rob05c commented on a change in pull request #4942:
URL: https://github.com/apache/trafficcontrol/pull/4942#discussion_r485218928
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File path: traffic_ops/traffic_ops_golang/api/api.go
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@@ -994,3 +994,36 @@ func CreateDeprecationAlerts(alternative *string)
tc.Alerts {
return tc.CreateAlerts(tc.WarnLevel, "This endpoint is
deprecated, and will be removed in the future")
}
}
+
+// GetLastUpdated checks for the resource in the database, and returns its
last_updated timestamp, if available.
+func GetLastUpdated(tx *sqlx.Tx, ID int, tableName string) (*tc.TimeNoMod,
error) {
+ lastUpdated := tc.TimeNoMod{}
+ rows, err := tx.Query(`select last_updated from `+tableName+` where
id=$1`, ID)
+ if err != nil {
+ return nil, err
+ }
+ defer rows.Close()
+ if !rows.Next() {
+ return nil, errors.New("no resource found with this id")
+ }
+ if err := rows.Scan(&lastUpdated); err != nil {
+ return nil, err
+ }
+ return &lastUpdated, nil
+}
+
+// IsUnmodified returns a boolean, saying whether or not the resource in
question was modified since the time specified in the headers.
+func IsUnmodified(h http.Header, existingLastUpdated *tc.TimeNoMod) bool {
+ _, iumsTime := rfc.GetETagOrIfUnmodifiedSinceTime(h)
+ existingEtag := rfc.ETag(existingLastUpdated.Time)
+
+ if h != nil {
+ if h.Get(rfc.IfMatch) != "" &&
!strings.Contains(h.Get(rfc.IfMatch), existingEtag) {
Review comment:
Maybe something like
```
func GetUnmodifiedTime(h http.Header) (time.Time, bool) {
if h == nil {
return time.Time{}, false
}
if im := h.Get(IfMatch); im != "" {
if et, ok := ParseETags(strings.Split(im, ",")); ok {
return et, true
}
}
if ius := h.Get(IfUnmodifiedSince); ius != "" {
if tm, ok := ParseHTTPDate(ius); ok {
return tm, true
}
}
return time.Time{}, false
}
// ParseETags the latest time of any valid ETag, and whether a valid ETag
was found.
func ParseETags(eTags []string) (time.Time, bool) {
latestTime := time.Time{}
for _, tag := range eTags {
tag = strings.TrimSpace(tag)
et, err := ParseETag(tag)
// errors are recoverable, keep going through the list of etags
if err != nil {
continue
}
if et.After(latestTime) {
latestTime = et
}
}
if latestTime == (time.Time{}) {
return time.Time{}, false
}
return latestTime, true
}
// IsUnmodified returns a boolean, saying whether or not the resource in
question was modified since the time specified in the headers.
func IsUnmodified(h http.Header, lastUpdated time.Time) bool {
unmodifiedTime, ok := rfc.GetUnmodifiedTime(h)
if !ok {
return true // no IUS/IM header: consider unmodified
}
return !lastUpdated.After(unmodifiedTime)
}
```
?
That would protect us against edge cases and future ETag changes, which will
be contained in the `ParseETag` func
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