Incorrect time-conversion in Go - go

I am trying to convert the time string "2020-02-01T12:30:00+01:00" (from the google calendar API) to time.Time format in Go, for some reason it keeps giving me "2020-01-01 12:30:00 +0000 UTC" as output (which is first of January, instead of first of February). Any idea what I'm doing wrong?
Thanks in advance!
package main
import (
"fmt"
"time"
"log"
)
func main() {
input := "2020-02-01T12:30:00+01:00"
output, err := StrToTime(input)
if err != nil{
log.Fatal(err)
}
fmt.Println(output)
}
func StrToTime(strDateTime string) (time.Time, error) {
layout := "2006-01-02T15:04:05+01:00"
t, err := time.Parse(layout, strDateTime)
if err != nil {
return time.Time{}, fmt.Errorf("could not parse datetime: %v", err)
}
return t, nil
}

It happens because you've specified the time offset portion wrong, it should be -07:00 not +01:00.
As of now it treats 01 as month portion, the second time, and overwrites the originally correctly parsed 02 as 01 (but not from the time offset part of the input).

Related

Convert timestamp and timezone into RFC3339 format

I am taking timestamp from the user like this
2015-05-28T17:00:00
And a timezone "America/Los_Angeles"
Now I want convert the date into something like
2015-05-28T17:00:00-07:00
Is that possible in go ,Please help me out in this ,if you have any links which you can share
You can use ParseInLocation to parse datetime in specific location.
package main
import (
"fmt"
"time"
)
func main() {
loc, err := time.LoadLocation("America/Los_Angeles")
if err != nil {
panic(err)
}
// Note: without explicit zone, returns time in given location.
const shortForm = "2015-05-28T17:00:00"
t, err := time.ParseInLocation("2006-01-02T15:04:05", shortForm, loc)
if err != nil {
panic(err)
}
fmt.Println(t)
}
Its output is:
2015-05-28 17:00:00 -0700 PDT
"timezone" translates to time.Location in go. To load a location by name:
loc, err := time.LoadLocation("America/Los_Angeles")
Parsing:
to interpret the string as "that timestamp in that location":
t, err := time.ParseInLocation("2006-01-02T15:04:05", input, loc)
to interpret the string as "that timestamp in UTC":
t, err := time.Parse("2006-01-02T15:04:05", input)
Formatting:
to format t according to RFC3339 :
fmt.Println(t.Format(time.RFC3339))
t carries its own time.Location, you can also translate that timestamp to the timezone you see fit:
fmt.Println(t.In(loc).Format(time.RFC3339))
fmt.Println(t.UTC().Format(time.RFC3339))
https://go.dev/play/p/g2BgfdYGxU_I

time.Parse offset parsing fails with "cannot parse <x>00 as -0700"

I wish to convert a string timestamp (for which no timezone was provided) to a time with timezone of UTC -08:00.
Code:
package main
import (
"fmt"
"log"
"time"
)
func main() {
layout := "1/02/2006 15:04:05 -700"
cellContent := "7/28/2021 22:45:34"
t, err := time.Parse(layout, fmt.Sprintf("%s %s", cellContent, "-800"))
if err == nil {
fmt.Println(t.String())
} else {
log.Fatal(err)
}
}
This fails with message:
parsing time "7/28/2021 22:45:34 -800" as "1/02/2006 15:04:05 -700":
cannot parse "800" as " -700"
I believe I have an error in my layout string, but haven't been able to identify it. What am I doing wrong?
Go Playground
See comment from #Adrian, who nailed it.
The layout timezone must have a leading zero. Thanks!

How i can to convert RFC3339 to UNIX in golang

I want to show some RFC3339 time as seconds. I found how to parse times string, but it not that
t, _ := time.Parse(time.RFC3339, "2012-11-01T22:08:41+00:00")
For example,
package main
import (
"fmt"
"time"
)
func main() {
t, err := time.Parse(time.RFC3339, "2012-11-01T22:08:41+00:00")
if err != nil {
fmt.Println(err)
return
}
fmt.Println(t)
// Unix returns t as a Unix time,
// the number of seconds elapsed since January 1, 1970 UTC.
fmt.Println(t.Unix())
}
Playground: https://play.golang.org/p/LG6G4lMIWt
Output:
2012-11-01 22:08:41 +0000 UTC
1351807721

Hour out of range on time.parse in golang

I am trying to parse a date time string in go. I pass the exact string as the format and get and error parsing time "01/31/2000 12:59 AM": hour out of range.
I am getting that string from an input. How can I make this work?
Here is the code (https://play.golang.org/p/Kg9KfFpU2z)
func main() {
layout := "01/31/2000 12:59 AM"
if t, err := time.Parse(layout, "01/31/2000 12:59 AM"); err == nil {
fmt.Println("Time decoded:", t)
} else {
fmt.Println("Failed to decode time:", err)
}
}
Based on your shared code, you should change the layout to 01/02/2006 03:04 AM to fix it:
Note:
If you have 24 hours format, you should change the hour part in layout to 15 instead of 03 and also to get rid of AM part e.g. 01/02/2006 15:04
package main
import (
"fmt"
"time"
)
func main() {
layout := "01/02/2006 03:04 AM"
if t, err := time.Parse(layout, "01/31/2000 12:59 AM"); err == nil {
fmt.Println("Time decoded:", t)
} else {
fmt.Println("Failed to decode time:", err)
}
}
Here is a good article that would help you to understand different layouts.
Your format needs to use a very specific date and time, see the docs:
https://golang.org/pkg/time/#example_Parse
Parse parses a formatted string and returns the time value it
represents. The layout defines the format by showing how the reference
time, defined to be
Mon Jan 2 15:04:05 -0700 MST 2006
So you need https://play.golang.org/p/c_Xc_R2OHb

TimeZone to Offset?

I want to get the offset in seconds from a specified time zone. That is exactly what tz_offset() in Perl's Time::Zone does: "determines the offset from GMT in seconds of a specified timezone".
Is there already a way of doing this in Go? The input is a string that has the time zone name and that's it, but I know that Go has LoadLocation() in the time package, so string => offset or location => offset should be fine.
Input: "MST"
Output: -25200
This should do the trick:
location, err := time.LoadLocation("MST")
if err != nil {
panic(err)
}
tzName, tzOffset := time.Now().In(location).Zone()
fmt.Printf("name: [%v]\toffset: [%v]\n", tzName, tzOffset)
Will print:
name: [MST] offset: [-25200]
Go Playground: https://play.golang.org/p/GVTgnpe1mB1
Here is the code, that calculates current offset between local and specified timezones. I agree with Ainar-G's comment that offset makes sense only with relation to specified moment in time:
package main
import (
"fmt"
"time"
)
func main() {
loc, err := time.LoadLocation("MST")
if err != nil {
fmt.Println(err)
}
now := time.Now()
_, destOffset := now.In(loc).Zone()
_, localOffset := now.Zone()
fmt.Println("Offset:", destOffset-localOffset)
}

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