I have recently been desgining a back end web server that is primarily used to manipulate data from a mysql database. The server is designed in a DOM format, with a controller folder and an app.js
I have implemented a few GET, POST PUT requests in such a format
This is what one GET request looks like
app.get("/movies/:movieID/", (req, res, next) => {
const movieID = parseInt(req.params.movieID);
// if userID is not a number, send a 400.
if (isNaN(movieID)) {
res.status(400).send();
console.log("Error has occured with getting movieID")
return;
}
movies.findByID(movieID, (error, movie) => {
if (error) {
res.status(500).send();
console.log("get Id has error")
return;
};
if (movie === null) {
res.status(404).send();
console.log("movie ID is invalid")
return;
};
//console.log(movie)
res.status(200).send(movie);
console.log("Successful movie ID")
});
});
This is inside the controller folder
,findByID: function (movieID, callback) {
var dbConn = db.getConnection();
const findMovieByIDQuery = "select * from movies left join genres on movies.genreid = genres.genreid left join reviews on reviews.movieid = movies.movieid where movies.movieid = ?;";
dbConn.connect(function (err) {
if (err) {
console.log(err);
return callback(err, null);
} else {
dbConn.query(findMovieByIDQuery, [movieID], (error, results) => {
dbConn.end();
if(error) {
return callback(error, null);
}
else if (results.length === 0) {
callback(null, null);
return;
};
console.log(results)
return callback(null, results[0]);
});
}
});
}
How ive implemented it is to take the users input, in this case a number and input it in the query based on the ? position.
However, I am now trying to create on whereby the user is able to search based on a string not just an ID number.
This is my code so far
app.get("/movies/:movieKeyword", (req, res, next) => {
console.log("Reached the app.js")
movies.findByKeyword((error, moviesAvailable) => {
if (error) {
console.log(error);
res.status(500).send();
};
res.status(200).send(moviesAvailable);
});
});
,findByKeyword: function(callback) {
console.log("Reached find by keyword")
var dbConn = db.getConnection();
const findAllMoviesQuery = "SELECT title, description, cast, time, opening_date, picture from movies WHERE title LIKE '% ? %';"
dbConn.connect(function (err){
dbConn.query(findAllMoviesQuery, (error, results) => {
if (error) {
return callback(error, null);
};
console.log(results)
return callback(null, results);
});
});
}
To use the LIKE query in mysql, I need the variable to be stored in this format: "% ? %"
However, I am not able to get this query to work as the program is not able to insert the variable into the ? this time as it is within 2 quotation marks and 2 percentage symbols
I think you can use Template Literals. Here is a resource, Template Literals. You can remove the percentage signs and replace them with this syntax ${variable_name}
Related
I'm using Facebook chat api to create a simple cli script that will reply to messages that are sent to my facebook account. I'm trying to assign and get the user name and my name to use them inside the reply but they are always undefined. I think that the object property aren't assigned correctly. Is there a fix for this?
require('dotenv').config();
const fs = require('fs');
const fb = require('facebook-chat-api');
const path = require('path');
const appStateFile = path.format({ dir: __dirname, base: 'appstate.json' });
let currentUser = null;
if( !fs.existsSync(appStateFile) ){
//debug .env
console.log(process.env);
fb({email: process.env.FB_EMAIL, password: process.env.FB_PWD}, (err, api) => {
if(err){
return console.log(err);
}
console.log(api);
api.setOptions({
listenEvents: true
});
fs.writeFileSync(appStateFile, JSON.stringify(api.getAppState()));
let id = api.getCurrentUserID();
api.getUserInfo(id, (err, profile) => {
console.log(profile); // profile is logged correctly
currentUser = profile;
});
api.listenMqtt( (err, event) => {
if(err){
return console.log(err);
}
if(event.type === 'message'){
console.log(event.body)
api.getUserInfo(event.senderID, (err, user) => {
if(err){
return console.log(err);
}
console.log(user); // user object is logged correctly
api.sendMessage('...', event.threadID)
});
}
});
});
}else{
fb({appState: JSON.parse(fs.readFileSync(appStateFile))}, (err, api) => {
if(err){
return console.log(err);
}
console.log(api);
api.setOptions({
listenEvents: true
});
let id = api.getCurrentUserID();
api.getUserInfo(id, (err, profile) => {
console.log(profile);
currentUser = profile;
});
api.listenMqtt( (err, event) => {
if(err){
return console.log(err);
}
if(event.type === 'message'){
console.log(event.body)
api.getUserInfo(event.senderID, (err, user) => {
if(err){
return console.log(err);
}
console.log(user)
api.sendMessage(`FB Pager v1.0.\nHi ${user.name}!Your message was forwarded with an email to ${currentUser.name}.`, event.threadID)
});
}
});
});
}
I think the problem here is that api.getUserInfo is asynchronous.
