33 lines
1.0 KiB
Go
33 lines
1.0 KiB
Go
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// Package secureurl holds the one transport rule for URLs that carry
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// credentials or session cookies: HTTPS, or plain HTTP to a loopback host for
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// local development and tests.
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package secureurl
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import (
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"errors"
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"fmt"
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"net/url"
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"strings"
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)
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// loopbackHosts are the only hosts plain HTTP is allowed for, compared
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// case-insensitively. url.URL's Hostname strips the brackets from "[::1]".
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var loopbackHosts = map[string]bool{"localhost": true, "127.0.0.1": true, "::1": true}
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// Check reports an error unless u is an absolute https:// URL, or an http://
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// URL whose host is localhost, 127.0.0.1 or ::1.
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func Check(u *url.URL) error {
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switch {
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case u.Hostname() == "":
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return errors.New("URL has no host")
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case u.Scheme == "https":
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return nil
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case u.Scheme == "http" && loopbackHosts[strings.ToLower(u.Hostname())]:
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return nil
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case u.Scheme == "http":
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return errors.New("plain http:// is allowed only for localhost, 127.0.0.1 or [::1]; use https://")
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default:
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return fmt.Errorf("unsupported scheme %q (want https://)", u.Scheme)
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}
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}
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