func updateSigs() (string, error) {
url, _, _ := config.UpdateOptions()
if url == "" {
return "Update is not available for this distribution of Siegfried", nil
}
response, err := getHttp(url)
if err != nil {
return "", err
}
var u Update
if err := json.Unmarshal(response, &u); err != nil {
return "", err
}
version := config.Version()
if version[0] < u.SfVersion[0] || (u.SfVersion[0] == version[0] && version[1] < u.SfVersion[1]) {
return "Your version of Siegfried is out of date; please install latest from http://www.itforarchivists.com/siegfried before continuing.", nil
}
s, err := siegfried.Load(config.Signature())
if err == nil {
if !s.Update(u.SigCreated) {
return "You are already up to date!", nil
}
} else {
// this hairy bit of golang exception handling is thanks to Ross! :)
if _, err = os.Stat(config.Home()); err != nil {
if os.IsNotExist(err) {
err = os.MkdirAll(config.Home(), os.ModePerm)
if err != nil {
return "", fmt.Errorf("Siegfried: cannot create home directory %s, %v", config.Home(), err)
}
} else {
return "", fmt.Errorf("Siegfried: error opening directory %s, %v", config.Home(), err)
}
}
}
fmt.Println("... downloading latest signature file ...")
response, err = getHttp(u.LatestURL)
if err != nil {
return "", fmt.Errorf("Siegfried: error retrieving pronom.gob.\nThis may be a network or firewall issue. See https://github.com/richardlehane/siegfried/wiki/Getting-started for manual instructions.\nSystem error: %v", err)
}
if len(response) != u.GobSize {
return "", fmt.Errorf("Siegfried: error retrieving pronom.gob; expecting %d bytes, got %d bytes", u.GobSize, len(response))
}
err = ioutil.WriteFile(config.Signature(), response, os.ModePerm)
if err != nil {
return "", fmt.Errorf("Siegfried: error writing to directory, %v", err)
}
fmt.Printf("... writing %s ...\n", config.Signature())
return "Your signature file has been updated", nil
}
func getHttp(url string) ([]byte, error) {
req, err := http.NewRequest("GET", url, nil)
if err != nil {
return nil, err
}
_, timeout, transport := config.UpdateOptions()
req.Header.Add("User-Agent", "siegfried/siegbot (+https://github.com/richardlehane/siegfried)")
req.Header.Add("Cache-Control", "no-cache")
timer := time.AfterFunc(timeout, func() {
transport.CancelRequest(req)
})
defer timer.Stop()
client := http.Client{
Transport: transport,
}
resp, err := client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
return ioutil.ReadAll(resp.Body)
}