Moved DSL comments to module

Author: joelvh

lib/tlaw/dsl.rb

@@ -20,6 +20,385 @@ module TLAW
   # documentation structure considered to be most informative.
   #
   module DSL
+    # @!method base(url)
+    #   Allows to set entire API base URL, all endpoints and namespaces
+    #   pathes are calculated relative to it.
+    #
+    #   **Works for:** API
+    #
+    #   @param url [String]
+
+    # @!method desc(text)
+    #   Allows to set description string for your API object. It can
+    #   be multiline, and TLAW will automatically un-indent excessive
+    #   indentations:
+    #
+    #   ```ruby
+    #       # ...several levels of indents while you create a definition
+    #       desc %Q{
+    #         This is some endpoint.
+    #         And it works!
+    #       }
+    #
+    #   # ...but when you are using it...
+    #   p my_api.endpoints[:endpoint].describe
+    #   # This is some endpoint.
+    #   # And it works!
+    #   # ....
+    #   ```
+    #
+    #   **Works for:** API, namespace, endpoint
+    #
+    #   @param text [String]
+
+    # @!method docs(link)
+    #   Allows to add link to documentation as a separate line to
+    #   object description. Just to be semantic :)
+    #
+    #   ```ruby
+    #   # you do something like
+    #   desc "That's my endpoint"
+    #
+    #   docs "http://docs.example.com/my/endpoint"
+    #
+    #   # ...and then somewhere...
+    #   p my_api.endpoints[:endpoint].describe
+    #   # That is my endpoint.
+    #   #
+    #   # Docs: http://docs.example.com/my/endpoint
+    #   # ....
+    #   ```
+    #
+    #   **Works for:** API, namespace, endpoint
+    #
+    #   @param link [String]
+
+    # @!method param(name, type = nil, keyword: true, required: false, **opts)
+    #   Defines parameter for current API (global), namespace or endpoint.
+    #
+    #   Param defnition defines several things:
+    #
+    #   * how method definition to call this namespace/endpoint would
+    #     look like: whether the parameter is keyword or regular argument,
+    #     whether it is required and what is default value otherwise;
+    #   * how parameter is processed: converted and validated from passed
+    #     value;
+    #   * how param is sent to target API: how it will be called in
+    #     the query string and formatted on call.
+    #
+    #   Note also those things about params:
+    #
+    #   * as described in {#namespace} and {#endpoint}, setting path template
+    #     will implicitly set params. You can rewrite this on implicit
+    #     param call, for ex:
+    #
+    #   ```ruby
+    #   endpoint :foo, '/foo/{bar}'
+    #   # call-sequence would be foo(bar = nil)
+    #
+    #   # But you can make it back keyword:
+    #   endpoint :foo, '/foo/{bar}' do
+    #     param :bar, keyword: true, default: 'test'
+    #   end
+    #   # call-sequence now is foo(bar: 'test')
+    #
+    #   # Or make it strictly required
+    #   endpoint :foo, '/foo/{bar}/{baz}' do
+    #     param :bar, required: true
+    #     param :baz, keyword: true, required: true
+    #   end
+    #   # call-sequence now is foo(bar, baz:)
+    #   ```
+    #
+    #   * param of outer namespace are passed to API on call from inner
+    #     namespaces and endpoints, for ex:
+    #
+    #   ```ruby
+    #   namespace :city do
+    #     param :city_name
+    #
+    #     namespace :population do
+    #       endpoint :by_year, '/year/{year}'
+    #     end
+    #   end
+    #
+    #   # real call:
+    #   api.city('London').population.by_year(2015)
+    #   # Will get http://api.example.com/city/year/2015?city_name=London
+    #   ```
+    #
+    #   **Works for:** API, namespace, endpoint
+    #
+    #   @param name [Symbol] Parameter name
+    #   @param type [Class, Symbol] Expected parameter type. Could by
+    #     some class (then parameter would be checked for being instance
+    #     of this class or it would be `ArgumentError`), or duck type
+    #     (method name that parameter value should respond to).
+    #   @param keyword [true, false] Whether the param will go as a
+    #     keyword param to method definition.
+    #   @param required [true, false] Whether this param is required.
+    #     It will be considered on method definition.
+    #   @param opts [Hash] Options
+    #   @option opts [Symbol] :field What the field would be called in
+    #     API query string (it would be `name` by default).
+    #   @option opts [#to_proc] :format How to format this option before
+    #     including into URL. By default, it is just `.to_s`.
+    #   @option opts [String] :desc Params::Base description. You could do it
+    #     multiline and with indents, like {#desc}.
