I've make a translation service in nodejs :
module.exports = {GetcountryFR, GetRegionFR, GetChildrenFR, GetHomeownFR, GetHomestyleFR, GetIncomeFR, GetLstatusFR, GetWdomainFR, GetWtypeFR, GetSexFR}
async function GetcountryFR(country) {
var countrix = country;
switch (countrix) {
case 'createuser.france': countrix = 'FRANCE'; break;
case 'createuser.belgique': countrix = 'BELGIQUE'; break;
default: countrix = 'UNKNOWN'; break;
}
return countrix;
}
And now I make a function which uses translat function
const translate = require('../services/translate');
exports.AllUserToCSV = async function CSV() {
try {
let user = User.find();
var data = [];
len = user.length;
for (i = 0; i < len; i++) {
let sexix = await translate.GetSexFr(user[i].sex);
let regionix = await translate.GetRegionFR(user[i].region);
let countrix = await translate.GetcountryFR(user[i].country);
let wtypix = await translate.GetWtypeFR(user[i].wtype);
let wdomainix = await translate.GetWdomainFR(user[i].wdomain);
temp = {
sex: sexix,
region: regionix,
country: countrix,
wtype: wtypix,
wdomain: wdomainix,
}
data.push(temp);
}
const csvData = csvjson.toCSV(data, { headers: 'key' })
filename2 = '/assets/media/' + 'TEST' + '.csv';
writeFile(filename, csvData, (err) => {
if (err) {
console.log(err); // Do something to handle the error or just throw it
throw new Error(err);
}
console.log('Success!');
});
} catch (e) {
console.error(e);
}
}
In results CSV file is Empty [].
If I put values in temp it's OK.
Why my translate function didn't work ??
Thanks for Help Good Friends :)
Simply await your call to the User model i.e let user = await User.find();
Also for the loop, try
let users = await User.find();
await Promise.all(users.map(async (user) => {
let sexix = await translate.GetSexFr(user.sex);
...
})));
Writing to file, you may want to use await fs.writeFile(...);. This will make sure file is written before processing the next.
Related
I'm learning NodeJs and having some problems using async/ await. I'm using Firebase database to read/write data. Here what i'm doing. (full function in case you need it).
async getImport(reqData: any): Promise<any> {
const username = 'kdat0310';
const db = admin.database();
const userRef = db.ref('/user');
const importRef = db.ref('/import');
const refAuthentication = db.ref('/Authentication');
const keyList = [];
const providerKey = [];
const khoList = [];
let index = 0;
const providerList = [];
const isValid = await refAuthentication.once('value', function (snapshot) {
for (const val of Object.values(snapshot.val())) {
if (
Object(val).username === Object(reqData).username &&
Object(val).token === Object(reqData).token
) {
return true;
}
}
return false;
});
if (isValid) {
await userRef.once('value', function (snapshot) {
for (const value of Object.values(snapshot.val())) {
if (value) {
if (Object(value).username == username) {
for (const val of Object(value).workAt) {
if (val) khoList.push(val.khoId);
}
}
}
}
});
const typeAndColorKey = [];
const typeAndColorValue = [];
const typeAndColorRef = db.ref('/TypeAndColor');
await typeAndColorRef.once('value', function (snapshot) {
let count = 0;
for (const key in snapshot.val()) {
typeAndColorKey.push(key);
}
for (const value of snapshot.val()) {
if (value !== undefined && value != null) {
typeAndColorValue.push({
id: typeAndColorKey[count],
type: value.type,
color: value.color,
});
count = count + 1;
}
}
});
const findTypeAndColor = (id: any) => {
for (const value of typeAndColorValue) {
if (id == value.id) {
return { type: value.type, color: value.color };
}
}
};
const userKey = [];
const userList = [];
await userRef.once('value', function (snapshot) {
let count = 0;
for (const key in snapshot.val()) {
userKey.push(key);
}
for (const value of Object(snapshot.val())) {
if (value != undefined && value != null) {
userList.push({
id: userKey[count],
name: Object(value).name,
});
count++;
}
}
});
const findUserName = (userId: any) => {
const returnValue = '';
for (const value of userList) {
if (userId == Object(value).id) {
return Object(value).name;
}
}
};
const importList = [];
await importRef.once('value', async function (snapshot) {
const importKey = [];
const cloneArr = snapshot.val().map((item: any) => {
return item;
});
for (const key in snapshot.val()) {
importKey.push(key);
}
let countTemp = 0;
for (const value of Object.values(cloneArr)) {
const goodsKeyList = [];
let count = 0;
if (khoList.indexOf(Object(value).warehouseId) !== -1) {
const listGoodsList = [];
if (Object(value).listGoods) {
for (const key in Object(value).listGoods) {
