Developing a Backend App with OAuth2

Backend driven apps can keep secrets private and may therefor use the client_secret to retrieve refresh_tokens without using PKCE, although using PKCE additionally is suggested.

For this guide we assume that you have read the general OAuth2 introduction as well as created an application as shown in the getting started guide.

You may find the whole source code project in this Github repository.

Preparing your ilert app

Before we can started, we need to make sure that our ilert application is configured correctly. Navigate to your application and make sure that you have entered a redirect url that fits your local or deployed webservice that should act as OAuth2 client. Also copy the client id and client secret, as we will need them to configure your application.

Redirecting the user

Using the parameters generated by ilert during the creation of our app, we can build a redirect url for our application, that will take unauthorized users to ilert and ask them to login and grant their permission for our app. In the case of our app, we ask for the profile scope (find more information on other available scopes here), as well as the source:w scope which will grant us permission to read the user's profile data, as well as to read and edit alert sources in the name of the authorizing user.

Make sure that the redirect_uri that is passed to the redirect url is exactly the same as the one the you have entered in your application's settings or the authorization will fail. This validation is necessary, as verifing the redirect_uri is a very important part of implementing a secure OAuth2 flow. In case you need to send optional data e.g. your own id, use the state query parameter. It will be returned to your client.

const url = "https://app.ilert.com/api/developers/oauth2/authorize";
const queryParams = new URLSearchParams({
    client_id: '0501439fd7dee9af0c25',
    response_type: 'code',
    redirect_uri: 'http://localhost:4597/authorize-result',
    scope: 'profile source:w',
    state: 'optional-state'
});

res.redirect(url + "?" + queryParams.toString());

curl --request GET \
  --url 'https://app.ilert.com/api/developers/oauth2/authorize?client_id=0501439fd7dee9af0c25&response_type=code&redirect_uri=http%3A%2F%2Flocalhost%3A4597%2Fauthorize-result&scope=profile%20source%3Aw&state=optional-state

In case the user is known to your application or especially if the application is limited to a single account. We suggest to redirect the user directly to the tenant (account url) of the user, this way he might be able to skip the login step if logged in already. e.g. https://someTenant.ilert.com/api/developers/oauth2/authorize instead of https://app.ilert.com/api/developers/...

User grant view

The user will be able to see the scopes that you have requested and grant them.

In case of an error

In case of any error, ilert's authorization server will send the user back to the provided redirect_uri while adding an error and error_description query parameter to it.

In case of successful authorization

If the user has accepted your scopes, ilert's authorization server will redirect the user back to your provided redirect_uri while adding a code query parameter to it. This code parameter can be used in the next step to fetch the access token.

http://localhost:4597/authorize-result?code=c82ec4eca4c0ac90061fdd4225d1&state=optional-state

Turning a code into a token

Using the code your backend can make an outbound HTTP request to the authorization server, providing your client secret.

Never expose your client_secret, keep it safe.

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://api.ilert.com/api/developers/oauth2/token',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  data: {
    client_id: '0501439fd7dee9af0c25',
    client_secret: '3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad',
    code: 'a74e0a0bfbfefbe62ab94a60942e',
    grant_type: 'authorization_code'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

curl --request POST \
  --url https://api.ilert.com/api/developers/oauth2/token \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --data client_id=0501439fd7dee9af0c25 \
  --data client_secret=3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad \
  --data code=a74e0a0bfbfefbe62ab94a60942e \
  --data grant_type=authorization_code

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://api.ilert.com/api/developers/oauth2/token"

	payload := strings.NewReader("client_id=0501439fd7dee9af0c25&client_secret=3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad&code=a74e0a0bfbfefbe62ab94a60942e&grant_type=authorization_code")

	req, _ := http.NewRequest("POST", url, payload)
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

import http.client

conn = http.client.HTTPSConnection("api.ilert.com")

payload = "client_id=0501439fd7dee9af0c25&client_secret=3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad&code=a74e0a0bfbfefbe62ab94a60942e&grant_type=authorization_code"

headers = {
    'Content-Type': "application/x-www-form-urlencoded"
}

conn.request("POST", "/api/developers/oauth2/token", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

In case of an error

You will receive an error response.

{
	"code": "invalid_grant",
	"error": "Provided code is unknown"
}

In case of successful token generation

If code and secret are valid, the authorization server will respond with an access as well as a refresh token.

