The different chunks of a path

E.g., /archive/<year>/<months>/ has a Static "archive" step followed by a Dynamic _ step followed by a Dynamic _ step. Each Dynamic _ step has an Resto.Arg payload describing the chunk.

Possible kind of conflictual error that can occur while registering services into a directory or while merging directories.

Dispatch tree

string_of_step step converts the given steps into a string.

string_of_conflict_kind conflict_kind converts the given conflict_kind into a string.

string_of_conflict conflict converts the given conflict into a string.

lookup d m p is Ok (Service _) if there is a service s registered in d and both the method of s is m and the path of s matches p. It is Error _ otherwise.

If it is Ok (Service _) then the returned value corresponds to the registered service.

lookup_uri_desc d p is Ok u where u is a formated URI description, if there is a service s registered in d and the path of s matches p. It is Error _ otherwise.

For instance, given the following path p: "/entries-by-date/2022/01/10" where "2022", "01", and "10" are expected to be paramaters in the path of s, the function will evaluate in "/entries-by-date/<year>/<month>/<day>".

allowed_methods d p is the set of methods m such that lookup d m p is Ok _. In other words, it is the set of methods m such that a service has been registered in d for a path that matches p.

Empty tree

prefix p d is a directory of services which includes a service registered on the path p / q for each service registered on the path q in d.

• raises [Invalid_argument]

  if p is a dynamic path.

merge ~strategy d1 d2 is a directory which includes all the services of d1 and d2.

It is possible to merge both static and dynamic trees.

• In case of static trees, the resulting merge will occur in a eager way at function call.
• In case of dynamic trees and because of their nature, the resulting merging directory can't however be computed directly: We don't know the subtree of such a tree before resolving it whith a proper argument key and thus don't have a way to merge it directly at function call. In such a case, the merging computation will be delayed at resolving time. This may not be a problem in most cases. But merging directories containing a lot of nested dynamic directories should still be avoided as it may impact queries performances.

As a few elements that constitutes a directory tree are not mergeable, it may be possible to come upon a collision case during a merge. Unmergeable elements are:

• Services
• Dynamic directories description.

If one or more of these elements from d1 collides with one or more element from d2, the function will make a choice depending on the given merging strategy:

• `Raise will raise a Conflict exception. This is the default choice.
• `Pick_left will pick the element from d1 to be part of the resulting directory.
• `Pick_right will pick the element from d2 to be part of the resulting directory.

• raises [Conflict]

  if:

  • One or more unmergeable element from d1 collides with one or more unmergeable element from d2 and the merging strategy is `Raise or unspecified.
  • Sub-directories can't be merged because of a structural conflict. For instance, if a path leads from d1 to a sub-directory d1' that is an URI parameter, but path also leads from d2 to a sub-directory d2' that is only a static segment of the URI.
  • Sub-directories can't be merged because of a typing conflict. For instance, if a path leads from d1 to a sub-directory d1' that is an URI parameter of type int, but path, also leads from d2 to a sub-directory d2' that is an URI parameter of type float.

Registring dynamic subtree.

Registring dynamic subtree. (Curryfied variant)

Registring a description service.