empty model fields

[Wilhelm]

Hi all,

Just getting started with erlyweb. I'm currently using the same form
in my views for both new and edit:

<%@ new(Friend) %>
<h2>Create Friend</h2>
<b><% friends:value(friends:first_name(Friend)) %></b><br/>
<form method="post" action="/friends/create">
<input type="submit" value="Create" />
</form>
<% a([".."], "Back") %>

<%@ edit({Friend}) %>
<h2>Edit Friend</h2>
<form method="post" action="/friends/edit">
<% friend_form(Friend) %>
<input type="submit" value="Edit" />
</form>
<% a([".."], "Back") %>

<%@ friend_form(Friend) %>
<table>
<% friend_field(Friend, first_name) %>
<% friend_field(Friend, last_name) %>
<% friend_field(Friend, picture) %>
</table>

<%@ friend_field(Friend, FieldName) %>
<tr>
<td>
<input type="text"
name="<% atom_to_list(FieldName) %>"
value="<% friends:FieldName(Friend) %>" />
</td>
</tr>

This doesn't work for the new page since the FieldName for a Friend is
empty. What do I do so that I can use the same form code for both new
and edit, so that it doesn't crash the code?

I've tried using this function instead of calling friends:FieldName
(Friend) directly:

value(Val) ->
case Val of
undefined ->
"";
_ ->
Val
end.

But it craps out with:
ERROR erlang code crashed:
File: appmod:0
Reason: {badarg,[{erlydb_base,get,2},
{erlyweb,'-render_response_body/7-fun-0-',6},
{erlyweb,'-render_response_body/7-fun-1-',3},
{lists,map,2},
{erlyweb,render_response_body,7},
{erlyweb,handle_request,6},
{yaws_server,deliver_dyn_part,8},
{yaws_server,aloop,3}]}
Req: {http_request,'GET',{abs_path,"/myapp/friends/new"},{1,1}}

What am I doing wrong?

[Yariv Sadan]

Can you double check that the 'friends' module has all the functions
('first_name', 'last_name', and 'picture')? Otherwise the code looks
good I think.

Btw, you should consider instead of passing the 'Friend' object to the
view to pass a function instead that lets the view indirectly access
the Friend object's field. E.g. instead of returning from the
controller function

{data, Friend}

return

{data, fun(Field) -> erlydb_base:field_to_iolist(Friend:Field()) end}

(field_to_iolist() knows how to convert erlydb field values to iolists).

Then, in the view, you can have snippets such as

<%@ show(Friend) %>name: <% Friend(name) %>

which is nicer I think than the original style.


Yariv