Support APIs which return links

[fgabolde]

I'm using a RESTful API (documented here) for the OpenStack message queue service. I have a complete SPORE spec for it, it works well enough.

My issue is with several types of responses that contain links to other resources; for instance, a common workflow with this API is to "claim" several messages on a given message queue. The server then tags those messages internally with the claim ID so that no one else will be able to claim them and returns a response with the claim ID and the messages.

$client->claim_messages(queue_name => 'tomato', limit => 10);

> POST /v1/queues/tomato/claims?limit=10
> {"ttl":60, "grace":60}
< 201 Created
< Location: /v1/queues/tomato/claims/a28ee94e-6cb4-11e2-b4d5-7703267a7926
< [ { "href":"/v1/queues/tomato/messages/50b68a50d6f5b8c8a7c62b01?claim_id=a28ee94e-6cb4-11e2-b4d5-7703267a7926", "body": ... }, ... ]

Now my problem is that although I know in advance what type of resources the various links in the response point to, I cannot call the corresponding client methods with the correct parameters, e.g.

# how can I get the values for queue_name, claim_id and message_id ?
$client->release_claim(queue_name => 'tomato', claim_id => 'a28ee94e-6cb4-11e2-b4d5-7703267a7926');
$client->delete_message(queue_name => 'tomato', message_id => '50b68a50d6f5b8c8a7c62b01', claim_id => 'a28ee94e-6cb4-11e2-b4d5-7703267a7926');

I can sort of get the querystring parameters, but extracting route parameters is going to be much harder. Ideally I'd do something like

$client->call_url(method => 'DELETE', url => '/v1/queues/tomato/messages/50b68a50d6f5b8c8a7c62b01?claim_id=a28ee94e-6cb4-11e2-b4d5-7703267a7926');

I've tried poking around in the internals of Net::HTTP::Spore but I don't believe this is possible without some refactoring.