--- a/server.py	Thu Feb 12 19:32:36 2009 -0800
+++ b/server.py	Thu Feb 12 20:06:17 2009 -0800
@@ -36,6 +36,7 @@
                 req = atulweb.Request(environ)
                 changeset = req.get_input('application/json')
                 changesets[cid] = changeset
+                return atulweb.Response('changeset committed.')
             else:
                 raise atulweb.HttpError('bad request',
                                         'invalid changeset id')

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/static-files/json2.js	Thu Feb 12 20:06:17 2009 -0800
@@ -0,0 +1,478 @@
+/*
+    http://www.JSON.org/json2.js
+    2008-11-19
+
+    Public Domain.
+
+    NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
+
+    See http://www.JSON.org/js.html
+
+    This file creates a global JSON object containing two methods: stringify
+    and parse.
+
+        JSON.stringify(value, replacer, space)
+            value       any JavaScript value, usually an object or array.
+
+            replacer    an optional parameter that determines how object
+                        values are stringified for objects. It can be a
+                        function or an array of strings.
+
+            space       an optional parameter that specifies the indentation
+                        of nested structures. If it is omitted, the text will
+                        be packed without extra whitespace. If it is a number,
+                        it will specify the number of spaces to indent at each
+                        level. If it is a string (such as '\t' or ' '),
+                        it contains the characters used to indent at each level.
+
+            This method produces a JSON text from a JavaScript value.
+
+            When an object value is found, if the object contains a toJSON
+            method, its toJSON method will be called and the result will be
+            stringified. A toJSON method does not serialize: it returns the
+            value represented by the name/value pair that should be serialized,
+            or undefined if nothing should be serialized. The toJSON method
+            will be passed the key associated with the value, and this will be
+            bound to the object holding the key.
+
+            For example, this would serialize Dates as ISO strings.
+
+                Date.prototype.toJSON = function (key) {
+                    function f(n) {
+                        // Format integers to have at least two digits.
+                        return n < 10 ? '0' + n : n;
+                    }
+
+                    return this.getUTCFullYear()   + '-' +
+                         f(this.getUTCMonth() + 1) + '-' +
+                         f(this.getUTCDate())      + 'T' +
+                         f(this.getUTCHours())     + ':' +
+                         f(this.getUTCMinutes())   + ':' +
+                         f(this.getUTCSeconds())   + 'Z';
+                };
+
+            You can provide an optional replacer method. It will be passed the
+            key and value of each member, with this bound to the containing
+            object. The value that is returned from your method will be
+            serialized. If your method returns undefined, then the member will
+            be excluded from the serialization.
+
+            If the replacer parameter is an array of strings, then it will be
+            used to select the members to be serialized. It filters the results
+            such that only members with keys listed in the replacer array are
+            stringified.
+
+            Values that do not have JSON representations, such as undefined or
+            functions, will not be serialized. Such values in objects will be
+            dropped; in arrays they will be replaced with null. You can use
+            a replacer function to replace those with JSON values.
+            JSON.stringify(undefined) returns undefined.
+
+            The optional space parameter produces a stringification of the
+            value that is filled with line breaks and indentation to make it
+            easier to read.
+
+            If the space parameter is a non-empty string, then that string will
+            be used for indentation. If the space parameter is a number, then
+            the indentation will be that many spaces.
+
+            Example:
+
+            text = JSON.stringify(['e', {pluribus: 'unum'}]);
+            // text is '["e",{"pluribus":"unum"}]'
+
+
+            text = JSON.stringify(['e', {pluribus: 'unum'}], null, '\t');
+            // text is '[\n\t"e",\n\t{\n\t\t"pluribus": "unum"\n\t}\n]'
+
+            text = JSON.stringify([new Date()], function (key, value) {
+                return this[key] instanceof Date ?
+                    'Date(' + this[key] + ')' : value;
+            });
+            // text is '["Date(---current time---)"]'
+
+
+        JSON.parse(text, reviver)
+            This method parses a JSON text to produce an object or array.
+            It can throw a SyntaxError exception.
+
+            The optional reviver parameter is a function that can filter and
+            transform the results. It receives each of the keys and values,
+            and its return value is used instead of the original value.
