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Process dates

Info

This how-to assumes you are familiar with setting up a project either manually or via VoltScript Dependency Management. If you are not, follow the Intro to VoltScript Tutorials.

Introduction

LotusScript has always had a date/time Variant (DataType 7). But it doesn't contain a timezone and is unaware of any daylight savings.

When dealing with data in middleware, ISO 8601 is a standard for date/times. But the values are passed in JSON as strings with datetime format. For use within VoltScript, it may be easier to convert to a date object. This is what ZuluVSE provides.

VoltScript dependencies

Incorporating ZuluVSE is straightforward. You just need to add the following JSON object to the vsesDependencies element in your atlas.json.

    "ZuluVSE": {
        "library": "25290",
        "version": "1.0.1",
        "module": "25891/20855",
    }

To use the extension in your script, enter UseVSE "*ZuluVSE".

Parse dates

The DateTimeParser class is used to parse a date string or number and return a DateTimeObject. There are a variety of in-built methods, depending on the value you start with.

Parse ISO dates

ISO dates can be parsed in UTC or with an offset. When dates are in UTC, they don't have an offset but end in "Z". The following code will convert a UTC date-time string to a DateTimeObject:

Function parseISOZuluDateString() as DateTimeObject
    Dim dateStr as String
    Dim parser as new DateTimeParser()
    Dim dateObj as DateTimeObject

    dateStr = "2023-08-15T09:50:20Z"
    Set dateObj = parser.parseISOString(dateStr)
    Return dateObj
End Function

Sometimes a date will be received with an offset. These can also be parsed using parseISOString():

Function parseISOOffsetDateString() as DateTimeObject
    Dim dateStr as String
    Dim parser as new DateTimeParser()
    Dim dateObj as DateTimeObject

    dateStr = "2023-08-15T02:50:20-07:00"
    Set dateObj = parser.parseISOString(dateStr)
    Print dateObj.defaultFormat
    Return dateObj
End Function

Build from epoch

DateTimeParser.buildDateFromEpoch() is used to build a DateTimeObject based on milliseconds since Jan 1 1970 midnight UTC, the Unix epoch. The following code can be used to build a date corresponding to August 15th 2023, 12:08:20 UTC.

Function parseDateEpoch()
    Dim parser as new DateTimeParser()
    Dim dateObj as DateTimeObject

    Set dateObj = parser.BuildDateTimeFromEpoch(1692101300)
    Print dateObj.defaultFormat
    Return dateObj
End Function

Build from constituent parts

DateTimeParser.buildDateTimeObject() is used to build a DateTimeObject passing year, month, day, hours, minutes, seconds and offset minutes from UTC. The following code can be used to build a DateTimeObject for August 4th 2023, 12:20:25 (UTC +01:00).

Function parseDateParts()
    Dim parser as new DateTimeParser()
    Dim dateObj as DateTimeObject

    Set dateObj = parser.BuildDateTimeObject(2023,8,4,11,20,25,-60)
    Print dateObj.defaultFormat
    Return dateObj
End Function

Build from string with formatting codes

DateTimeParser.ParseDateString() allows a string date to be parsed with a specific set of format codes for a specific timezone. This function uses formatting codes consistent with the underlying C/C++ format codes.

Formatting DateTimeObjects

Formatting to ISO date format

The basics - using the C/C++ format codes

We use the DateTimeObject.toString() method to return a date or date/time string formatted to fit our needs. This function uses formatting codes consistent with the underlying C/C++ format codes. Some more common examples are included in the comments of the example code below:

Sub toStringFormatExample()
    Dim dtObj as DateTimeObject, dtParser as New DateTimeParser
    Dim testISOStr as String, testFmtPattern1 as String, testFmtPattern2 as string, testFmtPattern3 as String
    testISOStr = "2023-02-20T20:49:13Z"
    testFmtPattern1 = "%Y-%m-%d %H:%M:%S %Z"
    testFmtPattern2 = "%F %T %Z"
    testFmtPattern3 = "%A, %B %d %Y %T %Z"

    Set dtObj = dtParser.ParseISOString(testISOStr)

    Print |Using test ISO String "| & testISOStr & |" with no locale code; |
    Print |Format pattern "| & testFmtPattern1 & |" returns "| & dtObj.toString(testFmtPattern1, "") & |",|
    Print |Format pattern "| & testFmtPattern2 & |" returns "| & dtObj.toString(testFmtPattern2, "") & |",|
    Print |Format pattern "| & testFmtPattern3 & |" returns "| & dtObj.toString(testFmtPattern3, "") & |"|
End Sub

In this example code, we have three different formatting patterns to test.

