photoprism/pkg/txt/datetime.go
Michael Mayer c7ad17b60c Metadata: Ignore unknown values when parsing timestamps #2510
Signed-off-by: Michael Mayer <michael@photoprism.app>
2022-07-22 12:38:25 +02:00

162 lines
3.9 KiB
Go

package txt
import (
"fmt"
"regexp"
"strings"
"time"
)
// regex tester: https://regoio.herokuapp.com/
var DateRegexp = regexp.MustCompile("\\D\\d{4}[\\-_]\\d{2}[\\-_]\\d{2,}")
var DatePathRegexp = regexp.MustCompile("\\D\\d{4}/\\d{1,2}/?\\d*")
var DateTimeRegexp = regexp.MustCompile("\\D\\d{2,4}[\\-_]\\d{2}[\\-_]\\d{2}.{1,4}\\d{2}\\D\\d{2}\\D\\d{2,}")
var DateIntRegexp = regexp.MustCompile("\\d{1,4}")
var YearRegexp = regexp.MustCompile("\\d{4,5}")
var IsDateRegexp = regexp.MustCompile("\\d{4}[\\-_]?\\d{2}[\\-_]?\\d{2}")
var IsDateTimeRegexp = regexp.MustCompile("\\d{4}[\\-_]?\\d{2}[\\-_]?\\d{2}.{1,4}\\d{2}\\D?\\d{2}\\D?\\d{2}")
var ExifDateTimeRegexp = regexp.MustCompile("((?P<year>\\d{4})|\\D{4})\\D((?P<month>\\d{2})|\\D{2})\\D((?P<day>\\d{2})|\\D{2})\\D((?P<h>\\d{2})|\\D{2})\\D((?P<m>\\d{2})|\\D{2})\\D((?P<s>\\d{2})|\\D{2})(\\.(?P<subsec>\\d+))?(?P<z>\\D)?(?P<zh>\\d{2})?\\D?(?P<zm>\\d{2})?")
var ExifDateTimeMatch = make(map[string]int)
// OneYear represents a duration of 365 days.
const OneYear = time.Hour * 24 * 365
func init() {
names := ExifDateTimeRegexp.SubexpNames()
for i := 0; i < len(names); i++ {
if name := names[i]; name != "" {
ExifDateTimeMatch[name] = i
}
}
}
var (
YearMin = 1990
YearMinShort = 90
YearMax = time.Now().Add(OneYear * 3).Year()
YearShort = Int(time.Now().Format("06"))
)
const (
MonthMin = 1
MonthMax = 12
DayMin = 1
DayMax = 31
HourMin = 0
HourMax = 24
MinMin = 0
MinMax = 59
SecMin = 0
SecMax = 59
)
// DateTime parses a time string and returns a valid time.Time if possible.
func DateTime(s, timeZone string) (t time.Time) {
defer func() {
if r := recover(); r != nil {
// Panic? Return unknown time.
t = time.Time{}
}
}()
// Empty time string?
if EmptyTime(s) {
return time.Time{}
}
s = strings.TrimLeft(s, " ")
// Timestamp too short?
if len(s) < 4 {
return time.Time{}
} else if len(s) > 50 {
// Clip to max length.
s = s[:50]
}
// Pad short timestamp with whitespace at the end.
s = fmt.Sprintf("%-19s", s)
v := ExifDateTimeMatch
m := ExifDateTimeRegexp.FindStringSubmatch(s)
// Pattern doesn't match? Return unknown time.
if len(m) == 0 {
return time.Time{}
}
// Default to UTC.
tz := time.UTC
// Local time zone currently not supported (undefined).
if timeZone == time.Local.String() {
timeZone = ""
}
// Set time zone.
loc, err := time.LoadLocation(timeZone)
// Location found?
if err == nil && timeZone != "" && tz != time.Local {
tz = loc
timeZone = tz.String()
} else {
timeZone = ""
}
// Does the timestamp contain a time zone offset?
z := m[v["z"]] // Supported values, if not empty: Z, +, -
zh := IntVal(m[v["zh"]], 0, 23, 0) // Hours.
zm := IntVal(m[v["zm"]], 0, 59, 0) // Minutes.
// Valid time zone offset found?
if offset := (zh*60 + zm) * 60; offset > 0 && offset <= 86400 {
// Offset timezone name example: UTC+03:30
if z == "+" {
// Positive offset relative to UTC.
tz = time.FixedZone(fmt.Sprintf("UTC+%02d:%02d", zh, zm), offset)
} else if z == "-" {
// Negative offset relative to UTC.
tz = time.FixedZone(fmt.Sprintf("UTC-%02d:%02d", zh, zm), -1*offset)
}
}
var nsec int
if subsec := m[v["subsec"]]; subsec != "" {
nsec = Int(subsec + strings.Repeat("0", 9-len(subsec)))
} else {
nsec = 0
}
// Create rounded timestamp from parsed input values.
t = time.Date(
IntVal(m[v["year"]], 1, YearMax, time.Now().Year()),
time.Month(IntVal(m[v["month"]], 1, 12, 1)),
IntVal(m[v["day"]], 1, 31, 1),
IntVal(m[v["h"]], 0, 23, 0),
IntVal(m[v["m"]], 0, 59, 0),
IntVal(m[v["s"]], 0, 59, 0),
nsec,
tz)
if timeZone != "" && loc != nil && loc != tz {
return t.In(loc)
}
return t
}
// IsTime tests if the string looks like a date and/or time.
func IsTime(s string) bool {
if s == "" {
return false
} else if m := IsDateRegexp.FindString(s); m == s {
return true
} else if m := IsDateTimeRegexp.FindString(s); m == s {
return true
}
return false
}