--- loncom/interface/lonsearchcat.pm	2001/03/15 18:51:09	1.20
+++ loncom/interface/lonsearchcat.pm	2001/03/15 19:36:42	1.30
@@ -424,6 +424,20 @@ sub advancedsearch {
     my ($r,$envhash)=@_;
     my %ENV=%{$envhash};
 
+    $r->print(<<END);
+Advanced searching is not yet implemented.
+END
+    return OK;
+}
+
+# ---------------------------------------------------- see if a field is filled
+sub filled {
+    if (/\S/) {
+	return 1;
+    }
+    else {
+	return 0;
+    }
 }
 
 # --------------------------------------------------- Performing a basic search
@@ -431,6 +445,11 @@ sub basicsearch {
     my ($r,$envhash)=@_;
     my %ENV=%{$envhash};
 
+    unless (&filled($ENV{'form.basicexp'})) {
+	&output_blank_field_error($r);
+	return OK;
+    }
+
     my $query=$ENV{'form.basicexp'};
     $query="select * from metadata where concat(title,\"    \",author) like '\%$ENV{'form.basicexp'}\%'";
     my $reply=&Apache::lonnet::metadata_query($query);
@@ -438,6 +457,50 @@ sub basicsearch {
     return OK;
 }
 
+sub output_blank_field_error {
+    my ($r)=@_;
+    # make query information persistent to allow for subsequent revision
+    my $persistent='';
+    map {
+	if (/^form\./ && !/submit/) {
+	    my $name=$_;
+	    my $key=$name;
+	    $name=~s/^form\.//;
+	    $persistent.=<<END;
+<INPUT TYPE='hidden' NAME='$name' VALUE='$ENV{$key}'>
+END
+        }
+    } (keys %ENV);
+
+    $r->print(<<BEGINNING);
+<html>
+<head>
+<title>The LearningOnline Network with CAPA</title>
+BEGINNING
+    $r->print(<<RESULTS);
+</head>
+<body bgcolor="#ffffff">
+<img align=right src=/adm/lonIcons/lonlogos.gif>
+<h1>Search Catalog</h1>
+<form method="post" action="/adm/searchcat">
+$persistent
+<input type='button' value='Revise search request'
+onClick='this.form.submit();'>
+<input type='button' value='CLOSE'
+onClick='self.close();'>
+<hr>
+<h3>Helpful Message</h3>
+<p>
+Incorrect search query due to blank entry fields.
+You need to fill in the relevant
+fields on the search page in order for a query to be
+processed.
+</p>
+</body>
+</html>
+RESULTS
+}
+
 # ----------------------------- format and output results based on a reply list
 sub output_results {
     my ($r,$envhash,@replylist)=@_;
@@ -483,7 +546,7 @@ onClick="javascript:select_data('$title'
 <br>
 END
             $compiledresult.=<<END;
-<b>URL: </b> <A HREF="http://$ENV{'HTTP_HOST'}/$url" TARGET='search_preview'>$url</A>
+<b>URL: </b> <A HREF="http://$ENV{'HTTP_HOST'}$url" TARGET='search_preview'>$url</A>
 <br>
 <b>Title:</b> $title<br>
 <b>Author(s):</b> $author<br>