goodsKeyList.push(key);
}
const refListGoods = db.ref(
'/import/' + importKey[countTemp] + '/listGoods',
);
await refListGoods.once('value', function (snapshot) {
let item: any;
for (item of Object.values(snapshot.val())) {
if (item) {
const tempItem = item.filter((n: any) => n);
listGoodsList.push({
typeAndColor: findTypeAndColor(goodsKeyList[count]),
listGoods: tempItem,
number: tempItem.length,
});
}
count++;
}
});
}
console.log('test 1', listGoodsList);
if (listGoodsList !== []) {
importList.push({
listGoods: listGoodsList,
driver: Object(value).driver,
userId: Object(value).importEmployee,
name: findUserName(Object(value).importEmployee),
orderId: Object(value).orderId,
warehouseId: Object(value).warehouseId,
time: Object(value).time,
});
}
}
countTemp++;
}
console.log('test 2', importList);
});
return importList;
}
return 'Invalid';
}
The problem show up when it came to await importRef.once When I tried to handle some data and add the Firebase once function "async" and await inside to push the data I need to the array. Then return importList; return nothing. I figure that the await refListGoods.once cause this problems. As i thought, the await inside had done its duty and I can console.log importList inside very well. But I thought that await importRef.once will finish before return too. when I delete await refListGoods.once, the return is fine but I dont get the data I need. Do I need to refactor all code as I do to findTypeAndColor and findUserName above or there's a better way to solve this problem?
If you want to use await on the Promise returned by once, you should not pass a callback function to it.
So instead of:
const isValid = await refAuthentication.once('value', function (snapshot) {
for (const val of Object.values(snapshot.val())) {
if (
Object(val).username === Object(reqData).username &&
Object(val).token === Object(reqData).token
) {
return true;
}
}
return false;
});
Do:
const snapshot = await refAuthentication.once('value');
let isValid = false;
snapshot.forEach((child) => {
const val = child.val();
if (val.username === Object(reqData).username &&
val.token === Object(reqData).token
) {
isValid = true;
}
})
I want to write a script that divides the lines read from the file into packages of 25, unfortunately the sample package returns 40 codes. I would like to do so that, for example, he divided me into packages of 25 items. I mean, I have, for example, 60 codes, this creates 2 packages of 25, and one with 10 codes. Unfortunately, I can't handle it.
const fs = require('fs');
fs.readFile('code.txt', function (err, data) {
if (err) throw err;
const array = data.toString().split("\n");
let count = 0;
let items = [];
for (let i in array) {
items.push({
PutRequest: {
Item: {
code: array[i]
}
}
});
let params = {
RequestItems: {
'TABLE_NAME': items
}
};
if (count === 25) {
dynamoDB.batchWrite(params, function (err, data) {
if (err) {
console.log(err);
} else {
count = 0;
items = [];
}
});
}else{
count++;
}
}
});
code.txt content
https://0bin.net/paste/NA8-4hkq#1Ohwt5uUkQqE0YscwnxTX2gxEqlvAUVKp1JRipBCsZg
Any idea what I do wrong?
Your dynamoDB.batchWrite() is asynchronous. Thus its callback is executed only after the loop has completed. So items and count are never reset ...
The easiest would be, if you could switch to an promise based approach like the following
const BATCHSIZE = 25;
const fs = require('fs').promises;
async function batchLoad() {
const lines = (await fs.readFile("code.txt", "utf-8")).split("\n");
while (lines.length > 0) {
const items = lines.splice(0, BATCHSIZE).map(l => ({PutRequest: {Item: { code: l }}}));
const params = { RequestItems: { TABLE_NAME: items}};
await new Promise((resolve, reject) => {
dynamoDb.batchWrite(params, (err) => {
if (err) return reject(err);
resolve();
});
});
}
}
A callback based approach could look like this
const BATCHSIZE = 25;
fs.readFile("code.txt", "utf-8", (err, data) => {
const lines = data.split("\n");
function writeBatch() {
if (!lines.length) return;
const items = lines.splice(0, BATCHSIZE).map(l => ({PutRequest: {Item: { code: l }}}));
const params = { RequestItems: { TABLE_NAME: items}};
dynamoDb.batchWrite(params, err => {
if (err) ...
else writeBatch();
});
}
writeBatch();
}
The function writeBatch takes a certain number of lines from your original array and writes them into the database. Only afer the write into the DB was successful, it recursively calls itself and handles the next batch. But be aware, that this approach may exceed the maximum call stack size and throw an error.
