go-micro.dev/v5@v5.12.0/store/postgres/metadata.go (about)

     1  // Copyright 2020 Asim Aslam
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     https://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  //
    15  // Original source: github.com/micro/go-plugins/v3/store/cockroach/metadata.go
    16  
    17  package postgres
    18  
    19  import (
    20  	"database/sql/driver"
    21  	"encoding/json"
    22  	"errors"
    23  )
    24  
    25  // https://github.com/upper/db/blob/master/postgresql/custom_types.go#L43
    26  type Metadata map[string]interface{}
    27  
    28  // Scan satisfies the sql.Scanner interface.
    29  func (m *Metadata) Scan(src interface{}) error {
    30  	source, ok := src.([]byte)
    31  	if !ok {
    32  		return errors.New("Type assertion .([]byte) failed.")
    33  	}
    34  
    35  	var i interface{}
    36  	err := json.Unmarshal(source, &i)
    37  	if err != nil {
    38  		return err
    39  	}
    40  
    41  	*m, ok = i.(map[string]interface{})
    42  	if !ok {
    43  		return errors.New("Type assertion .(map[string]interface{}) failed.")
    44  	}
    45  
    46  	return nil
    47  }
    48  
    49  // Value satisfies the driver.Valuer interface.
    50  func (m Metadata) Value() (driver.Value, error) {
    51  	j, err := json.Marshal(m)
    52  	return j, err
    53  }
    54  
    55  func toMetadata(m *Metadata) map[string]interface{} {
    56  	md := make(map[string]interface{})
    57  	for k, v := range *m {
    58  		md[k] = v
    59  	}
    60  	return md
    61  }