go-pkg/rsql/dbcolumns.go
2024-02-15 14:24:43 -07:00

91 lines
1.6 KiB
Go

package rsql
import (
"fmt"
"reflect"
"strings"
"unicode"
)
// DbColumns database model metadata
type DbColumns struct {
Cols []string
index map[string]int
Table string
View string
}
// Col returns the mapped column names
func (d *DbColumns) Col(column string) (s string, err error) {
idx, ok := d.Index(column)
if !ok {
err = fmt.Errorf("column not found on table: %v", column)
return
}
return d.Cols[idx], err
}
// Index returns the column number
func (d *DbColumns) Index(column string) (idx int, ok bool) {
idx, ok = d.index[column]
return
}
// GetDbColumns builds a metadata struct
func GetDbColumns(o interface{}) *DbColumns {
d := DbColumns{}
t := reflect.TypeOf(o)
d.index = make(map[string]int)
for i := 0; i < t.NumField(); i++ {
field := t.Field(i)
sp := append(strings.Split(field.Tag.Get("db"), ","), "")
tag := sp[0]
json := field.Tag.Get("json")
if tag == "" {
tag = json
}
graphql := field.Tag.Get("graphql")
if tag == "" {
tag = graphql
}
if tag == "-" {
continue
}
if tag == "" {
tag = field.Name
}
d.index[field.Name] = len(d.Cols)
if _, ok := d.index[tag]; !ok && tag != "" {
d.index[tag] = len(d.Cols)
}
if _, ok := d.index[json]; !ok && json != "" {
d.index[json] = len(d.Cols)
}
if _, ok := d.index[graphql]; !ok && graphql != "" {
d.index[graphql] = len(d.Cols)
} else if !ok && graphql == "" {
a := []rune(field.Name)
for i := 0; i < len(a); i++ {
if unicode.IsLower(a[i]) {
break
}
a[i] = unicode.ToLower(a[i])
}
graphql = string(a)
d.index[graphql] = len(d.Cols)
}
d.Cols = append(d.Cols, tag)
}
return &d
}