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Getting Started

1 Install​

go get github.com/Oudwins/zog

2 Create a user schema and its struct​

import (
  z "github.com/Oudwins/zog"
   )


type User struct {
  Name string `zog:"firstname"` // tag is optional. If not set zog will check for "name" field in the input data
  Age int
}

var userSchema = z.Struct(z.Schema{
  // its very important that schema keys like "name" match the struct field name NOT the input data
  "name": z.String().Min(3, z.Message("Override default message")).Max(10),
  "age": z.Int().GT(18).Required(z.Message("is required")),
})

3 Parse into the struct​

func main() {
  u := User{}
  m := map[string]string{
    "firstname": "Zog", // Note we are using "firstname" here as specified in the struct tag
    "age": "", // won't return an error because fields are optional by default
  }
  errsMap := schema.Parse(m, &u)
  if errsMap != nil {
    // handle errors -> see Errors section
  }
  u.Name // "Zog"
  // note that this might look weird but we didn't say age was required so Zog just skiped the empty string and we are left with the uninitialized int
  u.Age // 0
}

4. Its easy to use with http​

The zhttp package has you covered for JSON, Forms and Query Params, just do:

import (
  zhttp "github.com/Oudwins/zog/zhttp"
   )
err := userSchema.Parse(zhttp.Request(r), &user)

5. Or to validate your environment variables​

The zenv package has you covered, just do:

import (
  zenv "github.com/Oudwins/zog/zenv"
   )
err := envSchema.Parse(zenv.NewDataProvider(), &envs)

6. You can also parse individual fields​

var t = time.Time
errsList := Time().Required().Parse("2020-01-01T00:00:00Z", &t)

7 And do stuff before and after parsing​

var dest []string
Slice(String().Email().Required()).PreTransform(func(data any, ctx z.ParseCtx) (any, error) {
  s := val.(string)
  return strings.Split(s, ","), nil
}).PostTransform(func(destPtr any, ctx z.ParseCtx) error {
  s := val.(*[]string)
  for i, v := range s {
    s[i] = strings.TrimSpace(v)
  }
  return nil
}).Parse("foo@bar.com,bar@foo.com", &dest) // dest = [foo@bar.com bar@foo.com]