utils.js

const fetch = require('node-fetch');
const { onshapeApiUrl } = require('./config');

module.exports = {
    
    /**
     * Send a request to the Onshape API, and proxy the response back to the caller.
     * 
     * @param {string} apiPath The API path to be called. This can be absolute or a path fragment.
     * @param {Request} req The request being proxied.
     * @param {Response} res The response being proxied.
     */
    forwardRequestToOnshape: async (apiPath, req, res) => {
        try {
            const normalizedUrl = apiPath.indexOf(onshapeApiUrl) === 0 ? apiPath : `${onshapeApiUrl}/${apiPath}`;
            if (req.method == 'POST') {
                const resp = await fetch(normalizedUrl, { method: 'POST', body: JSON.stringify(req.body), headers: { Authorization: `Bearer ${req.user.accessToken}`, 'Content-Type':'application/json', Accept: 'application/vnd.onshape.v1+json'}});
                const data = await resp.text();
                const contentType = resp.headers.get('Content-Type');
                res.status(resp.status).contentType(contentType).send(data);
            } else {
                const resp = await fetch(normalizedUrl, { headers: { Authorization: `Bearer ${req.user.accessToken}` }});
                const data = await resp.text();
                const contentType = resp.headers.get('Content-Type');
                res.status(resp.status).contentType(contentType).send(data);
            }
        } catch (err) {
            res.status(500).json({ error: err });
        }
    }
}