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60 lines
1.1 KiB
Go
60 lines
1.1 KiB
Go
package valid
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import (
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"bytes"
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)
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var URIs = [][]byte{
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[]byte("http://"),
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[]byte("https://"),
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[]byte("ftp://"),
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[]byte("mailto:"),
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}
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var Paths = [][]byte{
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[]byte("/"),
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[]byte("./"),
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[]byte("../"),
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}
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// TODO: documentation
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func IsSafeURL(url []byte) bool {
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nLink := len(url)
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for _, path := range Paths {
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nPath := len(path)
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linkPrefix := url[:nPath]
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if nLink >= nPath && bytes.Equal(linkPrefix, path) {
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if nLink == nPath {
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return true
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} else if isAlnum(url[nPath]) {
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return true
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}
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}
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}
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for _, prefix := range URIs {
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// TODO: handle unicode here
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// case-insensitive prefix test
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nPrefix := len(prefix)
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if nLink > nPrefix {
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linkPrefix := bytes.ToLower(url[:nPrefix])
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if bytes.Equal(linkPrefix, prefix) && isAlnum(url[nPrefix]) {
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return true
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}
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}
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}
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return false
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}
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// isAlnum returns true if c is a digit or letter
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// TODO: check when this is looking for ASCII alnum and when it should use unicode
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func isAlnum(c byte) bool {
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return (c >= '0' && c <= '9') || isLetter(c)
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}
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// isLetter returns true if c is ascii letter
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func isLetter(c byte) bool {
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return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
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}
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