mirror of
https://github.com/MeshTender/MeshTender.git
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33 lines
900 B
Go
33 lines
900 B
Go
package web
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import (
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"encoding/base64"
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"encoding/json"
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)
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// EncodeCursor packs a keyset position into an opaque, URL-safe token. Callers
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// pass a small named struct with short JSON tags (the wire form is not stable
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// API — it only round-trips through the client's ?cursor/?before parameter).
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func EncodeCursor[T any](pos T) string {
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b, _ := json.Marshal(pos)
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return base64.RawURLEncoding.EncodeToString(b)
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}
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// DecodeCursor reverses EncodeCursor. A missing or malformed token decodes to the
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// zero value with ok=false, so a tampered or stale URL just resets paging to the
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// first page rather than erroring.
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func DecodeCursor[T any](tok string) (pos T, ok bool) {
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if tok == "" {
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return pos, false
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}
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b, err := base64.RawURLEncoding.DecodeString(tok)
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if err != nil {
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return pos, false
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}
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if json.Unmarshal(b, &pos) != nil {
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var zero T
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return zero, false
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}
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return pos, true
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}
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