130 lines
3.5 KiB
Go
130 lines
3.5 KiB
Go
// Copyright (c) 2023 Couchbase, 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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package sanitized
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import (
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"fmt"
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"regexp"
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"time"
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"github.com/blevesearch/bleve/v2/analysis"
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"github.com/blevesearch/bleve/v2/registry"
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)
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const Name = "sanitizedgo"
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var validMagicNumbers = map[string]struct{}{
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"2006": {},
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"06": {}, // Year
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"01": {},
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"1": {},
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"_1": {},
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"January": {},
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"Jan": {}, // Month
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"02": {},
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"2": {},
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"_2": {},
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"__2": {},
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"002": {},
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"Monday": {},
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"Mon": {}, // Day
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"15": {},
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"3": {},
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"03": {}, // Hour
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"4": {},
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"04": {}, // Minute
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"5": {},
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"05": {}, // Second
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"0700": {},
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"070000": {},
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"07": {},
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"00": {},
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"": {},
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}
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var layoutSplitRegex = regexp.MustCompile("[\\+\\-= :T,Z\\.<>;\\?!`~@#$%\\^&\\*|'\"\\(\\){}\\[\\]/\\\\]")
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var layoutStripRegex = regexp.MustCompile(`PM|pm|\.9+|\.0+|MST`)
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type DateTimeParser struct {
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layouts []string
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}
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func New(layouts []string) *DateTimeParser {
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return &DateTimeParser{
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layouts: layouts,
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}
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}
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func (p *DateTimeParser) ParseDateTime(input string) (time.Time, string, error) {
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for _, layout := range p.layouts {
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rv, err := time.Parse(layout, input)
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if err == nil {
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return rv, layout, nil
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}
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}
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return time.Time{}, "", analysis.ErrInvalidDateTime
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}
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// date time layouts must be a combination of constants specified in golang time package
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// https://pkg.go.dev/time#pkg-constants
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// this validation verifies that only these constants are used in the custom layout
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// for compatibility with the golang time package
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func validateLayout(layout string) bool {
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// first we strip out commonly used constants
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// such as "PM" which can be present in the layout
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// right after a time component, e.g. 03:04PM;
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// because regex split cannot separate "03:04PM" into
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// "03:04" and "PM". We also strip out ".9+" and ".0+"
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// which represent fractional seconds.
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layout = layoutStripRegex.ReplaceAllString(layout, "")
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// then we split the layout by non-constant characters
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// which is a regex and verify that each split is a valid magic number
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split := layoutSplitRegex.Split(layout, -1)
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for i := range split {
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_, found := validMagicNumbers[split[i]]
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if !found {
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return false
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}
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}
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return true
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}
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func DateTimeParserConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.DateTimeParser, error) {
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layouts, ok := config["layouts"].([]interface{})
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if !ok {
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return nil, fmt.Errorf("must specify layouts")
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}
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var layoutStrs []string
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for _, layout := range layouts {
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layoutStr, ok := layout.(string)
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if ok {
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if !validateLayout(layoutStr) {
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return nil, fmt.Errorf("invalid datetime parser layout: %s,"+
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" please refer to https://pkg.go.dev/time#pkg-constants for supported"+
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" layouts", layoutStr)
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}
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layoutStrs = append(layoutStrs, layoutStr)
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}
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}
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return New(layoutStrs), nil
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}
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func init() {
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err := registry.RegisterDateTimeParser(Name, DateTimeParserConstructor)
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if err != nil {
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panic(err)
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}
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}
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