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%% @doc Models and business logic for XEP-0079: Advanced Message Processing |
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%% This work was sponsored by Grindr LLC |
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%% @reference <a href="http://xmpp.org/extensions/xep-0079.html">XEP-0079</a> |
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%% @author <mongooseim@erlang-solutions.com> |
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%% @copyright 2014 Erlang Solutions, Ltd. |
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-module(amp). |
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-include("amp.hrl"). |
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-include("mongoose.hrl"). |
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-include("jlib.hrl"). |
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-export([extract_requested_rules/1, |
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make_response/3, |
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make_error_response/4, |
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rule_to_xmlel/1, |
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strip_amp_el/1, |
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binaries_to_rule/3, |
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is_amp_request/1 |
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]). |
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-ignore_xref([binaries_to_rule/3, is_amp_request/1, rule_to_xmlel/1]). |
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-export_type([amp_rule/0, |
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amp_rules/0]). |
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-spec binaries_to_rule(binary(), binary(), binary()) -> amp_rule() | amp_invalid_rule(). |
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binaries_to_rule(<<"deliver">> = Condition, Value, Action) -> |
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case are_valid_deliver_params(Value, Action) of |
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true -> mk_amp_rule('deliver', from_bin_(Value), from_bin_(Action)); |
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:-( |
false -> mk_amp_invalid_rule(Condition, Value, Action) |
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end; |
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binaries_to_rule(<<"match-resource">> = Condition, Value, Action) -> |
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case are_valid_match_resource_params(Value, Action) of |
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true -> mk_amp_rule('match-resource', from_bin_(Value), from_bin_(Action)); |
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:-( |
false -> mk_amp_invalid_rule(Condition, Value, Action) |
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end; |
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binaries_to_rule(<<"expire-at">> = Condition, Value, Action) -> |
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case are_valid_expire_at_params(Value, Action) of |
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true -> mk_amp_rule('expire-at', Value, from_bin_(Action)); %% Value is binary here! |
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:-( |
false -> mk_amp_invalid_rule(Condition, Value, Action) |
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end; |
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binaries_to_rule(Condition, Value, Action) -> |
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mk_amp_invalid_rule(Condition, Value, Action). |
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-spec extract_requested_rules(#xmlel{}) -> 'none' |
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| {rules, amp_rules()} |
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| {errors, [{amp_error(), amp_invalid_rule()}]}. |
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extract_requested_rules(#xmlel{} = Stanza) -> |
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case is_amp_request(Stanza) of |
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true -> parse_rules(Stanza); |
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_ -> none |
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end. |
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-spec make_response(amp_rule(), jid:jid(), #xmlel{}) -> #xmlel{}. |
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make_response(Rule, User, Packet) -> |
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OriginalId = exml_query:attr(Packet, <<"id">>, <<"original-id-missing">>), |
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OriginalSender = jid:to_binary(User), |
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OriginalRecipient = exml_query:attr(Packet, <<"to">>), |
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Amp = #xmlel{name = <<"amp">>, |
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attrs = [{<<"xmlns">>, ?NS_AMP}, |
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{<<"status">>, to_bin_(Rule#amp_rule.action)}, |
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{<<"to">>, OriginalRecipient}, |
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{<<"from">>, OriginalSender}], |
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children = [rule_to_xmlel(Rule)]}, |
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#xmlel{name = <<"message">>, |
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attrs = [{<<"id">>, OriginalId}], |
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children = [Amp]}. |
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-spec make_error_response([amp_error()], [amp_any_rule()], jid:jid(), #xmlel{}) |
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-> #xmlel{}. |
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make_error_response([E|_] = Errors, [_|_] = Rules, User, Packet) -> |
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OriginalId = exml_query:attr(Packet, <<"id">>, <<"original-id-missing">>), |
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Error = make_error_el(Errors, Rules), |
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Amp = #xmlel{name = <<"amp">>, |
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attrs = [{<<"xmlns">>, ?NS_AMP} | |
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error_amp_attrs(E, User, Packet)], |
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children = [rule_to_xmlel(R) || R <- Rules]}, |
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#xmlel{name = <<"message">>, |
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attrs = [{<<"id">>, OriginalId}, |
