README
¶
go-types
This is a library of types that are useful for dealing with JSON API's, and/or
database fields. Currently supports NullString and NullTime, both of which
can be serialized to/from JSON or a database.
Documentation
¶
Overview ¶
Package types implements several types for dealing with REST API's and databases.
PrefixUUID ¶
UUID's are very useful, but you often need to attach context to them; e.g. you cannot look at a UUID and know whether it points to a record in the accounts table or in the messages table. A PrefixUUID solves this problem, by embedding the additional useful information as part of the string.
a, _ := types.NewPrefixUUID("account6740b44e-13b9-475d-af06-979627e0e0d6")
fmt.Println(a.Prefix) // "account"
fmt.Println(a.UUID.String()) "6740b44e-13b9-475d-af06-979627e0e0d6"
fmt.Println(a.String()) "account6740b44e-13b9-475d-af06-979627e0e0d6"
If we had to write this value to the database as a string it would take up 43 bytes. Instead we use a UUID type and strip the prefix before saving it.
The converse, Value(), only returns the UUID part by default, since this is the only thing the database knows about. You can also attach the prefix manually in your SQL, like so:
SELECT 'job_' || id, created_at FROM jobs;
This will get parsed as part of the Scan(), and then you don't need to do anything. Alternatively, you can attach the prefix in your model, immediately after the query.
func Get(id types.PrefixUUID) *User {
var uid types.PrefixUUID
var email string
db.Conn.QueryRow("SELECT * FROM users WHERE id = $1").Scan(&uid, &email)
uid.Prefix = "usr"
return &User{
ID: uid,
Email: email
}
}
NullString ¶
A NullString is like the null string in `database/sql`, but can additionally be encoded/decoded via JSON.
json.NewEncoder(os.Stdout).Encode(NullString{Valid: false})
// Output: null
json.NewEncoder(os.Stdout).Encode(NullString{Valid: true, String: "hello"})
// Output: "hello"
NullTime ¶
A NullTime behaves exactly like NullString, but the value is a time.Time.
json.NewEncoder(os.Stdout).Encode(NullTime{Valid: false})
// Output: null
json.NewEncoder(os.Stdout).Encode(NullTime{Valid: true, Time: time.Now()})
// Output: "2016-05-02T08:33:46.005852482-07:00"
Index ¶
Examples ¶
Constants ¶
const ( Bit Bits = 1 Byte = 8 * Bit // https://en.wikipedia.org/wiki/Orders_of_magnitude_(data) Kilobyte = 1000 * Byte Megabyte = 1000 * Kilobyte Gigabyte = 1000 * Megabyte Terabyte = 1000 * Gigabyte Petabyte = 1000 * Terabyte Exabyte = 1000 * Petabyte )
const Version = "1.2"
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Bits ¶
type Bits int64
Bits represents a quantity of bits, bytes, kilobytes or megabytes. Bits are parsed and formatted using the IEEE / SI standards, which use multiples of 1000 to represent kilobytes and megabytes (instead of multiples of 1024). For more information see https://en.wikipedia.org/wiki/Megabyte#Definitions.
func ParseBits ¶
ParseBits parses a quantity of bits. A bit size is a possibly signed sequence of decimal numbers, each with optional fraction and a unit suffix. Valid units are "bit", "B", "kB", "MB", "GB", "TB". Kilobytes are converted to bytes by dividing by 1000, not 1024, per the IEEE standard.
type NullString ¶
A NullString is a String that may be null. It can be encoded or decoded from JSON or the database.
Example ¶
n := NullString{Valid: true, String: "foo"}
json.NewEncoder(os.Stdout).Encode(n)
Output: "foo"
func (NullString) MarshalJSON ¶
func (ns NullString) MarshalJSON() ([]byte, error)
func (*NullString) Scan ¶
func (ns *NullString) Scan(value interface{}) error
Scan implements the Scanner interface.
func (*NullString) UnmarshalJSON ¶
func (ns *NullString) UnmarshalJSON(b []byte) error
type NullTime ¶
A NullTime is a Time that may be null. It can be encoded or decoded from JSON or the database.
Example ¶
t, _ := time.Parse(time.RFC3339, "2016-05-02T09:03:04-07:00")
nt := NullTime{Valid: true, Time: t}
json.NewEncoder(os.Stdout).Encode(nt)
Output: "2016-05-02T09:03:04-07:00"
func (NullTime) MarshalJSON ¶
func (*NullTime) UnmarshalJSON ¶
type PrefixUUID ¶
A PrefixUUID stores an additional prefix as part of a UUID type.
Example ¶
p, _ := NewPrefixUUID("usr_6740b44e-13b9-475d-af06-979627e0e0d6")
fmt.Println(p.Prefix)
fmt.Println(p.UUID.String())
fmt.Println(p.String())
Output: usr_ 6740b44e-13b9-475d-af06-979627e0e0d6 usr_6740b44e-13b9-475d-af06-979627e0e0d6
func GenerateUUID ¶
func GenerateUUID(prefix string) PrefixUUID
GenerateUUID generates a UUID with the given prefix.
func NewPrefixUUID ¶
func NewPrefixUUID(caboodle string) (PrefixUUID, error)
NewPrefixUUID creates a PrefixUUID from the prefix and string uuid. Returns an error if uuidstr cannot be parsed as a valid UUID.
func (PrefixUUID) MarshalJSON ¶
func (pu PrefixUUID) MarshalJSON() ([]byte, error)
func (*PrefixUUID) Scan ¶
func (pu *PrefixUUID) Scan(value interface{}) error
Scan implements the Scanner interface. Note only the UUID gets scanned/set here, we can't determine the prefix from the database. `value` should be a [16]byte
func (PrefixUUID) String ¶
func (u PrefixUUID) String() string
func (*PrefixUUID) UnmarshalJSON ¶
func (pu *PrefixUUID) UnmarshalJSON(b []byte) error
Source Files