Archived project. No maintenance.
This project is not maintained anymore and is archived. Feel free to fork and
make your own changes if needed. For more detail read my blog post: Taking an indefinite sabbatical from my projects
Thanks to everyone for their valuable feedback and contributions.
Structs 
Structs contains various utilities to work with Go (Golang) structs. It was
initially used by me to convert a struct into a map[string]interface{}. With
time I've added other utilities for structs. It's basically a high level
package based on primitives from the reflect package. Feel free to add new
functions or improve the existing code.
Install
go get github.com/fatih/structs
Usage and Examples
Just like the standard lib strings, bytes and co packages, structs has
many global functions to manipulate or organize your struct data. Lets define
and declare a struct:
type Server struct {
Name string `json:"name,omitempty"`
ID int
Enabled bool
users []string // not exported
http.Server // embedded
}
server := &Server{
Name: "gopher",
ID: 123456,
Enabled: true,
}
// Convert a struct to a map[string]interface{}
// => {"Name":"gopher", "ID":123456, "Enabled":true}
m := structs.Map(server)
// Convert the values of a struct to a []interface{}
// => ["gopher", 123456, true]
v := structs.Values(server)
// Convert the names of a struct to a []string
// (see "Names methods" for more info about fields)
n := structs.Names(server)
// Convert the values of a struct to a []*Field
// (see "Field methods" for more info about fields)
f := structs.Fields(server)
// Return the struct name => "Server"
n := structs.Name(server)
// Check if any field of a struct is initialized or not.
h := structs.HasZero(server)
// Check if all fields of a struct is initialized or not.
z := structs.IsZero(server)
// Check if server is a struct or a pointer to struct
i := structs.IsStruct(server)
Struct methods
The structs functions can be also used as independent methods by creating a new
*structs.Struct. This is handy if you want to have more control over the
structs (such as retrieving a single Field).
// Create a new struct type:
s := structs.New(server)
m := s.Map() // Get a map[string]interface{}
v := s.Values() // Get a []interface{}
f := s.Fields() // Get a []*Field
n := s.Names() // Get a []string
f := s.Field(name) // Get a *Field based on the given field name
f, ok := s.FieldOk(name) // Get a *Field based on the given field name
n := s.Name() // Get the struct name
h := s.HasZero() // Check if any field is uninitialized
z := s.IsZero() // Check if all fields are uninitialized
Field methods
We can easily examine a single Field for more detail. Below you can see how we
get and interact with various field methods:
s := structs.New(server)
// Get the Field struct for the "Name" field
name := s.Field("Name")
// Get the underlying value, value => "gopher"
value := name.Value().(string)
// Set the field's value
name.Set("another gopher")
// Get the field's kind, kind => "string"
name.Kind()
// Check if the field is exported or not
if name.IsExported() {
fmt.Println("Name field is exported")
}
// Check if the value is a zero value, such as "" for string, 0 for int
if !name.IsZero() {
fmt.Println("Name is initialized")
}
// Check if the field is an anonymous (embedded) field
if !name.IsEmbedded() {
fmt.Println("Name is not an embedded field")
}
// Get the Field's tag value for tag name "json", tag value => "name,omitempty"
tagValue := name.Tag("json")
Nested structs are supported too:
addrField := s.Field("Server").Field("Addr")
// Get the value for addr
a := addrField.Value().(string)
// Or get all fields
httpServer := s.Field("Server").Fields()
We can also get a slice of Fields from the Struct type to iterate over all
fields. This is handy if you wish to examine all fields:
s := structs.New(server)
for _, f := range s.Fields() {
fmt.Printf("field name: %+v\n", f.Name())
if f.IsExported() {
fmt.Printf("value : %+v\n", f.Value())
fmt.Printf("is zero : %+v\n", f.IsZero())
}
}
Credits
License
The MIT License (MIT) - see LICENSE.md for more details