I have two questions:
Is the below example the right way to execute multiple Parse queries in a single Cloud Code function?
Is the below example going to provide all the data I'm querying with one HTTP request (when I call logbookEntries) and then count as two Parse requests on my account because it's two Parse queries?
Here's the code:
Parse.Cloud.define("logbookEntries", function(request, response) {
//::: Query 1 :::
var firstQuery = new Parse.Query("Logbook");
var returnData = [];
firstQuery.find().then(function(firstResults) {
returnData[0] = firstResults;
}).then(function(result) {
//::: Query 2 :::
var secondQuery = new Parse.Query("Logbook");
secondQuery.find().then(function(secondResults))
returnData[1] = secondResults;
}).then(function(result) {
response.success(returnData);
}, function(error) {
response.error(error);
});
});
Thanks in advance.
It's one way, though not quite correct.
Yes
Your code should really be:
Parse.Cloud.define("logbookEntries", function(request, response) {
//::: Query 1 :::
var firstQuery = new Parse.Query("Logbook");
var returnData = [];
firstQuery.find().then(function(firstResults) {
returnData[0] = firstResults;
var secondQuery = new Parse.Query("Logbook");
return secondQuery.find();
}).then(function(result) {
returnData[1] = result;
response.success(returnData);
}, function(error) {
response.error(error);
});
});
Or, a better way to structure it would be:
Parse.Cloud.define("logbookEntries", function(request, response) {
var firstQuery = new Parse.Query("Logbook");
var secondQuery = new Parse.Query("Logbook");
var promises = [];
promises.push(firstQuery.find());
promises.push(secondQuery.find());
Parse.Promise.when(promises).then(function(result1, result2) {
var returnData = [];
returnData[1] = result1;
returnData[2] = result2;
response.success(returnData);
}, function(error) {
response.error(error);
});
}
Just to update Wain's structured code:
Promise.when returns array when supplied with an array, so the correct code would be
Parse.Promise.when(promises).then(function([result1, result2]) {
and since there is no need to repack the array, it would simply be
Parse.Promise.when(promises).then(function(result) {
response.success(result);
See here for more info.
Related
I have two array as follows
var field_array=["booktitle","bookid","bookauthor"];
var data_array=["testtitle","testid","testauthor"];
I want to combine these two array and covert it to the following format
var data={
"booktitle":"testtitle",
"bookid":"testid",
"bookauthor":"testauthor"
}
I want to insert this data to database using nodejs
var lastquery= connection.query('INSERT INTO book_tbl SET ?',data, function (error, results, fields) {
if (error) {
res.redirect('/list');
}else{
res.redirect('/list');
}
});
Please help me to solve this.
var field_array = ["booktitle", "bookid", "bookauthor"];
var data_array = ["testtitle", "testid", "testauthor"];
var finalObj = {};
field_array.forEach(function (eachItem, i) {
finalObj[eachItem] = data_array[i];
});
console.log(finalObj); //finalObj contains ur data
You also can use reduce() in a similar way:
var field_array=["booktitle","bookid","bookauthor"];
var data_array=["testtitle","testid","testauthor"];
var result = field_array.reduce((acc, item, i) => {
acc[item] = data_array[i];
return acc;
}, {});
console.log(result);
Here I explaned my code line by line..Hope it will help
var field_array = ["booktitle", "bookid", "bookauthor"];
var data_array = ["testtitle", "testid", "testauthor"];
//Convert above two array into JSON Obj
var jsondata = {};
field_array.forEach(function (eachItem, i) {
jsondata[eachItem] = data_array[i];
});
//End
//Store Jsondata into an array according to Database column structure
var values = [];
for (var i = 0; i < jsondata.length; i++)
values.push([jsondata[i].booktitle, jsondata[i].bookid, jsondata[i].bookauthor]);
//END
//Bulk insert using nested array [ [a,b],[c,d] ] will be flattened to (a,b),(c,d)
connection.query('INSERT INTO book_tbl (booktitle, bookid, bookauthor) VALUES ?', [values], function(err, result) {
if (err) {
res.send('Error');
}
else {
res.send('Success');
}
//END
I am trying to make a node express app where I fetch data from different url's making a call to node-fetch to pull the body of some pages and other information about certain url endpoints. I want to then render a html table to display this data through an array of information. I am having trouble with the call to render the information as all the functions are asynchronous making it difficult to make sure all the promise calls have been resolved before making my call to render the page. I have been looking into using bluebird and other promise calls of .finally() and .all() but they don't seem to work on my data as it is not an array of promise calls, but an array of objects. Each object was 4 promise calls to fetch data relating to a column of my table all in one row. Is there a function or specific way to render the page after all promises are resolved?