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{<<"type">>, <<"error">>}], |
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children = [Error, Amp]}; |
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make_error_response(Errors, Rules, User, Packet) -> |
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?LOG_ERROR(#{what => make_error_response_failed, |
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text => <<"amp:make_error_response/4 got invalid data">>, |
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reason => invalid_data, errors => Errors, rules => Rules, |
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user => User#jid.luser, server => User#jid.lserver, |
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exml_packet => Packet}), |
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error(invalid_data). |
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error_amp_attrs('undefined-condition', User, Packet) -> |
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OriginalSender = jid:to_binary(User), |
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OriginalRecipient = exml_query:attr(Packet, <<"to">>), |
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[{<<"status">>, <<"error">>}, |
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{<<"to">>, OriginalRecipient}, |
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{<<"from">>, OriginalSender}]; |
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error_amp_attrs(_, _, _) -> []. |
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%% The lists are guaranteed to be non-empty and of equal |
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%% length by make_error_message/4 |
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-spec make_error_el([amp_error()], [amp_any_rule()]) -> #xmlel{}. |
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make_error_el(Errors, Rules) -> |
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ErrorMarker = #xmlel{name = error_marker_name(hd(Errors)), |
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attrs = [{<<"xmlns">>, ?NS_STANZAS}]}, |
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RuleContainer = #xmlel{name = rule_container_name(hd(Errors)), |
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attrs = [{<<"xmlns">>, ?NS_AMP}], |
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children = [ rule_to_xmlel(R) || R <- Rules ]}, |
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#xmlel{name = <<"error">>, |
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attrs = [{<<"type">>, <<"modify">>}, |
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{<<"code">>, error_code(hd(Errors))}], |
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children = [ErrorMarker, RuleContainer]}. |
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-spec rule_to_xmlel(amp_any_rule()) -> #xmlel{}. |
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rule_to_xmlel(#amp_rule{condition=C, value=V, action=A}) -> |
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#xmlel{name = <<"rule">>, |
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attrs = [{<<"condition">>, to_bin_(C)}, |
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{<<"value">>, to_bin_(V)}, |
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{<<"action">>, to_bin_(A)}]}; |
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rule_to_xmlel(#amp_invalid_rule{condition=C, value=V, action=A}) -> |
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#xmlel{name = <<"rule">>, |
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attrs = [{<<"condition">>, C}, |
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{<<"value">>, V}, |
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{<<"action">>, A}]}. |
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-spec strip_amp_el(#xmlel{}) -> #xmlel{}. |
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strip_amp_el(#xmlel{children = Children} = Elem) -> |
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NewChildren = [ C || C <- Children, not is_amp_el(C) ], |
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Elem#xmlel{children = NewChildren}. |
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%% Internal |
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%% @doc We want to keep `client->server' AMPed messages, |
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%% but filter out `server->client' AMPed responses. |
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%% We can distinguish them by the fact that s2c messages MUST have |
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%% a `status' attr on the `<amp>' element. |
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%% @end |
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-spec is_amp_request(exml:element()) -> boolean(). |
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is_amp_request(Stanza) -> |
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Amp = exml_query:subelement(Stanza, <<"amp">>), |
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(undefined =/= Amp) |
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andalso |
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(undefined == exml_query:attr(Amp, <<"status">>)) |
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andalso |
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(undefined == exml_query:subelement(Stanza, <<"error">>)). |
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-spec is_amp_el(#xmlel{}) -> boolean(). |
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is_amp_el(#xmlel{name = <<"amp">>}) -> true; |
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is_amp_el(_) -> false. |
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-spec parse_rules(#xmlel{}) -> none |
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| {rules, amp_rules()} |
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| {errors, [{amp_error(), amp_rule()}]}. |
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parse_rules(Stanza) -> |
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Amp = exml_query:subelement(Stanza, <<"amp">>), |
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RuleElems = exml_query:subelements(Amp, <<"rule">>), |
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MaybeRules = [ parse_rule(R) || R <- RuleElems ], |
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case lists:partition(fun is_valid_rule/1, MaybeRules) of |
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{[], []} -> none; |
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{Valid, []} -> {rules, Valid}; |
