Fix #352: add special treatment for accept_ranges

Add special treatment for the atom accept_ranges in output header
specifications for setting the standard "Accept-Ranges" header. Add
accept_ranges to the documentation.

doc/yaws.tex

@@ -1812,6 +1812,7 @@ \section{All out/1 Return Values}
     \item \verb+{www_authenticate, What}+ - Sets the \textit{WWW-Authenticate:}
       header.
     \item \verb+{vary, What}+ - Sets the \textit{Vary:} header.
+    \item \verb+{accept_ranges, What}+ - Sets the \textit{Accept-Ranges:} header.
   \end{itemize}
 
   All other headers must be added using the normal HTTP syntax. Example:

include/yaws.hrl

@@ -373,6 +373,7 @@
           transfer_encoding,
           www_authenticate,
           vary,
+          accept_ranges,
           other                % misc other headers
          }).
 

man/yaws_api.5

@@ -915,6 +915,11 @@ Sets the WWW-Authenticate: header.
 Sets the Vary: header.
 
 
+\fI{accept_ranges, What}\fR
+
+Sets the Accept-Ranges: header.
+
+
 All other headers must be added using the normal HTTP syntax.
 Example:
 

src/yaws.erl

@@ -2041,6 +2041,11 @@ accumulate_header({vary, What}) ->
 accumulate_header({"Vary", What}) ->
     accumulate_header({vary, What});
 
+accumulate_header({accept_ranges, What}) ->
+    put(outh, (get(outh))#outh{accept_ranges = ["Accept-Ranges: ", What, "\r\n"]});
+accumulate_header({"Accept-Ranges", What}) ->
+    accumulate_header({accept_ranges, What});
+
 %% non-special headers (which may be special in a future Yaws version)
 accumulate_header({Name, What}) when is_list(Name) ->
     H = get(outh),
@@ -2102,7 +2107,9 @@ erase_header(www_authenticate) ->
 erase_header(location) ->
     put(outh, (get(outh))#outh{location=undefined});
 erase_header(vary) ->
-    put(outh, (get(outh))#outh{vary=undefined}).
+    put(outh, (get(outh))#outh{vary=undefined});
+erase_header(accept_ranges) ->
+    put(outh, (get(outh))#outh{accept_ranges=undefined}).
 
 getuid() ->
     case os:type() of