From f22f1cafd254fef1dcf78fcd5007a1533baffb75 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20S=CC=8Ckoda?= <commits@skodak.org>
Date: Mon, 25 Mar 2013 16:06:02 +0100
Subject: [PATCH] MDL-38627 force byteserving abort on error

It is weird, but Chrome PDF viewer keeps retrying byteserving requests for anything but 407. This commit also normalises response headers on all error pages.
---
 lib/moodlelib.php       |  5 +++++
 lib/outputrenderers.php | 14 +++++++++-----
 lib/setuplib.php        |  9 +++------
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index a53a8de8fb8..fd1f8167293 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -2817,6 +2817,11 @@ function get_login_url() {
 function require_login($courseorid = NULL, $autologinguest = true, $cm = NULL, $setwantsurltome = true, $preventredirect = false) {
     global $CFG, $SESSION, $USER, $PAGE, $SITE, $DB, $OUTPUT;
 
+    // Must not redirect when byteserving already started.
+    if (!empty($_SERVER['HTTP_RANGE'])) {
+        $preventredirect = true;
+    }
+
     // setup global $COURSE, themes, language and locale
     if (!empty($courseorid)) {
         if (is_object($courseorid)) {
diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 019f01982ea..1c014595e39 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -2317,12 +2317,16 @@ EOD;
             }
             error_reporting($CFG->debug);
 
-            // Header not yet printed
-            if (isset($_SERVER['SERVER_PROTOCOL'])) {
-                // server protocol should be always present, because this render
-                // can not be used from command line or when outputting custom XML
-                @header($_SERVER['SERVER_PROTOCOL'] . ' 404 Not Found');
+            // Output not yet started.
+            $protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');
+            if (empty($_SERVER['HTTP_RANGE'])) {
+                @header($protocol . ' 404 Not Found');
+            } else {
+                // Must stop byteserving attempts somehow,
+                // this is weird but Chrome PDF viewer can be stopped only with 407!
+                @header($protocol . ' 407 Proxy Authentication Required');
             }
+
             $this->page->set_context(null); // ugly hack - make sure page context is set to something, we do not want bogus warnings here
             $this->page->set_url('/'); // no url
             //$this->page->set_pagelayout('base'); //TODO: MDL-20676 blocks on error pages are weird, unfortunately it somehow detect the pagelayout from URL :-(
diff --git a/lib/setuplib.php b/lib/setuplib.php
index 129147a9b1d..e8258447f81 100644
--- a/lib/setuplib.php
+++ b/lib/setuplib.php
@@ -1547,12 +1547,9 @@ width: 80%; -moz-border-radius: 20px; padding: 15px">
         }
 
         // In the name of protocol correctness, monitoring and performance
-        // profiling, set the appropriate error headers for machine consumption
-        if (isset($_SERVER['SERVER_PROTOCOL'])) {
-            // Avoid it with cron.php. Note that we assume it's HTTP/1.x
-            // The 503 ode here means our Moodle does not work at all, the error happened too early
-            @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
-        }
+        // profiling, set the appropriate error headers for machine consumption.
+        $protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');
+        @header($protocol . ' 503 Service Unavailable');
 
         // better disable any caching
         @header('Content-Type: text/html; charset=utf-8');