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Going through the docs, I encountered:

...you can call functions directly with an HTTP request or a call from the client.

~ source

there (link in the quote) is a mention about functions.https.onCall.

But in the tutorial here, another function functions.https.onRequest is used, so which one should I use and why? What is the difference/similarity between them?

Documentation for functions.https is here.

Going through the docs, I encountered:

...you can call functions directly with an HTTP request or a call from the client.

~ source

there (link in the quote) is a mention about functions.https.onCall.

But in the tutorial here, another function functions.https.onRequest is used, so which one should I use and why? What is the difference/similarity between them?

Documentation for functions.https is here.

• javascript
• firebase
• google-cloud-functions

Share Improve this question Follow edited Nov 26, 2020 at 14:47 benomatis 5,62377 gold badges3838 silver badges6060 bronze badges asked Jun 27, 2018 at 15:22 QwertyQwerty 31.9k2525 gold badges125125 silver badges152152 bronze badges 7

• 1 Possible duplicate of Is the new Firebase Cloud Functions https.onCall trigger better? – Doug Stevenson Commented Jun 27, 2018 at 16:16
• Thank you @DougStevenson, but I have read that question prior to asking this one and it did not help me understand the topic better. – Qwerty Commented Jun 27, 2018 at 17:41
• I don't think there's anything else to understand. What is your specific confusion? – Doug Stevenson Commented Jun 27, 2018 at 17:47
• 2 @DougStevenson For one, there seems to be a difference in how those functions can be invoked. One via url, other using an in-app call. – Qwerty Commented Jun 27, 2018 at 18:22
• 2 @DougStevenson Can you check my answer for possible mistakes please? Thanks! – Qwerty Commented Jul 23, 2018 at 11:39

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3 Answers 3

Sorted by: Reset to default 221

The official documentation for these concepts is quite helpful, but from the view of an amateur, the described differences were confusing at first.

• Both types, when deployed, are assigned with a unique HTTPS endpoint URL and can be accessed directly using an https client.

• However, there is one important difference in the way how they are intended to be called.

  • onCall: from the client's firebase.functions()
  • onRequest: via standard https client (e.g. fetch() API in JS)

onCall

• Can be invoked directly from the client app, which is its primary purpose.

   functions.httpsCallable('getUser')({uid})
     .then(r => console.log(r.data.email))
  

• It is implemented using user-provided data and automatic context.

   export const getUser = functions.https.onCall((data, context) => {
     if (!context.auth) return {status: 'error', code: 401, message: 'Not signed in'}
     return new Promise((resolve, reject) => {
       // find a user by data.uid and return the result
       resolve(user);
     })
   })
  

• The context automatically contains metadata about the request such as uid and token.

• Input data and response objects are automatically (de)serialized.

onRequest

• Firebase onRequest Docs

• Serves mostly as an Express API endpoint.

• It is implemented with express Request and Response objects.

   export const getUser = functions.https.onRequest((req, res) => {
     // verify user from req.headers.authorization etc.
     res.status(401).send('Authentication required.');
     // if authorized
     res.setHeader('Content-Type', 'application/json');
     res.send(JSON.stringify(user));
   })
  

• Depends on user-provided authorization headers.

• You are responsible for input and response data.

Read more here Is the new Firebase Cloud Functions https.onCall trigger better?

The main difference between onCall and onRequest for the client is the way they are invoked from client side. When you define a function using onCall e.g.

exports.addMessage = functions.https.onCall((data, context) => {
  // ...
  return ...
});

you can invoke it on the client side using the firebase function client SDK e.g.

// on the client side, you need to import functions client lib
// then you invoke it like this:
const addMessage = firebase.functions().httpsCallable('addMessage');
addMessage({ text: messageText })
  .then((result) => {
    // Read result of the Cloud Function.        
  });

more info for onCall: https://firebase.google.com/docs/functions/callable

But if you define your function using onRequest e.g.

exports.addMesssage = functions.https.onRequest((req, res) { 
  //...   
  res.send(...); 
}

you can call it using normal JS fetch API (no need to import firebase functions client lib on the client code) e.g.

fetch('<your cloud function endpoint>/addMessage').then(...)

this is the big difference that you need to consider when deciding on how to define your functions on the server.

more info for onRequest: https://firebase.google.com/docs/functions/http-events

One caveat I ran into was that the data parameter in functions.https.onCall is actually the raw request. To access the payload, we have to access the data field of the input.

Example

Client sends payload to cloud function:

const callFunction = httpsCallable(functions, 'addMessage');
const result = await callFunction({payload: 'payload'});

Access payload in cloud function:

exports.addMessage = functions.https.onCall((rawRequest, context) => {
  const payload = rawRequest.data.payload;
  return ...
});

I couldn't find this in the docs, please let me know if I'm missing something.

本文标签： javascriptFirebase Cloud Functions Difference between onRequest and onCallStack Overflow