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Output [object Object] when trying to identify 'body' parameter in path's apiDoc

See original GitHub issue

I was trying to do a PUT /inventories/{id} endpoint that will accept request body as: { "inventory": 100 }

I defined the apiDoc in each path js file, and this is the one for PUT.

// paths/inventories/{id}.js
const inventoryByIdPath = (inventoriesService) => {
  const PUT = (req, res) => {
    const id = _.get(req, 'params.id');
    const data = _.get(req, 'params.data');
    ...
  };
  PUT.apiDoc = {
   ...
    parameters: [
      {
        in: 'path',
        name: 'id',
        description: 'productId',
        required: true,
        type: 'string'
      },
      {
        in: 'body',
        name: 'data',
        description: 'Inventory Data',
        required: true,
        schema: {
          $ref: '../../configs/schemas.json#/Inventory'
        }
      }
  ]
  ...
}

// schemas.json:

{
  "Inventory": {
    "properties": {
      "inventory": {
        "type": "number"
      }
    }
  }
}

However, when I call this endpoint, it will always return html error response instead of json:

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <title>Error</title>
    </head>
    <body>
        <pre>[object Object]</pre>
    </body>
</html>

and console would have logged: [object Object] after I send the request, which I didn’t log it anywhere in code. After setting the break point, I found out it didn’t even make it to the line: const PUT = (req, res) => {...}

Though after removing:

{
  in: 'body',
  name: 'data',
  description: 'Inventory Data',
  required: true,
  schema: {
    $ref: '../../configs/schemas.json#/Inventory'
  }
}

It would work normal, but it won’t have ‘body’ in req.

I tried to find more similar examples online, but only found those provided in express-openapi docs. Having no clue where would it go wrong. Any ideas? And is there anyway I could know what’s inside that mystery [object, Object]?

Using these packages:

{
    "express": "^4.16.2",
    "express-openapi": "^1.2.0"
}

Issue Analytics

State:
Created 6 years ago
Comments:10 (5 by maintainers)

Top GitHub Comments

3reactions

alrikcommented, Jan 18, 2018

@BkunS @jsdevel I think i traced down the issue.

TLDR;: you might have no error handling middleware defined

I was able to reproduce this with the following 4 lines of code:

const express = require('express');
const app = express();

app.get('/', (req, res, next) => next({ status: 400 }) );
app.listen(9095, () => console.warn('Started'));

Launch http://localhost:9095 and see [object Object].

The same happens with express-openapi when a validation fails. The validator internally triggers next({ status : 400, ...someValidationErrorInfo }) in case of a failed validation. When you have no express error handler (err, req, res, next) => {}
or have not defined an express-openapi errorMiddleware express tries to convert the error in your case something like { status: 400, message: 'validation failed' } to a string and send it as error response.

2reactions

BkunScommented, Jan 18, 2018

@alrik @jsdevel Thanks! With the error handling middleware, I was able to know what’s inside the error now, and realized that this whole thing is just because I also didn’t use body-parser which I once thought was built in with express. This can be closed.