Never expose your user's tokens, especially not the refresh tokens treat them like passwords.

{
	"token_type": "Bearer",
	"access_token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJpbF9uIjoiNWNmIiwiaWxfYSI6MiwiaWxfcyI6InByb2ZpbGUgc291cmNlOnciLCJpc3MiOiJpbGVydCIsImlsX3UiOiJrcnlzdGlhbml0eSIsImlsX3QiOiJBQ0NFU1MiLCJpbF92IjoxLCJleHAiOjE2NDM3MjY3MjN9.Ao0dTxQpcez0IsaUOdsPzWqWhj31ob9Tzf-5KSoqJEmjC4lkeOiRJ255HI8w2IQyj7aunW_SM50rRQBcDHVkt8JmfuT4TgYJ3dvZiJzeZ-YGU1QDT6pCN30wJ9a3rpmv6Y6T2cJD1JvNuEh1qyjdjmJGuBVU3-_0qZSu-Y6CBaRxaBvM27JOf2JkQ4pAN7dK4c2Yw7-MyEkBhtwI_JEMhNCp6GF5SJGhCFBq-xPF1iFqpllIrpqaTWAvRz0ZCNWZCumXCaJAfvnS_OJJoPwEvr2DBV8x0bAuFpECgycE8_--rjU9gZafqiRd2cfFas7AmzQFuvvDGQx_1Zq7leW3EA",
	"expires_in": 3600,
	"scope": "profile source:w",
	"refresh_token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJpbGVydCIsImlsX3QiOiJPQVVUSCIsImlsX3YiOjEsImV4cCI6MTY3NTI1OTEyMywiaWxfayI6IjM0ZTMzYzdmZGUzZjQzZTdhMTEwOWJmYTgzMmRkNDdiIn0.ol0HwWO_zAAhKLjLPLDPwvxv7PNPnUnZq8IXd5fC1FY",
	"refresh_token_expires_in": 31536000
}

Using the access token

Your application backend should store the access and especially the refresh token safely. You can now make requests to ilert's API on behalf of the authorized user.

Do not forget the Bearer prefix in the authorization header before your access token.

var axios = require("axios").default;

var options = {
  method: 'GET',
  url: 'https://api.ilert.com/api/users/current',
  headers: {
    Authorization: 'Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJpbF9uIjoiNWNmIiwiaWxfYSI6MiwiaWxfcyI6InByb2ZpbGUgc291cmNlOnciLCJpc3MiOiJpbGVydCIsImlsX3UiOiJrcnlzdGlhbml0eSIsImlsX3QiOiJBQ0NFU1MiLCJpbF92IjoxLCJleHAiOjE2NDM3MjczNTR9.ZSxXJiR7yPF9BMfsfa9dYVpdv5E2o88iBTG1VFp7-vdF3wciNte7_fKQU2z2aMVudGIZ6dhpBuA8FnSJa3sjaXgsHy2r8Fjvj2XCTuPigaZgURTjAM0zqTC6bxHVkn-G9bKUoJ8mx40U8hFZFPsnD5b9qiZZ6CjqU0CCuiWjoEC8hapHe1TOYnNvqeFPRUYfOhJTXAuOoW0wmcKdrAyk6YbVN74nDVlEbG1TEGIXk893jVyLaoiShqHxkcnyliTWLYg9P_DG0JXFflxugyGttP3GaxAq28KAxI-5VAa_QptXlwybEVN9Q8072a7Xk4R0_jCKbp9uMKE3E4qH72f3PA'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

curl --request GET \
  --url https://api.ilert.com/api/users/current \
  --header 'Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJpbF9uIjoiNWNmIiwiaWxfYSI6MiwiaWxfcyI6InByb2ZpbGUgc291cmNlOnciLCJpc3MiOiJpbGVydCIsImlsX3UiOiJrcnlzdGlhbml0eSIsImlsX3QiOiJBQ0NFU1MiLCJpbF92IjoxLCJleHAiOjE2NDM3MjczNTR9.ZSxXJiR7yPF9BMfsfa9dYVpdv5E2o88iBTG1VFp7-vdF3wciNte7_fKQU2z2aMVudGIZ6dhpBuA8FnSJa3sjaXgsHy2r8Fjvj2XCTuPigaZgURTjAM0zqTC6bxHVkn-G9bKUoJ8mx40U8hFZFPsnD5b9qiZZ6CjqU0CCuiWjoEC8hapHe1TOYnNvqeFPRUYfOhJTXAuOoW0wmcKdrAyk6YbVN74nDVlEbG1TEGIXk893jVyLaoiShqHxkcnyliTWLYg9P_DG0JXFflxugyGttP3GaxAq28KAxI-5VAa_QptXlwybEVN9Q8072a7Xk4R0_jCKbp9uMKE3E4qH72f3PA'