var express = require('express');
var fetch = require('node-fetch');
fetch.Promise = require('bluebird');
var router = express.Router();
const client = require('../platform-support-tools');
function makeArray() {
var registry = client.getDirectory();
var data_arr = [];
for (var i = 0; i < registry.length; i++) {
var firstUp = 0;
for (var j = 0; i < registry[i]; j++) {
if (registry[i][j]['status'] == 'UP') {
firstUp = j;
break;
}
}
var object = registry[i][firstUp];
data_arr.push({
'name': object['app'],
'status': object['status'],
'swagUrl': object['homePageUrl'] + 'swagger-ui.html',
'swag': getSwag(object),
'version': getVersion(object['statusPageUrl']),
'timestamp': getTimestamp(object['statusPageUrl']),
'description': getDescription(object['healthCheckUrl'])
});
}
return data_arr;
}
function getSwag(object_in) {
var homeUrl = object_in['homePageUrl'];
if (homeUrl[homeUrl.length - 1] != '/'){
homeUrl += '/';
}
var datum = fetch(homeUrl + 'swagger-ui.html')
.then(function (res) {
return res.ok;
}).catch(function (err) {
return 'none';
});
return datum;
}
function getVersion(url_in) {
var version = fetch(url_in)
.then(function(res) {
return res.json();
}).then(function(body) {
return body['version'];
}).catch(function (error) {
return 'none';
});
return version;
}
function getTimestamp(url_in) {
var timestamp = fetch(url_in)
.then(function(res) {
return res.json();
}).then(function(body) {
return body['timestamp'];
}).then(function (res) {
return body['version'];
}).catch(function (error) {
return 'none';
});
return timestamp;
}
function getDescription(url_in) {
var des = fetch(url_in)
.then(function(res) {
return res.json();
}).then(function(body) {
return body['description'];
}).catch(function (error) {
return 'none';
});
return des;
}
/* GET home page. */
router.get('/', function (req, res, next) {
var data_arr = makeArray();
Promise.all(data_arr)
.then(function (response) {
//sorting by app name alphabetically
response.sort(function (a, b) {
return (a.name > b.name) ? 1 : ((b.name > a.name) ? -1 : 0);
});
res.render('registry', {title: 'Service Registry', arr: response})
}).catch(function (err) {
console.log('There was an error loading the page: '+err);
});
});
To wait on all those promises, you will have to put them into an array so you can use Promise.all() on them. You can do that like this:
let promises = [];
for (item of data_arr) {
promises.push(item.swag);
promises.push(item.version);
promises.push(item.timestamp);
promises.push(item.description);
}
Promise.all(promises).then(function(results) {
// all promises done here
})
If you want the values from all those promises, back into the object that's a bit more work.
let promises = [];
for (item of data_arr) {
promises.push(item.swag);
promises.push(item.version);
promises.push(item.timestamp);
promises.push(item.description);
}
Promise.all(promises).then(function(results) {
// replace promises with their resolved values
let index = 0;
for (let i = 0; i < results.length; i += 4) {
data_arr[index].swag = results[i];
data_arr[index].version = results[i + 1];
data_arr[index].timestamp = results[i + 2];
data_arr[index].description = results[i + 3];
++index;
});
return data_arr;
}).then(function(data_arr) {
// process results here in the array of objects
});
If you had to do this more often that just this once, you could remove the hard coding of property names and could iterate all the properties, collect the property names that contain promises and automatically process just those.