+    #   @option opts :default Default value for this param. Would be
+    #     rendered in method definition and then passed to target API
+    #     _(TODO: in future, there also would be "invisible" params,
+    #     that are just passed to target, always the same, as well as
+    #     params that aren't passed at all if user gave default value.)_
+    #   @option opts [Hash, Array] :enum Whether parameter only accepts
+    #     enumerated values. Two forms are accepted:
+    #
+    #     ```ruby
+    #     # array form
+    #     param :units, enum: %i[us metric britain]
+    #     # parameter accepts only :us, :metric, :britain values, and
+    #     # passes them to target API as is
+    #
+    #     # hash "accepted => passed" form
+    #     param :compact, enum: {true => 'gzip', false => nil}
+    #     # parameter accepts true or false, on true passes "compact=gzip",
+    #     # on false passes nothing.
+    #     ```
+
+    # @!method namespace(name, path = nil, &block)
+    #   Defines new namespace or updates existing one.
+    #
+    #   {Namespace} has two roles:
+    #
+    #   * on Ruby API, defines how you access to the final endpoint,
+    #     like `api.namespace1.namespace2(some_param).endpoint(...)`
+    #   * on calling API, it adds its path to entire URL.
+    #
+    #   **NB:** If you call `namespace(:something)` and it was already defined,
+    #   current definition will be added to existing one (but it can't
+    #   change path of existing one, which is reasonable).
+    #
+    #   **Works for:** API, namespace
+    #
+    #   @param name [Symbol] Name of the method by which namespace would
+    #     be accessible.
+    #   @param path [String] Path to add to API inside this namespace.
+    #     When not provided, considered to be `/<name>`. When provided,
+    #     taken literally (no slashes or other symbols added). Note, that
+    #     you can use `/../` in path, redesigning someone else's APIs on
+    #     the fly. Also, you can use [RFC 6570](https://www.rfc-editor.org/rfc/rfc6570.txt)
+    #     URL templates to mark params going straightly into URI.
+    #
+    #     Some examples:
+    #
+    #     ```ruby
+    #     # assuming API base url is http://api.example.com
+    #
+    #     namespace :foo
+    #     # method would be foo(), API URL would be http://api.example.com/foo
+    #
+    #     namespace :bar, '/foo/bar'
+    #     # metod would be bar(), API URL http://api.example.com/foo/bar
+    #
+    #     namespace :baz, ''
+    #     # method baz(), API URL same as base: useful for gathering into
+    #     # quazi-namespace from several unrelated endpoints.
+    #
+    #     namespace :quux, '/foo/quux/{id}'
+    #     # method quux(id = nil), API URL http://api.example.com/foo/quux/123
+    #     # ...where 123 is what you've passed as id
+    #     ```
+    #   @param block Definition of current namespace params, and
+    #     namespaces and endpoints inside current.
+    #     Note that by defining params inside this block, you can change
+    #     namespace's method call sequence.
+    #
+    #     For example:
+    #
+    #     ```ruby
+    #     namespace :foo
+    #     # call-sequence: foo()
+    #
+    #     namespace :foo do
+    #       param :bar
+    #     end
+    #     # call-sequence: foo(bar: nil)
+    #
+    #     namespace :foo do
+    #       param :bar, required: true, keyword: false
+    #       param :baz, required: true
+    #     end
+    #     # call-sequence: foo(bar, baz:)
+    #     ```
+    #
+    #     ...and so on. See also {#param} for understanding what you
+    #     can change here.
+    #
+
+    # @!method endpoint(name, path = nil, **opts, &block)
+    #   Defines new endpoint or updates existing one.
+    #
+    #   {Endpoint} is the thing doing the real work: providing Ruby API
+    #   method to really call target API.
+    #
+    #   **NB:** If you call `endpoint(:something)` and it was already defined,
+    #   current definition will be added to existing one (but it can't
+    #   change path of existing one, which is reasonable).
+    #
+    #   **Works for:** API, namespace
+    #
+    #   @param name [Symbol] Name of the method by which endpoint would
+    #     be accessible.
+    #   @param path [String] Path to call API from this endpoint.
+    #     When not provided, considered to be `/<name>`. When provided,
+    #     taken literally (no slashes or other symbols added). Note, that
+    #     you can use `/../` in path, redesigning someone else's APIs on
+    #     the fly. Also, you can use [RFC 6570](https://www.rfc-editor.org/rfc/rfc6570.txt)
+    #     URL templates to mark params going straightly into URI.
+    #
+    #     Look at {#namespace} for examples, idea is the same.
+    #
+    #   @param opts [Hash] Some options, currently only `:xml`.
