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%%============================================================================== |
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%% Copyright 2016 Erlang Solutions Ltd. |
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%% |
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%% Licensed under the Apache License, Version 2.0 (the "License"); |
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%% you may not use this file except in compliance with the License. |
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%% You may obtain a copy of the License at |
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%% |
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%% http://www.apache.org/licenses/LICENSE-2.0 |
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%% |
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%% Unless required by applicable law or agreed to in writing, software |
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%% distributed under the License is distributed on an "AS IS" BASIS, |
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%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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%% See the License for the specific language governing permissions and |
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%% limitations under the License. |
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%%============================================================================== |
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-module(mongoose_rdbms_pgsql). |
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-author('konrad.zemek@erlang-solutions.com'). |
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-behaviour(mongoose_rdbms_backend). |
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-include_lib("epgsql/include/epgsql.hrl"). |
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-type options() :: #{host := string(), |
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port := inet:port_number(), |
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database := string(), |
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username := string(), |
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password := string(), |
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atom() => any()}. |
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-export([escape_binary/1, unescape_binary/1, connect/2, disconnect/1, |
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query/3, prepare/5, execute/4]). |
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%% API |
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-spec escape_binary(binary()) -> iodata(). |
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escape_binary(Bin) when is_binary(Bin) -> |
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:-( |
[<<"decode('">>, base64:encode(Bin), <<"','base64')">>]. |
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-spec unescape_binary(binary()) -> binary(). |
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unescape_binary(<<"\\x", Bin/binary>>) -> |
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:-( |
base16:decode(Bin); |
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unescape_binary(Bin) when is_binary(Bin) -> |
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:-( |
Bin. |
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-spec connect(options(), QueryTimeout :: non_neg_integer()) -> |
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{ok, Connection :: term()} | {error, Reason :: any()}. |
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connect(Options, QueryTimeout) -> |
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:-( |
case epgsql:connect(db_opts(Options)) of |
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{ok, Pid} -> |
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epgsql:squery(Pid, [<<"SET statement_timeout=">>, integer_to_binary(QueryTimeout)]), |
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epgsql:squery(Pid, <<"SET standard_conforming_strings=off">>), |
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:-( |
{ok, Pid}; |
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Error -> |
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:-( |
Error |
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end. |
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-spec disconnect(Connection :: epgsql:connection()) -> ok. |
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disconnect(Connection) -> |
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:-( |
epgsql:close(Connection). |
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-spec query(Connection :: term(), Query :: any(), |
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Timeout :: infinity | non_neg_integer()) -> mongoose_rdbms:query_result(). |
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query(Connection, Query, _Timeout) -> |
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pgsql_to_rdbms(epgsql:squery(Connection, Query)). |
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-spec prepare(Connection :: term(), Name :: atom(), Table :: binary(), |
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Fields :: [binary()], Statement :: iodata()) -> |
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{ok, term()} | {error, any()}. |
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prepare(Connection, Name, _Table, _Fields, Statement) -> |
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BinName = [atom_to_binary(Name, latin1)], |
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ReplacedStatement = replace_question_marks(Statement), |
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case epgsql:parse(Connection, BinName, ReplacedStatement, []) of |
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{ok, _} -> epgsql:describe(Connection, statement, BinName); |
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Error -> Error |
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end. |
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-spec execute(Connection :: term(), StatementRef :: term(), Params :: [term()], |
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Timeout :: infinity | non_neg_integer()) -> mongoose_rdbms:query_result(). |
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execute(Connection, StatementRef, Params, _Timeout) -> |
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pgsql_to_rdbms(epgsql:prepared_query(Connection, StatementRef, Params)). |
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%% Helpers |
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-spec db_opts(options()) -> epgsql:connect_opts(). |
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db_opts(Options) -> |
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BasicOpts = maps:with([host, port, database, username, password], Options), |
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TLSOpts = tls_opts(Options), |
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maps:merge(BasicOpts#{codecs => [{mongoose_rdbms_pgsql_codec_boolean, []}]}, TLSOpts). |
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tls_opts(#{tls := TLSOpts}) -> |
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#{ssl => ssl_mode(TLSOpts), |
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ssl_opts => just_tls:make_ssl_opts(maps:remove(required, TLSOpts))}; |
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tls_opts(#{}) -> |
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#{}. |
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ssl_mode(#{required := true}) -> required; |
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ssl_mode(#{required := false}) -> true. |
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-spec pgsql_to_rdbms(epgsql:reply(term())) -> mongoose_rdbms:query_result(). |
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pgsql_to_rdbms(Items) when is_list(Items) -> |
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lists:reverse([pgsql_to_rdbms(Item) || Item <- Items]); |
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pgsql_to_rdbms({error, #error{codename = unique_violation}}) -> |
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:-( |
{error, duplicate_key}; |
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pgsql_to_rdbms({error, #error{message = Message}}) -> |
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{error, unicode:characters_to_list(Message)}; |
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pgsql_to_rdbms({ok, Count}) -> |
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{updated, Count}; |
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pgsql_to_rdbms({ok, Count, _Column, Value}) -> |
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:-( |
{updated, Count, Value}; |
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pgsql_to_rdbms({ok, _Columns, Rows}) -> |
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{selected, Rows}. |
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-spec replace_question_marks(Statement :: iodata()) -> iodata(). |
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replace_question_marks(Statement) when is_list(Statement) -> |
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:-( |
replace_question_marks(iolist_to_binary(Statement)); |
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replace_question_marks(Statement) when is_binary(Statement) -> |
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:-( |
[Head | Parts] = binary:split(Statement, <<"?">>, [global]), |
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Placeholders = [<<"$", (integer_to_binary(I))/binary>> || I <- lists:seq(1, length(Parts))], |
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:-( |
PartsWithPlaceholders = lists:zipwith(fun(A, B) -> [A, B] end, Placeholders, Parts), |
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:-( |
[Head | PartsWithPlaceholders]. |