You can also make either of this approaches not manipulate the lines array (which may be quite expensive), but just get out the current slice
const BATCHSIZE = 25;
const fs = require('fs').promises;
async function batchLoad() {
const lines = (await fs.readFile("code.txt", "utf-8")).split("\n");
let currentIndex = 0;
while (currentIndex < lines.length) {
const items = lines.slice(currentIndex, currentIndex + BATCHSIZE).map(l => ({PutRequest: {Item: { code: l }}}));
const params = { RequestItems: { TABLE_NAME: items}};
await new Promise((resolve, reject) => {
dynamoDb.batchWrite(params, (err) => {
if (err) return reject(err);
resolve();
});
});
currentIndex += BATCHSIZE;
}
}
and
const BATCHSIZE = 25;
fs.readFile("code.txt", "utf-8", (err, data) => {
const lines = data.split("\n");
function writeBatch(currentIndex) {
if (currentIndex >= lines.length) return;
const items = lines.slice(currentIndex, currentIndex + BATCHSIZE).map(l => ({PutRequest: {Item: { code: l }}}));
const params = { RequestItems: { TABLE_NAME: items}};
dynamoDb.batchWrite(params, err => {
if (err) ...
else writeBatch(currentIndex + BATCHSIZE);
});
}
writeBatch(0);
}
To prevent stumbling into a maximum callstack exception you may also add the next batch to the eventloop and not call it recursively. Ie
dynamoDb.batchWrite(params, err => {
if (err) ...
else setTimeout(()=> { writeBatch(currentIndex + BATCHSIZE);}, 0);
});
This way you won't build up a massive callstack from recursive calls.
To keep track of how many records are already saved to the db you could simply store the current counter in a file. When you restart the process, load that file and check how many lines to skip. Don't forget to remove the file, once all records have been saved ... For example with the first approach:
const BATCHSIZE = 25;
const fs = require('fs').promises;
async function batchLoad() {
const lines = (await fs.readFile("code.txt", "utf-8")).split("\n");
const skipLines = 0;
try {
skipLines = +(await fs.readFile("skip.txt", "utf-8"));
if (isNaN(skipLines)) skipLines = 0;
lines.splice(0, skipLines);
} catch (e) {
skipLines = 0;
}
while (lines.length > 0) {
const items = lines.splice(0, BATCHSIZE).map(l => ({PutRequest: {Item: { code: l }}}));
const params = { RequestItems: { TABLE_NAME: items}};
await new Promise((resolve, reject) => {
dynamoDb.batchWrite(params, (err) => {
if (err) return reject(err);
resolve();
});
});
skipLines += BATCHSIZE;
await fs.writeFile("skip.txt", `${skipLines}`);
}
try {
await fs.unlink("skip.txt");
} catch (e) {
}
}
I don't know about the correct title for my problem. I just need a value going out of a function, just like return but I think it's not same.
i have code snippet from controller in adonisjs framework:
var nmeadata = "";
jsondata.forEach(element => {
var x = element.nmea
var buff = new Buffer(x, 'base64')
zlib.unzip(buff, (err, res) => {
if(err)
{
//
}
else
{
nmeadata += "greed island"
nmeadata += res.toString()
}
})
});
return view.render('admin.index', {
data: datanmea.toJSON(),
nmea: nmeadata
})
I need the result of unzipped string data that inserted to nmeadata from zlib function then send it to view. But, for this time, even I cannot displaying a simple output like greed island to my view.
thank you.
UPDATE
Still not working after using promises:
class NmeaController {
async index({view})
{
const datanmea = await NmeaModel.all()
const jsondata = datanmea.toJSON()
var promises = [];
var nmeadata = "";
jsondata.forEach(element => {
promises.push(
new Promise(resolve => {
let x = element.nmea
let buff = new Buffer(x, 'base64')
zlib.unzip(buff,
(err, res) => {
if (err) {
//
} else {
nmeadata += "test add text"
// nmeadata += res.toString()
}
//im also try using resolve() and resolve("any text")
resolve(nmeadata);
})
}
)
)
});
await Promise.all(promises);
return view.render('admin.index', {
data: datanmea.toJSON(),
nmea: nmeadata
});
}
UPDATE AUGUST 22 2019
i'm already tried solution from maksbd19 but still not working
class NmeaController {
async index({view})
{
const datanmea = await NmeaModel.all()
const jsondata = datanmea.toJSON()
var promises = [];
var nmeadata = "";
jsondata.forEach(element => {
promises.push(
new Promise(resolve => {
let x = element.nmea
let buff = new Buffer(x, 'base64')
zlib.unzip(buff,
(err, res) => {
if (err) {
// since you are interested in the text only, so no need to reject here
return resolve("");
}
return resolve("greed island")
})
}
)
)
});
const result = await Promise.all(promises); // this will be an array of results of each promises respectively.
nmeadata = result.join(""); // process the array of result
return view.render('admin.index', {
data: datanmea.toJSON(),
nmea: nmeadata
});
}
}
I'd suggest two things-
modify zlib.unzip callback function to resolve properly;
(err, res) => {
if (err) {
// since you are interested in the text only, so no need to reject here
return resolve("");
}
return resolve(res.toString())
}
retrieve the final data from the result of Promise.all
const result = await Promise.all(promises); // this will be an array of results of each promises respectively.
nmeadata = result.join(""); // process the array of result
In this approach every promise will resolve and finally you will get the expected result in array.
