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Add 'packages/pg-cursor/' from commit '492fbdbb65f6f33396d1017fa4cdbbb247dd3895'
git-subtree-dir: packages/pg-cursor git-subtree-mainline: ebb81db git-subtree-split: 492fbdb
2 parents ebb81db + 492fbdb commit 37d1574

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‎packages/pg-cursor/.eslintrc

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{
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"extends": ["eslint:recommended"],
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"parserOptions": {
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"ecmaVersion": 2017
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},
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"plugins": ["prettier"],
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"rules": {
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"prettier/prettier": "error",
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"prefer-const": "error",
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"no-var": "error"
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},
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"env": {
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"es6": true,
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"node": true,
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"mocha": true
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}
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}

‎packages/pg-cursor/.gitignore

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node_modules

‎packages/pg-cursor/.travis.yml

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language: node_js
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dist: trusty
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sudo: false
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node_js:
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- '8'
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- '10'
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- '12'
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env:
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- PGUSER=postgres
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services:
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- postgresql
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addons:
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postgresql: '9.6'
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before_script:
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- psql -c 'create database travis;' -U postgres | true

‎packages/pg-cursor/Makefile

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.PHONY: test
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test:
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npm test
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.PHONY: patch
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patch: test
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npm version patch -m "Bump version"
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git push origin master --tags
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npm publish
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.PHONY: minor
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minor: test
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npm version minor -m "Bump version"
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git push origin master --tags
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npm publish

‎packages/pg-cursor/README.md

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node-pg-cursor
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==============
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Use a PostgreSQL result cursor from node with an easy to use API.
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### install
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```sh
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$ npm install pg-cursor
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```
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___note___: this depends on _either_ `npm install pg` or `npm install pg.js`, but you __must__ be using the pure JavaScript client. This will __not work__ with the native bindings.
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### :star: [Documentation](https://node-postgres.com/api/cursor) :star:
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### license
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The MIT License (MIT)
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Copyright (c) 2013 Brian M. Carlson
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.

‎packages/pg-cursor/index.js

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'use strict'
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const Result = require('pg/lib/result.js')
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const prepare = require('pg/lib/utils.js').prepareValue
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const EventEmitter = require('events').EventEmitter
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const util = require('util')
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let nextUniqueID = 1 // concept borrowed from org.postgresql.core.v3.QueryExecutorImpl
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function Cursor(text, values, config) {
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EventEmitter.call(this)
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this._conf = config || {}
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this.text = text
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this.values = values ? values.map(prepare) : null
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this.connection = null
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this._queue = []
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this.state = 'initialized'
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this._result = new Result(this._conf.rowMode, this._conf.types)
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this._cb = null
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this._rows = null
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this._portal = null
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this._ifNoData = this._ifNoData.bind(this)
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this._rowDescription = this._rowDescription.bind(this)
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}
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util.inherits(Cursor, EventEmitter)
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Cursor.prototype._ifNoData = function() {
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this.state = 'idle'
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this._shiftQueue()
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}
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Cursor.prototype._rowDescription = function() {
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if (this.connection) {
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this.connection.removeListener('noData', this._ifNoData)
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}
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}
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Cursor.prototype.submit = function(connection) {
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this.connection = connection
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this._portal = 'C_' + nextUniqueID++
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const con = connection
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con.parse(
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{
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text: this.text,
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},
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true
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)
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con.bind(
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{
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portal: this._portal,
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values: this.values,
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},
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true
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)
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con.describe(
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{
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type: 'P',
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name: this._portal, // AWS Redshift requires a portal name
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},
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true
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)
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con.flush()
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if (this._conf.types) {
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this._result._getTypeParser = this._conf.types.getTypeParser
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}
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con.once('noData', this._ifNoData)
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con.once('rowDescription', this._rowDescription)
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}
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Cursor.prototype._shiftQueue = function() {
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if (this._queue.length) {
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this._getRows.apply(this, this._queue.shift())
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}
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}
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Cursor.prototype._closePortal = function() {
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// because we opened a named portal to stream results
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// we need to close the same named portal. Leaving a named portal
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// open can lock tables for modification if inside a transaction.
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// see https://github.com/brianc/node-pg-cursor/issues/56
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this.connection.close({ type: 'P', name: this._portal })
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this.connection.sync()
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}
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Cursor.prototype.handleRowDescription = function(msg) {
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this._result.addFields(msg.fields)
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this.state = 'idle'
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this._shiftQueue()
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}
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Cursor.prototype.handleDataRow = function(msg) {
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const row = this._result.parseRow(msg.fields)
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this.emit('row', row, this._result)
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this._rows.push(row)
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}
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Cursor.prototype._sendRows = function() {
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this.state = 'idle'
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setImmediate(() => {
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const cb = this._cb
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// remove callback before calling it
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// because likely a new one will be added
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// within the call to this callback
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this._cb = null
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if (cb) {
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this._result.rows = this._rows
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cb(null, this._rows, this._result)
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}
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this._rows = []
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})
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}
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Cursor.prototype.handleCommandComplete = function(msg) {
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this._result.addCommandComplete(msg)
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this._closePortal()
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}
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Cursor.prototype.handlePortalSuspended = function() {
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this._sendRows()
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}
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Cursor.prototype.handleReadyForQuery = function() {
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this._sendRows()
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this.state = 'done'
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this.emit('end', this._result)
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}
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Cursor.prototype.handleEmptyQuery = function() {
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this.connection.sync()
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}
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Cursor.prototype.handleError = function(msg) {
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this.connection.removeListener('noData', this._ifNoData)
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this.connection.removeListener('rowDescription', this._rowDescription)
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this.state = 'error'
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this._error = msg
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// satisfy any waiting callback
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if (this._cb) {
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this._cb(msg)
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}
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// dispatch error to all waiting callbacks
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for (let i = 0; i < this._queue.length; i++) {
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this._queue.pop()[1](msg)
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}
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if (this.listenerCount('error') > 0) {
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// only dispatch error events if we have a listener
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this.emit('error', msg)
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}
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// call sync to keep this connection from hanging
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this.connection.sync()
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}
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Cursor.prototype._getRows = function(rows, cb) {
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this.state = 'busy'
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this._cb = cb
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this._rows = []
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const msg = {
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portal: this._portal,
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rows: rows,
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}
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this.connection.execute(msg, true)
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this.connection.flush()
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}
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// users really shouldn't be calling 'end' here and terminating a connection to postgres
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// via the low level connection.end api
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Cursor.prototype.end = util.deprecate(function(cb) {
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if (this.state !== 'initialized') {
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this.connection.sync()
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}
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this.connection.once('end', cb)
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this.connection.end()
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}, 'Cursor.end is deprecated. Call end on the client itself to end a connection to the database.')
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Cursor.prototype.close = function(cb) {
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if (this.state === 'done') {
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if (cb) {
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return setImmediate(cb)
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} else {
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return
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}
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}
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this._closePortal()
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this.state = 'done'
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if (cb) {
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this.connection.once('closeComplete', function() {
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cb()
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})
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}
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}
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Cursor.prototype.read = function(rows, cb) {
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if (this.state === 'idle') {
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return this._getRows(rows, cb)
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}
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if (this.state === 'busy' || this.state === 'initialized') {
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return this._queue.push([rows, cb])
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}
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if (this.state === 'error') {
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return setImmediate(() => cb(this._error))
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}
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if (this.state === 'done') {
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return setImmediate(() => cb(null, []))
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} else {
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throw new Error('Unknown state: ' + this.state)
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}
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}
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module.exports = Cursor

