Hart
Hash router
Description
Hart is a generic routing library that walks a hash and detects matches according to a given pair of verb and path arguments.
Usage
A basic example would look like this:
words = {
"c" => {
"o" => {
"d" => {
define: "A husk; a pod; as, a peascod.",
"a" => {
define: "Concluding passage of a piece or movement."
},
"e" => {
define: "System of rules relating to one subject.",
"c" => {
define: "Device that compresses and decompresses data."
},
"x" => {
define: "A book; a manuscript."
}
}
}
}
}
}
h = Hart.new(words)
h.call(:define, "/c/o/d") #=> "A husk; a pod; as, a peascod."
h.call(:define, "/c/o/d/e") #=> "System of rules relating to one subject."
h.call(:define, "/c/o/d/e/r") #=> nilThe call method accepts two arguments: a verb, which must be a
symbol, and a path, which must be a string in the form "/a/b/c".
It is possible to define more than one verb per element:
countries = {
"argentina" => {
population: 43_417_000,
area: 2_780_400,
},
"france" => {
population: 66_200_000,
area: 640_679,
}
}
h = Hart.new(countries)
h.call(:population, "/argentina") #=> 43417000
h.call(:population, "/france") #=> 66200000
h.call(:area, "/argentina") #=> 2780400
h.call(:area, "/france") #=> 640679The default value for a miss can be configured as follows:
countries[:default] = "Country not found."After adding that key to the previous example, any miss will return
the string "Country not found.".
h.call(:population, "/foobar") #=> "Country not found."The value of each entry can be anything that responds to [](key).
For instance, a proc could be used:
countries["peru"] = proc { |key|
case key
when :population
30_400_000
when :area
1_285_216
else
nil
end
}
h.call(:population, "/peru") #=> 30400000If the special symbol :id is present as an element, it will match
any path segment in that position, given that no other matches
occurred.
countries[:id] = proc { |key|
"No information about #{key}"
}
h.call(:area, "/foobar") #=> "No information about foobar"The next example combines all the concepts explained so far, and
shows how to match HTTP requests based on REQUEST_METHOD and
PATH_INFO.
routes = {
default: [404, {}, ["Not Found"]],
GET: [200, {}, ["GET /"]],
"foo" => {
"bar" => {
GET: [200, {}, ["GET /foo/bar"]],
PUT: [200, {}, ["PUT /foo/bar"]],
}
},
"users" => {
GET: [200, {}, ["GET /users"]],
id: proc { |id|
{
GET: [200, {}, ["GET /users/#{id}"]],
}
}
}
}
h = Hart.new(routes)
h.call(:GET, "/foo/bar") #=> [200, {}, ["GET /foo/bar"]]
h.call(:PUT, "/foo/bar") #=> [200, {}, ["PUT /foo/bar"]]
h.call(:GET, "/users/42") #=> [200, {}, ["GET /users/42"]]
h.call(:GET, "/baz") #=> [404, {}, ["Not Found"]]API
call: Accepts two arguments: a verb, which must be a symbol, and
a path, which must be a string in the form "/a/b/c".
Installation
$ gem install hart