%% @author Marc Worrell <marc@worrell.nl>
%% @copyright 2021-2022 Marc Worrell
%% @doc Fetch data from URLs. Interfaces to z_url_fetch and z_url_metadata.
%% @end
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
-module(z_fetch).
-export([
fetch/3,
fetch_json/3,
fetch_partial/3,
fetch/5,
fetch_json/5,
metadata/3,
as_data_url/3,
error_msg/2
]).
-include("../../include/zotonic.hrl").
%% @doc Fetch data from an URL. Let modules change the fetch options.
-spec fetch(Url, Options, Context) -> z_url_fetch:fetch_result() when
Url :: string() | binary(),
Options :: z_url_fetch:options(),
Context :: z:context().
fetch(Url, Options, Context) ->
Url1 = z_convert:to_binary(Url),
Options1 = add_options(get, Url1, Options, Context),
z_url_fetch:fetch(Url1, Options1).
%% @doc Fetch JSON data from an URL. Let modules change the fetch options. On success, the returned
%% body is parsed with jsxrecord and returned.
-spec fetch_json(Url, Options, Context) -> {ok, JSON} | {error, term()} when
Url :: string() | binary(),
Options :: z_url_fetch:options(),
Context :: z:context(),
JSON :: term().
fetch_json(Url, Options, Context) ->
Url1 = z_convert:to_binary(Url),
Options1 = [ {accept, "application/json"} | proplists:delete(accept, Options) ],
Options2 = add_options(get, Url1, Options1, Context),
case z_url_fetch:fetch(Url1, Options2) of
{ok, {_Final, _Hs, _Length, <<>>}} ->
{ok, #{}};
{ok, {_Final, _Hs, _Length, Body}} ->
{ok, jsxrecord:decode(Body)};
{error, _} = Error ->
Error
end.
%% @doc Fetch data from an URL. Let modules change the fetch options.
-spec fetch_partial(Url, Options, Context) -> z_url_fetch:fetch_result() when
Url :: string() | binary(),
Options :: z_url_fetch:options(),
Context :: z:context().
fetch_partial(Url, Options, Context) ->
Url1 = z_convert:to_binary(Url),
Options1 = add_options(get, Url1, Options, Context),
z_url_fetch:fetch_partial(Url1, Options1).
%% @doc Perform a request and data from an URL. Let modules change the fetch options.
-spec fetch(Method, Url, Payload, Options, Context) -> Result when
Method :: get | post | delete | put,
Url :: string() | binary(),
Payload :: list() | binary() | map(),
Options :: z_url_fetch:options(),
Context :: z:context(),
Result :: z_url_fetch:fetch_result().
fetch(Method, Url, Args, Options, Context) ->
Payload = payload(Args),
Url1 = z_convert:to_binary(Url),
Options1 = [
{content_type, "application/x-www-form-urlencoded"}
| Options
],
Options2 = add_options(post, Url1, Options1, Context),
z_url_fetch:fetch(Method, Url1, Payload, Options2).
%% @doc Perform a request and fetch JSON data from an URL. Let modules change the fetch options. On success, the
%% returned body is parsed with jsxrecord and returned.
-spec fetch_json(Method, Url, Payload, Options, Context) -> Result when
Method :: get | post | delete | put,
Url :: string() | binary(),
Payload :: list() | binary() | map(),
Options :: z_url_fetch:options(),
Context:: z:context(),
Result :: {ok, term()} | {error, term()}.
fetch_json(Method, Url, Args, Options, Context) ->
Options1 = [
{accept, "application/json"}
| proplists:delete(accept, Options)
],
case fetch(Method, Url, Args, Options1, Context) of
{ok, {_Final, _Hs, _Length, <<>>}} ->
{ok, #{}};
{ok, {_Final, _Hs, _Length, Body}} ->
{ok, jsxrecord:decode(Body)};
{error, _} = Error ->
Error
end.
payload(B) when is_binary(B) -> B;
payload(M) when is_map(M) -> cow_qs:qs(maps:to_list(M));
payload(L) when is_list(L) -> cow_qs:qs(L).