Problem:
I have created a chaincode .In one function of this code, I have called another function of the same chaincode. This is how that code looks like.
async nthUsersLands(stub, args) {
if (args.length != 1) {
throw new Error(
"Incorrect number of arguments. Expecting NIC ex: 942990014V"
);
}
let nic = args[0];
let queryString = {};
queryString.selector = {};
queryString.selector.docType = "land";
queryString.selector.user = nic;
let method = thisClass["getQueryResultForQueryString"];
let queryResults = await method(
stub,
JSON.stringify(queryString),
thisClass
);
// let queryResults = await methods.getQueryResultForQueryString(stub,JSON.stringify(queryString))
console.log(queryResults.toString());
return queryResults;
}
async getQueryResultForQueryString(stub, queryString, thisClass) {
console.info("- getQueryResultForQueryString queryString:\n" + queryString);
let resultsIterator = await stub.getQueryResult(queryString);
let method = thisClass["getAllResults"];
let results = await method(resultsIterator, false);
// let results = await methods.getAllResults(resultsIterator,false)
return Buffer.from(JSON.stringify(results));
}
async getAllResults(iterator, isHistory) {
let allResults = [];
while (true) {
let res = await iterator.next();
if (res.value && res.value.value.toString()) {
let jsonRes = {};
console.log(res.value.value.toString('utf8'));
if (isHistory && isHistory === true) {
jsonRes.TxId = res.value.tx_id;
jsonRes.Timestamp = res.value.timestamp;
jsonRes.IsDelete = res.value.is_delete.toString();
try {
jsonRes.Value = JSON.parse(res.value.value.toString('utf8'));
} catch (err) {
console.log(err);
jsonRes.Value = res.value.value.toString('utf8');
}
} else {
jsonRes.Key = res.value.key;
try {
jsonRes.Record = JSON.parse(res.value.value.toString('utf8'));
} catch (err) {
console.log(err);
jsonRes.Record = res.value.value.toString('utf8');
}
}
allResults.push(jsonRes);
}
if (res.done) {
console.log('end of data');
await iterator.close();
console.info(allResults);
return allResults;
}
}
}
But when I invoke this getNthUsersLands leaves to me an error like this.
TypeError: Cannot read property 'getQueryResultForQueryString' of
undefined
I tried a lot to find a solution using three questions regarding this problem in stack overflow but I was unable to cater to this problem using those. Can someone help me with this problem? Thank You!
Node.js database result return late inside the function
const db = req.app.db;
function getFeaturebyID(featureids) {
db.planFeatures.findOne({"_id": featureids }).then(features => {
return features.planFeaturesTitle;
});
}
const planLists ={};
db.planManagement.find({}).toArray((err, planList) => {
// res.end(JSON.stringify(planList));
featurearray = [];
var j =1;
planList.forEach(function(row) {
planLists._id = row._id;
features = row.planFeatures.split(',');
for (let i = 0; i < features.length; i++) {
featurearray[i] = getFeaturebyID(features[i]);
// console.log(getFeaturebyID(features[i]));
}
//row.planFeaturesName[j] = featurearray;
console.log(featurearray);
j++;
});
//console.log(planList);
// res.end(JSON.stringify(req.session));
res.render('stylist/plan_selection', {
top_results: planList,
title: 'Schedule',
config: req.app.config,
session: req.session,
message: common.clearSessionValue(req.session, 'message'),
messageType: common.clearSessionValue(req.session, 'messageType'),
helpers: req.handlebars.helpers,
showFooter: 'showFooter'
});
});
});
return features.planFeaturesTitle; return a value late while calling the function. I try callback but not works
This is due to asynchronous nature of node.js,
First declare your function async like this,
const getFeaturebyID = async (featureids) => {
const features = await db.planFeatures.findOne({"_id": featureids });
return features.planFeaturesTitle;
}
Then use it like this,
planList.forEach(async (row) => {
// your code here
for (let i = 0; i < features.length; i++) {
featurearray[i] = await getFeaturebyID(features[i]);
}
// your code here
});