Invoking Edge Functions from client in Supabase

Introduction

Edge Functions let you run code close to users for faster responses. Calling them from the client means your app can get data or do tasks quickly and securely.

You want to fetch data from your backend without exposing your database directly.

You need to run custom logic like sending emails or processing payments triggered by user actions.

You want to keep your app fast by running code near the user's location.

You want to keep sensitive operations on the server but trigger them from the app.

You want to handle user requests that require authentication and authorization.

Syntax

Supabase

const { data, error } = await supabase.functions.invoke('function-name', {
  body: JSON.stringify({ key: 'value' }),
  headers: { 'Content-Type': 'application/json' }
})

Replace 'function-name' with your deployed Edge Function's name.

The body is optional and should be a JSON string if you send data.

Examples

Call an Edge Function named 'hello-world' without sending any data.

Supabase

const { data, error } = await supabase.functions.invoke('hello-world')

Call 'add-user' function and send a username in the request body.

Supabase

const { data, error } = await supabase.functions.invoke('add-user', {
  body: JSON.stringify({ username: 'alice' })
})

Call 'get-profile' function with an authorization token in headers.

Supabase

const { data, error } = await supabase.functions.invoke('get-profile', {
  headers: { 'Authorization': 'Bearer your-token' }
})

Sample Program

This example creates a Supabase client and calls an Edge Function named 'hello-world'. It logs the response or error to the console.

Supabase

import { createClient } from '@supabase/supabase-js'

const supabaseUrl = 'https://xyzcompany.supabase.co'
const supabaseKey = 'public-anonymous-key'
const supabase = createClient(supabaseUrl, supabaseKey)

async function callEdgeFunction() {
  const { data, error } = await supabase.functions.invoke('hello-world')
  if (error) {
    console.error('Error calling function:', error.message)
  } else {
    console.log('Function response:', data)
  }
}

callEdgeFunction()

Important Notes

Always handle errors when calling Edge Functions to avoid app crashes.

Use JSON.stringify to send data in the request body.

Edge Functions run on the server side, so keep secrets and sensitive logic there.

Summary

Edge Functions run code near users for fast responses.

You call them from the client using supabase.functions.invoke().

Send data as JSON and handle errors properly.

Practice

1. What is the main purpose of using supabase.functions.invoke() in a client application?

easy

A. To create new user accounts automatically

B. To directly access the database without authentication

C. To upload files to Supabase storage

D. To call Edge Functions and get fast responses near the user

Solution

1. Step 1: Understand what Edge Functions do

   Edge Functions run code close to users to reduce delay and improve speed.

2. Step 2: Identify the role of supabase.functions.invoke()

   This method is used to call those Edge Functions from the client side.

3. Final Answer:

   To call Edge Functions and get fast responses near the user -> Option D

4. Quick Check:

   Invoke calls Edge Functions [OK]

Hint: Invoke calls Edge Functions for fast user responses [OK]

Common Mistakes:

• Thinking it accesses database directly
• Confusing with file upload methods
• Assuming it creates users automatically

2. Which of the following is the correct syntax to invoke an Edge Function named hello using Supabase client in JavaScript?

easy

A. await supabase.functions.invoke('hello')

B. supabase.invoke.functions('hello')

C. await supabase.functions.call('hello')

D. supabase.functions.run('hello')

Solution

1. Step 1: Recall the correct method name

   The method to call Edge Functions is supabase.functions.invoke().

2. Step 2: Check the syntax for calling a function named 'hello'

   The correct syntax is await supabase.functions.invoke('hello').

3. Final Answer:

   await supabase.functions.invoke('hello') -> Option A

4. Quick Check:

   Correct method is invoke() [OK]

Hint: Use supabase.functions.invoke('functionName') [OK]

Common Mistakes:

• Using wrong method names like call or run
• Swapping order of functions and invoke
• Forgetting to await the async call

3. What will be the output of the following code snippet if the Edge Function returns {"message": "Hello World"}?

const { data, error } = await supabase.functions.invoke('greet');
if (error) {
  console.log('Error:', error.message);
} else {
  console.log(data.message);
}

medium

A. Hello World

B. Error: Function not found

C. undefined

D. SyntaxError

Solution

1. Step 1: Understand the function response

   The Edge Function returns an object with a key "message" and value "Hello World".

2. Step 2: Analyze the code output

   The code logs data.message which is "Hello World" if no error occurs.

3. Final Answer:

   Hello World -> Option A

4. Quick Check:

   data.message logs "Hello World" [OK]

Hint: Check data.message for function response output [OK]

Common Mistakes:

• Assuming error always occurs
• Confusing data with error object
• Expecting raw JSON string instead of parsed object

4. Identify the error in this code snippet that tries to invoke an Edge Function named dataFetch:

const response = supabase.functions.invoke('dataFetch')
console.log(response.data)

medium

A. No error, code is correct

B. Missing await keyword for the async invoke call

C. Using console.log instead of alert

D. Incorrect function name 'dataFetch'

Solution

1. Step 1: Check async call usage

   supabase.functions.invoke() returns a promise and must be awaited.

2. Step 2: Identify missing await

   The code assigns the promise to response without awaiting, so response.data is undefined.

3. Final Answer:

   Missing await keyword for the async invoke call -> Option B

4. Quick Check:

   Async calls need await [OK]

Hint: Always await async invoke calls [OK]

Common Mistakes:

• Forgetting await on async functions
• Assuming invoke returns data synchronously
• Ignoring promise nature of invoke()

5. You want to send JSON data {"userId": 123} to an Edge Function named getUserData and handle errors properly. Which code snippet correctly does this?

hard

A. const { data, error } = await supabase.functions.invoke('getUserData', body: { userId: 123 }); if (error) console.error(error); else console.log(data);

B. const { data, error } = supabase.functions.invoke('getUserData', { body: JSON.stringify({ userId: 123 }) }); if (error) console.error(error); else console.log(data);

C. const { data, error } = await supabase.functions.invoke('getUserData', { body: JSON.stringify({ userId: 123 }) }); if (error) console.error(error); else console.log(data);

D. const response = await supabase.functions.invoke('getUserData', { userId: 123 }); console.log(response.data);

Solution

1. Step 1: Understand the body format

   The body must be a JSON string, so use JSON.stringify() on the data object.

2. Step 2: Use await and handle error properly

   The call must be awaited and error checked before using data.

3. Final Answer:

   const { data, error } = await supabase.functions.invoke('getUserData', { body: JSON.stringify({ userId: 123 }) }); if (error) console.error(error); else console.log(data); -> Option C

4. Quick Check:

   Body as JSON string and await invoke [OK]

Hint: Stringify body JSON and await invoke call [OK]

Common Mistakes:

• Passing body as object instead of JSON string
• Not awaiting the invoke call
• Ignoring error handling