43 lines
1.0 KiB
Go
43 lines
1.0 KiB
Go
package captcha
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"image"
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"strconv"
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"time"
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)
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const DefaultExpiredScanInterval = 60 * time.Second
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// ID is a CAPTCHA identifier.
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type ID string
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// NewID generates an ID as a sha256 hash of additionalData (usually IP-address),
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// current time, answer and more, it adds a set of random bytes and encodes all
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// of it with base64 in raw URL variant.
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func NewID(additionalData string, answer Answer) ID {
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idHash := sha256.New()
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idHash.Write([]byte(additionalData))
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idHash.Write([]byte(strconv.FormatInt(time.Now().UnixMicro(), 16)))
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idHash.Write([]byte(answer))
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randData := make([]byte, 32)
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rand.Read(randData)
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idHash.Write(randData)
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return ID(base64.RawURLEncoding.EncodeToString(idHash.Sum(nil)))
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}
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// DB interface with all necessary methods.
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type DB interface {
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New(data string, captcha Captcha) (Captcha, ID)
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GetExpiry() time.Duration
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SetExpiry(expiry time.Duration)
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Image(id ID, style string) *image.Image
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Solve(id ID, answer Answer) bool
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IsSolved(id ID) bool
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Remove(id ID)
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}
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