stream header flag + export from mongo

This commit is contained in:
Jan Prochazka
2021-04-08 17:49:57 +02:00
parent a5d37eb528
commit 20fccf51d9
9 changed files with 83 additions and 12 deletions

View File

@@ -1,9 +1,13 @@
const EnsureStreamHeaderStream = require('../utility/EnsureStreamHeaderStream');
function copyStream(input, output) {
return new Promise((resolve, reject) => {
const ensureHeader = new EnsureStreamHeaderStream();
const finisher = output['finisher'] || output;
finisher.on('finish', resolve);
finisher.on('error', reject);
input.pipe(output);
input.pipe(ensureHeader);
ensureHeader.pipe(output);
});
}

View File

@@ -3,9 +3,8 @@ const stream = require('stream');
const byline = require('byline');
class ParseStream extends stream.Transform {
constructor({ header, limitRows }) {
constructor({ limitRows }) {
super({ objectMode: true });
this.header = header;
this.wasHeader = false;
this.limitRows = limitRows;
this.rowsWritten = 0;
@@ -13,7 +12,14 @@ class ParseStream extends stream.Transform {
_transform(chunk, encoding, done) {
const obj = JSON.parse(chunk);
if (!this.wasHeader) {
if (!this.header) this.push({ columns: Object.keys(obj).map(columnName => ({ columnName })) });
if (
!obj.__isStreamHeader &&
// TODO remove isArray test
!Array.isArray(obj.columns)
) {
this.push({ columns: Object.keys(obj).map(columnName => ({ columnName })) });
}
this.wasHeader = true;
}
if (!this.limitRows || this.rowsWritten < this.limitRows) {
@@ -24,12 +30,12 @@ class ParseStream extends stream.Transform {
}
}
async function jsonLinesReader({ fileName, encoding = 'utf-8', header = true, limitRows = undefined }) {
async function jsonLinesReader({ fileName, encoding = 'utf-8', limitRows = undefined }) {
console.log(`Reading file ${fileName}`);
const fileStream = fs.createReadStream(fileName, encoding);
const liner = byline(fileStream);
const parser = new ParseStream({ header, limitRows });
const parser = new ParseStream({ limitRows });
liner.pipe(parser);
return parser;
}

View File

@@ -8,10 +8,16 @@ class StringifyStream extends stream.Transform {
this.wasHeader = false;
}
_transform(chunk, encoding, done) {
let skip = false;
if (!this.wasHeader) {
if (this.header) this.push(JSON.stringify(chunk) + '\n');
skip =
(chunk.__isStreamHeader ||
// TODO remove isArray test
Array.isArray(chunk.columns)) &&
!this.header;
this.wasHeader = true;
} else {
}
if (!skip) {
this.push(JSON.stringify(chunk) + '\n');
}
done();

View File

@@ -1,6 +1,5 @@
const { quoteFullName, fullNameToString } = require('dbgate-tools');
const requireEngineDriver = require('../utility/requireEngineDriver');
const { decryptConnection } = require('../utility/crypting');
const connectUtility = require('../utility/connectUtility');
async function tableReader({ connection, pureName, schemaName }) {
@@ -10,6 +9,13 @@ async function tableReader({ connection, pureName, schemaName }) {
const fullName = { pureName, schemaName };
if (driver.dialect.nosql) {
// @ts-ignore
console.log(`Reading collection ${fullNameToString(fullName)}`);
// @ts-ignore
return await driver.readQuery(pool, JSON.stringify(fullName));
}
const table = await driver.analyseSingleObject(pool, fullName, 'tables');
const query = `select * from ${quoteFullName(driver.dialect, fullName)}`;
if (table) {