Omit port from Host header on redirect to well-known port

ERL-316, as part of 19.3, adds the port number to the Host header
upon automatic redirection. The port number is included even if it
is a well-known port (80, 443). This is different from the
behaviour of most HTTP clients, as well as httpc's own for new
requests.

The added port number can lead to problems such as this one, where
the request signature assumes the client will not send the :443
suffix on redirection to an https URL:
https://github.com/nerves-project/nerves/issues/96

I was unable to add a test case, since that would require a server
on a well-known port, but I manually verified that the GitHub/S3
signing issue was indeed resolved with this patch.

3 files changed, 20 insertions, 11 deletions

diff --git a/lib/inets/src/http_client/httpc.erl b/lib/inets/src/http_client/httpc.erl
index bd5f6df39e..418b6247b0 100644
--- a/lib/inets/src/http_client/httpc.erl
+++ b/lib/inets/src/http_client/httpc.erl
@@ -524,7 +524,7 @@ handle_request(Method, Url,
 	    Options       = request_options(Options0), 
 	    Sync          = proplists:get_value(sync,   Options),
 	    Stream        = proplists:get_value(stream, Options),
-	    Host2         = header_host(Scheme, Host, Port), 
+	    Host2         = http_request:normalize_host(Scheme, Host, Port),
 	    HeadersRecord = header_record(NewHeaders, Host2, HTTPOptions),
 	    Receiver      = proplists:get_value(receiver, Options),
 	    SocketOpts    = proplists:get_value(socket_opts, Options),
@@ -1035,14 +1035,6 @@ bad_option(Option, BadValue) ->
     throw({error, {bad_option, Option, BadValue}}).
 
 
-header_host(https, Host, 443 = _Port) ->
-    Host;
-header_host(http, Host, 80 = _Port) ->
-    Host;
-header_host(_Scheme, Host, Port) ->
-    Host ++ ":" ++ integer_to_list(Port).
-
-
 header_record(NewHeaders, Host, #http_options{version = Version}) ->
     header_record(NewHeaders, #http_request_h{}, Host, Version).
 
diff --git a/lib/inets/src/http_client/httpc_response.erl b/lib/inets/src/http_client/httpc_response.erl
index 0fd5faa466..5fbceb8ad0 100644
--- a/lib/inets/src/http_client/httpc_response.erl
+++ b/lib/inets/src/http_client/httpc_response.erl
@@ -362,8 +362,9 @@ redirect(Response = {StatusLine, Headers, Body}, Request) ->
 		    {ok, error(Request, Reason), Data};
 		%% Automatic redirection
 		{ok, {Scheme, _, Host, Port, Path,  Query}} -> 
+		    HostPort = http_request:normalize_host(Scheme, Host, Port),
 		    NewHeaders = 
-			(Request#request.headers)#http_request_h{host = Host++":"++integer_to_list(Port)},
+			(Request#request.headers)#http_request_h{host = HostPort},
 		    NewRequest = 
 			Request#request{redircount = 
 					Request#request.redircount+1,
diff --git a/lib/inets/src/http_lib/http_request.erl b/lib/inets/src/http_lib/http_request.erl
index c77b616f0d..4c50edb5ef 100644
--- a/lib/inets/src/http_lib/http_request.erl
+++ b/lib/inets/src/http_lib/http_request.erl
@@ -22,7 +22,7 @@
 
 -include("http_internal.hrl").
 
--export([headers/2, http_headers/1, is_absolut_uri/1, key_value/1]).
+-export([headers/2, http_headers/1, is_absolut_uri/1, key_value/1, normalize_host/3]).
 
 
 key_value(KeyValueStr) ->
@@ -85,6 +85,22 @@ is_absolut_uri("https://" ++ _) ->
 is_absolut_uri(_) ->
     false.
 
+%%-------------------------------------------------------------------------
+%% normalize_host(Scheme, Host, Port) -> string()
+%%   Scheme - http | https
+%%   Host - string()
+%%   Port - integer()
+%%
+%% Description: returns a normalized Host header value, with the port
+%% number omitted for well-known ports
+%%-------------------------------------------------------------------------
+normalize_host(https, Host, 443 = _Port) ->
+    Host;
+normalize_host(http, Host, 80 = _Port) ->
+    Host;
+normalize_host(_Scheme, Host, Port) ->
+    Host ++ ":" ++ integer_to_list(Port).
+
 %%%========================================================================
 %%% Internal functions
 %%%========================================================================