httpc: add option to do automatic chunked transfer-encoding

This is specially useful when a client doesn't know in advance the
length of the payload (so that it can't set the
Content-Length header).

Example:

-module(httpc_post_stream_test).
-compile(export_all).

prepare_data() ->
    crypto:start(),
    {ok, Fd} = file:open("test_data.dat", [binary, write]),
    ok = file:write(Fd, lists:duplicate(crypto:rand_uniform(8182, 32768), "1")),
    ok = file:close(Fd).

test() ->
    inets:start(),
    ok = prepare_data(),
    {ok, Fd1} = file:open("test_data.dat", [binary, read]),
    BodyFun = fun(Fd) ->
        case file:read(Fd, 512) of
        eof ->
            eof;
        {ok, Data} ->
            {ok, Data, Fd}
        end
    end,
    %% header 'Transfer-Encoding: chunked' is added by httpc
    {ok, {{_,200,_}, _, _}} = httpc:request(post, {"http://localhost:8888",
        [], "text/plain", {chunkify, BodyFun, Fd1}}, [], []),
    ok = file:close(Fd1).

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/inets/doc/src/httpc.xml b/lib/inets/doc/src/httpc.xml
index df333074cd..8b04b4c7f3 100644
--- a/lib/inets/doc/src/httpc.xml
+++ b/lib/inets/doc/src/httpc.xml
@@ -89,7 +89,9 @@ headers()       = [header()]
 header()        = {field(), value()}
 field()         = string() 
 value()         = string() 
-body()            = string() | binary() | {fun(acc()) -> send_fun_result(), acc()}
+body()            = string() | binary() |
+                    {fun(acc()) -> send_fun_result(), acc()} |
+                    {chunkify, fun(acc()) -> send_fun_result(), acc()}
 send_fun_result() = eof | {ok, iolist(), acc()}
 acc()             = term()
 filename()      = string()