I want to pass data from the server to the client (GET request), when I was using pug I did it with
// Server:
res.render('pageToRender', { variableToPass: value })
And on the client side I just referred to it with variableToPass. How can I do this with html and javascript though? I cannot find out...
It is possible via hack by inlining string value of javascript variable in a template
Here the example:
template.pug
<p>Forbes's Pug source code!</p>
<script>
var variableToPass = JSON.parse('#{variableToPass}')
console.log(variableToPass)
</script>
server.js
res.render('pageToRender', { variableToPass: JSON.stringify(value) })
Related
example in Express I have a route that linked to my ejs middleware.
Code 1 :
app.all("/sample", function(req,res,next){
ejs.renderFile("./sample.ejs", {req,res,next,require,module:require("module")} {}, function(e, dt){
res.send(dt.toString());
});
});
everything fine in the first code. and in sample.ejs (second code) I want to request to some text file in Internet and return to HTML (and should use HTTP module)
Code 2:
<%
var http=require("http");
var url=require("url");
var opt = url.parse("http://website.com/thisfile.txt");
/* it will return "Hello World!" btw */
var dt = ""
var hReq = http.request(opt, function(hRes){
hRes.on("data", function(chunk){
dt+=chunk.toString();
});
});
hReq.end();
%>
<h2>Here is the data is <%= dt %></h2>
and while i try to my browser. it just give me
Code 3:
<h2>Here is the data is </h2>
where I want it gave me
Code 4:
<h2>Here is the data is Hello World!</h2>
How could I get that?
I just want to use HTTP Module or Net Socket Module. and I just want to edit the Code 2. Code 1 is permanently like that.
While EJS can run full JavaScript, you generally want to leave as much as possible out of the template and put more of your logic in your main express request handler.
Since the rendering is done server side anyway, nothing will change other than making it easier to read and test.
You should consider moving the HTTP request made in your EJS template into your app.all('/sample') handler and then just inject the result into your template. In this case that would be the final string collected from the HTTP request. You'll then end up with something like this. (This is untested code).
Also, while it is not required at all, I'd suggest taking a look at something like the request, this makes HTTP requests much easier!
var request = require('request');
app.all("/sample", function(req,res,next){
// Make the HTTP request
request('http://www.website.com/file.txt', function(err, response, body) {
// Render the ejs template
ejs.renderFile("./sample.ejs", {file: body}, function(e, dt) {
// Send the compiled HTML as the response
res.send(dt.toString());
});
});
});
I am using the setInterval() function to update a few variables(prices from various API's) every 'x' seconds in NodeJS
I want to display these variables in HTML and have them update real time every 'x' seconds.
How do I go about this using Socket.io or without using it
If you don't want to use socket.io, you can use AJAX calls but I think it's the more painful way...
If you use socket.io, there are great examples on their GitHub : Chat example.
In your NodeJS :
var io = require('socket.io')(8080); // The port should be different of your HTTP server.
io.on('connection', function (socket) { // Notify for a new connection and pass the socket as parameter.
console.log('new connection');
var incremental = 0;
setInterval(function () {
console.log('emit new value', incremental);
socket.emit('update-value', incremental); // Emit on the opened socket.
incremental++;
}, 1000);
});
This code should be start in your application.
And in your view :
<html>
<body>
<pre id="incremental"></pre>
<script src="https://code.jquery.com/jquery-1.10.2.min.js"></script>
<script>
var socket = io('http://localhost:8080'); // Connect the socket on the port defined before.
socket.on('update-value', function (value) { // When a 'update-value' event is received, execute the following code.
console.log('received new value', value);
$('#incremental').html(value);
});
</script>
</body>
</html>
My code isn't complete but shows the essential to know.
Try Templating and template engines.
Template engine are stuff that enable you to pass variables to Templates. These engines render the template file, with data you provide in form of HTML page.
I will suggest you to try 'ejs', as it very closely signify HTML files. ejs template are simply HTML syntax with placefolder for you to pass Data.
But that will require you to refresh the page continously after regular time. So you can try 'AJAX' which let you refresh part of page, simultaneously sends and receives data from server
Is it possible to fetch data from MongoDB and render a html template on the server side itself for a node-js project?
As of now in my serverside js file I've done the following.
//Failing array will be populated by a db.find later on.
var failing = [
{ name: "Pop" },
{ name: "BOB" }
];
/*Now i have to send a mail from the server for which I'm using nodemailer.
Where do i store the template ? This is what I've done in the same file */
var template = "<body>{#failing} <p>{.name}</p> {/failing}</body>"
// Add this as the body of the mail and send it.
I'm not sure how to render the data and how to get it displayed. I'm aware storing the template in the variable isn't right but I'm not sure what else to do.
If your template is that short, you can store it in a variable without problem. Obviously, you can store it in a file also.
Let's say you decide to store it in a file index.dust:
<body>{#failing} <p>{.name}</p> {/failing}</body>
Now, in your node controller you need to load the file and generate the html content from it:
const fs = require('fs');
const dust = require('dustjs-linkedin');
// Read the template
var src = fs.readFileSync('<rest_of_path>/index.dust', 'utf8');
// Compile and load it. Note that we give it the index name.
var compiled = dust.compile(src, 'index');
dust.loadSource(compiled);
// Render the template with the context. Take into account that this is
// an async function
dust.render('index', { failing: failing }, function(err, html) {
// In html you have the generated html.
console.log(html);
});
Check the documentation in order not to have to compile the template every time you have to use it.
What I usually do is:
res.render('myJadeTemplate');
but I want to add another transformation to the html before attaching it to the response.
How can I get the rendered HTML then modify it and send it over via res.send()
If you are using Express3. There is an additional (and optional) parameter to res.render() that is a callback that will give you the rendered HTML rather than sending it directly to the client.
res.render('myJadeTemplate', function (err, html) {
// html => rendered HTML from jade template
});
Ok I found a solution:
var jade = require('jade');
var fs = require('fs');
var jadetemplate = jade.compile(fs.readFileSync('code.jade', 'utf8'));
var html = jadetemplate({
params:"{Some parames}"
});
console.log(html);
Thanks for this thread
Node says Jade has no method "renderFile", why?
I'm running a test app in Express.js using EJS as the templating engine. I'd like to access functions stored in a .js file to run server side and not client side. For instance if I have:
<%= console.log("I'm in the server console"); %>
the server catches the console output, and if I have:
<script type="text/javascript"> console.log("I'm in the client-side console"); </script>
Now if I have a function to output the same for the client side I can include it this way:
<script type="text/javascript" src="/javascripts/clientSideCode.js"> clientSideOutput(); </script>
But how do I include a file and its functions that way so EJS can execute server side code? It appears that the public folder in express is just for client side code.
You can create helper functions that your templates can access via app.locals:
http://expressjs.com/api.html#app.locals
You can use node.js and Socket.IO to emit real time events between client and server. For instance the client would do something like:
<script>window onload = function() {
socket.emit('request_customer_list', { state: "tx" });
socket.on('receive_customer_list', function(data) {
$.each(data.customer_list, function(key, value) {
socket.set(key, value); // store the customer data and then print it later
});
});}
On your server you can have a routine to load the customer list and send it back in similar format:
socket.on('connection')
socket.on('request_customer_list', function(data){
state = data.state;
var customer_list;
// pretend i loaded a list of customers from whatever source right here
socket.emit('receive_customer_list', {customer_list: customer_list});
)} )};