Factorial =
52 | 53 |\n",quote(lists:flatten(io_lib:format("~p",[X]))), ""].
62 |
63 | quote("<" ++ T) -> "<" ++ quote(T);
64 | quote("&" ++ T) -> "&" ++ quote(T);
65 | quote([H|T]) -> [H|quote(T)];
66 | quote([]) -> [].
67 |
68 | classify_extension(".GIF") -> gif;
69 | classify_extension(".jpg") -> jpeg;
70 | classify_extension(".js") -> js;
71 | classify_extension(".css") -> css;
72 | classify_extension(_) -> html.
73 |
--------------------------------------------------------------------------------
/mochiweb_adapter.erl:
--------------------------------------------------------------------------------
1 | -module(mochiweb_adapter).
2 | -compile(export_all).
3 |
4 | start_link([{port,Port},{handler,F}]) ->
5 | Z = mochiweb_http:start_link([{port, Port},
6 | {loop, {?MODULE, handle_http, [F]}}
7 | ]),
8 | ok.
9 |
10 | handle_http(Req, F) ->
11 | case (catch F({?MODULE, Req})) of
12 | {'EXIT', Why} ->
13 | io:format("EXIT:~p~n",[Why]);
14 | X ->
15 | X
16 | end.
17 |
18 | json_to_erl([{Str,[]}], _) ->
19 | mochijson2:decode(Str).
20 |
21 | send_data(Type, Data, {_,Req}) ->
22 | Req:ok({mime_type(Type),[], Data}).
23 |
24 | send_file(File, {_, Req}) ->
25 | case filename:extension(File) of
26 | ".ehe" ->
27 | {ok, Bin} = file:read_file(File),
28 | {Data, Bs} = ehe:expand_binary(Bin, [{'Req', {?MODULE,Req}}]),
29 | Req:ok({mime_type(html),[],Data});
30 | Ext ->
31 | {ok, Bin} = file:read_file(File),
32 | Req:ok({mime_type(classify_extension(Ext)),[],Bin})
33 | end.
34 |
35 | magic(_) ->
36 | "Hello from the mochiweb adapter".
37 |
38 | get(path, {_,Req}) ->
39 | Path = Req:get(path),
40 | case filename:split(Path) of
41 | ["/"|T] -> T;
42 | Path -> Path
43 | end;
44 | get(args, {_,Req}) ->
45 | Req:parse_qs().
46 |
47 | reply_json(Obj, {_,Req}) ->
48 | Json = mochijson2:encode(Obj),
49 | Req:ok({mime_type(json), [], Json}).
50 |
51 | header(X) ->
52 | {"Content-Type", mime_type(X)}.
53 |
54 | mime_type(gif) -> "image/gif";
55 | mime_type(jpg) -> "image/jpeg";
56 | mime_type(png) -> "image/png";
57 | mime_type(css) -> "text/css";
58 | mime_type(special) -> "text/plain; charset=x-user-defined";
59 | mime_type(json) -> "application/json";
60 | mime_type(swf) -> "application/x-shockwave-flash";
61 | mime_type(html) -> "text/html";
62 | mime_type(xul) -> "application/vnd.mozilla.xul+xml";
63 | mime_type(js) -> "application/x-javascript";
64 | mime_type(svg) -> "image/svg+xml".
65 |
66 | pre(X, _) ->
67 | ["\n",quote(lists:flatten(io_lib:format("~p",[X]))), ""].
68 |
69 | quote("<" ++ T) -> "<" ++ quote(T);
70 | quote("&" ++ T) -> "&" ++ quote(T);
71 | quote([H|T]) -> [H|quote(T)];
72 | quote([]) -> [].
73 |
74 |
75 | classify_extension(".GIF") -> gif;
76 | classify_extension(".jpg") -> jpeg;
77 | classify_extension(".js") -> js;
78 | classify_extension(".css") -> css;
79 | classify_extension(_) -> html.
80 |
--------------------------------------------------------------------------------
/Readme:
--------------------------------------------------------------------------------
1 | This is an experiment in the use of the adapter pattern
2 |
3 |
9 |
10 | I have made simple adapters for misultin/mochiweb and cowboy.
11 |
12 | The example assumes that misultin/mochiweb and cowboy have been
13 | installed and compiled on your machine.
14 |
15 | On my machine I have downloaded the latest zip files from github
16 | and built the packages
17 |
18 | I have added three lines in ${HOME}.erlang so that the erlang loader
19 | can find these three programs.
20 |
21 | code:add_patha("/Users/joe/nobackup/mochi-mochiweb-af4cb95/ebin").
22 | code:add_patha("/Users/joe/nobackup/extend-cowboy-e7b6e2a/ebin").
23 | code:add_patha("/Users/joe/nobackup/installed/mochi-mochiweb-b7f3693/ebin").
24 |
25 | There are three adapters
26 |
27 | misultin_adapter.erl
28 | cowboy_adapter.erl
29 | mochiweb_adapter.erl
30 |
31 | Using these adapters we can write server.erl in a generic manner.
