Develop Reference

How do I search for a data in the database with Node JS, Postgres, and dust js

I'm making a webpage with Node JS with dustjs and PostgreSQL. How do I make a search query in the html, so I can pass the value to the app.get
Do I need to use JQuery?
app.get('/teachers', function(req, res){
pool.connect(function(err, client, done){
if(err) {
return console.error("error", err);
}
client.query('SELECT * FROM teachers', function(err, result){
if(err){
return console.error('error running query', err)
}
res.render('teacherindex', {teachers: result.rows});
done();
});
});
});
app.get('/teachers/:str', (req,res)=>{
pool.connect((err, client, done) => {
if (err) throw err
client.query('SELECT * FROM teachers WHERE name = $1', [req.query.namesearch], (err, result) => {
done()
if (err) {
console.log(err.stack)
} else {
res.render('teacherindex', {teachers: result.rows});
}
})
})
})
This is my JQuery
$("#myBtn").click(function(){
var str = $("#myInput").val();
var url = '/teachers/'+str;
if(confirm('Search Record?')){
$.ajax({
url: url,
type: 'put',
success: function(result){
console.log('Searching');
window.location.href='/teachers';
},
error: function(err){
console.log(err);
}
});
}
});
My HTML
<input type="text" id="myInput" data-id="namesearch">
<button type="button" id="myBtn">Show Value</button>
Thank you!

FINAL ANSWER:
Ok so it turns out the issue you were having was something completely different. You are trying to use server side rendering for this, and I was showing you how to render the retrieved data on the client side.
I have forked, and updated your repo - which can be found at the link below..
Please review my changes and let me know if you have any questions.
Working repo: https://github.com/oze4/hanstanawi.github.io
Demo Video: https://raw.githubusercontent.com/oze4/hanstanawi.github.io/master/fake_uni_demo.mp4
EDIT:
I went ahead and built a repository to try and help you grasp these concepts. You can find the repo here - I tried to keep things as simple and understandable as possible, but let me know if you have any questions.
I had to make some minor changes to the paths, which I have commented explanations on the code in the repo.
I am using a "mock" database (just a JSON object in a different file) but the logic remains the same.
The index.js is the main entry point and contains all route data.
The index.html file is what gets sent to the user, and is the main HTML file, which contains the jQuery code.
If you download/fork/test out the code in that repo, open up your browsers developer tools, go to the network tab, and check out the differences.
Using req.params
Using req.query
ORIGINAL ANSWER:
So there are a couple of things wrong with your code and why you are unable to see the value of the textbox server side.
You are sending a PUT request but your server is expecting a GET request
You are looking for the value in req.query when you should be looking for it in req.params
You are looking for the incorrect variable name in your route (on top of using query when you should be using params) req.query.namesearch needs to be req.params.str
See here for more on req.query vs req.params
More detailed examples below.
In your route you are specifying app.get - in other words, you are expecting a GET request to be sent to your server.. but your are sending a PUT request..
If you were sending your AJAX to your server by using something like /teachers?str=someName then you would use req.query.str - or if you wanted to use namesearch you would do: /teachers?namesearch=someName and then to get the value: req.query.namesearch
If you send your AJAX to your server by using the something like /teachers/someName then you should be using req.params.str
// ||
// \/ Server is expecting a GET request
app.get('/teachers/:str', (req, res) => {
// GET THE CORRECT VALUE
let namesearch = req.params.str;
pool.connect((err, client, done) => {
// ... other code here
client.query(
'SELECT * FROM teachers WHERE name = $1',
// SPECIFY THE CORRECT VALUE
namesearch,
(err, result) => {
// ... other code here
})
})
});
But in your AJAX request, you are specifying PUT.. (should be GET)
By default, AJAX will send GET requests, so you really don't have to specify any type here, but I personally like to specify GET in type, just for the sake of brevity - just more succinct in my opinion.
Again, specifying GET in type is not needed since AJAX sends GET by default, specifying GET in type is a matter of preference.
$("#myBtn").click(function () {
// ... other code here
let textboxValue = $("#myTextbox").val();
let theURL = "/teachers/" + textboxValue;
// OR if you wanted to use `req.query.str` server side
// let theURL = "/teachers?str=" + textboxValue;
if (confirm('Search Record?')) {
$.ajax({
url: theURL,
// ||
// \/ You are sending a PUT request, not a GET request
type: 'put', // EITHER CHANGE THIS TO GET OR JUST REMOVE type
// ... other code here
});
}
});
It appears you are grabbing the value correctly from the textbox, you just need to make sure your server is accepting the same type that you are sending.

