Im new in backend development (using NodeJs Express).
Its very basic question (I didn't find any good tutorial about it)
Question is:
I have this line of code:
app.get('/test', function (req ,res){
res.send('test');
});
What I wanna do is: BackEnd only sends res to FrontEnd, if FrontEnd send some JSON first.
Like Backend will show Something to FrontEnd, only if FrontEnd send JSON first;
How to handle it? What code to write?
Or what to type in google search to find this kind of tutorial
You are building a REST API with node. In REST we don't keep states. When we receive a request we process and respond. In the Front end, you can do wait until the response is received. use promises, async-await or callbacks to wait until the response in the Front end. Use these methods to connect with back end from front-end axios, fetch. To process the incoming JSON body use body-parser. Based on the request body you can process and send the response. PS: Every request should be given a response. That's how REST behaves.
In Query
yourbackend.com/test?message=welcomeToStackOverflow
This is how you can access with in query:
const {message} = req.query;
console.log(message);
// welcomeToStackOverflow
In Params
yourbackend.com/test/:message
This is how you can access with in params :
const {message} = req.params;
console.log(message);
// welcomeToStackOverflow
Here you have working example : https://codesandbox.io/s/trusting-rosalind-37brf?file=/routes/test.js
Related
Currently building a RESTful API with express on my web server, and some routes like the delete route for a document with mongoose ex. await Note.findByIdAndRemove(request.params.id) response.status(204).end() send response statuses with end()
Why do I need to add the .end()? What in these cases, and why cant one just send response.status(204)
With some responses that return json, the response.status(201).json works fine
Only certain methods with Express or the http interface will send the response. Some methods such as .status() or .append() or .cookie() only set state on the outgoing response that will be used when the response is actually sent - they don't actually send the response itself. So, when using those methods, you have to follow them with some method that actually sends the response such as .end().
In your specific example of:
response.status(204)
You can use the Express version that actually sends the response:
response.sendStatus(204)
If you choose to use .status() instead, then from the Express documentation, you have to follow it with some other method that causes the response to be sent. Here are examples from the Express documentation for .status():
res.status(403).end()
res.status(400).send('Bad Request')
res.status(404).sendFile('/absolute/path/to/404.png')
Since all three of these other methods will cause the response to be sent and when the response goes out, it will pick up the previously set status.
I've set up a react form running on http://localhost:3000/about and I've the backend running on port 5000 (localhost:5000). On react's package.json I set up "proxy":"localhost:5000:.
When I use postman and I send the post to localhost:5000/api/contact, the email is sent correctly (I send the data as JSON - name, email and message). Status 200
When I use the react form, the data is well prepared as json but I can't figure out the baseURL to send correctly the method post. status 404. I tried:
localhost:3000/about/api/contact;
localhost:3000/api/contact;
localhost:3000/api.... None works...
FYI
the server is set up with the following middleware and is working ok:
app.use('/api',contactRoute)
the controller is imported and coded as following:
router.post('/contact', (req, res)=>{
const data = req.body;
The React part is not posting correctly with axios and is coded as following:
onSubmit: async (values) => {
//values.preventDefault();
try {
const data = (JSON.stringify(values, null, 2))
setLoader(true);
console.log(data)
await axios.post('/contact', data);
The method post in react is never completed, when I check the console.log of data, is correctly structured as JSON...status 404
use the post parameter in your axois request {port: 5000} then It will use your actual backend port.
By default, axios uses the base path from the URL. So, here when an API request is made.
await axios.post('/contact', data);
It is actually making the post request on localhost:3000 rather than your backend server at localhost:5000. Also, "api" should also be prepended.
One simple way is to use absolute URL which should work.
await axios.post('http://localhost:5000/api/contact', data);
We use axios for http requests such as get, post, etc.
We use express for the same purpose also.
However according to what I read, they are for different purposes.
Please explain how.
PS: If you explain it by giving an example, it would be great!
You can think of express.js as a warehouse:
app.get('/item/:name', async function (req, res) {
res.send(await findItemByName(req.params.name));
});
If you want to get an item, for example a pencil, from this warehouse, you can use axios.js.
axios.get('/item/pencil')
Axios is used to send a web request whereas express is used to listen and serve these web requests.
In simple words, express is used to respond to the web requests sent by axios.
If you know about the fetch() method in javascript, axios is just an alternative to fetch().
I would say that express is used to create HTTP servers. So the server runs somewhere and responds to a request.
Axios is an HTTP client. It creates requests!
In very simple words axios is just passing the web request to the server-side (express). They basically work together (axios -> express -> DB)
I made a form post request from my react front end. In my express route I handle it, and I send the data to the browser, as such:
app.post("/api/fetchuser", async (req, res) => {
// Doing some stuff here
res.send(req.body.user);
});
My question is: How can I get the data from this POST request route back to my client side? Previously, I did axios.get(...) to retrieve data on a app.get(...) route in a similar fashion, however, this is a POST route. How can I solve this issue?
Just do axios.post request. See Performing a POST request section of axios documentation.
Edit: Yes you can also retrieve data by POST request. You don't have to post any data to the server while performing the request.
axios.post('/api/fetchuser/',{})
.then(res => console.log(res.data));
I'm using Context.io's Node.js client library to get the body of emails from my account which is done in my code below.
Once I have that data, I am confused as to how I would get them over to the front-end. I'm new to the whole MEAN stack, and from my research of the basics, I have gathered that with Node, you can make the http calls, parse the json response and then write it to the server, but it seems as if I would have to make an API to then be able to call it from Angular and display it how I wish. I know that with other back-end languages like PHP, you can just write the code within the html, and not need a middle structure to get the info from PHP to the front-end. Is there an easier way than writing my own API in Node after having already made an API request to Context.io?
ctxioClient.accounts(ID).messages().get({limit:10}, function ( err, response) {
if(err) throw err;
console.log("getting responses...");
var messages = response.body;
console.log("message id is " );
console.log(messages.body);
You should implement the backend in JSON using something like res.json and make AJAX requests via Angular $http or something similar.