2786055df4
- New parser written from scratch, allows easier and complete parsing of the full S3 Select SQL syntax. Parser definition is directly provided by the AST defined for the SQL grammar. - Bring support to parse and interpret SQL involving JSON path expressions; evaluation of JSON path expressions will be subsequently added. - Bring automatic type inference and conversion for untyped values (e.g. CSV data).
113 lines
2.7 KiB
Go
113 lines
2.7 KiB
Go
/*
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* Minio Cloud Storage, (C) 2019 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package json
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import (
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"bytes"
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"encoding/csv"
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"fmt"
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"strings"
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"github.com/minio/minio/pkg/s3select/sql"
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"github.com/tidwall/gjson"
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"github.com/tidwall/sjson"
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)
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// Record - is JSON record.
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type Record struct {
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data []byte
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}
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// Get - gets the value for a column name.
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func (r *Record) Get(name string) (*sql.Value, error) {
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result := gjson.GetBytes(r.data, name)
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switch result.Type {
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case gjson.Null:
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return sql.FromNull(), nil
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case gjson.False:
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return sql.FromBool(false), nil
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case gjson.Number:
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return sql.FromFloat(result.Float()), nil
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case gjson.String:
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return sql.FromString(result.String()), nil
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case gjson.True:
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return sql.FromBool(true), nil
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}
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return nil, fmt.Errorf("unsupported gjson value %v; %v", result, result.Type)
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}
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// Set - sets the value for a column name.
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func (r *Record) Set(name string, value *sql.Value) (err error) {
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var v interface{}
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if b, ok := value.ToBool(); ok {
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v = b
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} else if f, ok := value.ToFloat(); ok {
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v = f
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} else if i, ok := value.ToInt(); ok {
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v = i
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} else if s, ok := value.ToString(); ok {
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v = s
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} else if value.IsNull() {
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v = nil
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} else if b, ok := value.ToBytes(); ok {
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v = string(b)
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} else {
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return fmt.Errorf("unsupported sql value %v and type %v", value, value.GetTypeString())
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}
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name = strings.Replace(name, "*", "__ALL__", -1)
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r.data, err = sjson.SetBytes(r.data, name, v)
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return err
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}
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// MarshalCSV - encodes to CSV data.
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func (r *Record) MarshalCSV(fieldDelimiter rune) ([]byte, error) {
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var csvRecord []string
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result := gjson.ParseBytes(r.data)
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result.ForEach(func(key, value gjson.Result) bool {
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csvRecord = append(csvRecord, value.String())
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return true
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})
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buf := new(bytes.Buffer)
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w := csv.NewWriter(buf)
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w.Comma = fieldDelimiter
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if err := w.Write(csvRecord); err != nil {
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return nil, err
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}
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w.Flush()
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if err := w.Error(); err != nil {
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return nil, err
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}
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data := buf.Bytes()
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return data[:len(data)-1], nil
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}
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// MarshalJSON - encodes to JSON data.
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func (r *Record) MarshalJSON() ([]byte, error) {
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return r.data, nil
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}
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// NewRecord - creates new empty JSON record.
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func NewRecord() *Record {
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return &Record{
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data: []byte("{}"),
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}
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}
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