POST/PATCH works in LoopBack Explorer but not Postman

Question

I am building an Angular app that uses a REST API built from NodeJS and LoopBack. When trying to create new records, I'm getting a weird error both from my app and also in Postman. (Property names have been changed to protect the innocent)

The `ObjectName` instance is not valid. 
Details: `id` can't be blank (value: undefined); 
`property2` can't be blank (value: undefined); 
`property3` can't be blank (value: undefined).

This is what I have posted:

{
    "id":0,
    "property2":"foo",
    "property3":"bar",
    "property4":"R"
}

The weirdest part of this is that when I try to run this through the LoopBack API Explorer, it works just fine. I have the same issues with PATCH methods as well.

Any thoughts?

Thanks

Answer 1

I found the cause. In previous APIs I have worked with, the back-end was set up with a model binder that would apply the properties it needed and discard the ones it did not. So I have typically send the entire object in POSTs/PUTs/etc. In this case, we do not have that, so it was throwing this weird error. Once I added a method to my Angular auto-mapper that would strip the object down to only the bare necessities, it worked just fine.

In the end, I could have figured that out if the error message had been better.