So you would need to nest them to get it to work.
Or you can try this, since getUSerInfo allows you to add an array of user ids to get the data for:
api.listenMqtt((err, event) => {
if (err) {
return console.log(err);
}
if (event.type === "message") {
const currentUserId = api.getCurrentUserID();
const senderId = event.senderID;
api.getUserInfo([currentUserId, senderId], (err, ret) => {
if(err) return console.error(err);
// Ret should contain the two users
// See: https://github.com/Schmavery/facebook-chat-api/blob/master/DOCS.md#getUserInfo
console.log(ret);
});
}
});
Nesting user calls method:
api.listenMqtt((err, event) => {
if (err) {
return console.log(err);
}
if (event.type === "message") {
let currentUserId = api.getCurrentUserID();
api.getUserInfo(currentUserId, (err1, signedInUser) => {
if (err1) {
return console.log(err);
}
api.getUserInfo(event.senderID, (err2, userInMessage) => {
if (err2) {
return console.log(err);
}
console.log(signedInUser, userInMessage)
api.sendMessage("...", event.threadID);
});
});
}
});
After a lot of debug I've found the correct way to access the needed informations. Since the user informations after that are retrived are mapped to another object that is the userId, the only way to access to each property is to use a for loop. Initially I was thinking that this can be avoided but unfortunately it's necessary otherwise using only dot notation will result in undefined. This is how I've solved
api.getUserInfo(userId, (err, user) => {
let username;
if(err){
return console.log(err);
}
for(var prop in user){
username = user[prop].name;
}
api.sendMessage(`Hello ${username!}`, event.threadID);
});
My backend is consist of Api and DB. When I want to get response from DB I have had delayed output by 1 query.
API (I think api is ok. Start read DB first)
app.post('/api/query', (req, res) => {
console.log(`\n Query input : ${JSON.stringify(req.body)}`);
let queryInput = (Object.values(req.body).join(' '));
if(!dbApi.checkArray(queryInput)){ //If array is not made from clear strings
res.json(dbApi.queryFromUser(queryInput));
}
else{
res.json(dbApi.queryOutput);
}
});
app.listen(dbConfig.server.port, () =>
console.log(`Server running on port ${dbConfig.server.port}`));
DB
queryOutput = [];
const receivingQuery =(queryInput) => {
db.query(queryInput, (err, result) =>{
if(err) throw err+' : '+queryInput;
queryOutput = result;
console.log("\nQuery output "+ JSON.stringify(queryOutput)); //Output (result) is ok
});
return queryOutput //Here is Output from previous query (sends to API)
}
module.exports = {
queryOutput: queryOutput,
queryFromUser: receivingQuery,
}
I tryied callback method and I rewrite it couple of times. But I dont have enough skill to solve it.
