[LON-CAPA-cvs] cvs: loncom /xml lontexconvert.pm

[raeburn]

raeburn		Thu Feb 10 19:28:29 2011 EDT

  Modified files:              
    /loncom/xml	lontexconvert.pm 
  Log:
  - Bugs: 5925, 6424.
    - Eliminate separate call for SSL servers to IO::Socket::SSL to retrieve
      vertical alignment for mimetex images. Use IO::Socket::INET for both
      SSL and non-SSL web servers. Rewrite rules may need to be changed on
      SSL web servers to serve HEAD requests for /cgi-bin/mimetex.cgi from port 80.
  
  
Index: loncom/xml/lontexconvert.pm
diff -u loncom/xml/lontexconvert.pm:1.104 loncom/xml/lontexconvert.pm:1.105
--- loncom/xml/lontexconvert.pm:1.104	Thu Jun 10 15:54:06 2010
+++ loncom/xml/lontexconvert.pm	Thu Feb 10 19:28:29 2011
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.104 2010/06/10 15:54:06 bisitz Exp $
+# $Id: lontexconvert.pm,v 1.105 2011/02/10 19:28:29 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -49,7 +49,6 @@
 use LONCAPA;
 use URI::Escape;
 use IO::Socket::INET;
-use IO::Socket::SSL;
 
 # ====================================================================== Header
 
@@ -248,19 +247,12 @@
     my $valign = 0;
     my $lonhost = $Apache::lonnet::perlvar{'lonHostID'};
     my $hostname = &Apache::lonnet::hostname($lonhost);
-    my $protocol = $Apache::lonnet::protocol{$lonhost};
     my $path = '/cgi-bin/mimetex.cgi?'.$esc_texstring;
     my $socket;
     &Apache::lonxml::start_alarm();
-    if ($protocol eq 'https') {
-        $socket = IO::Socket::SSL->new(PeerAddr => $hostname,
-                                       PeerPort => 'https(443)',
-                                       Proto    => 'tcp');
-    } else {
-        $socket = IO::Socket::INET->new(PeerAddr => $hostname,
+    my $socket = IO::Socket::INET->new(PeerAddr => $hostname,
                                         PeerPort => 'http(80)',
                                         Proto    => 'tcp');
-    }
     if ($socket) {
         my $headreq = "HEAD $path HTTP/1.0\r\n\r\n";
         print $socket $headreq;
@@ -269,12 +261,7 @@
                 $valign = $1;
             }
         }
-        if ($protocol eq 'https') {
-            $socket->close(SSL_no_shutdown => 1,
-                           SSL_ctx_free => 1);
-        } else {
-            $socket->close();
-        }
+        $socket->close();
     }
     &Apache::lonxml::end_alarm();
     return $valign;
@@ -528,6 +515,39 @@
 
 =item init_math_support()
 
+=item mimetex_valign()
+
+ Makes a HEAD call to /cgi-bin/mimetex.cgi via IO:: to retrieve the 
+ vertical alignment, before the subsequent call to mimetex_converted()
+ which generates the <img> tag and the corresponding image.
+
+ Input: 1.  $esc_texstring (escaped TeX to be rendered by mimetex).
+ Output: 1. $valign - number of pixels: positive or negative integer 
+            which will be included in <img> tag for mimetex image to
+            support vertical alignment of image within a line of text.
+
+ If a server is running SSL, and Apache rewrite rules are in place 
+ to rewrite requests for http to https, modification will most likely 
+ be needed for pass through for HEAD requests for /cgi-bin/mimetex.cgi. 
+
+ Example rewrite rules which rewrite all http traffic to https, 
+ except HEAD requests for /cgi-bin/mimetex.cgi are:
+
+ <IfModule mod_rewrite.c>
+     RewriteEngine On
+     RewriteLogLevel 0
+
+     RewriteCond %{HTTPS} off
+     RewriteCond %{HTTP:Host} (.*)
+     RewriteCond %{REQUEST_METHOD} !HEAD 
+     RewriteRule ^/(.*) https://%1/$1 [R=301,L]
+
+     RewriteCond %{HTTPS} off
+     RewriteCond %{HTTP:Host} (.*)
+     RewriteCond %{REQUEST_METHOD} HEAD
+     RewriteCond %{REQUEST_URI} !^/cgi-bin/mimetex.cgi
+     RewriteRule ^/(.*) https://%1/$1 [R=301,L]
+ </IfModule>
 
 =item mimetex_converted()