|
| 1 | +package tags |
| 2 | + |
| 3 | +import ( |
| 4 | + "errors" |
| 5 | + "fmt" |
| 6 | + "regexp" |
| 7 | + "strings" |
| 8 | + |
| 9 | + "github.com/uptrace/bun" |
| 10 | +) |
| 11 | + |
| 12 | +const tagDelimiterChar string = "|" |
| 13 | +const tagPatternExp string = `^[a-zA-Z0-9_\-+*/.:~=]+$` |
| 14 | +const tagEscapeChar string = "!" |
| 15 | +const tagEscapedChars string = `%_[]^-{}` |
| 16 | + |
| 17 | +var tagPattern = regexp.MustCompile(tagPatternExp) |
| 18 | + |
| 19 | +// TODO vendor out to seperate package |
| 20 | +func reducex[T any, S ~[]T, U any](s S, f func(T, U) (U, error)) (U, error) { |
| 21 | + var zero U |
| 22 | + var result U |
| 23 | + for _, t := range s { |
| 24 | + var err error |
| 25 | + result, err = f(t, result) |
| 26 | + if err != nil { |
| 27 | + return zero, err |
| 28 | + } |
| 29 | + } |
| 30 | + return result, nil |
| 31 | +} |
| 32 | + |
| 33 | +func parseTag(expr string, qb bun.QueryBuilder, mode bool, negate bool) (bun.QueryBuilder, error) { |
| 34 | + var err error |
| 35 | + |
| 36 | + expr = strings.TrimSpace(expr) |
| 37 | + |
| 38 | + // and |
| 39 | + if exprs := splitOnTopLevelChar(expr, '&'); len(exprs) > 1 { |
| 40 | + // TODO test |
| 41 | + return reducex(exprs, func(expr string, qb bun.QueryBuilder) (bun.QueryBuilder, error) { |
| 42 | + return parseTag(expr, qb, true != negate, negate) |
| 43 | + }) |
| 44 | + |
| 45 | + // for _, expr = range exprs { |
| 46 | + // qb, err = parseTag(expr, qb, true != negate, negate) |
| 47 | + // if err != nil { |
| 48 | + // return nil, err |
| 49 | + // } |
| 50 | + // } |
| 51 | + // return qb, nil |
| 52 | + } |
| 53 | + |
| 54 | + // or |
| 55 | + if exprs := splitOnTopLevelChar(expr, '|'); len(exprs) > 1 { |
| 56 | + // TODO test |
| 57 | + return reducex(exprs, func(expr string, qb bun.QueryBuilder) (bun.QueryBuilder, error) { |
| 58 | + return parseTag(expr, qb, false != negate, negate) |
| 59 | + }) |
| 60 | + |
| 61 | + // for _, expr = range exprs { |
| 62 | + // qb, err = parseTag(expr, qb, false != negate, negate) |
| 63 | + // if err != nil { |
| 64 | + // return nil, err |
| 65 | + // } |
| 66 | + // } |
| 67 | + // return qb, nil |
| 68 | + } |
| 69 | + |
| 70 | + // negation |
| 71 | + expr, negated := strings.CutPrefix(expr, "!") |
| 72 | + |
| 73 | + expr = strings.TrimSpace(expr) |
| 74 | + |
| 75 | + // braces |
| 76 | + if strings.HasPrefix(expr, "(") && strings.HasSuffix(expr, ")") { |
| 77 | + expr = expr[1 : len(expr)-1] // removes braces |
| 78 | + |
| 79 | + operator := map[bool]string{ |
| 80 | + true: " AND ", |
| 81 | + false: " OR ", |
| 82 | + }[mode] |
| 83 | + |
| 84 | + if negated { |
| 85 | + // return nil, fmt.Errorf("negating braces is unsupported: %s", expr) |
| 86 | + // Does not work because bun is a *****.... |
| 87 | + // ... is what i would say, but i didn't even check if sql supports it. |
| 88 | + // operator += "NOT " |
| 89 | + |
| 90 | + // well, i think i got an idea ^^ |
| 91 | + negate = !negate |
| 92 | + } |
| 93 | + |
| 94 | + qb = qb.WhereGroup(operator, func(qb bun.QueryBuilder) bun.QueryBuilder { |
