go-common/library/conf/dsn/dsn.go
2019-04-22 02:59:20 +00:00

109 lines
3.0 KiB
Go

// Package dsn provide parse dsn and bind to struct
// see http://git.bilibili.co/platform/go-common/issues/279
package dsn
import (
"net/url"
"reflect"
"strings"
"gopkg.in/go-playground/validator.v9"
)
var _validator *validator.Validate
func init() {
_validator = validator.New()
}
// DSN a DSN represents a parsed DSN as same as url.URL.
type DSN struct {
*url.URL
}
// Bind dsn to specify struct and validate use use go-playground/validator format
//
// The bind of each struct field can be customized by the format string
// stored under the 'dsn' key in the struct field's tag. The format string
// gives the name of the field, possibly followed by a comma-separated
// list of options. The name may be empty in order to specify options
// without overriding the default field name.
//
// A two type data you can bind to struct
// built-in values, use below keys to bind built-in value
// username
// password
// address
// network
// the value in query string, use query.{name} to bind value in query string
//
// As a special case, if the field tag is "-", the field is always omitted.
// NOTE: that a field with name "-" can still be generated using the tag "-,".
//
// Examples of struct field tags and their meanings:
// // Field bind username
// Field string `dsn:"username"`
// // Field is ignored by this package.
// Field string `dsn:"-"`
// // Field bind value from query
// Field string `dsn:"query.name"`
//
func (d *DSN) Bind(v interface{}) (url.Values, error) {
assignFuncs := make(map[string]assignFunc)
if d.User != nil {
username := d.User.Username()
password, ok := d.User.Password()
if ok {
assignFuncs["password"] = stringsAssignFunc(password)
}
assignFuncs["username"] = stringsAssignFunc(username)
}
assignFuncs["address"] = addressesAssignFunc(d.Addresses())
assignFuncs["network"] = stringsAssignFunc(d.Scheme)
query, err := bindQuery(d.Query(), v, assignFuncs)
if err != nil {
return nil, err
}
return query, _validator.Struct(v)
}
func addressesAssignFunc(addresses []string) assignFunc {
return func(v reflect.Value, to tagOpt) error {
if v.Kind() == reflect.String {
if addresses[0] == "" && to.Default != "" {
v.SetString(to.Default)
} else {
v.SetString(addresses[0])
}
return nil
}
if !(v.Kind() == reflect.Slice && v.Type().Elem().Kind() == reflect.String) {
return &BindTypeError{Value: strings.Join(addresses, ","), Type: v.Type()}
}
vals := reflect.MakeSlice(v.Type(), len(addresses), len(addresses))
for i, address := range addresses {
vals.Index(i).SetString(address)
}
if v.CanSet() {
v.Set(vals)
}
return nil
}
}
// Addresses parse host split by ','
// For Unix networks, return ['path']
func (d *DSN) Addresses() []string {
switch d.Scheme {
case "unix", "unixgram", "unixpacket":
return []string{d.Path}
}
return strings.Split(d.Host, ",")
}
// Parse parses rawdsn into a URL structure.
func Parse(rawdsn string) (*DSN, error) {
u, err := url.Parse(rawdsn)
return &DSN{URL: u}, err
}