Schema Decoder: Ignore unknown fields by default

[kabychow]

Hi Guys,

Thanks for your great work! It seems like BodyParser is generating error when there are unknown fields in the form/query. For example:

type User struct {
	Email string `form:"email"`
	Password string `form:"password"`
}

If I send the request with these parameters:
email: abc@gmail.com
password: abc
token_type: jwt

It will generate error schema: invalid path "token_type"

I think it should be ignored peacefully. Let me know how you think :)

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[Fenny]

Welcome @Khaibin, thanks for opening your first issue.

I invite the @gofiber/maintainers to also give their feedback on whether we should enable IgnoreUnknownKeys by default in our schema decoder

[kabychow]

Hi @Fenny, thanks for your reply :)

Consider this:

user := &User{}
err := c.BodyParser(user)
if err != nil {
  c.SendStatus(400)
}

By default, the server should not return with 400 (Bad request) when additional fields are present. There are cases where we need some extra fields to do further processing.

Gorilla schema returns the error instance as MultiError and it will complicate the process of handling unknown fields.

Gin are ignoring the fields by default for all Binding methods:
https://github.com/gin-gonic/gin#model-binding-and-validation

[Fenny]

@Khaibin if you could add testing for this by adding another field to the struct in the ctx_test.go#L156 that would be great.

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