handle ISO8601 for time.Time JSON values

[adamdecaf]

Our API docs currently state (as part of POST /files/create's response):

{
  "fileCreationDate": "102318",
  "fileCreationTime": "1601"
}

Source: https://api.moov.io/#operation/addFile

However, this format might be annoying for folks. Should we support RFC 3339 and YYMMDD / HHMM?

Our api returns RFC 3339 now, which is Go's default).

$ curl -s -H "cookie: moov_auth=..." https://api.moov.io/v1/ach/files/docrlxnuinuoouhilfws | jq '.file.fileHeader' | grep fileCreation
  "fileCreationDate": "2018-10-08T00:00:00Z",
  "fileCreationTime": "2018-10-08T00:00:00Z", 

Examples:

• https://github.com/moov-io/ach/blob/master/fileHeader.go#L48
• https://github.com/moov-io/ach/blob/master/addenda99.go#L151
• https://github.com/moov-io/ach/blob/master/iatBatchHeader.go#L128

[wadearnold]

We use to store it as a default Go time in the library but those time values are used for looking up the transaction later. That's why we now use the specification. I would recommend that we marshal in and out of the javascript standard of ISO-8601

Date, time and timezone
ISO 8601 notation to be used for Date time
ISO 8601 uses the 24-hour clock system. The basic format is [hh][mm][ss] and the extended format is [hh]:[mm]:[ss].
ISO_8601

Datetime with time zone is necessary for calculating cutoff times. We may want to default to Eastern TIme zone unless an offset is supplied.

yyyy-mm-ddThh:mm:ss.nnnnnn+|-hh:mm
2008-09-15T15:53:00+05:00

[adamdecaf]

It looks like ISO 8601 was long ago removed from Go due to incorrect parsing. golang/go#734

[adamdecaf]

Also, a few of the popular javascript libraries support RFC 3339 parsing - https://stackoverflow.com/a/11318911

[adamdecaf]

https://stackoverflow.com/questions/522251/whats-the-difference-between-iso-8601-and-rfc-3339-date-formats

They aren't swappable with each other, ugh. We could support ISO 8601 by adding a base.Time struct.

type Time struct {
	*time.Time
}

func (t Time) MarshalJSON() ([]byte, error) {
	// ...	
}

func (t *Time) UnmarshalJSON(data []byte) error {
	// ...
}

Example: https://github.com/joeshaw/iso8601/blob/master/iso8601.go

We should add something like ^ into the base repository with more tests.

[adamdecaf]

I started on this in a time.go for our base repository (root level)

// Copyright 2018 The Moov Authors
// Use of this source code is governed by an Apache License
// license that can be found in the LICENSE file.

import (
	"time"
)

type Time struct {
	*time.Time
}

// 2018-10-30T17:48:48+00:00
// 2018-10-30T17:48:48Z

// javascript
// 2018-10-30T18:24:56.945Z

// Go format
// Mon Jan 2 15:04:05 -0700 MST 2006

// MarshalJSON implements the json.Marshaler interface.
// The time is a quoted string in ISO 8601 format.
func (t Time) MarshalJSON() ([]byte, error) {
	str, err := t.Format(

	// if y := t.Year(); y < 0 || y >= 10000 {
	// 	// RFC 3339 is clear that years are 4 digits exactly.
	// 	// See golang.org/issue/4556#c15 for more discussion.
	// 	return nil, errors.New("Time.MarshalJSON: year outside of range [0,9999]")
	// }

	// b := make([]byte, 0, len(RFC3339Nano)+2)
	// b = append(b, '"')
	// b = t.AppendFormat(b, RFC3339Nano)
	// b = append(b, '"')
	// return b, nil
}

// UnmarshalJSON implements the json.Unmarshaler interface.
// The time is expected to be a quoted string in RFC 3339 format.
func (t *Time) UnmarshalJSON(data []byte) error {
	// // Ignore null, like in the main JSON package.
	// if string(data) == "null" {
	// 	return nil
	// }
	// // Fractional seconds are handled implicitly by Parse.
	// var err error
	// *t, err = Parse(`"`+RFC3339+`"`, string(data))
	// return err
}

[wadearnold]

This seems safe

[adamdecaf]

See https://github.com/moov-io/api/issues/33 and moov-io/base#7