And, here's a more general version that takes an array of objects where some properties on the objects are promises. This implementation modifies the promise properties on the objects in place (it does not copy the array of the objects).
function promiseAllProps(arrayOfObjects) {
let datum = [];
let promises = [];
arrayOfObjects.forEach(function(obj, index) {
Object.keys(obj).forEach(function(prop) {
let val = obj[prop];
// if it smells like a promise, lets track it
if (val && val.then) {
promises.push(val);
// and keep track of where it came from
datum.push({obj: obj, prop: prop});
}
});
});
return Promise.all(promises).then(function(results) {
// now put all the results back in original arrayOfObjects in place of the promises
// so now instead of promises, the actaul values are there
results.forEach(function(val, index) {
// get the info for this index
let info = datum[index];
// use that info to know which object and which property this value belongs to
info.obj[info.prop] = val;
});
// make resolved value be our original (now modified) array of objects
return arrayOfObjects;
});
}
You would use this like this:
// data_arr is array of objects where some properties are promises
promiseAllProps(data_arr).then(function(r) {
// r is a modified data_arr where all promises in the
// array of objects were replaced with their resolved values
}).catch(function(err) {
// handle error
});
Using the Bluebird promise library, you can make use of both Promise.map() and Promise.props() and the above function would simply be this:
function promiseAllProps(arrayOfObjects) {
return Promise.map(arrayOfObjects, function(obj) {
return Promise.props(obj);
});
}
Promise.props() iterates an object to find all properties that have promises as values and uses Promise.all() to await all those promises and it returns a new object with all the original properties, but the promises replaced by the resolved values. Since we have an array of objects, we use Promise.map() to iterate and await the whole array of those.
I am using bramski/angular-indexedDB in my application. Basic CRUD operations are working fine, but the custom queries are not working as expected.
I am using the code
angular.module('myModuleName', ['indexedDB'])
.config(function ($indexedDBProvider) {
$indexedDBProvider
.connection('myIndexedDB')
.upgradeDatabase(1, function(event, db, tx){
var objStore = db.createObjectStore('people', {keyPath: 'ssn'});
objStore.createIndex('name_idx', 'age', {unique: false});
objStore.createIndex('name_idx, age_idx', ['name', 'age'] , {unique: false});
});
Basic query operations are working like follows
$indexedDB.openStore('people', function(x){
var find = x.query();
find = find.$eq('John');
find = find.$index("name_idx");
x.eachWhere(find).then(function(e){
$scope.list= e;
});
});
which results following query.
