I am trying to fetch food by its key. In postman api is working fine but is the forntend it has no response.
backend code
app.get('/foods/:key', (req, res) => {
foodsCollection.find({ key: req.params.key }).toArray((err, documents) => {
res.send(documents[0])
})
})
frontend code
const { key } = useParams()
const [foodById, setFoodById] = useState({})
useEffect(() => {
fetch(`http://localhost:5000/foods/${key}`)
.then((res) => res.json())
.then((data) => {
setFoodById(data)
})
}, [key])
Although you've added some images above, the most important is missing, namely, what are the Browser's Developer Tools stating the problem is. You should see some message in the Console tab, as well as in the Network tab for that particular request, if it is indeed being made. Until anyone sees this, it will be very difficult to help in fixing your problem.
If your not already, I suggest scaffolding any react app with create-react-app (CRA). This will give you a working app to start from. You can ignore CORS related issues in development, if using CRA, by adding "proxy": "http://localhost:5000", to your package.json file, see here for more on this method, but remember, this is only works for local development. You can also start Chrome to ignore Web Security by running it with the --disable-web-security flag e.g. chromium --disable-web-security, but that isn't a great idea really, more a way to quickly determine if you are having CORS problems, as Chrome masks some problems as CORS related, when in fact they aren't.
I'd also suggest changing your fetch code to use await, so instead you'd have:
const response = await fetch(`http://localhost:5000/foods/${key}`);
if (!response.ok) {
console.error(`Error message: ${response.statusText} ${response.status}`);
}
const result = response.json();
console.log(result);
This isn't necessary, but I've always found it way easier to read than the then/catch/finally method.
Reason for error
You need to stringify an object before sending it to the client with the JSON.stringify() method. When we exchange data to/from a web server, it must be a string.
Solution:
Proper way to send response to the client would to wrap the entire API in a try-catch block and explicitly specify the HTTP Status Code along with the stringified data in every response.
Note: Although 500 status code is used for error handling, you should choose one as per the use case.
app.get('/foods/:key', (req, res) => {
try {
/*
rest of the code
*/
foodsCollection.find({ key: req.params.key }).toArray((err, documents) => {
if (err) {
// 500 stands for internal server error
return res.status(500).send(JSON.stringify('Here goes a meaningful error message!'));
}
// 200 stands for success
res.status(200).send(JSON.stringify(documents[0]));
});
/*
rest of the code
*/
} catch (error) {
// 500 stands for internal server error
res.status(500).send(JSON.stringify('Here goes another meaningful error message!'));
}
})
The problem is that you haven't set the CORS headers of response in your backend code. and you are using different ports in your backend and frontend (5000 & 3000) so the Same Origin Policy disallows reading the remote resource, indicating that the request was blocked due to violating the CORS security rules.
you've to set the CORS headers.
you can install the CORS npm package and follow it's instructions to resolve the issue like this:
var express = require('express')
var cors = require('cors')
var app = express()
app.use(cors())
.
.
.
And one other issue that I'm seeing is that you've put the react-router default route before your specified path. so move the <route path="*"> after <route path="/foods/:key">
Related
I'm working on a react-native app with spotify integration. I've set up the oAuth flow w/ auth code grant where I can get the authorization code. I've then set up cloud function on firebase to proxy the actual token exchange (I don't want to reveal my secret to the client!). I've added logs and can see that the function is correctly completing the exchange with the spotify token endpoint, and receiving a refresh and access token.
const tokenRequeset = functions.https.onCall(async (data, context) => {
// spotify network request, error handling, etc here ....
// I want to emphasize that this network request completes
// properly - my log statement below verifies in server logs
// that I'm getting the expected value.
const resp = await axios.post(
"https://accounts.spotify.com/api/token",
QueryString.stringify({
grant_type: "authorization_code",
code: code,
redirect_uri: redirectURI,
}),
{
headers: {
"Authorization": `Basic ${BEARER_TOKEN}`,
"Content-Type": "application/x-www-form-urlencoded",
},
}
);
console.log(resp.data.access_token);
return { status: "success", token: resp.data.access_token };
});
export default tokenRequest
resp.data.access_token is the JWT access token used to hit the spotify API - it's a string value according to the API. (I'd provide an example one, but it is an auth token)
However, when I try to use the firebase/functions package to call my function from my app, I will sometimes get a 'FirebaseError: Response is not valid JSON object.'
What makes this extra fun is that it's inconsistent - yesterday I had the issue, and then it went away (without changing my code!). I was able to hit both the local emulator function and then the deployed function no problem, but today the 'FirebaseError: Response is not valid JSON object.' error is back.
I have checked the logs for the failed invocations both locally and on the deployed function, and in both cases the spotify API call is working - I'm getting all the expected behavior right up until the return (which isn't working for some reason).
