# ForestAgent-NodeJS : How to access the context to identify user in a 3rd party tool (like Sentry)

**URL:** <https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245>\
**Category:** Help me!\
**Tags:** typescript, agent\
**Created:** [May 3, 2023, 2:11pm UTC](https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245 "2023-05-03T14:11:07Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![ajubin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.forestadmin.com/ajubin/32/5467_2.png) [@ajubin](https://community.forestadmin.com/u/ajubin)\
**Post date:** [May 3, 2023, 2:11pm UTC](https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245/1 "2023-05-03T14:11:07Z")

</div>

## Feature(s) impacted

I’m using the forestadmin/agent mounted on an express app (only the admin is running on this app though) and I’m setting up Sentry to monitor perf and bugs.

I want to identify the user doing the request, but I don’t understand how I can tap into the agent.

Today, I’m adding a middleware to read and decode the authorization header but maybe there’s a cleaner solution.

## Context

- Project name: Muzzo
- Team name: Muzzo
- Environment name: Local
- Agent type & version:

```javascript
"@forestadmin/agent": "^1.8.8",
"@forestadmin/datasource-sql": "^1.3.0",
"@forestadmin/datasource-toolkit": "^1.4.2"

```

---

<div class="post-metadata">

**Author:** ![ajubin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.forestadmin.com/ajubin/32/5467_2.png) [@ajubin](https://community.forestadmin.com/u/ajubin)\
**Post date:** [May 3, 2023, 2:22pm UTC](https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245/2 "2023-05-03T14:22:44Z")

</div>

Also, I’ve noticed something I still don’t understand. When I add a middleware before mounting the agent, I can see it’s executed but when I add it after mounting the agent, it doesn’t seem to be executed.

So I can’t tap into forest context after mounting it

### My Setup

```ts

const myMiddlewareFactory = (message:string) => (req, res, next) => {
 console.log('middleware:', message);
 next();
}

const app = express();

app.use(myMiddlewareFactory('before')); // I see logs

await agent.mountOnExpress(app).start();

app.use(myMiddlewareFactory('after')); // can't see logs

app.listen(env.PORT);

```

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<div class="post-metadata">

**Author:** ![anon39848301](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@anon39848301](https://community.forestadmin.com/u/anon39848301)\
**Post date:** [May 3, 2023, 2:28pm UTC](https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245/3 "2023-05-03T14:28:08Z")

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Hey @ajubin, and welcome to our community 👋

We do provide a way to customize log using the `logger`, `loggerLevel`, and `customizeErrorMessage` options with documentation [here](https://docs.forestadmin.com/developer-guide-agents-nodejs/getting-started/install/create-your-agent#logger-function-and-loggerlevel-string-defaults-to-info). However, there are currently no way to retrieve the user this way.

Depending on your needs, [hooks](https://docs.forestadmin.com/developer-guide-agents-nodejs/agent-customization/hooks) could maybe also do the trick.

> Also, I’ve noticed something I still don’t understand. When I add a middleware before mounting the agent, I can see it’s executed but when I add it after mounting the agent, it doesn’t seem to be executed.

Indeed, `after` will not be called on forest routes, but that’s related to how express middleware works.

For eg, if you add a route definition **after** your `after` middleware, you should be able to see `before` and `after` message being displayed.

Let me know if that helps.

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<div class="post-metadata">

**Author:** ![ajubin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.forestadmin.com/ajubin/32/5467_2.png) [@ajubin](https://community.forestadmin.com/u/ajubin)\
**Post date:** [May 3, 2023, 2:35pm UTC](https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245/4 "2023-05-03T14:35:52Z")

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Hi @jeffladira,

thanks for the quick answer and the explanation about forest middleware, as I’m not using them on other projects, maybe I can make silly mistakes 😄

I’ve looked at `logger`, `loggerLevel` and `customizeErrorMessage` but I’m not sure if it’s the appropriate way to report error on Sentry (a monitoring tool)

For the hooks, it’s only at a collection level so it can’t do the trick in my case

---

<div class="post-metadata">

**Author:** ![anon39848301](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@anon39848301](https://community.forestadmin.com/u/anon39848301)\
**Post date:** [May 3, 2023, 2:48pm UTC](https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245/5 "2023-05-03T14:48:54Z")

</div>

Then your solution would be the cleanest we offer right now.

If you want to retrieve info from a route level, express middleware would be the best one.  
If you want to retrieve error messages on sentry (Without user infos), Hooks or `logger`, `loggerLevel` and `customizeErrorMessage` would be the way to go.  
If you want to retrieve both in a single line, then this is not currently supported, and I can push this to our product board.

Let me know 🙏

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<div class="post-metadata">

**Author:** ![ajubin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.forestadmin.com/ajubin/32/5467_2.png) [@ajubin](https://community.forestadmin.com/u/ajubin)\
**Post date:** [May 3, 2023, 3:33pm UTC](https://community.forestadmin.com/t/forestagent-nodejs-how-to-access-the-context-to-identify-user-in-a-3rd-party-tool-like-sentry/6245/6 "2023-05-03T15:33:22Z")

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For the record, here is what I did

### To identify user in `Sentry`

```ts
 // identify user based on jwt
  app.use((req, res, next) => {
    if (req.headers.authorization) {
      const [, jwtToken] = req.headers.authorization.split(' ');
      const decodedToken = jwt.decode(jwtToken, {
        complete: true,
      });

      if (decodedToken.payload.email) {
        Sentry.setUser({ email: decodedToken.payload.email });
      }
    }

    next();
  });

```

### To report error in `Sentry`

```ts
// on createAgent function
const agent = createAgent({
  logger: (level, data, error) => {
      // Default logger copy pasted from: https://github.com/ForestAdmin/agent-nodejs/blob/95ee789933417ccde1be26c0ba587b38fd7d4264/packages/agent/src/utils/options-validator.ts#LL20C8-L20C8
      const loggerLevel = 'Info';
      const loggerPrefix = {
        Debug: '\x1b[34mdebug:\x1b[0m',
        Info: '\x1b[32minfo:\x1b[0m',
        Warn: '\x1b[33mwarning:\x1b[0m',
        Error: '\x1b[31merror:\x1b[0m',
      };
      const levels = Object.keys(loggerPrefix);
      if (levels.indexOf(level) >= levels.indexOf(loggerLevel)) {
        // eslint-disable-next-line no-console
        console.error(loggerPrefix[level], data);
      }
      // end of default logger

      if (level === 'Warn' || level === 'Error') {
        Sentry.captureException(error);
      }
    },

})
```