If You want to return result of query so simply do following things:
add query method to db module:
function query(sql, args = []) {
return new Promise(function(resolve, reject) {
db.query(sql, args, (err, result) => {
if (err) return reject(err);
resolve(result);
});
});
}
// extra feature, getting user by id
async function getUserById(id) {
const result = await query('SELECT * FROM users WHER id = ? LIMIT 1', [id]);
if (Array.isArray(result) && result[0]) return result[0];
return null;
}
module.exports = {
query,
getUserById, // export user by id
queryOutput,
queryFromUser: receivingQuery,
}
use it (with async and await):
app.post('/api/query', async (req, res) => {
try {
console.log('Query input:', req.body);
const queryInput = Object.values(req.body).join(' ');
const result = await dbApi.query(queryInput);
res.json(result);
}
catch (error) {
console.error(error);
res.status(500).json({message: 'Please try again soon'});
}
});
app.get('/api/users/:id', async (req, res) => {
try {
const user = await dbApi.getUserById(req.params.id);
if (!user) return res.status(404).json({message: 'User not found'});
res.status(200).json(user);
}
catch (error) {
console.error(error);
res.status(500).json({message: 'Please try again soon'});
}
});
app.listen(dbConfig.server.port, () =>
console.log('Server running on port', dbConfig.server.port));
I have created an api using nodejs, express and mongodb. I am fetching data now without sending any query. But in my frontend I have an input where the user can search for a recipe. So for example if a user types "Today" i should get response related to today only. How to check that in db and retrieve data?
module.exports = function(app, db) {
app.get("/dates/", (req, res) => {
db
.collection("dates")
.find()
.toArray((err, item) => {
if (err) {
res.send({ error: "An error has occured" });
} else {
res.send(item);
}
});
});
While making the api call , pass the dish as query parameter
For example '/recipes/?dish="Pizza" '
and in the express use the following.
module.exports = function(app, db) {
app.get("/recipes/", (req, res) => {
let queryDish = req.query.dish; // assuming /recipes/?dish="Pizza"
let query = { 'title' : { '$regex' : queryDish, '$options' : 'i' } };
db
.collection("recipes")
.find(query)
.toArray((err, item) => {
if (err) {
res.send({ error: "An error has occured" });
} else {
res.send(item);
}
});
});
I have to insert multiple different JSON objects in MongoDB and then check whether the some of the data already exist in the database and run another query based on whether the data exists or not for each JSON Object. How can I do in expressjs? I am using mongojs package for working with MongoDB. The code I typed is below:
app.post('/addcard/:id', function(req, res) {
console.log("Received Add Card Request");
var date = new Date();
var year = date.getFullYear();
var month = date.getMonth();
var day = date.getDate();
var yrval = req.body.yrval;
var monval = req.body.monval;
var dateval = req.body.dateval;
for (var i=0;i<req.body.phone.length;i++){
//console.log(i);
var card = new Card({
cardType : req.body.cardtype,
cardTitle : req.body.cardtitle,
allowMultipleStore : false,
phoneNumber : req.body.phone[i],
messageUser : req.body.message,
expiryDate : new Date(year+yrval,month+monval,day+dateval),
creditPoints : req.body.creditpoints,
punchCount : req.body.punch,
messageReachPunchLimit : req.body.limitmessage,
merchantUsersId : mongoose.Types.ObjectId(req.body.merchantuserid),
merchantId : mongoose.Types.ObjectId(req.params.id)
});
console.log(card);
db.carddata.insert(card, function (err,docInserted){
// console.log(card);
console.log(i);
if (err) throw err;
db.userdata.find({phoneNumber:req.body.phone},function (err,docs){
console.log("hiss");
if (err) throw err;
if (docs.length!=0){
var carduser = new CardUsersAssignment({
cardId : docInserted._id,
userId : docs[0]._id,
remainingCreditPoints : req.body.creditpoints,
remainingPunchCount : req.body.punch
});
db.carduser.insert(carduser,function (err){
console.log(" Card Details saved successfully_existing");
//console.log(i);
})
}//If (docs.length!=0)
else{
console.log(" Card Details saved successfully");
}
})//Finding by PhoneNumber
console.log(i+1);
})//Insert Function
console.log("hi");
} // End of For Loop
res.json({
success:true,
message:"Hello. You did it!"
});
});
This code is written as if I were writing for sequential execution. I know that NodeJS is asynchronous. I tried async.waterfall but it is giving error with the mongodb query function. Any help would be great. I am a NodeJS noob. Links to article which discuss similar scenarios would also be great.
You can achieve this using async library.
There is two way to do it.
Use async each to iterate your data and inside each check data is first check data is already exist or not, based on find result you can return or insert the doc.
It is the same as 1st, the only different is you just can to use waterfall for find and insert.