select * from people where name='John'
But, in the above scenario how we can execute custom quires like
select * from people where name='John' and age='25';
delete from people where name='John' and age='25';
The library you are using doesn't have complex queries, however you can write a pure-js solution for it, similar to this:
First you need to define your index as:
objStore.createIndex('name_age_idx', ['name', 'age'] , {unique: false});
Then you can have a search query for only those values that match the search result
searchIndexedDB = function (name, age, callback) {
var request = indexedDB.open(dbName);
request.onsuccess = function(e) {
var db = e.target.result;
var trans = db.transaction(objectStoreName, 'readonly');
var store = trans.objectStore(objectStoreName);
var index = store.index('name_age_idx');
var keyRange = IDBKeyRange.only([name, age]);
// open the index for all objects with the same name and age
var openCursorRequest = index.openCursor(keyRange);
openCursorRequest.onsuccess = function(e) {
let result = e.target.result;
// first check if value is found
if(result){
callback(result.value); // your callback will be called per object
// result.delete() - to delete your object
result.continue(); // to continue itterating - calls the next cursor request
}
};
trans.oncomplete = function(e) {
db.close();
};
openCursorRequest.onerror = function(e) {
console.log("Error Getting: ", e);
};
};
request.onerror = myStorage.indexedDB.onerror;
}
If you need a range from and too index, all you need is change the keyrange to:
var keyRange = IDBKeyRange.bound([name,fromAge], [value, toAge]);
hai I am new to tedious and Es-6,It may be a silly question but I am struggling,
I want the total data in a array, using tedious connections here is my code:
getZipData() {
var Connection = require('tedious').Connection;
Request = require('tedious').Request;
var config = {
userName: 'xx',
password: 'xxxx',
server: 'xxx', // You can use 'localhost\\instance' to connect to named instance
options: {
database: 'xxxxx',
rowCollectionOnDone:'true'
}
}
var connection = new Connection(config);
var jsonArray = [];
connection.on('connect', function (err) {
if (err) {
console.log(err)
}
var sql = "SELECT * FROM xxxxx";
return new Promise(function(resolve,reject){
var request = new Request(sql,
(err, rowCount, rows)=>{
if (err) {
reject(err);
}
else {
alert("rows");
console.log(rowCount + 'rows');
}
});
request.on('row', (columns)=>{
var rowObject = {};
columns.forEach((column)=> {
rowObject[column.metadata.colName] = column.value;
});
jsonArray.push(rowObject);
});
connection.execSql(request);
request.on('done', function(rowCount, more) {
console.log(rowCount + ' rows returned');
alert("jsonArray2:"+jsonArray);
resolve(jsonArray)
});
});
})
}
componentWillMount() {
this.getZipData().then(function(resolved){
console.log(resolved);
alert("data:"+resolved);
}).catch(function(rejected){
console.log(rejected);
})
}
when i add the request.on('done', function(rowCount, more) also i didn't get any data can any one give the solution for it,
I want the total data to be displayed
It looks like you're calling resolve before your query has been executed:
var jsonArray = [];
// Register callback for row event
request.on('row', (columns)=>{
var rowObject = {};
columns.forEach((column)=> {
rowObject[column.metadata.colName] = column.value;
});
jsonArray.push(rowObject);
});
// Call resolve before executing request
resolve(jsonArray);
connection.execSql(request);
The docs mention a done event that indicates a request has completed:
request.on('done', function (rowCount, more, rows) {
// Call resolve here instead?
resolve(jsonArray);
});
Disclaimer: I've haven't actually used Tedious, but from the docs linked this looks like what you're looking for.
I work with a line chart in ExtJS4 now. The chart is based on the data of the store. The store change its data with help 'loadRawData()' function.
Familiar situation, isn't it?
AJAX sends strings every 10 seconds and I need to built JSON from this pieces of strings. I'm trying:
success: function(response) {
var requestMassive = JSON.parse(response.responseText);
var jArray = [];
for(var i=0;i<requestMassive.length;i++){
var firstPiece = JSON.parse(response.responseText)[i].date;
var secondPiece = JSON.parse(response.responseText)[i].connectCount;
var recording = "{'machinesPlayed':"+firstPiece+", 'machinesOnline':"+secondPiece+"}";
jArray.push(recording);
}
jArray = '['+jArray+']';
store.loadRawData(jArray);
}
But it is wrong way. How to do it properly?
You could use loadData() function instead of loadRawData(). loadData() only needs an array of objects.
success: function(response) {
var requestMassive = JSON.parse(response.responseText);
var jArray = [];
for(var i=0;i<requestMassive.length;i++){
jArray.push({ machinesPlayed: requestMassive[i].date, machinesOnline: requestMassive[i].connectCount});
}
store.loadData(jArray);
}
I didnt get what you are trying to achieve.But it can be formed this way.Try this out.
var recording = {
"machinesPlayed" : firstPiece,
"machinesOnline" : secondPiece
}
jArray.push(recording);
OR
jArray.push({
"machinesPlayed" : firstPiece,
"machinesOnline" : secondPiece
});