OAuth App implementation

Introduction

The Criteo API allows you to build custom apps that help the world's advertisers grow their businesses.

In order for your app to function, your users will have to delegate permissions for one or more of the Criteo advertisers that they oversee.

To do this, you will need to direct the user to a unique consent delegation page using a standard OAuth integration (Authorization Code Grant Type). Below we describe how to implement this flow.

These guides assume you have created a developer account, are part of an organization. Instructions for getting started can be found here.

Creating an Authorization code app

Once you have logged in to the Criteo Partners Portal, create a new App by clicking on "+" in the My apps section.

This will open a modal where you can select type of application. To create an OAuth app use the "Authorization code" app.

Define the name, description and image of your app. This will create your App page.

In your App page you will be able to define the scope of your application and the OAuth parameters. Please see this page to see more details on how to define your app scope.

Set up your OAuth parameters

Once you have defined the scope of your application, you will be able to setup what you need for the OAuth workflow

You can now publish the app, and start an authorization code workflow.

Consent URL creation

Once you have defined the parameters of your App you can start implementing your authorization code flow.

To request access to a user to access their data, you will create a Consent link (to be sent to the user or implemented through a button in your platform that will redirect the user to the link) with the following structure and parameters:

https://consent.criteo.com/request
?response_type=code
&client_id=6e75a
&redirect_uri=https%3A%2F%2Fyourwebsite.com%2Fauth%2Fredirect
&state=4lr4e

The Consent link will direct your user to Criteo Consent page:

They can choose what advertisers from their portfolio they want to give access to.

They approve the request by clicking on "Approve".

A consent request is displayed to a user in all cases except in the following:

• The client_id does not match any published API app.
• The redirect_uri is not authorized (e.g not accessible from public network)
• An unexpected error occurred in our backend.

In any of the cases above an error message will be displayed.

Redirection and access code

Once the user has completed the Consent Delegation flow, we redirect your user to the following URL:

https://yourwebsite.com/auth/redirect
?code=eyJ.abc.def
&state=4lr4e

This URL is forged with the authorized redirect_uri and the following query parameters:

If the consent request is denied, we redirect to the same redirect-uri but with an 'error' query parameter instead of a 'code'.

Exchanging access code for access token

Now that you have an authorization code, you can trade it for an access token with the following request:

POST https://api.criteo.com/oauth2/token
 
grant_type=authorization_code
&code=eyJ.abc.def
&redirect_uri=https://yourwebsite.com/auth/redirect
&client_id=6e75a
&client_secret=j7MfAp

The response from Criteo API will be the following:

{
  "access_token": "eyJ.fiZfef.dls",
  "refresh_token": "eyJ.ela4a9e.afd",
  "token_type": "Bearer",
  "expires_in": 900
}

🚧

Note about token lifetime

The refresh token will be revoked if the user that provided consent to an account changes the role or leaves the organization. Such an account needs to be re-authorized by launching the new consent flow and having the new administrator accept the consent.

Using refresh token

When an access token is close to expiration, you can get a new one using a refresh token via the following request:

POST https://api.criteo.com/oauth2/token
 
grant_type=refresh_token
&refresh_token=eyJ.ela4a9e.afd
&client_id=6e75a
&client_secret=j7MfAp

The response will be the same as when issuing an access token

Demo

Below you can find a code for a demo application in NodeJS that uses Express JS framework.

var express = require('express');
var passport = require('passport');
var OAuth2Strategy = require('passport-oauth2').Strategy;
var app = express();
var port = 3000;

// Passport setup
passport.use(new OAuth2Strategy({
    clientID: 'CLIENT_ID', // Enter your client_id here
    clientSecret: 'CLIENT_SECRET', // Enter your client_secret here
    authorizationURL: 'https://consent.criteo.com/request',
    callbackURL: `http://localhost:${port}/criteo-auth/callback`,
    tokenURL: 'https://api.criteo.com/oauth2/token',
    state: 'togorot'
  },
  function(accessToken, refreshToken, profile, cb) {
    cb(null, { accessToken, refreshToken });
  }
));
app.use(passport.initialize());

// Route declarations
app.get('/', function(req, res) {
  res.send('<a href="/criteo-auth">Link my Criteo account!</a>');
});

app.get('/criteo-auth', passport.authenticate('oauth2'));

app.get('/criteo-auth/callback',
  passport.authenticate('oauth2', { session: false }),
  function(req, res) {
    res.send(`<div>Authentication successful!</div><div>Access token:</div><textarea>${req.user.accessToken}</textarea><div>Refresh token:</div><textarea>${req.user.refreshToken}</textarea>`);
  }
);

console.log(`OAuth test app started on http://localhost:${port}`);
app.listen(port);

{
  "name": "oauth-node",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "node index.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "ejs": "^3.1.6",
    "express": "^4.17.1",
    "passport": "^0.4.1",
    "passport-oauth2": "^1.6.0"
  }
}

How to run the demo?

1. Run npm install
2. Connect to the developer portal and create an app according to the instructions above
3. Create an "Authorization code" app.
4. Generate app credentials and enter the client_id and client_secret in index.js.
5. Register "http://localhost:3000/criteo-auth/callback" as the redirect URI.
6. Run npm run start
7. Open http://localhost:3000

FAQ

What happens if my client_id and client_secret are compromised?
You will need to delete the set of credentials in the App page and create a new one. You will need to request access again to your users.