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%% @doc Manage the configuration and initialization of HTTP handlers |
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-module(mongoose_http_handler). |
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-export([config_spec/0, process_config/2, cowboy_host/1, get_routes/1]). |
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-type options() :: #{host := '_' | string(), |
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path := string(), |
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module := module(), |
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atom() => any()}. |
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-type path() :: iodata(). |
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-type routes() :: [{path(), module(), #{atom() => any()}}]. |
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-export_type([options/0, path/0, routes/0]). |
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-callback config_spec() -> mongoose_config_spec:config_section(). |
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-callback routes(options()) -> routes(). |
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-optional_callbacks([config_spec/0, routes/1]). |
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-include("mongoose.hrl"). |
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-include("mongoose_config_spec.hrl"). |
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%% @doc Return a config section with a list of sections for each handler type |
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-spec config_spec() -> mongoose_config_spec:config_section(). |
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config_spec() -> |
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Items = maps:from_list([{atom_to_binary(Module), |
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#list{items = handler_config_spec(Module), |
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wrap = none}} |
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|| Module <- configurable_handler_modules()]), |
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#section{items = Items#{default => #list{items = common_handler_config_spec(), |
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wrap = none}}, |
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format_items = list, |
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validate_keys = module, |
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include = always}. |
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%% @doc Return a config section with handler options |
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-spec handler_config_spec(module()) -> mongoose_config_spec:config_section(). |
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handler_config_spec(Module) -> |
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mongoose_config_utils:merge_sections(common_handler_config_spec(), Module:config_spec()). |
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common_handler_config_spec() -> |
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#section{items = #{<<"host">> => #option{type = string, |
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validate = non_empty, |
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process = fun ?MODULE:cowboy_host/1}, |
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<<"path">> => #option{type = string} |
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}, |
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required = [<<"host">>, <<"path">>], |
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process = fun ?MODULE:process_config/2}. |
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process_config([item, HandlerType | _], Opts) -> |
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Opts#{module => binary_to_atom(HandlerType)}. |
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%% @doc Return the list of Cowboy routes for the specified handler configuration. |
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%% Cowboy will search for a matching Host, then for a matching Path. If no Path matches, |
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%% Cowboy will not search for another matching Host. So, we must merge all Paths for each Host, |
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%% add any wildcard Paths to each Host, and ensure that the wildcard Host '_' is listed last. |
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%% A proplist ensures that the user can influence Host ordering if wildcards like "[...]" are used. |
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-spec get_routes([options()]) -> cowboy_router:routes(). |
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get_routes(Handlers) -> |
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Routes = lists:foldl(fun add_handler_routes/2, [], Handlers), |
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WildcardPaths = proplists:get_value('_', Routes, []), |
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Merge = fun(Paths) -> Paths ++ WildcardPaths end, |
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Merged = lists:keymap(Merge, 2, proplists:delete('_', Routes)), |
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Final = Merged ++ [{'_', WildcardPaths}], |
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?LOG_DEBUG(#{what => configured_cowboy_routes, routes => Final}), |
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Final. |
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add_handler_routes(#{host := Host, path := Path, module := Module} = HandlerOpts, Routes) -> |
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HandlerRoutes = case mongoose_lib:is_exported(Module, routes, 1) of |
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true -> Module:routes(HandlerOpts); |
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false -> [{Path, Module, HandlerOpts}] |
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end, |
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HostRoutes = proplists:get_value(Host, Routes, []), |
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lists:keystore(Host, 1, Routes, {Host, HostRoutes ++ HandlerRoutes}). |
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%% @doc Translate "_" used in TOML to '_' expected by COwboy |
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cowboy_host("_") -> '_'; |
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cowboy_host(Host) -> Host. |
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%% @doc All handlers implementing config_spec/0 are listed here |
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configurable_handler_modules() -> |
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[mod_websockets, |
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mongoose_client_api, |
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mongoose_admin_api, |
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mongoose_graphql_handler]. |