package main

import (
	"fmt"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://api.ilert.com/api/users/current"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("Authorization", "Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJpbF9uIjoiNWNmIiwiaWxfYSI6MiwiaWxfcyI6InByb2ZpbGUgc291cmNlOnciLCJpc3MiOiJpbGVydCIsImlsX3UiOiJrcnlzdGlhbml0eSIsImlsX3QiOiJBQ0NFU1MiLCJpbF92IjoxLCJleHAiOjE2NDM3MjczNTR9.ZSxXJiR7yPF9BMfsfa9dYVpdv5E2o88iBTG1VFp7-vdF3wciNte7_fKQU2z2aMVudGIZ6dhpBuA8FnSJa3sjaXgsHy2r8Fjvj2XCTuPigaZgURTjAM0zqTC6bxHVkn-G9bKUoJ8mx40U8hFZFPsnD5b9qiZZ6CjqU0CCuiWjoEC8hapHe1TOYnNvqeFPRUYfOhJTXAuOoW0wmcKdrAyk6YbVN74nDVlEbG1TEGIXk893jVyLaoiShqHxkcnyliTWLYg9P_DG0JXFflxugyGttP3GaxAq28KAxI-5VAa_QptXlwybEVN9Q8072a7Xk4R0_jCKbp9uMKE3E4qH72f3PA")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))
}

import http.client

conn = http.client.HTTPSConnection("api.ilert.com")

payload = ""

headers = {
    'Authorization': "Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJpbF9uIjoiNWNmIiwiaWxfYSI6MiwiaWxfcyI6InByb2ZpbGUgc291cmNlOnciLCJpc3MiOiJpbGVydCIsImlsX3UiOiJrcnlzdGlhbml0eSIsImlsX3QiOiJBQ0NFU1MiLCJpbF92IjoxLCJleHAiOjE2NDM3MjczNTR9.ZSxXJiR7yPF9BMfsfa9dYVpdv5E2o88iBTG1VFp7-vdF3wciNte7_fKQU2z2aMVudGIZ6dhpBuA8FnSJa3sjaXgsHy2r8Fjvj2XCTuPigaZgURTjAM0zqTC6bxHVkn-G9bKUoJ8mx40U8hFZFPsnD5b9qiZZ6CjqU0CCuiWjoEC8hapHe1TOYnNvqeFPRUYfOhJTXAuOoW0wmcKdrAyk6YbVN74nDVlEbG1TEGIXk893jVyLaoiShqHxkcnyliTWLYg9P_DG0JXFflxugyGttP3GaxAq28KAxI-5VAa_QptXlwybEVN9Q8072a7Xk4R0_jCKbp9uMKE3E4qH72f3PA"
    }

conn.request("GET", "/api/users/current", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

Refreshing an access token

As access tokens are short lived (read more about token lifetime here), you will have to refresh them regularly, at least in case they expire and the ilert API returns a 401 HTTP status code error.

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://api.ilert.com/api/developers/oauth2/token',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  data: {
    client_id: '0501439fd7dee9af0c25',
    client_secret: '3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad',
    refresh_token: 'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJpbGVydCIsImlsX3QiOiJPQVVUSCIsImlsX3YiOjEsImV4cCI6MTY3NTI1OTEyMywiaWxfayI6IjM0ZTMzYzdmZGUzZjQzZTdhMTEwOWJmYTgzMmRkNDdiIn0.ol0HwWO_zAAhKLjLPLDPwvxv7PNPnUnZq8IXd5fC1FY',
    grant_type: 'refresh_token'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

curl --request POST \
  --url https://api.ilert.com/api/developers/oauth2/token \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --data client_id=0501439fd7dee9af0c25 \
  --data client_secret=3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad \
  --data refresh_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJpbGVydCIsImlsX3QiOiJPQVVUSCIsImlsX3YiOjEsImV4cCI6MTY3NTI1OTEyMywiaWxfayI6IjM0ZTMzYzdmZGUzZjQzZTdhMTEwOWJmYTgzMmRkNDdiIn0.ol0HwWO_zAAhKLjLPLDPwvxv7PNPnUnZq8IXd5fC1FY \
  --data grant_type=refresh_token