Each of the patterns (testFmtPattern1, testFmtPattern2, and testFmtPattern3) specifies various date time components and the order in which they should appear.

  • testFmtPattern1 %Y-%m-%d %H:%M:%S %Z: This pattern specifies year-month-day hour:minute:second timezone.
  • testFmtPattern2 %F %T %Z: This pattern utilizes special shorthand codes. %Y-%m-%d can be abbreviated to %F, while %H:%M:%S can be abbreviated to simply %T. This pattern therefore also specifies year-month-day hour:minute:second timezone.
  • testFmtPattern3 %A, %B %d %Y %T %Z: This pattern demonstrates some additional codes. The day of the week uses the code %A, and the name of the month uses the code %B, both of which will be returned in the appropriate language for the locale. This pattern specifies day-of-week, name-of-month day-of-month four-digit-year hour:minute:second timezone.
Common shorthand codes for date/time components
Format code Description
%B Full month name
%b Abbreviated month name
%A Full day name
%a Abbreviated day name
%m Month
%d Day of month
%0d Day of month (2 digit)
%Y Year as four digits
%F Equivalent of %Y-%m-%d
%H Hour
%M Minute
%S Second
%T Equivalent of %H:%M:%S
%Z Locale-dependent time zone name or abbreviation

The locale parameter

The locale parameter in DateTimeObject.toString(*format*, *locale*) allows you to display the names of things like months and days of the week using a country or regionally specific language.

Warning

Before using Locales, you must ensure that the appropriate locale has been installed.

Locale codes consist of appropriate ISO 639 Language Codes and ISO 3166 Country Codes concatenated with an underscore, followed by a period and the encoding format.

Examples:

  • en_US.utf8 specifies English (United States)
  • es_MX.utf8 specifies Spanish (Mexico)
  • fr_BE.utf8 specifies French (Belgium)

A table of locale codes (less the encoding format) can be found here.

Assuming you were to install locales for both English and French, then using the code "en_US.utf8" would produce Monday, February 20 2023 20:49:13 UTC, and "fr_FR.utf8" would produce lundi, février 20 2023 20:49:13 UTC.

Info

Using different locales will require the relevant language pack installed on the operating system.

The VoltScript Dev Container is based on Red Hat Enterprise Linux 8 (RHEL 8). This distribution only has a dedicated English langpack for locales, with all others packaged in glibc-all-langpacks. Installing all locales can be quite large (200+ MB), so glibc-all-langpacks only installs the locales defined in the build macro _install_langs to save space.

To select the locales to install:

  1. Open a root terminal into the container. See Creating the Dev Container for more details.

  2. Edit /etc/rpm/macros.image-language-conf to define _install_langs as the locales you want installed. This is a colon separated list of locale prefixes (ISO 639 Language Codes), for example de:fr:es. If a prefix does not contain a _, it is added. The special argument all means to install all locales and must be present by itself. You can change the languages to install with this command, replacing <lang> with the locales to install:

    sed -i 's!%_install_langs.*!%_install_langs <lang>!' /etc/rpm/macros.image-language-conf

  3. Install glibc-all-langpacks. This can be done with this command:

    microdnf install glibc-all-langpacks && microdnf clean all
    Locales will be installed to /usr/lib/locale/locale-archive.

  4. Inspect the available locales by running locale -a.

    For more information on selecting what locales to install, run build-locale-archive -h after installing glibc-all-langpacks. This is the tool which compiles the locale archive. The build macro _install_langs is passed as the argument to --install-langs.

    You can change the installed locales by editing /etc/rpm/macros.image-language-conf, then reinstalling glibc-all-langpacks:

    sed -i 's!%_install_langs.*!%_install_langs de:fr:es!' /etc/rpm/macros.image-language-conf
microdnf reinstall glibc-all-langpacks && microdnf clean all