Added catch for missing POST body when posted to profileparameters

[kdamichie]

This PR closes #4428

---

Which Traffic Control components are affected by this PR?

• Documentation
• Traffic Ops

What is the best way to verify this PR?

Make sure all of the tests pass

For manual testing, try to send a POST to the profileparameters with an empty body. The result should be a 400 error.

If this is a bugfix, which Traffic Control versions contained the bug?

-master

PR submission checklist

• This PR has tests
• This PR has documentation
• This PR has a CHANGELOG.md entry
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[kdamichie]

Removed changed traffic-ops-test.conf. Accidentally commited

[ocket8888]

The test cases here that claim to have empty bodies actually don't. Note that you can't fix that just by setting RequestBody to nil - nil marshals to null, not an empty request body. Sending an empty request may not be very easy to do using the same format as all the other tests. I don't think there's anything you can put in for RequestBody that will do what you want.

[ocket8888]

This doesn't actually test the behavior being fixed in this PR. This a list of length 1 (not 0!) whose only element has the default/"zero" values for all of its properties. The result when Go marshals that is, accordingly, an array with one object element.

[ocket8888]

This doesn't actually test the behavior being fixed in this PR. Marshalling an empty map appropriately produces an empty object - not an empty request body!

[ocket8888]

Same as above

[ocket8888]

I don't think there's anything you can put in for RequestBody that will do what you want.

Actually, I take that back. It's actually fairly easy to create a type that marshals to an empty request body.

Example

package main

import (
	"encoding/json"
	"fmt"
)

type emptyJSONTester struct{}

func (emptyJSONTester) MarshalJSON() ([]byte, error) {
	return []byte{}, nil
}

func main() {
	bts, _ := json.Marshal(emptyJSONTester{})
	fmt.Printf("'%s'\n", string(bts))
	// Output: ''
}

[srijeet0406]

Code looks good. Manual and automated tests pass. Good work! :)