No signature of method: net.hedtech.restfulapi.EtagGenerator.shaFor() is applicable for argument types

[rhodebump]

Hello again,
I went through the document at https://github.com/restfulapi/restful-api/blob/master/README.md to setup an application (grails 2.4.3) and using the plugin dependency method (not git method) to use the restful-api

I have a "ProductService" grails service

I try to invoke it via browser:
http://localhost:8080/pim/api/products/

I get the following error:
{"errors":[{"type":"general","errorMessage":"No signature of method: net.hedtech.restfulapi.EtagGenerator.shaFor() is applicable for argument types: (java.util.ArrayList, null, java.lang.String) values: [[forgebiz.Product : 1], null, application/json]\nPossible solutions: shaFor(java.lang.Object, java.lang.String), shaFor(java.util.Collection, long, java.lang.String)"}]}

Thank you,
Phillip

[chasdev]

Hi. This appears to be occurring because the 'count' (aka total count) is null. The count (representing the total count) is needed for both ETag generation as well as to support paging.

The best way to provide the total count is to return a 'grails.orm.PagedResultList' from your service list method. Alternatively, you can provide your own implementation of 'net.hedtech.restfulapi.PagedResultList' or use the 'net.hedtech.restfulapi.PagedResultArrayList' implementation. If you do not return either one of these, you will need to expose a 'count' method on your service.

Please see the README 'Service layer contract' section, 'count method' paragraph which discusses the above.

Nevertheless, this is not a great error, so we should improve the reporting of this situation. (So even if you confirm that using one of the above mentioned approaches addresses this for you, I'll leave this issue open until we report a better error when the count is not provided.) Thanks again for taking the time to provide feedback.