43 lines
1.2 KiB
Go
43 lines
1.2 KiB
Go
package config
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import (
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"math/rand"
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"net/http"
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"time"
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)
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const (
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tokenSize = 80
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letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
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letterIdxBits = 6 // 6 bits to represent a letter index
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letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
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letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
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)
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// CheckToken checs if current token is the same as the one used in the request
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func (c Config) CheckToken(r *http.Request) bool {
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token := r.Header.Get("Token")
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return c.Token == token
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}
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// GenerateToken geneerates a new token
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func (c *Config) GenerateToken() {
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src := rand.NewSource(time.Now().UnixNano())
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b := make([]byte, tokenSize)
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// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
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// future reference: http://stackoverflow.com/questions/22892120/how-to-generate-a-random-string-of-a-fixed-length-in-golang
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for i, cache, remain := tokenSize-1, src.Int63(), letterIdxMax; i >= 0; {
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if remain == 0 {
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cache, remain = src.Int63(), letterIdxMax
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}
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if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
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b[i] = letterBytes[idx]
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i--
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}
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cache >>= letterIdxBits
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remain--
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}
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c.Token = string(b)
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}
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