32 |
33 | I have also made a simple scripting language ehe.
34 |
35 | About ehe
36 | =========
37 |
38 | Ehe is *very* simple.
39 |
40 | Files with the .ehe extension are assumed to be html files containing embedded
41 | Erlang.
42 |
43 | The syntax assumes the bit inside the delimiters is a sequence
44 | or Erlang expressions. The replacement value of the sequence is the
45 | *last* value in the sequence. Binndings created in the squence are propagated
46 | to the next block of embedded erlang.
47 |
48 | The Global variable 'Req' inside an embedded Erlang expression is the
49 | paramterised module which allows the appropriate adapter to be called.
50 |
51 | Thus 'Req:magic()' calls (for example) calls mochiweb_adapter:magic(Req)
52 | if we are using the mochiweb adapter.
53 |
54 | To play with this
55 | =================
56 |
57 | 1) install mochiweb, misultin and cowboy
58 | 2) edit your .erlang so that the system can find the mochiweb, misultin and
59 | cowboy compiled beam files
60 | 3) type
61 | > make server1
62 | > make server2
63 | > make server3
64 | to test
65 | 4) Take a look at the (generic) server.erl
66 | 5) Take a look at json_round_trip.ehe
67 |
68 | Note: this assumes the script openchrome starts a chrome browser
69 | you will have to tweak openchrome to start some other browser
70 |
71 |
72 |
73 |
74 |
--------------------------------------------------------------------------------
/cowboy_adapter.erl:
--------------------------------------------------------------------------------
1 | -module(cowboy_adapter).
2 | -compile(export_all).
3 |
4 | start_link([{port,Port},{handler,F}]) ->
5 | ok = application:start(cowboy),
6 | Dispatch = [{'_', [{'_', ?MODULE, F}]}], %% server is the name of this module
7 | NumberOfAcceptors = 100,
8 | cowboy:start_listener(my_named_thing,
9 | NumberOfAcceptors,
10 | cowboy_tcp_transport, [{port, Port}],
11 | cowboy_http_protocol, [{dispatch, Dispatch}]),
12 | ok.
13 |
14 |
15 | init({tcp, http}, Req, Opts) -> {ok, Req, Opts}.
16 |
17 | terminate(_, _) -> ok.
18 |
19 | handle(Req, F) ->
20 | case (catch F({?MODULE, Req, F})) of
21 | {'EXIT', Why} ->
22 | io:format("EXIT:~p~n",[Why]);
23 | X ->
24 | X
25 | end.
26 |
27 | json_to_erl([{Str,[]}], _) ->
28 | mochijson2:decode(Str).
29 |
30 | send_data(Type, Data, {_,Req, F}) ->
31 | %% warning Type ignored ... fix me ...
32 | {ok, Req1} = cowboy_http_req:reply(200, [], Data, Req),
33 | {ok, Req1, F}.
34 |
35 | send_file(File, {_, Req, F}) ->
36 | %% should check the mime type here ... do later
37 | case filename:extension(File) of
38 | ".ehe" ->
39 | {ok, Bin} = file:read_file(File),
40 | {Data, Bs} = ehe:expand_binary(Bin, [{'Req', {?MODULE,Req, F}}]),
41 | {ok, Req1} = cowboy_http_req:reply(200, [], Data, Req),
42 | {ok, Req1, F};
43 | Ext ->
44 | {ok, Bin} = file:read_file(File),
45 | {ok, Req1} = cowboy_http_req:reply(200, [], Bin, Req),
46 | {ok, Req1, F}
47 | end.
48 |
49 | magic(_) ->
50 | "Hello from the cowboy adapter".
51 |
52 |
53 | get(path, {_, Req, _}) ->
54 | {Path, _} = cowboy_http_req:path(Req),
55 | [binary_to_list(I) || I <- Path];
56 | get(args, {_, Req, _}) ->
57 | {Args, _} = cowboy_http_req:qs_vals(Req),
58 | Args1 = [{cvt(K),cvt(V)} || {K,V} <- Args],
59 | Args1.
60 |
61 | cvt(X) when is_binary(X) -> binary_to_list(X);
62 | cvt(true) -> [].
63 |
64 | reply_json(Obj, {_,Req, F}) ->
65 | Json = mochijson2:encode(Obj),
66 | {ok, Req1} = cowboy_http_req:reply(200, [], Json, Req),
67 | {ok, Req1, F}.
68 |
69 | header(X) ->
70 | {"Content-Type", mime_type(X)}.
71 |
72 | mime_type(gif) -> "image/gif";
73 | mime_type(jpg) -> "image/jpeg";
74 | mime_type(png) -> "image/png";
75 | mime_type(css) -> "text/css";
76 | mime_type(special) -> "text/plain; charset=x-user-defined";
77 | mime_type(json) -> "application/json";
78 | mime_type(swf) -> "application/x-shockwave-flash";
79 | mime_type(html) -> "text/html";
80 | mime_type(xul) -> "application/vnd.mozilla.xul+xml";
81 | mime_type(js) -> "application/x-javascript";
82 | mime_type(svg) -> "image/svg+xml".
