sort-route-addresses

An algorithm for ordering route addresses

Definition of a "route address"

For the purposes of this algorithm, a route address is a string containing:

• An optional HTTP verb (or ALL) prefix, followed by a space, followed by:
• 1 or more path components, where each path component is:
  • A forward slash /, followed by:
  • A colon : followed by any combination of letters and numbers (a "param"), OR
  • A star * (a "wildcard"), OR
  • Any combination of letters and numbers (a "static path component")

In other words, any Sails-compatible route path.

Algorithm

Given an unordered list of route addresses:

1. Find the maximum number of parts (maxParts) in any address, by ignoring the optional verb prefix and initial forward slash and splitting each address on the remaining / characters.

2. For each address, construct a string (rank) by examining each part in the address from left to right and:

   • Adding a 1 to the string for each static path component
   • Adding a 2 to the string for each param component
   • Adding a 3 to the string for each wildcard component
   • If the address being examined has fewer than maxParts parts, pad the string with 0s if no wildcards were encountered, or 4s if wildcards were encountered.
   • Add a 0 to the end of the string if the address has a specific verb prefix (i.e. not ALL), and a 1 if it has a ALL prefix or no prefix.
   • Finally, prefix a 5 at the beginning of the string if the path has no static components¹.

3. Sort the addresses by their rank, with lesser ranks coming before greater ones.

Example

RANK  ADDRESS
----  -----
1000  GET /foo
1001  /foo
1101  /foo/bar
1111  /foo/bar/baz
1120  GET /foo/bar/:baz
1121  /foo/bar/:baz
1130  GET /foo/bar/*
1131  /foo/bar/*
1201  /foo/:bar
1211  /foo/:bar/baz
1221  /foo/:bar/:baz
1311  /foo/*/baz
1341  /foo/*
2101  /:foo/bar
2111  /:foo/bar/baz
2121  /:foo/bar/:baz
2211  /:foo/:bar/baz
3111  /*/bar/baz
3131  /*/baz/*
3141  /*/baz
52001 /:foo
52201 /:foo/:bar
52221 /:foo/:bar/:baz
52231 /:foo/:bar/*
52341 /:foo/*
53440 GET /*
53441 /*

---

¹: This ensures that addresses like /*/baz/* are ranked above ones like /:foo/:bar/:baz -- the static baz component implies that the author intends for */baz/* to handle request URLs of at least three components, one of which is baz; if /:foo/:bar/:baz/ were ranked higher in the list, it would swallow the subset of those URLs with exactly three components.

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Contributing

Please observe the guidelines and conventions laid out in the Sails project contribution guide when opening issues or submitting pull requests.

License

Like the Sails framework, this package is free and open-source under the MIT License.