137 lines
3.4 KiB
TypeScript
137 lines
3.4 KiB
TypeScript
/**
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* 极简 mysqldump 解析器。
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*
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* 只做一件事：从 mysqldump 导出的 .sql 文本里取出 `INSERT INTO `表名` VALUES (...),(...)` 的行数据。
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* 不解析 DDL，不处理多语句逻辑。
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*/
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export type SqlValue = string | number | null;
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/** 解码 MySQL 字符串中的反斜杠转义。未识别的转义按 MySQL 语义保留反斜杠。 */
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function decodeEscape(e: string): string {
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switch (e) {
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case '0':
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return '\0';
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case 'b':
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return '\b';
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case 'n':
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return '\n';
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case 'r':
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return '\r';
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case 't':
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return '\t';
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case 'Z':
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return '\x1a';
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case '\\':
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return '\\';
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case "'":
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return "'";
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case '"':
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return '"';
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default:
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return '\\' + e;
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}
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}
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/**
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* 把 `VALUES` 之后的载荷解析成二维数组。
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* 每个字段的三种形态：带引号的字符串 / NULL / 数字。
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*/
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export function parseTupleList(payload: string): SqlValue[][] {
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const rows: SqlValue[][] = [];
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const n = payload.length;
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let i = 0;
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const skipSeparators = (): void => {
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while (i < n && (payload[i] === ',' || payload[i]! <= ' ')) i++;
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};
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skipSeparators();
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while (i < n) {
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if (payload[i] !== '(') {
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throw new Error(`位置 ${i} 处期望 '('，实际是 ${JSON.stringify(payload[i])}`);
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}
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i++;
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const row: SqlValue[] = [];
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let closed = false;
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while (!closed) {
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while (i < n && payload[i]! <= ' ') i++;
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if (payload[i] === "'") {
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i++;
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let s = '';
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for (;;) {
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const c = payload[i];
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if (c === undefined) throw new Error('字符串未闭合');
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if (c === '\\') {
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s += decodeEscape(payload[i + 1] ?? '');
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i += 2;
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continue;
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}
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if (c === "'") {
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if (payload[i + 1] === "'") {
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s += "'";
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i += 2;
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continue;
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}
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i++;
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break;
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}
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s += c;
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i++;
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}
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row.push(s);
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} else {
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let token = '';
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while (i < n && payload[i] !== ',' && payload[i] !== ')') {
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token += payload[i];
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i++;
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}
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token = token.trim();
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row.push(token === '' || token.toUpperCase() === 'NULL' ? null : Number(token));
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}
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while (i < n && payload[i]! <= ' ' && payload[i] !== ',' && payload[i] !== ')') i++;
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const c = payload[i];
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if (c === ',') {
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i++;
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continue;
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}
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if (c === ')') {
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i++;
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closed = true;
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continue;
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}
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throw new Error(`位置 ${i} 处期望 ',' 或 ')'，实际是 ${JSON.stringify(c)}`);
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}
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rows.push(row);
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skipSeparators();
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}
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return rows;
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}
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/** 取出某张表全部 INSERT 行。表不存在时返回空数组。 */
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export function readTable(sql: string, table: string): SqlValue[][] {
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const re = new RegExp('INSERT INTO `' + table.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') + '` VALUES (.*?);\\n', 'gs');
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const rows: SqlValue[][] = [];
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for (const m of sql.matchAll(re)) {
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rows.push(...parseTupleList(m[1]!));
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}
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return rows;
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}
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/** 转成对象数组，便于按字段名取值。 */
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export function toObjects(rows: SqlValue[][], columns: string[]): Record<string, SqlValue>[] {
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return rows.map((row) => {
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const obj: Record<string, SqlValue> = {};
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columns.forEach((col, idx) => {
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obj[col] = row[idx] ?? null;
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});
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return obj;
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});
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}
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