Valaa Core

TODO. Now just specifying Valaa URI's.

1. Valaa URIS, references and raw id's

Valaa reference URI (or just Valaa URI) is a URI used to specify a reference to a Valaa Resource. It has two major parts separated by the URI fragment separator #: partition URI part and a local reference part.

Partition URI identifies the target authority and partition of the reference. It corresponds to scheme, hierarchical and query parts of an URI; everything but the fragment. Its precise structure and interpretation is specified by the scheme but typically the scheme and hierarchical part identify an authority and query part identifies a partition.

Local reference identifies a particular resource inside a partition but also contains optional coupling, ghost path, lens (and other) parts which further parameterize the reference itself. It corresponds to the URI fragment part but has sub-structure which is specified in this document.

                                            reference URI
┌────────────────────────────────────────────────┴─────────────────────────────────────────────────┐
                  partition URI                                    local reference
┌───────────────────────┴────────────────────────┐ ┌───────────────────────┴───────────────────────┐
                         resource URI                                     reference options
┌──────────────────────────────┴─────────────────────────────────┐ ┌───────────────┴───────────────┐ 
         authority URI              partition id     resource id        coupling        lens name
┌──────────────┴──────────────┐    ┌──────┴──────┐ ┌──────┴──────┐ ┌───────┴────────┐ ┌─────┴──────┐

valaa-aws://example.com:123/dev?id=abcd-123...2343#987b-72f...8263?coupling=relations&lens=ROOT_LENS

└───┬───┘   └──────┬──────┘└┬─┘ └───────┬────────┘ └───────────────────────┬───────────────────────┘
 scheme        authority   path        query                         fragment
            └────────┬────────┘
             hierarchical part                    

1.1. Curious pluralistic dualisms of partition URI and local reference

The division between partition URI and local reference has many curious dualistic qualities: backend vs. frontend, hierarchical vs. flat, routing vs. computation, extensible vs. fixed, absolute vs. contextual, coarse vs. granular, self-contained vs. part-of-a-whole.

1.1.1. Partition URI domain is backend, local reference domain is front-end

Valaa backends deal with the indivisible partitions and thus don't care about the particularities of local references to individual resources. This corresponds to how in web architecture URI fragments are not sent to backend with resource requests. Conversely, Valaa frontends don't care where a resource comes from once it has been loaded, but about its identity, relationships and the parameters of those relationships. This is reflected in how frontend code regularily drops the partition URI.

1.1.2. Partition URI structure is specified by the scheme, local reference structure is specified by Valaa

By the nature of its distributed event sourcing architecture Valaa focuses heavily on the frontend. The cross-compatibility between components is driven by how new backends can integrate and talk with existing front-end clients. This is facilitated by front-end plugin systems which enables new valaa URI schemes to specify new routing solutions and fundamentally new backend infrastructures, as long as said infrastructures can route valaa event streams to clients. This corresponds to how Valaa doesn't specify how a partition URI identifies and locates partitions and authorities but leaves it to the scheme specifications and their reference implementations of frontend plugins.

1.1.3. Partitions URI's identify self-contained wholes, resource references need their context

Web architecture specifies that all or none of the document is retrieved. This corresponds to the behaviour of Valaa partitions which are always retrieved as a whole. Partition URI's contain all and nothing but the components which identify web resources, that is everything but the fragment.

1.1.4. Etc.

1.2. Resource id

Resources have id's, which are just raw strings with restricted character set of [-_0-9a-zA-Z] or url-and-filename-ready base64url characters.

Note: As of now resource raw id's must be globally unique: uuid v4 is recommended.

Note: derived id's currently break character set requirement as they use regular base64 encoding and can contain + and / . For backwards compatibility they are permitted, but considered equal to the base64url using + <-> -, / <-> _ character mappings.

1.3. ValaaReference

Javascript class which implements Valaa reference URI and associated operations.