How to print contents crawled by JavaScript on HTML

I crawled some contents by JavaScript, and want to print it on HTML.
JavaScript code below is named 'js.js'(worked well on CMD)
var request = require('request');
var cheerio = require('cheerio');
request('...URL...', function (err, res, body) {
if (err) console.log('Err :' + err);
var $ = cheerio.load(body);
$('.class').each(function () {
var content = $(this).find('.abc').text().trim();
document.write(content);
});
});
But "error:require is not defined" was printed, so I looking for solutions.
I found this page and follow advice which said that use webpack or browseify.
new code(2MB after bundled) give me 2 new error:"fail to fetch" and "access-control-allow-origin". What should I do?

the require() keyword does not exists in browser/client JavaScript, that is why you need to use webpack to transpile nodejs code to browser compatible javascript.
For the "access-control-allow-origin", the url you are tying to connect to does not allow response to unknown origin.
If you own the API/URL you could add a response header Access-Control-Allow-Origin: *.
For reference: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin

NodeJS Express Api -- calling res.send outside route works but res.status does not work no matter what

To keep things clean in my express route page I have a local function that is called in every route and it passes the sql query together with the req and res objects.
This works fine for sending a successful result and calling res.send works.
The problem that I'm having is I can't seem to find a way to get res.status to work and no matter the syntax it simply times-out and gives no error whatsoever in the console OR on the front end.
The tricky thing is, when it's inside the specific route it does work but the error message does not seem to get sent through instead it's just blank body?
`async function queryDatabase(queryParam, req, res) {
try {
const cp = new sql.ConnectionPool(config);
await cp.connect();
let result = await cp.request().query(queryParam);
cp.close();
res.send(result.recordset);
} catch (err) {
res.statusMessage = `Database error: ${err}`;
res.status(520);
}
}`

res.status(520) only sets the status value in the response object. It does not actually send the response. So, to send the response, you have several options. In the more recent versions of Express, you can use this shortcut:
res.sendStatus(520);
This will both set the status and send the response.
But, you can also do this in any version of Express:
res.status(520).end();
Which also sets the status and then sends the response.

You should end your response, use res.status(520).end() instead of res.status(520)

WEB SCRAPING - nightmare js and request

I am using combination of nightmare, cheerio and request in NODEjs, for making custom web scraping bot... I did authentication and filter setup with nightmare js, and now I need to call function like
request(URL, function(err, response, body){
if (err) console.error(err);
var scraping = cheerio.load(body);
.
.
.
.
But problem is that I don't know how to forward loaded "body" (by nightmare). I can't use URL because it's dynamically generated content (tables), which means that URL is always the same... I tried to use this instead of URL, but it wont work.
Any suggestions?
Thank you

You don't need to use request. In fact, you shouldn't. Nightmare itself can pass the html data to cheerio.
Once you logged in and went to your desired webpage in nightmare, use evaluate to get the html. You can do something like this:
nightmare
.viewport(1280, 800)
.goto(url)
.wait('#emailselectorId')
.type('#emailselectorId', 'theEmail\u000d')
.type('#ap_password', 'thePassword\u000d')
.click('#signInSubmit')
//do something in the chain to go to your desired page.
.evaluate(() => document.querySelector('body').outerHTML)
.then(function (html) {
cheerio.load(html);
// do something
})
.catch(function (error) {
console.error('Error:', error);
});

Neither Node.js PUT or POST routes are presenting the data that is being received

I tried this with a number of different modules and methods.
Even by proving the other modules do work as expected in Node by building a separate test project and testing each module individually.
Posting FROM Node's hosted router to a remote API (not TO Node's hosted API)
This problem is not one of SENDING data to an API. It must IMO a problem in the receiving API's not giving up the data it IS receiving for some reason.
I've proven the PUT or POST calls are sending the data by sending the call to http://httpbin/org. That site shows me I'm sending what I expect to be sending.
Here is how I'm sending. I can even see in the receiving API that that API is certainly getting called successfully.
-- sending -- ((Again. This shows my node.http attempt. But I get the same problem using requestjs, requestifyjs, needlejs))
router.get('/', function (req, res, next) {
var hst = req.headers.host.split(':');
var lookbackURL = 'https://' + req.headers.host + req.baseUrl;
lookbackURL = 'http"httpbin.org/put';
var dat = {
what: 'ever'
, try: 'again'
};
var bdy = JSON.stringify(dat);
var options = {
host: hst[0], port: hst[1], path: req.baseUrl, method: 'PUT'
, headers: { 'Content-Type': 'application/json' }
};
var r = nodeHttp.request(options); r.write(bdy); r.end();
res.sendStatus(200);
});
-- receiving --
router.put('/', function (req, res, next) {
console.log('r', req);
});
No matter what module or method I use, in all cases, the receiving req object doesn't contain the what or try data.
BUT in my test project the data is there as I expect it to be, in all cases.
Doing the same console.log(req); in the test project, reqestjs, requestjs, needlejs, node.http all show a proper body object.
But in this problem there isn't a body object in req.
And sending this put/post to http://httpbin.org I can see the body object is being sent.
Any ideas?

Issue found. And it was something no one on here could have gotten for the code I posted.
For reasons I will not go into I have to take body-parser out this application. This also means app.use() won't have a parser given to it.
And that means I have to deal with getting the data on my own. So I've added a req.on('data') listener to read the chunk from the call to the API.
router.put('/', function (req, res, next) {
var data = '';
req.on('data', function (chunk) {
data += chunk;
.....
});
.....
I also decided to do this as a PUT using Requestify.
This just goes to show how easy it is to become complacent and forget how things really work; the assumption of body-parser (or other things) always being there for instance. Or what it is really doing for you.
NEXT I have to figure out how to get a value out of the `req.on('data) back to the method PUTting to the API. Any tips? Appreciated.