffixHosts, pattern)
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} else {
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w.exactHosts[pattern] = struct{}{}
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}
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}
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return w
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}
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// IsWhitelisted checks if a URL's host is in the whitelist.
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func (w *HostWhitelist) IsWhitelisted(u *url.URL) bool {
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if u == nil {
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return false
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}
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host := strings.ToLower(u.Hostname())
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if host == "" {
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return false
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}
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// Check exact match
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if _, ok := w.exactHosts[host]; ok {
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return true
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}
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// Check suffix match
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for _, suffix := range w.suffixHosts {
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if strings.HasSuffix(host, suffix) {
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return true
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}
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// Also match if host equals the suffix without the leading dot
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// e.g., pattern ".example.com" should match "example.com"
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if host == strings.TrimPrefix(suffix, ".") {
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return true
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}
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}
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return false
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}
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// IsEmpty returns true if the whitelist has no entries.
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func (w *HostWhitelist) IsEmpty() bool {
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return len(w.exactHosts) == 0 && len(w.suffixHosts) == 0
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}
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// Count returns the total number of whitelist entries.
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func (w *HostWhitelist) Count() int {
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return len(w.exactHosts) + len(w.suffixHosts)
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}
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