10.5.11. /db/_design/design-doc/_rewrite/path

ANY /{db}/_design/{ddoc}/_rewrite/{path}

Rewrites the specified path by rules defined in the specified design document.

The rewrite rules are defined in array field of the design document called rewrites. Each rule is an object with next structure:

  • from (string): The path rule used to bind current uri to the rule. It use pattern matching for that
  • to (string): Rule to rewrite an url. It can contain variables depending on binding variables discovered during pattern matching and query args (url args and from the query member)
  • method (string): HTTP request method to bind the request method to the rule. Default is "*"
  • query (object): Query args you want to define they can contain dynamic variable by binding the key

The to``and ``from paths may contains string patterns with leading : or * characters.

For example: /somepath/:var/*

  • This path is converted in Erlang list by splitting /
  • Each var are converted in atom
  • "" are converted to '' atom
  • The pattern matching is done by splitting / in request url in a list of token
  • A string pattern will match equal token
  • The star atom ('*' in single quotes) will match any number of tokens, but may only be present as the last pathterm in a pathspec
  • If all tokens are matched and all pathterms are used, then the pathspec matches

The pattern matching is done by first matching the HTTP request method to a rule. method is equal to "*" by default, and will match any HTTP method. It will then try to match the path to one rule. If no rule matches, then a 404 Not Found response returned.

Once a rule is found we rewrite the request url using the to and query fields. The identified token are matched to the rule and will replace var. If '*' is found in the rule it will contain the remaining part if it exists.


Rule Url Rewrite to Tokens
{“from”: “/a”, “to”: “/some”} /a /some  
{“from”: “/a/*”, “to”: “/some/*} /a/b/c /some/b/c  
{“from”: “/a/b”, “to”: “/some”} /a/b?k=v /some?k=v k=v
{“from”: “/a/b”, “to”: “/some/:var”} /a/b /some/b?var=b var=b
{“from”: “/a/:foo/”, “to”: “/some/:foo/”} /a/b/c /some/b/c?foo=b foo=b
{“from”: “/a/:foo”, “to”: “/some”, “query”: { “k”: ”:foo” }} /a/b /some/?k=b&foo=b foo=b
{“from”: “/a”, “to”: “/some/:foo”} /a?foo=b /some/?b&foo=b foo=b

Request method, header, query parameters, request payload and response body are depended on endpoint to which url will be rewritten.

  • db – Database name
  • ddoc – Design document name
  • path – URL path to rewrite