Erlang Picasa API, it works, and here's some reason why...

The Post request to the picasa web service:

request_picasa(AuthToken, User, ImgName, Data) ->
     Body = iolist_to_binary(Data),
     Authorization = <<"GoogleLogin auth=", AuthToken/binary>>,
     Url = "http://picasaweb.google.com/data/feed/api/user/" ++ User ++ "/album/blog",
     case http:request(post,
                     {       Url,
                             [ { "Authorization", binary_to_list(Authorization) },
                               { "Slug", ImgName }
                             ],
                             "image/jpeg",                           % Content-type
                             Body                                    % Body
                     },
             [ {timeout, 30000}, {sync, false} ],            % HTTPOptions
             [ {body_format, binary} ]) of                   % Options

             {ok, Result} ->
                     case Result of
                             {{_, 201, _}, Headers, Response} ->
                                     {ok, Headers, Response};

                             {_,_,Response} ->
                                     Response
                     end;

             {error, Reason} ->
                     io:format("Error: ~p~n", [Reason])
     end.

And what's you must note is the following:

• a new url to Post your image.
• a new header named 'Slug' holding the value of the filename you want for your image
• a timeout of 30 seconds, letting enough time for the upload process to complete.

Other headers are mandatory, and hopefully already set by 'http:request':

• content-length holding the size of the binary data of your image
• content-type holding the image type, here 'image/jpeg'

I choose to use the 'prim_file:load_file/1' fun to retrieve a binary stream of octet composing the image I want to upload:

      {ok, File} = prim_file:read_file(Image),
      {value, {_, Auth}} = lists:keysearch(picasa, 1, State#state.auth),
      case request_picasa(Auth, User, ImgName, File ) of

The variable File holds the binary data, the Auth variable holds the 'correct' Picasa AuthToken, so the 'request_picasa/4' fun can be called correctly...

I'll upgrade later the project http://code.google.com/p/googerl, because I want the 'request_picasa' fun to return {ok, ImageUrl}, and to do that I need to parse the atom response sent by Google... And I'm asking myself wether I doit using xmerl or leex ;]