On the client side, I'm configuring firebase like so:
const firebaseConfig = {
// Shhhhhh
};
// Initialize Firebase
const app = initializeApp(firebaseConfig);
const functions = getFunctions(app);
// Uncomment to run locally
connectFunctionsEmulator(functions, "localhost", 5001);
export { app, functions };
And then exposing and calling it like so:
const SpotifyAuth = httpsCallable(functions, "spotify-auth");
const resp = await SpotifyAuth(code, redirectURI)
(I know this isn't full code - I grabbed the relevant portions. Happy to provide more if needed).
I tried looking up this error, and I found results from ~2018/2020 with the old style of firebase/functions, but they seem to be related to region and I'm deployed in the default us-central1 - according to the SDK documentation that means I shouldn't touch it.
The existing solutions to the problem also seem to be based on the old style of function calls, rather than the more recent httpsCallable() and getFunctions(app).
I'm going insane trying to figure out why sometimes I'm getting this error
EDIT:
More information on the error - I ran my code again today and didn't see the error locally, but I DID see it when I hit the deployed function.
Again, I want to emphasize that I think the error is in the firebase network response - if you look at the network request I receive a 200 but the response is empty.
Did an additional full mockup of a function to see what would happen:
const test = functions.https.onCall((data, context) => {
console.log("function call");
return { status: "success", token: "asdfasdfasdfasdfasfs" };
});
export default test;
I'm getting the same error.
UPDATE:
I've given up on using the sdk and onCall method for firebase cloud functions - all of my testing thus far indicates that this is a bug or error on the google cloud function side, and there's nothing I can do from my side.
The good news is the onRequest approach seems to not have this issue - it's behaving properly and reliably.
I really hope that I've messed up along the way and there's a solution I've missed - the SDK seems fantastic and I like the integration it (is supposed to) offer, but as far as I'm aware right now unless there's a bug fix (or update to the documentation if I'm doing something wrong) it seems like it simply won't work.
I'm still planning on using firebase, but from my experience thus far I'd advise anyone early in their server work to consider using another offering (at least if you need to use the functions - I was able to get storage working).
I'm having some trouble with the fetch and node.js.
In my frontend when i click a button, i would like to send a post request in order to receive an array from my backend as answer. I'n my backend i'm using node.js with express, in my frontend i'm using the fetch function.
The error that occours is the following:
Access to fetch at 'http://localhost:8080/api' from origin 'real localhost address' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
Code Here
const getArray = async() => {
const data = await fetch ("http://localhost:8080/api");
const dataJson = await data.json();
console.log(dataJson)
}
getArray();
In my server i've got
app.post("/api", (req,res) => {
res.sendFile(JSON.stringify(arr));
});
You need to add request options. Please refer to the MDN docs for further information.
As #Kudah said, you should read the docs.
Fetch (and XMLHttpRequest) follow the same-origin policy. This means that browsers restrict cross-origin HTTP requests from within scripts. A cross-origin request occurs when one domain (for example http://example2.com/) requests a resource from a separate domain (for example http://example1.com/).
The easiest way to solve this, (If you don't want to dig too much into this)
const whiteList = [ "https://myRealBackendUrl-1", "https://myRealBackendUrl-2" ];
// you can also pass a string here instead here instead of array
const corsOptions = {
credentials: true,
origin: process.env.NODE_ENV !== production ? "http://localhost:4000" : whiteList
// if you are in a dev environment, you probably want something like localhost
// http://localhost:4000 is just a demo backend. replace it with your own.
// if you are in a production environment, for example heroku then your backend
// url will be something like http://example.herokuapp.com
// in that case `const whiteList = [ "http://example.herokuapp.com" ];`
};
app.use(cors(corsOptions));
The above code should be enough for the normal use case.
There is also callback function, it is if you want to run some function of your own. Don't read it if you dont plan to use any dynamic checking
var corsOptionsDelegate = async (req, callback) => {
var corsOptions = { origin: false };
try {
// you can do some dynamic check here
// For example: check database for some conditions then allow access
if( myDatabaseSays == true ) corsOptions.origin = true;
else corsOptions.origin = false;
} catch (err) {
console.log(err);
// corsOptions.origin = false;
}
callback(null, corsOptions) // chain it
}
Anyway read the docs properly for more info
[1]: https://expressjs.com/en/resources/middleware/cors.html
So let me first explain what I'm trying to achieve even though it's probably not the right way to go about this.
I make discord bots and my goal is to have the bot check with the website before starting/running commands. I (for obvious reasons) don't want to put the true/false in the code in the event I need to stop a bot from starting remotely.
I set something up on my Express app so that when the specific section of the response matches the client ID in the array, then grab the piece from the response where it says true or false. Act on it if it doesn't and do nothing if the object is equal to true. I have this part down, however the part that I don't know how to do is access this "object" from the bot.
Does anybody know how to do this?
app.get('/botAuthentication/getToken', (req, res) => {
if(['7838193829389238'].includes(req.query.authorization)) {
res.status(200)
res.send({
botAuth: true
})
} else {
return res
.status(401)
.send( { code: 401, message: "You can't view this page."})
}
});
This code returns the shown object when opened in the browser.
