/
url_filter.go
141 lines (123 loc) · 3.19 KB
/
url_filter.go
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package urlvalues
import (
"strings"
"github.com/go-pg/pg"
"github.com/go-pg/pg/internal"
"github.com/go-pg/pg/orm"
"github.com/go-pg/pg/types"
)
// URLFilter is used with Query.Apply to add WHERE clauses from the URL values:
// - ?foo=bar - Where(`"foo" = 'bar'`)
// - ?foo=hello&foo=world - Where(`"foo" IN ('hello','world')`)
// - ?foo__neq=bar - Where(`"foo" != 'bar'`)
// - ?foo__exclude=bar - Where(`"foo" != 'bar'`)
// - ?foo__gt=42 - Where(`"foo" > 42`)
// - ?foo__gte=42 - Where(`"foo" >= 42`)
// - ?foo__lt=42 - Where(`"foo" < 42`)
// - ?foo__lte=42 - Where(`"foo" <= 42`)
// - ?foo__ieq=bar - Where(`"foo" ILIKE 'bar'`)
// - ?foo__match=bar - Where(`"foo" SIMILAR TO 'bar'`)
type Filter struct {
values Values
allowed map[string]struct{}
}
func NewFilter(values Values) *Filter {
return &Filter{
values: values,
}
}
// Values returns URL values.
func (f *Filter) Values() Values {
return f.values
}
func (f *Filter) Allow(filters ...string) {
if f.allowed == nil {
f.allowed = make(map[string]struct{})
}
for _, filter := range filters {
f.allowed[filter] = struct{}{}
}
}
func (f *Filter) isAllowed(filter string) bool {
if len(f.allowed) == 0 {
return true
}
_, ok := f.allowed[filter]
return ok
}
func (f *Filter) Filters(q *orm.Query) (*orm.Query, error) {
if f == nil {
return q, nil
}
var b []byte
for filter, values := range f.values {
if strings.HasSuffix(filter, "[]") {
filter = filter[:len(filter)-2]
}
if !f.isAllowed(filter) {
continue
}
var operation string
if ind := strings.Index(filter, "__"); ind != -1 {
filter, operation = filter[:ind], filter[ind+2:]
}
if q.GetModel().Table().HasField(filter) {
if b != nil {
b = append(b, " AND "...)
}
b = addOperator(b, filter, operation, values)
}
}
if len(b) > 0 {
q = q.Where(internal.BytesToString(b))
}
return q, nil
}
// Filters is a shortcut for NewFilter(urlValues).Filters.
func Filters(values Values) func(*orm.Query) (*orm.Query, error) {
return NewFilter(values).Filters
}
func addOperator(b []byte, field, op string, values []string) []byte {
switch op {
case "", "include":
b = forAllValues(b, field, values, " = ", " IN ")
case "exclude", "neq":
b = forAllValues(b, field, values, " != ", " NOT IN ")
case "gt":
b = forEachValue(b, field, values, " > ")
case "gte":
b = forEachValue(b, field, values, " >= ")
case "lt":
b = forEachValue(b, field, values, " < ")
case "lte":
b = forEachValue(b, field, values, " <= ")
case "ieq":
b = forEachValue(b, field, values, " ILIKE ")
case "match":
b = forEachValue(b, field, values, " SIMILAR TO ")
}
return b
}
func forEachValue(
b []byte, field string, values []string, opValue string,
) []byte {
for _, value := range values {
b = types.AppendField(b, field, 1)
b = append(b, opValue...)
b = types.AppendString(b, value, 1)
}
return b
}
func forAllValues(
b []byte, field string, values []string, singleOpValue, multiOpValue string,
) []byte {
if len(values) <= 1 {
return forEachValue(b, field, values, singleOpValue)
}
b = types.AppendField(b, field, 1)
b = append(b, multiOpValue...)
b = append(b, '(')
b = pg.Strings(values).AppendValue(b, 1)
b = append(b, ')')
return b
}