+            If it returns what it received, then the structure is not modified.
+            If it returns undefined then the member is deleted.
+
+            Example:
+
+            // Parse the text. Values that look like ISO date strings will
+            // be converted to Date objects.
+
+            myData = JSON.parse(text, function (key, value) {
+                var a;
+                if (typeof value === 'string') {
+                    a =
+/^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)Z$/.exec(value);
+                    if (a) {
+                        return new Date(Date.UTC(+a[1], +a[2] - 1, +a[3], +a[4],
+                            +a[5], +a[6]));
+                    }
+                }
+                return value;
+            });
+
+            myData = JSON.parse('["Date(09/09/2001)"]', function (key, value) {
+                var d;
+                if (typeof value === 'string' &&
+                        value.slice(0, 5) === 'Date(' &&
+                        value.slice(-1) === ')') {
+                    d = new Date(value.slice(5, -1));
+                    if (d) {
+                        return d;
+                    }
+                }
+                return value;
+            });
+
+
+    This is a reference implementation. You are free to copy, modify, or
+    redistribute.
+
+    This code should be minified before deployment.
+    See http://javascript.crockford.com/jsmin.html
+
+    USE YOUR OWN COPY. IT IS EXTREMELY UNWISE TO LOAD CODE FROM SERVERS YOU DO
+    NOT CONTROL.
+*/
+
+/*jslint evil: true */
+
+/*global JSON */
+
+/*members "", "\b", "\t", "\n", "\f", "\r", "\"", JSON, "\\", apply,
+    call, charCodeAt, getUTCDate, getUTCFullYear, getUTCHours,
+    getUTCMinutes, getUTCMonth, getUTCSeconds, hasOwnProperty, join,
+    lastIndex, length, parse, prototype, push, replace, slice, stringify,
+    test, toJSON, toString, valueOf
+*/
+
+// Create a JSON object only if one does not already exist. We create the
+// methods in a closure to avoid creating global variables.
+
+if (!this.JSON) {
+    JSON = {};
+}
+(function () {
+
+    function f(n) {
+        // Format integers to have at least two digits.
+        return n < 10 ? '0' + n : n;
+    }
+
+    if (typeof Date.prototype.toJSON !== 'function') {
+
+        Date.prototype.toJSON = function (key) {
+
+            return this.getUTCFullYear()   + '-' +
+                 f(this.getUTCMonth() + 1) + '-' +
+                 f(this.getUTCDate())      + 'T' +
+                 f(this.getUTCHours())     + ':' +
+                 f(this.getUTCMinutes())   + ':' +
+                 f(this.getUTCSeconds())   + 'Z';
+        };
+
+        String.prototype.toJSON =
+        Number.prototype.toJSON =
+        Boolean.prototype.toJSON = function (key) {
+            return this.valueOf();
+        };
+    }
+
+    var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
+        escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
+        gap,
+        indent,
+        meta = {    // table of character substitutions
+            '\b': '\\b',
+            '\t': '\\t',
+            '\n': '\\n',
+            '\f': '\\f',
+            '\r': '\\r',
+            '"' : '\\"',
+            '\\': '\\\\'
+        },
+        rep;
+
+
+    function quote(string) {
+
+// If the string contains no control characters, no quote characters, and no
+// backslash characters, then we can safely slap some quotes around it.
+// Otherwise we must also replace the offending characters with safe escape
+// sequences.
+
+        escapable.lastIndex = 0;
+        return escapable.test(string) ?
+            '"' + string.replace(escapable, function (a) {
+                var c = meta[a];
+                return typeof c === 'string' ? c :
+                    '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
+            }) + '"' :
+            '"' + string + '"';
+    }
+
+
+    function str(key, holder) {
+
+// Produce a string from holder[key].
+
+        var i,          // The loop counter.
+            k,          // The member key.
+            v,          // The member value.
+            length,
+            mind = gap,
+            partial,
+            value = holder[key];
+
+// If the value has a toJSON method, call it to obtain a replacement value.