‎packages/pg-cursor/package.json

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{
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"name": "pg-cursor",
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"version": "2.0.1",
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"description": "Query cursor extension for node-postgres",
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"main": "index.js",
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"directories": {
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"test": "test"
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},
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"scripts": {
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"test": " mocha && eslint ."
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},
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"repository": {
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"type": "git",
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"url": "git://github.com/brianc/node-pg-cursor.git"
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},
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"author": "Brian M. Carlson",
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"license": "MIT",
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"devDependencies": {
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"eslint": "^6.5.1",
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"eslint-config-prettier": "^6.4.0",
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"eslint-plugin-prettier": "^3.1.1",
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"mocha": "^6.2.2",
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"pg": "7.x",
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"prettier": "^1.18.2"
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},
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"prettier": {
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"semi": false,
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"printWidth": 120,
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"trailingComma": "es5",
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"singleQuote": true
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}
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}

‎packages/pg-cursor/test/close.js

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const assert = require('assert')
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const Cursor = require('../')
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const pg = require('pg')
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const text = 'SELECT generate_series as num FROM generate_series(0, 50)'
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describe('close', function() {
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beforeEach(function(done) {
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const client = (this.client = new pg.Client())
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client.connect(done)
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client.on('drain', client.end.bind(client))
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})
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it('can close a finished cursor without a callback', function(done) {
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const cursor = new Cursor(text)
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this.client.query(cursor)
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this.client.query('SELECT NOW()', done)
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cursor.read(100, function(err) {
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assert.ifError(err)
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cursor.close()
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})
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})
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it('closes cursor early', function(done) {
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const cursor = new Cursor(text)
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this.client.query(cursor)
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this.client.query('SELECT NOW()', done)
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cursor.read(25, function(err) {
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assert.ifError(err)
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cursor.close()
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})
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})
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it('works with callback style', function(done) {
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const cursor = new Cursor(text)
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const client = this.client
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client.query(cursor)
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cursor.read(25, function(err) {
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assert.ifError(err)
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cursor.close(function(err) {
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assert.ifError(err)
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client.query('SELECT NOW()', done)
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})
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})
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})
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})

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