TLDR; How do I grab that object from the website using some sort of library or method?
I know this might not be the proper way to do this; I am new to web development.
Thank you in advance!
In your bot I suggest you use axios as it is a very easy to use fetch library, but you can use node-fetch, request or pick from many others....
const axios = require('axios')
// Somewhere in your bot...
axios.get('https://my-bot-command-and-control.example.com/botAuthentication/getToken', {
params: : {
authorization: '7838193829389238'
}
}).then((response) => {
if (response.botAuth) {
// do bot stuff
}
})
A couple of points... As a security perspective, it is imperative that you keep the secret authorization code a secret. That means no putting it in git and outside of your development environment, you must deploy the express server behind SSL termnination so the connection between your bot and the API is encrypted. Otherwise you will be transmitting the authorization code in plaintext.
I'm using Firebase-Firestore on Javascript (web) with a Progressive web app. I ran into this error:
INTERNAL ASSERTION FAILED: Got result for empty write pipeline
Because Firebase runs asynchronously with XHR requests, it was difficult to determine the exact source of the error - it seemed like any onSnapshot, set or update was throwing this error for me.
And after that first error came a flurry of other errors:
INTERNAL ASSERTION FAILED: AsyncQueue is already failed: Error: FIRESTORE (5.3.0) INTERNAL ASSERTION FAILED: Got result for empty write pipeline
I thought my operation was pretty normal - just using the API set(), update() , onSnapshot() functions when it happened.
It's not a mission critical error - the code runs fine, but I'm hit with a couple thousand errors when I open debug, so it's prohibitive in that regard.
For my PWA I was using a cache-first, web-reupdate model which returns cachedResponse but also fetch()es the response and caches the fetched response.
Anyone have any insights?
It was the PWA! Using the PWA, I was catching all GET requests, including Firebase's own GET's. Filtering to ensure CORS requests don't return from cache fixed the problem.
To solve this, I added this code to my PWA:
self.addEventListener("fetch", event => {
if (event.request.method == "GET") {
event.respondWith(
(async function() {
const cachedResponse = await cache.match(event.request, {
ignoreSearch: true
});
// Returned the cached response if we have one, otherwise return the network response.
if (cachedResponse && event.request.type!="cors") {
//AVOID CORS FOR THINGS LIKE FIREBASE
updateCache(event);
return cachedResponse;
} else return await updateCache(event);
})()
);
} else {
event.respondWith(fetch(event.request));
}
});
If you're new to the PWA space, want to get a jump start to ANY PWA project, or want to just 'share notes', the repo with the full comprehensive PWA file is here: https://github.com/acenturyandabit/genUI/blob/master/Javascript/pwa.js
I've personally put a lot of time into this so I hope it helps :)
I'm trying to fetch data from http://www.recipepuppy.com/api/?q=onion&p=1. (Sample query)
It works in a browser, but I was trying to fetch it inside my React app and I'm encountering “No 'Access-Control-Allow-Origin' header is present on the requested resource error.
So I changed my strategy and now I'm trying to use JSONP (https://github.com/mzabriskie/axios/blob/master/COOKBOOK.md#jsonp).
But I can't make it work. I'm getting this error all the time. Can someone please help me with my issue?
Error:
Uncaught ReferenceError: jp0 is not defined
at ?q=onion&p=1&callback=__jp0:1
My Code:
import jsonp from 'jsonp'
export const FETCH_RECIPES = 'FETCH_RECIPE'
export const SHOW_INFO = 'SHOW_INFO'
export function fetchRecipes (searchTermToDOoooooooooo) {
const request = jsonp('http://www.recipepuppy.com/api/?q=onion&p=1', null, function (err, data) {
if (err) {
console.error(err.message)
} else {
console.log(data)
}
})
return (dispatch) => {
/*
request.then(({ data: data1 }) => {
dispatch({ type: FETCH_RECIPES, payload: data1 })
})
*/
}
}
export function showInfo (info) {
return {
type: SHOW_INFO,
payload: info
}
}
How that error looks in dev tools:
You can't do it with client-only code, at least not with JSONP+Axios (Axios doesn't (natively) support JSONP; the "jsonp" library is different from Axios), because it's the server you're getting information from that's in violation of the cross-origin rules. In this case, it's Recipe Puppy that isn't set up for Access-Control-Allow-Origin headers.
One option is to use a server-side proxy, as #Pointy mentions.
Your flow would then shift to:
Client calls server-side proxy for information.
Proxy calls Recipe Puppy's API and translates or passes through information as needed.
Proxy relays that information to the client-side code for further processing.
As for your current shift to jsonp, it appears the jsonp library is not exporting jp0 properly for some reason. This could be an error with your build tool. You'll want to double-check your setup and make sure your build tool is picking up the jsonp library and actually putting it into the compiled source.