PHPでランダム文字列ぽいものを作る方法

1. koyama@hoge.org
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2. about me
id:koyhoge
2007 OSS
2

3. agenda
id generate
encode/decode
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4. RFC4648
The Base16, Base32, and Base64 Data
Encodings
Base 64 Encoding with URL and Filename
Safe Alphabet
base64url
+ → -, / → _
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5. id generate
DB Sequence id
1 → NWoZK3kTsExUV00Ywo1G5jlU
2 → 2kuSN7rMzfGcB2DKt67EqDWQ
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6. static public function genUniqHash($input, $options = null) {
$seed = array_val($options, 'seed', 0);
$length = array_val($options, 'length', 18); / 18 = non-padding max
/
static $search = array('+', '/');
static $replace = array('-', '_');
/ limit check: sha1() returns 20 bytes
/
if (($length <= 0) || (20 < $length)) {
$length = 20;
}
if (($seed + $length) > 20) {
$seed = 20 - $length;
}
$out = base64_encode(substr(sha1($input, true), $seed, $length));
return str_replace($search, $replace, $out);
}
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7. encode/decode
gzip +base64url
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8. static public function tinyEncode($input) {
static $search = array('+', '/');
static $replace = array('-', '_');
$gzed = gzdeflate($input);
$encoded = base64_encode($gzed);
$result = str_replace($search, $replace, $encoded);
/ trim trailing '='
/
return rtrim($result, '=');
}
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9. static public function tinyDecode($encoded) {
static $search = array('-', '_');
static $replace = array('+', '/');
$str = str_replace($search, $replace, $encoded);
$decoded = base64_decode($str);
return gzinflate($decoded);
}
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10. Thanks for hearing
10