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://api.ilert.com/api/developers/oauth2/token"

	payload := strings.NewReader("client_id=0501439fd7dee9af0c25&client_secret=3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad&refresh_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJpbGVydCIsImlsX3QiOiJPQVVUSCIsImlsX3YiOjEsImV4cCI6MTY3NTI1OTEyMywiaWxfayI6IjM0ZTMzYzdmZGUzZjQzZTdhMTEwOWJmYTgzMmRkNDdiIn0.ol0HwWO_zAAhKLjLPLDPwvxv7PNPnUnZq8IXd5fC1FY&grant_type=refresh_token")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))
}

import http.client

conn = http.client.HTTPSConnection("api.ilert.com")

payload = "client_id=0501439fd7dee9af0c25&client_secret=3908acda0291d0c4c1e77171aac3b4e501cbbbfc6797f13be1c7a607241498ad&refresh_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJpbGVydCIsImlsX3QiOiJPQVVUSCIsImlsX3YiOjEsImV4cCI6MTY3NTI1OTEyMywiaWxfayI6IjM0ZTMzYzdmZGUzZjQzZTdhMTEwOWJmYTgzMmRkNDdiIn0.ol0HwWO_zAAhKLjLPLDPwvxv7PNPnUnZq8IXd5fC1FY&grant_type=refresh_token"

headers = {
    'Content-Type': "application/x-www-form-urlencoded"
}

conn.request("POST", "/api/developers/oauth2/token", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))

The responses will be equal to the ones of Turning a code into a token above.

Accessing token information

You could parse the JWT token yourself, however we offer a token info endpoint for convience. Note that this endpoint only accepts access tokens.

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://api.ilert.com/api/developers/oauth2/token_info',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  data: {
    token: 'eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJpbF9uIjoiNWNmIiwiaWxfYSI6MiwiaWxfcyI6InByb2ZpbGUgc291cmNlOnciLCJpc3MiOiJpbGVydCIsImlsX3UiOiJrcnlzdGlhbml0eSIsImlsX3QiOiJBQ0NFU1MiLCJpbF92IjoxLCJleHAiOjE2NDM3MjczNTR9.ZSxXJiR7yPF9BMfsfa9dYVpdv5E2o88iBTG1VFp7-vdF3wciNte7_fKQU2z2aMVudGIZ6dhpBuA8FnSJa3sjaXgsHy2r8Fjvj2XCTuPigaZgURTjAM0zqTC6bxHVkn-G9bKUoJ8mx40U8hFZFPsnD5b9qiZZ6CjqU0CCuiWjoEC8hapHe1TOYnNvqeFPRUYfOhJTXAuOoW0wmcKdrAyk6YbVN74nDVlEbG1TEGIXk893jVyLaoiShqHxkcnyliTWLYg9P_DG0JXFflxugyGttP3GaxAq28KAxI-5VAa_QptXlwybEVN9Q8072a7Xk4R0_jCKbp9uMKE3E4qH72f3PA'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

You will receive an info response like this:

{
	"active": true,
	"tenant_id": "someTenant",
	"username": "someUser",
	"scope": "profile source:w",
	"app_id": 250
}

Revoking a refresh token

Just like the user may at any time revoke the refresh token that was issued to your application, your application may also proactively revoke the refresh token.

var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://api.ilert.com/api/developers/oauth2/revoke',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  data: {
    token: 'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJpbGVydCIsImlsX3QiOiJPQVVUSCIsImlsX3YiOjEsImV4cCI6MTY3NTI1OTEyMywiaWxfayI6IjM0ZTMzYzdmZGUzZjQzZTdhMTEwOWJmYTgzMmRkNDdiIn0.ol0HwWO_zAAhKLjLPLDPwvxv7PNPnUnZq8IXd5fC1FY'
  }
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});

Make sure to checkout further information on OAuth2 apps.

PreviousUnderstanding OAuth2 NextDeveloping a web or native App with OAuth2 and PKCE

Last updated 1 year ago