%% @doc Fetch the metadata from an URL. Let modules change the fetch options.
-spec metadata( string() | binary(), z_url_fetch:options(), z:context() ) -> {ok, z_url_metadata:metadata()} | {error, term()}.
metadata(Url, Options, Context) ->
Options1 = add_options(get, Url, Options, Context),
z_url_metadata:fetch(Url, Options1).
%% @doc Fetch data from an URL. Return the data as a data url.
-spec as_data_url( string() | binary() | undefined, z_url_fetch:options(), z:context()) -> {ok, binary()} | {error, term()}.
as_data_url(Url, Options, Context) ->
case fetch(Url, Options, Context) of
{ok, {_Final, Hs, _Size, Data}} ->
Mime = content_type(Hs),
{ok, iolist_to_binary([
<<"data:">>, Mime,
<<";base64,">>,
base64:encode(Data)
])};
{error, _} = Error ->
Error
end.
-spec content_type( [ {string(), string()} ]) -> binary().
content_type(Hs) ->
case proplists:get_value("content-type", Hs) of
undefined ->
<<"application/octet-stream">>;
CT ->
[ Mime | _ ] = binary:split(z_convert:to_binary(CT), <<";">>),
z_string:trim(Mime)
end.
%% @doc Map (http) errors to readable format.
-spec error_msg(integer() | {error, term()}, z:context()) -> binary().
error_msg({Status, _Url, _Hs, _Length, _Body}, Context) ->
error_msg(Status, Context);
error_msg(401, Context) ->
?__("Unauthorized to access the remote resource URL.", Context);
error_msg(403, Context) ->
?__("Forbidden to access the remote resource URL.", Context);
error_msg(404, Context) ->
?__("The resource at the URL can not be found.", Context);
error_msg(410, Context) ->
?__("The resource at the URL is gone.", Context);
error_msg(429, Context) ->
?__("Too many requests for the remote server, try again later.", Context);
error_msg(S4xx, Context) when S4xx >= 400, S4xx < 500 ->
?__("The remote server can not handle this URL.", Context);
error_msg(503, Context) ->
?__("The remote server for the URL is having temporary problems.", Context);
error_msg(S5xx, Context) when S5xx >= 500 ->
?__("The remote server for the URL is having problems.", Context);
error_msg(_, Context) ->
?__("Could not fetch the remote resource URL.", Context).
%% @doc Add or modify fetch options. For development sites the 'insecure' options is added, as
%% development sites are using self-signed certificates. The #url_fetch_options notification is
%% used to add an authorization header or other option for a specific site. If no language is
%% set in the options then the current context language is used for the preferred language.
add_options(Method, Url, Options, Context) ->
Options1 = case proplists:is_defined(insecure, Options) of
false ->
case m_site:environment(Context) of
development -> [ insecure | Options ];
_ -> Options
end;
true ->
Options
end,
Options2 = case proplists:is_defined(language, Options1) of
false ->
[ {language, z_context:language(Context)} | Options1 ];
true ->
Options1
end,
Options3 = case uri_string:parse(Url) of
#{ host := Host } = Parts ->
HostPort = case maps:find(port, Parts) of
{ok, Port} -> <<Host/binary, $:, (integer_to_binary(Port))/binary>>;
error -> Host
end,
case z_notifier:first(#url_fetch_options{
method = Method,
url = Url,
host = HostPort,
options = Options2
}, Context)
of
undefined -> Options1;
ExtOptions when is_list(ExtOptions) -> ExtOptions
end;
_ ->
Options2
end,
cleanup_options(Options3).
cleanup_options(Options) ->
lists:filter(
fun
({authorization, None}) when
None =:= undefined;
None =:= none;
None =:= <<>>;
None =:= "" -> false;
(_) ->
true
end,
Options).