+    #   @option opts [true, false] :xml Whether endpoint's response should
+    #     be parsed as XML (JSON otherwise & by default). Parsing in this
+    #     case is performed with [crack](https://github.com/jnunemaker/crack),
+    #     producing the hash, to which all other rules of post-processing
+    #     are applied.
+    #   @param block Definition of endpoint's params and docs.
+    #     Note that by defining params inside this block, you can change
+    #     endpoints's method call sequence.
+    #
+    #     For example:
+    #
+    #     ```ruby
+    #     endpoint :foo
+    #     # call-sequence: foo()
+    #
+    #     endpoint :foo do
+    #       param :bar
+    #     end
+    #     # call-sequence: foo(bar: nil)
+    #
+    #     endpoint :foo do
+    #       param :bar, required: true, keyword: false
+    #       param :baz, required: true
+    #     end
+    #     # call-sequence: foo(bar, baz:)
+    #     ```
+    #
+    #     ...and so on. See also {#param} for understanding what you
+    #     can change here.
+
+    # @!method process(key = nil, &block)
+    #   Sets post-processors for response.
+    #
+    #   There are also {#process_replace} (for replacing entire
+    #   response with something else) and {#process_items} (for
+    #   post-processing each item of sub-array).
+    #
+    #   Notes:
+    #
+    #   * you can set any number of post-processors of any kind, and they
+    #     will be applied in exactly the same order they are set;
+    #   * you can set post-processors in parent namespace (or for entire
+    #     API), in this case post-processors of _outer_ namespace are
+    #     always applied before inner ones. That allow you to define some
+    #     generic parsing/rewriting on API level, then more specific
+    #     key postprocessors on endpoints;
+    #   * hashes are flattened again after _each_ post-processor, so if
+    #     for some `key` you'll return `{count: 1, continue: false}`,
+    #     response hash will immediately have
+    #     `{"key.count" => 1, "key.continue" => false}`.
+    #
+    #   @overload process(&block)
+    #     Sets post-processor for whole response. Note, that in this case
+    #     _return_ value of block is ignored, it is expected that your
+    #     block will receive response and modify it inplace, like this:
+    #
+    #     ```ruby
+    #     process do |response|
+    #       response['coord'] = Geo::Coord.new(response['lat'], response['lng'])
+    #     end
+    #     ```
+    #     If you need to replace entire response with something else,
+    #     see {#process_replace}
+    #
+    #   @overload process(key, &block)
+    #     Sets post-processor for one response key. Post-processor is
+    #     called only if key exists in the response, and value by this
+    #     key is replaced with post-processor's response.
+    #
+    #     Note, that if `block` returns `nil`, key will be removed completely.
+    #
+    #     Usage:
+    #
+    #     ```ruby
+    #     process('date') { |val| Date.parse(val) }
+    #     # or, btw, just
+    #     process('date', &Date.method(:parse))
+    #     ```
+    #
+    #     @param key [String]
+
+    # @!method process_items(key, &block)
+    #   Sets post-processors for each items of array, being at `key` (if
+    #   the key is present in response, and if its value is array of
+    #   hashes).
+    #
+    #   Inside `block` you can use {#process} method as described
+    #   above (but all of its actions will be related only to current
+    #   item of array).
+    #
+    #   Example:
+    #
+    #   Considering API response like:
+    #
+    #   ```json
+    #   {
+    #     "meta": {"count": 100},
+    #     "data": [
+    #       {"timestamp": "2016-05-01", "value": "10", "dummy": "foo"},
+    #       {"timestamp": "2016-05-02", "value": "13", "dummy": "bar"}
+    #     ]
+    #   }
+    #   ```
+    #   ...you can define postprocessing like this:
+    #
+    #   ```ruby
+    #   process_items 'data' do
+    #     process 'timestamp', &Date.method(:parse)
+    #     process 'value', &:to_i
+    #     process('dummy'){nil} # will be removed
+    #   end
+    #   ```
+    #
+    #   See also {#process} for some generic explanation of post-processing.
+    #
+    #   @param key [String]
+
+    # @!method process_replace(&block)
+    #   Just like {#process} for entire response, but _replaces_
+    #   it with what block returns.
+    #
+    #   Real-life usage: WorldBank API typically returns responses this
+    #   way:
+    #
+    #   ```json
+    #   [
+    #      {"count": 100, "page": 1},
+    #      {"some_data_variable": [{}, {}, {}]}
+    #   ]
+    #   ```
+    #   ...e.g. metadata and real response as two items in array, not
+    #   two keys in hash. We can easily fix this:
+    #
+    #   ```ruby
+    #   process_replace do |response|
+    #     {meta: response.first, data: response.last}
+    #   end
+    #   ```
+    #
+    #   See also {#process} for some generic explanation of post-processing.
   end
 end