Node.js - Extracting part of the URL - javascript

In my node.js server i havce a URL variable.
It is either in the form of "https://www.URL.com/USEFUL_PART/blabla", or "URL.com/USEFUL_PART/blabla".
From this, i want to extract only the 'USEFUL_PART' information.
How do i do that with Javascript?
I know there are two ways to do this, one with vanilla js and one with regular expressions.
I searched the web but i only found SO solutions to specific questions. Unfortunately, i coulnd't find a generic tutorial i could replicate or work out my solution.

Since you're using Express, you can specify the part of the URL you want as parameters, like so:
app.get('/:id/blabla', (req, res, next) => {
console.log(req.params); // Will be { id: 'some ID from the URL']
});
See also: https://expressjs.com/en/api.html#req.params

In Node.js you can use "URL"
https://nodejs.org/docs/latest/api/url.html
const myURL = new URL('https://example.org/abc/xyz?123');
console.log(myURL.pathname);
// Prints /abc/xyz

One way is to check whether the url starts with http or https, if not then manually add http, parse the url using the URL api, take the patname from parsed url, and get the desired part
let urlExtractor = (url) =>{
if(!/^https?:\/\//i.test(url)){
url = "http://" + url
}
let parsed = new URL(url)
return parsed.pathname.split('/')[1]
}
console.log(urlExtractor("https://www.URL.com/USEFUL_PART/blabla"))
console.log(urlExtractor("URL.com/USEFUL_PART/blabla"))

Hey if you are using express then you can do something like this
app.get('/users/:id/blabla',function(req, res, next){
console.log(req.params.id);
}
Another way is to use javascript replace and split function
str = str.replace("https://www.URL.com/", "");
str = str.split('/')[0];

Related

Extract From Cursor-Based Pagination URL from HTTP Request Response Headers - Google Apps Script

I am using Google Apps Script to make a series of HTTP Requests. The endpoint I have been using just switched to cursor-based pagination.
The response looks like this.
{...
Link=
<https://x.shopify.com/admin/api/2019-10/inventory_levels.json?limit=250&page_info=abc>;rel="previous",
<https://x.shopify.com/admin/api/2019-10/inventory_levels.json?limit=250&page_info=def>;rel="next"
}
I can use response['Link'] to get it down to
<https://x.shopify.com/admin/api/2019-10/inventory_levels.json?limit=250&page_info=abc>;rel="previous",
<https://x.shopify.com/admin/api/2019-10/inventory_levels.json?limit=250&page_info=def>;rel="next"
Is there a way to extract page_info reliably from the "next" URL without regular expression? I am fine resorting to regular expression but I wondered if there was specific method for getting it.
Thanks in advance for your help. I dabble and get that I still have a ton to learn.
You can use a regex to extract the URL and whether the link is the next or previous page.
/<(.*)>; rel=\"(.*)\"/
To use this against your code you you could do something like this:
const urls = headers.links.map(link => {
const linkContents = link.match(/<(.*)>; rel=\"(.*)\"/)
const url = linkContents[1]
const type = linkContents[2] // next or previous
return { url, type }
})

It is possible to use a wildcard for the URL when mocking axios?

I would like to know if it is possible to mock certain URLs using wildcards, e.g. all URLs that start with /auth. Can I do something like /auth*?
Yes, per the docs you can use a regex as the URL. One of their examples is similar to your use case:
Using variables in regex
const usersUri = '/users';
const url = new RegExp(`${usersUri}/*`);
mock.onGet(url).reply(200, users);

