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package monitor
import (
"fmt"
"io/ioutil"
"log"
"net/http"
"golang.org/x/mod/sumdb/note"
"golang.org/x/mod/sumdb/tlog"
)
type Database struct {
URL string
Key string
}
func (db *Database) readRemote(path string) ([]byte, error) {
log.Printf("GET %s", path)
resp, err := http.Get("https://" + db.URL + path)
if err != nil {
return nil, err
}
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("get %s: expected HTTP OK but got %s", path, resp.Status)
}
if resp.ContentLength > 1e6 {
return nil, fmt.Errorf("get %s: body too large (%d bytes)", path, resp.ContentLength)
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("get %s: %v", err)
}
return body, nil
}
func (db *Database) VerifyNote(msg []byte) (*note.Note, error) {
verifier, err := note.NewVerifier(db.Key)
if err != nil {
return nil, err
}
return note.Open(msg, note.VerifierList(verifier))
}
func (db *Database) FetchSTH() (tlog.Tree, error) {
resp, err := db.readRemote("/latest")
if err != nil {
return tlog.Tree{}, err
}
note, err := db.VerifyNote(resp)
if err != nil {
return tlog.Tree{}, err
}
return tlog.ParseTree([]byte(note.Text))
}
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