forked from TrueCloudLab/distribution
147 lines
2.6 KiB
Go
147 lines
2.6 KiB
Go
package util
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import (
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"bytes"
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srand "crypto/rand"
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"encoding/binary"
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"math/rand"
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"net/http"
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"net/url"
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"sort"
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"time"
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)
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const dictionary = "_0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
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//CreateRandomString create random string
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func CreateRandomString() string {
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b := make([]byte, 32)
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l := len(dictionary)
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_, err := srand.Read(b)
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if err != nil {
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// fail back to insecure rand
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rand.Seed(time.Now().UnixNano())
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for i := range b {
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b[i] = dictionary[rand.Int()%l]
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}
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} else {
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for i, v := range b {
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b[i] = dictionary[v%byte(l)]
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}
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}
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return string(b)
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}
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// Encode encodes the values into ``URL encoded'' form
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// ("acl&bar=baz&foo=quux") sorted by key.
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func Encode(v url.Values) string {
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if v == nil {
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return ""
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}
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var buf bytes.Buffer
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keys := make([]string, 0, len(v))
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for k := range v {
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keys = append(keys, k)
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}
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sort.Strings(keys)
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for _, k := range keys {
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vs := v[k]
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prefix := url.QueryEscape(k)
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for _, v := range vs {
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if buf.Len() > 0 {
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buf.WriteByte('&')
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}
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buf.WriteString(prefix)
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if v != "" {
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buf.WriteString("=")
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buf.WriteString(url.QueryEscape(v))
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}
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}
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}
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return buf.String()
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}
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func GetGMTime() string {
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return time.Now().UTC().Format(http.TimeFormat)
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}
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//
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func randUint32() uint32 {
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return randUint32Slice(1)[0]
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}
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func randUint32Slice(c int) []uint32 {
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b := make([]byte, c*4)
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_, err := srand.Read(b)
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if err != nil {
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// fail back to insecure rand
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rand.Seed(time.Now().UnixNano())
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for i := range b {
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b[i] = byte(rand.Int())
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}
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}
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n := make([]uint32, c)
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for i := range n {
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n[i] = binary.BigEndian.Uint32(b[i*4 : i*4+4])
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}
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return n
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}
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func toByte(n uint32, st, ed byte) byte {
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return byte(n%uint32(ed-st+1) + uint32(st))
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}
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func toDigit(n uint32) byte {
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return toByte(n, '0', '9')
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}
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func toLowerLetter(n uint32) byte {
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return toByte(n, 'a', 'z')
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}
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func toUpperLetter(n uint32) byte {
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return toByte(n, 'A', 'Z')
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}
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type convFunc func(uint32) byte
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var convFuncs = []convFunc{toDigit, toLowerLetter, toUpperLetter}
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// tools for generating a random ECS instance password
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// from 8 to 30 char MUST contain digit upper, case letter and upper case letter
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// http://docs.aliyun.com/#/pub/ecs/open-api/instance&createinstance
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func GenerateRandomECSPassword() string {
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// [8, 30]
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l := int(randUint32()%23 + 8)
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n := randUint32Slice(l)
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b := make([]byte, l)
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b[0] = toDigit(n[0])
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b[1] = toLowerLetter(n[1])
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b[2] = toUpperLetter(n[2])
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for i := 3; i < l; i++ {
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b[i] = convFuncs[n[i]%3](n[i])
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}
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s := make([]byte, l)
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perm := rand.Perm(l)
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for i, v := range perm {
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s[v] = b[i]
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}
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return string(s)
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}
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