Add Ability to Define a Date Format for URLEncodedFormEncoder and URLEncodedFormDecoder

[thecheatah]

Created pull request #2273

Steps to reproduce

Currently, the URL Coders code and decode to Unix Timestamp. I would like to be able to override code/decode to support ISO 8601 and custom date formats.

ISO 8601 Supports all of the following date formats (and more):

• 2020-03-29
• 2020-03-29T14:25:05+00:00
• 2020-03-29T14:25:05Z

Expected behavior

Modify URLEncodedFormDecoder.Configuration to take an array of enum values DateFormat where decoding will be tried with the date formats provided in the array. Defaults to decoding as Unix Timestamp and if that doesn't work ISO8601 ([.timeIntervalSince1970, .iso8601]).

Where URLEncodedFormDecoder.Configuration.DateFormat is

        /// Supported date formats
        public enum DateFormat {
            /// Seconds since 1 January 1970 00:00:00 UTC
            case unixTimestamp
            /// ISO 8601 formatted date
            case iso8601
            /// Using custom callback
            case custom((Decoder) throws -> Date)
        }

Modify URLEncodedFormEncoder.Configuration to take in enum value DateFormat. Defaults to Unix Timestamp (.unixTimestamp)

Where URLEncodedFormEncoder.Configuration.DateFormat is

        /// Supported date formats
        public enum DateFormat {
            /// Seconds since 1 January 1970 00:00:00 UTC
            case unixTimestamp
            /// ISO 8601 formatted date
            case iso8601
            /// Using custom callback
            case custom((Date, Encoder) throws -> Void)
        }

Actual behavior

No ability to override date formatting.

Environment

• Vapor Framework version: 4
• Vapor Toolbox version:
• OS version: Linux

[Joannis]

Can this be added post-release/without breaking API? I think so, in which case adding this with the current method as default would be preferred for me.

[thecheatah]

@Joannis Thanks for taking a look. We can default it to timeIntervalSinceReferenceDate, but it didn't make sense for it to be the default as it's Apple specific.

I have a feeling that not a lot of people have tried to Encode/Decode to date from the URLEncodedForm, otherwise someone would have raised it as a bug.

I can default it to timeIntervalSinceReferenceDate if considering the above, we are OK with defaulting date encoding/decoding to something non-standard. Vapor 4 implementations will go live expecting Apple's timeIntervalSinceReferenceDate

[thecheatah]

Default to timeIntervalSinceReferenceDate

[tanner0101]

Duplicate of #2133