First Approach:
async.each(req.body.phone, function(data, callback) {
// Create card Info
db.carddata.insert(card, function (err,docInserted){
if (err) {throw err;}
db.userdata.find({phoneNumber:req.body.phone},function (err,docs){
if (err) {throw err;
} else if ( docs.length ){
// create carduser data
db.carduser.insert(carduser,function (err){
if (err) {throw err;}
callback();
}
} else {
console.log(" Card Details saved successfully");
callback();
}
}
}, function(err) {
// if any of the file processing produced an error, err would equal that error
if( err ) {
// One of the iterations produced an error.
// All processing will now stop.
console.log('A file failed to process');
} else {
console.log('All files have been processed successfully');
}
});
Second Approach:
async.each(req.body.phone, function(data, callback) {
//create card data
let data = {}
data.phone = req.body.phone;
data.docInserted = data.docInserted;
data.cardata = cardData;
async.waterfall([
insertCard,
updateDataFind,
cardDataInsert,
async.apply('insertCard', data)
], function (err, result) {
if(err){
if(err.success){
callback();
}
throw err;
}
callback();
});
}, function(err) {
// if any of the file processing produced an error, err would equal that error
if( err ) {
// One of the iterations produced an error.
// All processing will now stop.
console.log('A file failed to process');
} else {
console.log('All files have been processed successfully');
}
});
function insertCard(data, callback){
db.carddata.insert(card, function (err,data.docInserted){
if(err){throw err;}
callback(null, data);
}
}
function updateDataFind(data, callback){
db.userdata.find({phoneNumber:data.phone},function (err,docs){
if (err) {throw err;}
else if (docs.length!=0){ callback(null, data); }
else { callback({success:true}) }
}
}
function cardDataInsert(data, callback){
// create card user or pass from data.
db.carduser.insert(carduser,function (err){
if (err) {throw err;}
callback(null, data);
}
}
i am stacking on this problem since a week, it's a problem of synchronize on Node JS.
The process that I want to do is :
1- check the existence of table (collection). --> if not insertion of data
2- if the table was created, then i have to find all data on table and compare it with the data that i want to insert.
3- if the new data is already exist on the database (table) the program doesn't do any thing, if not the program inserts the new data to the the database (table).
So we have 3 functions should be scheduled.
function 1
var getCollection = function(collection, new_theme, nbr_indicateur,callback) {
dbObject.listCollections().toArray(function(err, collections){
if ( err ) throw err;
assert.equal(err, null);
collections.forEach(function(collect){
if(collect.name == collection)
{
callback(true);
}
else {
dbObject.collection(collection).insertOne( {
"name_theme" : new_theme,
"nbr_indicateur" : nbr_indicateur
}, function(err, result) {
assert.equal(err, null);
console.log("Inserted a document into the Table_Mapping_Theme collection.");
});
callback(false);
}
});
});
};
function 2 :
var getData = function(value, collection, theme, callback) {
var clb = true;
if(value)
{
dbObject.collection(collection).find({}).toArray(function(err, docs){
if ( err ) throw err;
assert.equal(err, null);
docs.forEach(function(doc){
if(doc.name_theme == theme)
{
console.log("ce theme existe déja");
clb = false;
}
});
});
}
callback(clb);
};
function 3 :
var insertData = function(value, collection, new_theme, nbr_indicateur, callback) {
if(value)
{
dbObject.collection(collection).insertOne( {
"name_theme" : new_theme,
"nbr_indicateur" : nbr_indicateur
}, function(err, result) {
assert.equal(err, null);
console.log("Inserted a document into the "+collection+" collection.");
});
}
callback("done");
};
calling those functions (app.post using express js)
here i tried with pyramid method but it doesn't work
app.post('/setting/add_theme', urlencodedParser, function(req, res) {
getCollection('Table_Theme', req.body.new_theme, req.body.nbr_indicateur, function(value0){ console.log("0"+value0);
getData(value0,'Table_Theme', req.body.new_theme, function(value1) { console.log("1"+value1);
insertData(value1, 'Table_Theme', req.body.new_theme, req.body.nbr_indicateur, function(value2){ console.log("2"+value2);
});
});
});
res.redirect('/setting');
});