[Coffee Machine] Wrong use of resolve in uriVariables

[egekorkan]

In the coffee machine tutorial, there is the following code:

    thing.setPropertyReadHandler('availableResourceLevel', (options) => {

        // Check if uriVariables are provided
        if (options && typeof options === 'object' && 'uriVariables' in options) {
            const uriVariables: any = options['uriVariables'];
            if ('id' in uriVariables) {
                return thing.readProperty('allAvailableResources').then((resources) => {
                    const id = uriVariables['id'];
                    return new Promise((resolve, reject) => {
                        resolve(resources[id]);
                    });
                });
            }
        }
        return new Promise((resolve, reject) => {
            resolve('Please specify id variable as uriVariables.');
        });
    });

The first part is completely fine but the last lines on returning a Promise will actually make the Client think that everything is OK since in HTTP it would map to 200 status code. The correct way would be to return an HTTP 400 Bad Request but this is not possible at the moment (See this issue on node-wot: eclipse-thingweb/node-wot#140). For now, this should at least be a reject instead of a resolve.

Could you correct this @fatadel ?

[fatadel]

I had that in the very beginning since it also seems more logical to me. However, I have changed it resolve + error message, since using reject doesn't give any error to a client and the client just infinitely awaits a response. And only on the producer Thing side, the error says (node:2155) UnhandledPromiseRejectionWarning: Please specify id variable as uriVariables. So, I guess there are some additional promise rejection mechanisms missing.

[egekorkan]

Did you try a generic REST client like Postman? It should receive 500 status code

[fatadel]

I am using Insomnia which is essentially the same as Postman and the result was exactly I have described.

[SergioCasCeb]

Same with this issue, is this still relevant with the new website, and having in mind that the documentation will mostly come from other Repositories? @egekorkan

[egekorkan]

This should stay until we fix it and change the tutorial at https://thingweb.io/hands-on/articles/smart-coffee-machine