Express Javascript Regex to only allow strings without periods

I have an express route that handles localhost:3000/test. I want everything after this that doesn't have a period to render with the same router.get command. I'm struggling to figure out the correct Javascript regex string.
router.get('/test/:path[\s^.]*$', function () {
//res.render etc
}
So, when I visit localhost:3000/test/math or localhost:3000/test/math/geometry I want it to use the same route. But when I navigate to localhost:3000/test/math/geometry.test I want it to use a different route. I have used regex before just not sure how to combine it with the express params functionality.
EDIT: adeneo's idea will not work since I cannot chain my functions correctly using a check for a period. This is the point of regex, so that I check the url before I do the page logic.
Raul I'm afraid you have misunderstood the question. Let me try to state it more clearly.
I have a list of folders like this:
test
--folder1
----test1.js
----test2.js
----test3.js
--folder2
----folder2-1
----folder2-3
------test4.js
------test5.js
----test6.js
--folder3
The following urls should have one regex expression that captures them:
test/folder1
test/folder2
test/folder2/folder2-3
and another that only catches the following:
test/folder1/test1.js
test/folder2/folder2-3/test4.js
test/folder2/test6.js
Like I said, I have done regex, I just cannot figure out how to use the :paramName functionality of Express with it.
The order does matter in this case.
If you put first the exceptions yo will handled the path.
app.get('/test/math/geometry.test', function (req, res) {
res.send('catch it');
});
app.get('/test/:path*', function (req, res) {
res.send('the params are ' + JSON.stringify(req.params));
});
If you try this routes with for example ´/test/maths/dificults´ you can see in the end that req.params have something like:
{"0":"/maths/dificults","path":"maths"}
You can access to the raw param by position, in this case '0' because by name you have the params cut in the first '/'
EDIT
You can apply the same concept and use the real regular expression inside:
app.get(/\/test\/[^\.]*$/, function (req, res) {
res.send('catch it without dot');
});
app.get('/test/*', function (req, res) {
res.send('catch it with dot');
});
And you can use parentesis () to capture params in
req.params like //test/([^.]*)$/

Express - Send a page AND custom data to the browser in a single request?

How simultaneously to render a page and transmit my custom data to browser. As i understood it needs to send two layers: first with template and second with JSON data. I want to handle this data by backbone.
As i understood from tutorials express and bb app interact as follows:
res.render send a page to browser
when document.ready trigger jQuery.get to app.get('/post')
app.get('/post', post.allPosts) send data to page
This is three steps and how to do it by one?
var visitCard = {
name: 'John Smit',
phone: '+78503569987'
};
exports.index = function(req, res, next){
res.render('index');
res.send({data: visitCard});
};
And how i should catch this variable on the page- document.card?
I created my own little middleware function that adds a helper method called renderWithData to the res object.
app.use(function (req, res, next) {
res.renderWithData = function (view, model, data) {
res.render(view, model, function (err, viewString) {
data.view = viewString;
res.json(data);
});
};
next();
});
It takes in the view name, the model for the view, and the custom data you want to send to the browser. It calls res.render but passes in a callback function. This instructs express to pass the compiled view markup to the callback as a string instead of immediately piping it into the response. Once I have the view string I add it onto the data object as data.view. Then I use res.json to send the data object to the browser complete with the compiled view :)
Edit:
One caveat with the above is that the request needs to be made with javascript so it can't be a full page request. You need an initial request to pull down the main page which contains the javascript that will make the ajax request.
This is great for situations where you're trying to change the browser URL and title when the user navigates to a new page via AJAX. You can send the new page's partial view back to the browser along with some data for the page title. Then your client-side script can put the partial view where it belongs on the page, update the page title bar, and update the URL if needed as well.
If you are wanting to send a fully complete HTML document to the browser along with some initial JavaScript data then you need to compile that JavaScript code into the view itself. It's definitely possible to do that but I've never found a way that doesn't involve some string magic.
For example:
// controller.js
var someData = { message: 'hi' };
res.render('someView', { data: JSON.stringify(someData) });
// someView.jade
script.
var someData = !{data};
Note: !{data} is used instead of #{data} because jade escapes HTML by default which would turn all the quotation marks into " placeholders.
It looks REALLY strange at first but it works. Basically you're taking a JS object on the server, turning it into a string, rendering that string into the compiled view and then sending it to the browser. When the document finally reaches the browser it should look like this:
// someSite.com/someView
<script type="text/javascript">
var someData = { "message": "hi" };
</script>
Hopefully that makes sense. If I was to re-create my original helper method to ease the pain of this second scenario then it would look something like this:
app.use(function (req, res, next) {
res.renderWithData = function (view, model, data) {
model.data = JSON.stringify(data);
res.render(view, model);
};
next();
});
All this one does is take your custom data object, stringifies it for you, adds it to the model for the view, then renders the view as normal. Now you can call res.renderWithData('someView', {}, { message: 'hi' });; you just have to make sure somewhere in your view you grab that data string and render it into a variable assignment statement.
html
head
title Some Page
script.
var data = !{data};
Not gonna lie, this whole thing feels kind of gross but if it saves you an extra trip to the server and that's what you're after then that's how you'll need to do it. Maybe someone can think of something a little more clever but I just don't see how else you'll get data to already be present in a full HTML document that is being rendered for the first time.
Edit2:
Here is a working example: https://c9.io/chevex/test
You need to have a (free) Cloud9 account in order to run the project. Sign in, open app.js, and click the green run button at the top.
My approach is to send a cookie with the information, and then use it from the client.
server.js
const visitCard = {
name: 'John Smit',
phone: '+78503569987'
};
router.get('/route', (req, res) => {
res.cookie('data', JSON.stringify(pollsObj));
res.render('index');
});
client.js
const getCookie = (name) => {
const value = "; " + document.cookie;
const parts = value.split("; " + name + "=");
if (parts.length === 2) return parts.pop().split(";").shift();
};
const deleteCookie = (name) => {
document.cookie = name + '=; max-age=0;';
};
const parseObjectFromCookie = (cookie) => {
const decodedCookie = decodeURIComponent(cookie);
return JSON.parse(decodedCookie);
};
window.onload = () => {
let dataCookie = getCookie('data');
deleteCookie('data');
if (dataCookie) {
const data = parseObjectFromCookie(dataCookie);
// work with data. `data` is equal to `visitCard` from the server
} else {
// handle data not found
}
Walkthrough
From the server, you send the cookie before rendering the page, so the cookie is available when the page is loaded.
Then, from the client, you get the cookie with the solution I found here and delete it. The content of the cookie is stored in our constant. If the cookie exists, you parse it as an object and use it. Note that inside the parseObjectFromCookie you first have to decode the content, and then parse the JSON to an object.
Notes:
If you're getting the data asynchronously, be careful to send the cookie before rendering. Otherwise, you will get an error because the res.render() ends the response. If the data fetching takes too long, you may use another solution that doesn't hold the rendering that long. An alternative could be to open a socket from the client and send the information that you were holding in the server. See here for that approach.
Probably data is not the best name for a cookie, as you could overwrite something. Use something more meaningful to your purpose.
I didn't find this solution anywhere else. I don't know if using cookies is not recommended for some reason I'm not aware of. I just thought it could work and checked it did, but I haven't used this in production.
Use res.send instead of res.render. It accepts raw data in any form: a string, an array, a plain old object, etc. If it's an object or array of objects, it will serialize it to JSON for you.
var visitCard = {
name: 'John Smit',
phone: '+78503569987'
};
exports.index = function(req, res, next){
res.send(visitCard};
};
Check out Steamer, a tiny module made for this this exact purpose.
https://github.com/rotundasoftware/steamer
Most elegant and simple way of doing this is by using rendering engine (at least for that page of concern). For example use ejs engine
node install ejs -s
On server.js:
let ejs = require('ejs');
app.set('view engine', 'ejs');
then rename desired index.html page into index.ejs and move it to the /views directory. After that you may make API endpoit for that page (by using mysql module):
app.get('/index/:id', function(req, res) {
db.query("SELECT * FROM products WHERE id = ?", [req.params.id], (error, results) => {
if (error) throw error;
res.render('index', { title: results[0] });
});
});
On the front-end you will need to make a GET request, for example with Axios or directly by clicking a link in template index.ejs page that is sending request:
<a v-bind:href="'/index/' + co.id">Click</a>
where co.id is Vue data parameter value 'co' that you want to send along with request

