Regex in Jersey Path Annotation

Question

I'm currently facing a simple idea with a API that looks like this:

/users                  -> return a collection of users
/users/1                -> return all data included in one user
/users/1/information    -> return the information json
/users/1/dogs/rex       -> return the information of the users dog rex :)
/users/1/dogs/          -> return the collection of the users dogs

Note these represent a folderstructure in a file system where users, 1, dogs, rex are folders and information would be file including a json (doesn't really matter what is in it)

So my idea was building this with a regex (why?! I want to make this a little generic - all I'm doing here is only "a little figment").

1 Folder:            \/[a-zA-Z0-9]+
2 Folders:           \/[a-zA-Z0-9]+\/[a-zA-Z0-9]+
2 Folders - 1 File:  \/[a-zA-Z0-9]+\/[a-zA-Z0-9]+\/[a-zA-Z0-9]+
4 Folders:           \/[a-zA-Z0-9]+\/[a-zA-Z0-9]+\/[a-zA-Z0-9]+\/[a-zA-Z0-9]+ //should be the first loop of 2 folders.

So how do I get a regex does also match a loop (i know 2 Folders *3 -> 6 Folders) and (2 Folders + 1 File)*2 -> 6 "Folders") but at this point it doesn't really matter for me.

Answer 1

If you want to model folders and files and their relationship, I propose a different approach. It is not necassary to duplicate the file/folder relationshipt in the URLs. Such information can be part of the representation of each file/folder resource.

The Resources

Files

A File has an ID, a name, and possibly some other properties. It is contained in a folder.

{
  "id": "file-1",
  "link": "/files/file-1",
  "name": "file-1.txt",
  "folder": "folder-1"
}

The collection resource of all files has the URL

/files

A single file has the URL

/files/{id}

for example

/files/file-1

Folders

A folder has an ID, a name, and possibly some other properties. It contains zero or more files and folders.

{
  "id": "folder-1",
  "link": "/folders/folder-1",
  "name": "folder-1",
  "children": [
    {
      "id": "folder-2",
      "link": "/folders/folder-2"
    },
    {
      "id": "file-1"
      "link": "/files/file-1"
    }
  ]
}

The collection resource of all folders has the URL

/folders

A single folder has the URL

/folders/{id}

for example

/folders/folder-1

The Root Folder

The root folder has some known ID, for examle

/folders/root

Answer 2

I know this isn't what you wanted but rather than try and shoe-horn your solution into regex, why don't you capture the whole path with @PathParam and parse it out in java?

@Path("/operation/{path:.+}")
public String getFile(@PathParam("path") String path) {
    // Parse "path"
}

The path parameter shown should capture everything after the /operation/ in the rest call.