🔥 Feature: Add CustomTypeRegister for form

[rockcreation7]

Add "CustomTypeRegister" for form data bodyparser, allow you to input any custom type, provide flexibility for form, so you can register you own custom type in form.

Please provide enough information so that others can review your pull request:

I added "CustomTypeRegister" struct just above the bodyparser, and optional parameter for form bodyparser.
The comment above "CustomTypeRegister" provide example and how to use.

Explain the details for making this change. What existing problem does the pull request solve?

You can do custom type in JSON format, Create custom type and related "UnmarshalJSON" method.
But in form you need to register converter in decoder, I added option for supporting this feature. In order to solve problem when you need custom type for form.

For example:
It is mostly happen when people will sent you "2020-12-15" in browser form instead of RFC3339 format.
You can register this custom format, instead of force to use RFC3339. Other use case like, You can register own member ID type, etc.

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[welcome]

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[rockcreation7]

I have provided a unit test with parameter, just under Test_Ctx_BodyParser, it could be doing in Test_Ctx_BodyParser, but it require extra condition and ReleaseCtx.

[Fenny]

PR looks good, I'm just not sure about struct naming. Since it's a public method attached to Fiber, we won't be able to change it in the future.

What do you think about BodyParserType or BodyParserRegister?

[rockcreation7]

Thanks, it is about adding type and eventually it is adding type to BodyParser, "BodyParserType" is related and descriptive. one consideration is bodyparser is also working on json, dont know if user will confuse/think BodyParserType will work on json too.

But I believe doc will explain, I plan to work on the doc on this too.

Btw the doc of fiber and recipe section is clear and good, it helps a lot to me.

[Fenny]

After I saw #1084, maybe we should provide an option to override the schema decoder globally?

[rockcreation7]

Will be update

[rockcreation7]

More elaboration on the code:

Added Following function for override the schema decoder globally

customType := BodyParserType{
		Customtype: customType{},
		Converter:  timeConverter,
}

SetBodyParserDecoder(
         BodyParserConfig{
		IgnoreUnknownKeys: true,
		BodyParserType:    []BodyParserType{customType},
		ZeroEmpty:         true,
		SetAliasTag:       "form",
	}
)

The test is also update in last commit.

Please let me know if there any change/idea should be update for merging.
Enjoy Holidays guys

[rockcreation7]

Closing this branch, duplication, new branch with bigger scope