| 95 | + qb, err = parseTag(expr, qb, true != negate, negate) |
| 96 | + return qb |
| 97 | + }) |
| 98 | + |
| 99 | + if err != nil { |
| 100 | + return nil, err |
| 101 | + } |
| 102 | + return qb, nil |
| 103 | + } |
| 104 | + |
| 105 | + // raw tag value |
| 106 | + { |
| 107 | + if !tagPattern.MatchString(expr) { |
| 108 | + return nil, fmt.Errorf("invalid tag: %s", expr) |
| 109 | + } |
| 110 | + |
| 111 | + // escape special chars just to be sure |
| 112 | + for _, c := range tagEscapedChars { |
| 113 | + expr = strings.ReplaceAll(expr, string(c), tagEscapeChar+string(c)) |
| 114 | + } |
| 115 | + // enable wildcards |
| 116 | + expr = strings.ReplaceAll(expr, "**", "%") |
| 117 | + expr = strings.ReplaceAll(expr, "*", "_") |
| 118 | + |
| 119 | + query := map[bool]string{ |
| 120 | + true: "tag NOT LIKE ? ESCAPE '" + tagEscapeChar + "'", |
| 121 | + false: "tag LIKE ? ESCAPE '" + tagEscapeChar + "'", |
| 122 | + }[negated != negate] |
| 123 | + |
| 124 | + if mode { |
| 125 | + return qb.Where(query, expr), nil |
| 126 | + } else { |
| 127 | + return qb.WhereOr(query, expr), nil |
| 128 | + } |
| 129 | + } |
| 130 | +} |
| 131 | + |
| 132 | +func splitOnTopLevelChar(expr string, op rune) []string { |
| 133 | + var result []string |
| 134 | + depth := 0 |
| 135 | + start := 0 |
| 136 | + |
| 137 | + for i, ch := range expr { |
| 138 | + switch ch { |
| 139 | + case '(': |
| 140 | + depth++ |
| 141 | + case ')': |
| 142 | + depth-- |
| 143 | + case op: |
| 144 | + if depth == 0 { |
| 145 | + result = append(result, expr[start:i]) |
| 146 | + start = i + 1 |
| 147 | + } |
| 148 | + } |
| 149 | + } |
| 150 | + |
| 151 | + result = append(result, expr[start:]) |
| 152 | + return result |
| 153 | +} |
| 154 | + |
| 155 | +func ValidateTag(tag string) error { |
| 156 | + sq := &bun.SelectQuery{} |
| 157 | + _, err := parseTag(tag, sq.QueryBuilder(), true, false) |
| 158 | + return err |
| 159 | +} |
| 160 | + |
| 161 | +func GetTagQueryBuilder(tag string) (func(bun.QueryBuilder) bun.QueryBuilder, error) { |
| 162 | + if err := ValidateTag(tag); err != nil { |
| 163 | + return nil, err |
| 164 | + } |
| 165 | + return func(qb bun.QueryBuilder) bun.QueryBuilder { |
| 166 | + qb, _ = parseTag(tag, qb, true, false) |
| 167 | + return qb |
| 168 | + }, nil |
| 169 | +} |
| 170 | + |
| 171 | +func SplitTags(tag string) ([]string, error) { |
| 172 | + tag, exists_prefix := strings.CutPrefix(tag, tagDelimiterChar) |
| 173 | + tag, exists_suffix := strings.CutSuffix(tag, tagDelimiterChar) |
| 174 | + if !exists_prefix || !exists_suffix { |
| 175 | + return nil, errors.New("Prefix or suffix is missing") |
| 176 | + } |
| 177 | + |
| 178 | + return strings.Split(tag, tagDelimiterChar), nil |
| 179 | +} |
| 180 | + |
| 181 | +func SplitTagsSafe(tag string) []string { |
| 182 | + tags, _ := SplitTags(tag) |
| 183 | + return tags |
| 184 | +} |
| 185 | + |
| 186 | +func JoinTags(tags []string) string { |
| 187 | + return tagDelimiterChar + strings.Join(tags, tagDelimiterChar) + tagDelimiterChar |
| 188 | +} |
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