How to get Nice-Looking URLS - Node.JS

I have been looking around the web for a way to get the URL that is like:
example.com/games/game1 instead of example.com/games?id=game1
I have looked around the Node.JS website but I couldn't find anything that seemed to apply to my situation.
Any help is very appreciated. I have found an answer that did this using a .HTACCESS file, but I couldn't find a node.js alternative. The question/answer that I found was, creating nice looking URLs
Any help is very appreciated.
This URL example.com/games?id=game1 is passing the id as a GET parameter. To replace it with example.com/games/game1, you just have to come with a strategy on how to pass this id. This strategy is usually referred to node.js as routes, and, they are plenty of options on how to achieve your goal:
If you are using Express framework, you have built in ability to do stuff like this (based off TJ Holowaychuk's route separation examples):
app.get('/games/:id', games.view);
Then, in your game.js file:
exports.view = function(req, res){
console.log(req.params.id); //gives you game1
//...
};
- Another way to do it is to use something specific for routing (instead of a whole framework). Director comes to mind.
var viewGame = function(gameId) { console.log(gameId); };
var routes = {
'/games/:gameId': viewGame
};
You can list to all requests, then parse request.url to decide which page to render or whether to return a 404 / 302 or whatever you want to do. This is just a small example. You probably want to separate your routing from your logic:
var http = require("http");
http.createServer(function(request, response) {
var parts = request.url.split('/');
if(parts[0] === 'games'){
var id = parts[1];
// Check if valid id
// And render the correct page
}
}).listen(80);

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