mirror of
https://github.com/ninenines/cowboy.git
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127 lines
3.4 KiB
Erlang
127 lines
3.4 KiB
Erlang
%% Feel free to use, reuse and abuse the code in this file.
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%% @doc Pastebin handler.
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-module(toppage_handler).
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%% Standard callbacks.
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-export([init/2]).
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-export([allowed_methods/2]).
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-export([content_types_provided/2]).
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-export([content_types_accepted/2]).
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-export([resource_exists/2]).
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%% Custom callbacks.
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-export([create_paste/2]).
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-export([paste_html/2]).
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-export([paste_text/2]).
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init(Req, Opts) ->
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random:seed(now()),
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{cowboy_rest, Req, Opts}.
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allowed_methods(Req, State) ->
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{[<<"GET">>, <<"POST">>], Req, State}.
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content_types_provided(Req, State) ->
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{[
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{{<<"text">>, <<"plain">>, []}, paste_text},
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{{<<"text">>, <<"html">>, []}, paste_html}
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], Req, State}.
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content_types_accepted(Req, State) ->
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{[{{<<"application">>, <<"x-www-form-urlencoded">>, []}, create_paste}],
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Req, State}.
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resource_exists(Req, _State) ->
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case cowboy_req:binding(paste_id, Req) of
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undefined ->
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{true, Req, index};
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PasteID ->
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case valid_path(PasteID) and file_exists(PasteID) of
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true -> {true, Req, PasteID};
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false -> {false, Req, PasteID}
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end
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end.
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create_paste(Req, State) ->
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PasteID = new_paste_id(),
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{ok, [{<<"paste">>, Paste}], Req2} = cowboy_req:body_qs(Req),
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ok = file:write_file(full_path(PasteID), Paste),
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case cowboy_req:method(Req2) of
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<<"POST">> ->
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{{true, <<$/, PasteID/binary>>}, Req2, State};
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_ ->
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{true, Req2, State}
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end.
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paste_html(Req, index) ->
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{read_file("index.html"), Req, index};
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paste_html(Req, Paste) ->
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#{lang := Lang} = cowboy_req:match_qs([lang], Req),
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{format_html(Paste, Lang), Req, Paste}.
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paste_text(Req, index) ->
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{read_file("index.txt"), Req, index};
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paste_text(Req, Paste) ->
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#{lang := Lang} = cowboy_req:match_qs([lang], Req),
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{format_text(Paste, Lang), Req, Paste}.
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% Private
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read_file(Name) ->
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{ok, Binary} = file:read_file(full_path(Name)),
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Binary.
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full_path(Name) ->
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filename:join([code:priv_dir(rest_pastebin), Name]).
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file_exists(Name) ->
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case file:read_file_info(full_path(Name)) of
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{ok, _Info} -> true;
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{error, _Reason} -> false
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end.
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valid_path(<<>>) -> true;
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valid_path(<<$., _T/binary>>) -> false;
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valid_path(<<$/, _T/binary>>) -> false;
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valid_path(<<_Char, T/binary>>) -> valid_path(T).
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new_paste_id() ->
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Initial = random:uniform(62) - 1,
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new_paste_id(<<Initial>>, 7).
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new_paste_id(Bin, 0) ->
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Chars = <<"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890">>,
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<< <<(binary_part(Chars, B, 1))/binary>> || <<B>> <= Bin >>;
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new_paste_id(Bin, Rem) ->
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Next = random:uniform(62) - 1,
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new_paste_id(<<Bin/binary, Next>>, Rem - 1).
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format_html(Paste, plain) ->
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Text = escape_html_chars(read_file(Paste)),
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<<"<!DOCTYPE html><html>",
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"<head><title>paste</title></head>",
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"<body><pre><code>", Text/binary, "</code></pre></body></html>\n">>;
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format_html(Paste, Lang) ->
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highlight(full_path(Paste), Lang, "html").
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format_text(Paste, plain) ->
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read_file(Paste);
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format_text(Paste, Lang) ->
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highlight(full_path(Paste), Lang, "ansi").
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highlight(Path, Lang, Type) ->
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Path1 = binary_to_list(Path),
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Lang1 = binary_to_list(Lang),
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os:cmd(["highlight --syntax=", Lang1,
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" --doc-title=paste ",
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" --out-format=", Type,
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" --include-style ", Path1]).
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% Escape some HTML characters that might make a fuss
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escape_html_chars(Bin) ->
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<< <<(escape_html_char(B))/binary>> || <<B>> <= Bin >>.
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escape_html_char($<) -> <<"<">>;
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escape_html_char($>) -> <<">">>;
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escape_html_char($&) -> <<"&">>;
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escape_html_char(C) -> <<C>>.
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