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{_, Invalid} -> {errors, [ {'not-acceptable', R} || R <- Invalid ]} |
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end. |
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-spec parse_rule(#xmlel{}) -> amp_rule() | amp_invalid_rule(). |
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parse_rule(#xmlel{attrs = Attrs}) -> |
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GetF = fun(Value) -> proplists:get_value(Value, Attrs, <<"attribute-missing">>) end, |
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{C, V, A} = {GetF(<<"condition">>), |
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GetF(<<"value">>), |
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GetF(<<"action">>)}, |
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binaries_to_rule(C, V, A). |
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-spec is_valid_rule(amp_rule() | amp_invalid_rule()) -> boolean(). |
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is_valid_rule(#amp_rule{}) -> true; |
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is_valid_rule(#amp_invalid_rule{}) -> false. |
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is_valid_action(Action) -> |
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lists:member(Action, ?AMP_LEGAL_ACTIONS). |
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are_valid_deliver_params(Value, Action) -> |
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lists:member(Value, ?AMP_LEGAL_DELIVER_VALUES) andalso |
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is_valid_action(Action). |
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are_valid_match_resource_params(Value, Action) -> |
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lists:member(Value, ?AMP_LEGAL_MATCH_RESOURCE_VALUES) andalso |
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is_valid_action(Action). |
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are_valid_expire_at_params(_Value, Action) -> |
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%% We may check the value with a regexp for a proper date in the future. |
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is_valid_action(Action). |
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mk_amp_rule(C, V, A) -> |
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#amp_rule{condition = C, value = V, action = A}. |
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mk_amp_invalid_rule(C, V, A) -> |
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#amp_invalid_rule{condition = C, value = V, action = A}. |
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error_code('not-acceptable') -> <<"405">>; |
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error_code('undefined-condition') -> <<"500">>; |
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error_code(_) -> <<"400">>. |
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error_marker_name('not-acceptable') -> <<"not-acceptable">>; |
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error_marker_name('unsupported-actions') -> <<"bad-request">>; |
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error_marker_name('unsupported-conditions') -> <<"bad-request">>; |
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error_marker_name('undefined-condition') -> <<"undefined-condition">>. |
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rule_container_name('not-acceptable') -> <<"invalid-rules">>; |
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rule_container_name('unsupported-actions') -> <<"unsupported-actions">>; |
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rule_container_name('unsupported-conditions') -> <<"unsupported-conditions">>; |
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rule_container_name('undefined-condition') -> <<"failed-rules">>. |
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-spec to_bin_(amp_action() | amp_condition() | amp_value() | amp_error()) -> |
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binary(). |
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to_bin_(A) when is_atom(A) -> atom_to_binary(A, utf8); |
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to_bin_(X) when is_binary(X) -> X. |
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-spec from_bin_(binary()) -> amp_action() | amp_condition() | |
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amp_value() | amp_error(). |
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%% @doc WARNING! This is a partial function. Only values that have been |
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%% verified as legal in binaries_to_rule/3 should be passed here. |
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%% DO NOT EXPORT!!! |
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%% conditons |
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from_bin_(<<"deliver">>) -> 'deliver'; |
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from_bin_(<<"expire-at">>) -> 'expire-at'; |
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from_bin_(<<"match-resource">>) -> 'match-resource'; |
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%% non-date values |
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from_bin_(<<"direct">>) -> 'direct'; |
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from_bin_(<<"forward">>) -> 'forward'; |
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from_bin_(<<"gateway">>) -> 'gateway'; |
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from_bin_(<<"none">>) -> 'none'; |
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from_bin_(<<"stored">>) -> 'stored'; |
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from_bin_(<<"any">>) -> 'any'; |
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from_bin_(<<"exact">>) -> 'exact'; |
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from_bin_(<<"other">>) -> 'other'; |
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%% actions |
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from_bin_(<<"alert">>) -> 'alert'; |
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from_bin_(<<"drop">>) -> 'drop'; |
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from_bin_(<<"error">>) -> 'error'; |
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from_bin_(<<"notify">>) -> 'notify'; |
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%% amp error types |
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from_bin_(<<"unsupported-actions">>) -> 'unsupported-actions'; |
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from_bin_(<<"unsupported-conditions">>) -> 'unsupported-conditions'. |