/* Copyright 2021 The Dapr Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package query import ( "errors" "fmt" ) type Filter interface { Parse(interface{}) error } // ParseFilter parses a filter struct using the visitor pattern returning a built Filter interface. func ParseFilter(obj interface{}) (Filter, error) { m, ok := obj.(map[string]interface{}) if !ok { return nil, errors.New("filter unit must be a map") } if len(m) != 1 { return nil, errors.New("filter unit must have a single element") } for k, v := range m { switch k { case "EQ": f := &EQ{} err := f.Parse(v) return f, err case "NEQ": f := &NEQ{} err := f.Parse(v) return f, err case "GT": f := >{} err := f.Parse(v) return f, err case "GTE": f := >E{} err := f.Parse(v) return f, err case "LT": f := <{} err := f.Parse(v) return f, err case "LTE": f := <E{} err := f.Parse(v) return f, err case "IN": f := &IN{} err := f.Parse(v) return f, err case "AND": f := &AND{} err := f.Parse(v) return f, err case "OR": f := &OR{} err := f.Parse(v) return f, err default: return nil, fmt.Errorf("unsupported filter %q", k) } } return nil, nil } type EQ struct { Key string Val interface{} } func (f *EQ) Parse(obj interface{}) error { m, ok := obj.(map[string]interface{}) if !ok { return errors.New("EQ filter must be a map") } if len(m) != 1 { return errors.New("EQ filter must contain a single key/value pair") } for k, v := range m { f.Key = k f.Val = v } return nil } type NEQ struct { Key string Val interface{} } func (f *NEQ) Parse(obj interface{}) error { m, ok := obj.(map[string]interface{}) if !ok { return errors.New("NEQ filter must be a map") } if len(m) != 1 { return errors.New("NEQ filter must contain a single key/value pair") } for k, v := range m { f.Key = k f.Val = v } return nil } type GT struct { Key string Val interface{} } func (f *GT) Parse(obj interface{}) error { m, ok := obj.(map[string]interface{}) if !ok { return errors.New("GT filter must be a map") } if len(m) != 1 { return errors.New("GT filter must contain a single key/value pair") } for k, v := range m { f.Key = k f.Val = v } return nil } type GTE struct { Key string Val interface{} } func (f *GTE) Parse(obj interface{}) error { m, ok := obj.(map[string]interface{}) if !ok { return errors.New("GTE filter must be a map") } if len(m) != 1 { return errors.New("GTE filter must contain a single key/value pair") } for k, v := range m { f.Key = k f.Val = v } return nil } type LT struct { Key string Val interface{} } func (f *LT) Parse(obj interface{}) error { m, ok := obj.(map[string]interface{}) if !ok { return errors.New("LT filter must be a map") } if len(m) != 1 { return errors.New("LT filter must contain a single key/value pair") } for k, v := range m { f.Key = k f.Val = v } return nil } type LTE struct { Key string Val interface{} } func (f *LTE) Parse(obj interface{}) error { m, ok := obj.(map[string]interface{}) if !ok { return errors.New("LTE filter must be a map") } if len(m) != 1 { return errors.New("LTE filter must contain a single key/value pair") } for k, v := range m { f.Key = k f.Val = v } return nil } type IN struct { Key string Vals []interface{} } func (f *IN) Parse(obj interface{}) error { m, ok := obj.(map[string]interface{}) if !ok { return errors.New("IN filter must be a map") } if len(m) != 1 { return errors.New("IN filter must contain a single key/value pair") } for k, v := range m { f.Key = k if f.Vals, ok = v.([]interface{}); !ok { return errors.New("IN filter value must be an array") } } return nil } type AND struct { Filters []Filter } func (f *AND) Parse(obj interface{}) (err error) { f.Filters, err = parseFilters("AND", obj) return } type OR struct { Filters []Filter } func (f *OR) Parse(obj interface{}) (err error) { f.Filters, err = parseFilters("OR", obj) return } func parseFilters(t string, obj interface{}) ([]Filter, error) { arr, ok := obj.([]interface{}) if !ok { return nil, fmt.Errorf("%s filter must be an array", t) } if len(arr) < 2 { return nil, fmt.Errorf("%s filter must contain at least two entries", t) } filters := make([]Filter, len(arr)) for i, entry := range arr { var err error if filters[i], err = ParseFilter(entry); err != nil { return nil, err } } return filters, nil }