83 |
84 | pre(X, _) ->
85 | ["\n",quote(lists:flatten(io_lib:format("~p",[X]))), ""].
86 |
87 | quote("<" ++ T) -> "<" ++ quote(T);
88 | quote("&" ++ T) -> "&" ++ quote(T);
89 | quote([H|T]) -> [H|quote(T)];
90 | quote([]) -> [].
91 |
92 |
--------------------------------------------------------------------------------
/ehe.erl:
--------------------------------------------------------------------------------
1 | -module(ehe).
2 | -compile(export_all).
3 | -import(lists, [reverse/1, reverse/2]).
4 |
5 | expand_file(File, Bs) ->
6 | {ok, Bin} = file:read_file(File),
7 | expand_string(binary_to_list(Bin), Bs).
8 |
9 | expand_binary(Str, Bs) ->
10 | expand_string(binary_to_list(Str), Bs).
11 |
12 | expand_string(Str, Bs) ->
13 | B1 = make_bindings(Bs, erl_eval:new_bindings()),
14 | expand(Str, 0, B1, []).
15 |
16 | make_bindings([{K,V}|T], B) -> make_bindings(T, erl_eval:add_binding(K,V,B));
17 | make_bindings([], B) -> B.
18 |
19 | expand("
20 | {Str, Ln1, T1} = collect_form(T, Ln, []),
21 | {Value, B1} = string2value(Str, Ln, B0),
22 | expand(T1, Ln1, B1, reverse(Value, L));
23 | expand([$\n|T], Ln, B, L) ->
24 | expand(T, Ln+1, B, [$\n|L]);
25 | expand([H|T], Ln, B, L) ->
26 | expand(T, Ln, B, [H|L]);
27 | expand([], _, B, L) ->
28 | {reverse(L), B}.
29 |
30 | collect_form("?>" ++ T, Ln, L) -> {reverse(L), Ln, T};
31 | collect_form([$\n|T], Ln, L) -> collect_form(T, Ln+1, [$\n|L]);
32 | collect_form([H|T], Ln, L) -> collect_form(T, Ln, [H|L]);
33 | collect_form([], Ln, L) -> {reverse(L), Ln, []}.
34 |
35 | string2value(Str, Ln, Bindings0) ->
36 | case erl_scan:string(Str ++ ".", Ln) of
37 | {ok, Tokens, _} ->
38 | case erl_parse:parse_exprs(Tokens) of
39 | {ok, Exprs} ->
40 | {value, Value, Bindings1} = eval(Exprs, Bindings0),
41 | {Value, Bindings1};
42 | Other ->
43 | io:format("cannot parse:~p Reason=~p~n",[Tokens,Other])
44 | end;
45 | Other ->
46 | io:format("cannot tokenise:~p Reason=~p~n",[Str,Other])
47 | end.
48 |
49 | %% eval([{call,_,{remote,_,{atom,_,ehe},{atom,_,bindings}},[]}|T], B0) ->
50 | %% {B0, B0},
51 |
52 |
53 | eval(Exprs, B0) ->
54 | %% io:format("ehe:~p~n",[Exprs]),
55 | case (catch erl_eval:exprs(Exprs, B0, {eval, fun local/3})) of
56 | {'EXIT', Why} ->
57 | Error = pre({error,evaluating,Exprs,content,B0,was,Why}),
58 | {value, Error, B0};
59 | {redirect, X} ->
60 | throw({redirect,X});
61 | Other ->
62 | Other
63 | end.
64 |
65 | local(bindings, [], B0) ->
66 | {value, B0, B0};
67 | local(pre, [Expr], B0) ->
68 | {value, Val, B1} = eval([Expr], B0),
69 | {value, pre(Val), B1};
70 | local(show_bindings,[],B0) ->
71 | {value, pre(B0), B0};
72 | local(redirect, [Expr], B0) ->
73 | {value, Val, B1} = eval([Expr], B0),
74 | io:format("Redirecting to:~p~n",[Val]),
75 | throw({redirect, Val});
76 | local(Name, Args, B0) ->
77 | io:format("local handler called:~p~n",[{Name,Args,B0}]),
78 | {true, B0}.
79 |
80 | pre(X) ->
81 | ["\n",quote(lists:flatten(io_lib:format("~p",[X]))), ""].
82 |
83 | quote("<" ++ T) -> "<" ++ quote(T);
84 | quote("&" ++ T) -> "&" ++ quote(T);
85 | quote([H|T]) -> [H|quote(T)];
86 | quote([]) -> [].
87 |
88 | require_arg(Key, [{Key,Val}]) -> Val;
89 | require_arg(Key, [_|T]) -> require_arg(Key, T);
90 | require_arg(Key, []) -> io:format("Missign argument:~p~n",[Key]),
91 | exit(ebadInput).
92 |
93 |
94 |
95 |
--------------------------------------------------------------------------------
/mochijson2.erl:
--------------------------------------------------------------------------------
1 | %% @author Bob Ippolito | t |