From 8fd28a91858d5a530a73773591a199c1091b74c1 Mon Sep 17 00:00:00 2001
From: Jakub Holy <jakub.holy@iterate.no>
Date: Sun, 24 Mar 2013 17:58:01 +0100
Subject: [PATCH 1/2] Better error reporting for external Markdown files

1. Show an alert when loading the file throws an exception
2. Whenever the status isn't success (2xx) - upon exception or e.g.
  "file not found" - replace the section's content with information
  about the failure (instead of being silent about it and showing
  a blank slide).

We need to inform the user something went wrong, not just be silent
about it. An experienced developer, upon seing a blank slide, will
likely check the javascript console - but the rest will profit from
being told about the problem (and solution) explicitely.
---
 plugin/markdown/markdown.js | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/plugin/markdown/markdown.js b/plugin/markdown/markdown.js
index b6b5a9b..11a6fc2 100644
--- a/plugin/markdown/markdown.js
+++ b/plugin/markdown/markdown.js
@@ -101,12 +101,21 @@
 
                 xhr.onreadystatechange = function () {
                     if( xhr.readyState === 4 ) {
-                        section.outerHTML = slidifyMarkdown( xhr.responseText, section.getAttribute('data-separator'), section.getAttribute('data-vertical') );
+                        if (xhr.status >= 200 && xhr.status < 300) {
+                            section.outerHTML = slidifyMarkdown( xhr.responseText, section.getAttribute('data-separator'), section.getAttribute('data-vertical') );
+                        } else {
+                            section.outerHTML = '<section data-state="alert">ERROR: The attempt to fetch ' + url + ' failed with the HTTP status ' + xhr.status +
+                                '. Check your browser\'s JavaScript console for more details.</section>';
+                        }
                     }
                 };
 
                 xhr.open('GET', url, false);
-                xhr.send();
+                try {
+                    xhr.send();
+                } catch (e) {
+                    alert('Failed to get the Markdown file ' + url + '. Make sure that the presentation and the file are served by a HTTP server and the file can be found there. ' + e);
+                }
 
             } else if( section.getAttribute('data-separator') ) {
 

From f6487dc312539bb011434c7a8f9a80bc5b238a7c Mon Sep 17 00:00:00 2001
From: Jakub Holy <jakub.holy@iterate.no>
Date: Sun, 24 Mar 2013 23:30:50 +0100
Subject: [PATCH 2/2] More verbose error slide (HTTP necessary)

---
 plugin/markdown/markdown.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/plugin/markdown/markdown.js b/plugin/markdown/markdown.js
index 11a6fc2..3e31203 100644
--- a/plugin/markdown/markdown.js
+++ b/plugin/markdown/markdown.js
@@ -26,11 +26,11 @@
         return text;
 
     };
-    
+
     var twrap = function(el) {
       return '<script type="text/template">' + el + '</script>';
     };
-    
+
     var slidifyMarkdown = function(markdown, separator, vertical) {
 
         separator = separator || '^\n---\n$';
@@ -105,7 +105,8 @@
                             section.outerHTML = slidifyMarkdown( xhr.responseText, section.getAttribute('data-separator'), section.getAttribute('data-vertical') );
                         } else {
                             section.outerHTML = '<section data-state="alert">ERROR: The attempt to fetch ' + url + ' failed with the HTTP status ' + xhr.status +
-                                '. Check your browser\'s JavaScript console for more details.</section>';
+                                '. Check your browser\'s JavaScript console for more details.' +
+                                '<p>Remember that you need to serve the presentation HTML from a HTTP server and the Markdown file must be there too.</p></section>';
                         }
                     }
                 };