+
+        if (value && typeof value === 'object' &&
+                typeof value.toJSON === 'function') {
+            value = value.toJSON(key);
+        }
+
+// If we were called with a replacer function, then call the replacer to
+// obtain a replacement value.
+
+        if (typeof rep === 'function') {
+            value = rep.call(holder, key, value);
+        }
+
+// What happens next depends on the value's type.
+
+        switch (typeof value) {
+        case 'string':
+            return quote(value);
+
+        case 'number':
+
+// JSON numbers must be finite. Encode non-finite numbers as null.
+
+            return isFinite(value) ? String(value) : 'null';
+
+        case 'boolean':
+        case 'null':
+
+// If the value is a boolean or null, convert it to a string. Note:
+// typeof null does not produce 'null'. The case is included here in
+// the remote chance that this gets fixed someday.
+
+            return String(value);
+
+// If the type is 'object', we might be dealing with an object or an array or
+// null.
+
+        case 'object':
+
+// Due to a specification blunder in ECMAScript, typeof null is 'object',
+// so watch out for that case.
+
+            if (!value) {
+                return 'null';
+            }
+
+// Make an array to hold the partial results of stringifying this object value.
+
+            gap += indent;
+            partial = [];
+
+// Is the value an array?
+
+            if (Object.prototype.toString.apply(value) === '[object Array]') {
+
+// The value is an array. Stringify every element. Use null as a placeholder
+// for non-JSON values.
+
+                length = value.length;
+                for (i = 0; i < length; i += 1) {
+                    partial[i] = str(i, value) || 'null';
+                }
+
+// Join all of the elements together, separated with commas, and wrap them in
+// brackets.
+
+                v = partial.length === 0 ? '[]' :
+                    gap ? '[\n' + gap +
+                            partial.join(',\n' + gap) + '\n' +
+                                mind + ']' :
+                          '[' + partial.join(',') + ']';
+                gap = mind;
+                return v;
+            }
+
+// If the replacer is an array, use it to select the members to be stringified.
+
+            if (rep && typeof rep === 'object') {
+                length = rep.length;
+                for (i = 0; i < length; i += 1) {
+                    k = rep[i];
+                    if (typeof k === 'string') {
+                        v = str(k, value);
+                        if (v) {
+                            partial.push(quote(k) + (gap ? ': ' : ':') + v);
+                        }
+                    }
+                }
+            } else {
+
+// Otherwise, iterate through all of the keys in the object.
+
+                for (k in value) {
+                    if (Object.hasOwnProperty.call(value, k)) {
+                        v = str(k, value);
+                        if (v) {
+                            partial.push(quote(k) + (gap ? ': ' : ':') + v);
+                        }
+                    }
+                }
+            }
+
+// Join all of the member texts together, separated with commas,
+// and wrap them in braces.
+
+            v = partial.length === 0 ? '{}' :
+                gap ? '{\n' + gap + partial.join(',\n' + gap) + '\n' +
+                        mind + '}' : '{' + partial.join(',') + '}';
+            gap = mind;
+            return v;
+        }
+    }
+
+// If the JSON object does not yet have a stringify method, give it one.
+
+    if (typeof JSON.stringify !== 'function') {
+        JSON.stringify = function (value, replacer, space) {
+
+// The stringify method takes a value and an optional replacer, and an optional
+// space parameter, and returns a JSON text. The replacer can be a function
+// that can replace values, or an array of strings that will select the keys.
+// A default replacer method can be provided. Use of the space parameter can
+// produce text that is more easily readable.
+
+            var i;
+            gap = '';
+            indent = '';
+
+// If the space parameter is a number, make an indent string containing that
+// many spaces.
+
+            if (typeof space === 'number') {
+                for (i = 0; i < space; i += 1) {
+                    indent += ' ';
+                }
+
+// If the space parameter is a string, it will be used as the indent string.
+
+            } else if (typeof space === 'string') {
+                indent = space;
+            }
+
+// If there is a replacer, it must be a function or an array.
+// Otherwise, throw an error.
+
+            rep = replacer;
+            if (replacer && typeof replacer !== 'function' &&
+                    (typeof replacer !== 'object' ||
+                     typeof replacer.length !== 'number')) {
+                throw new Error('JSON.stringify');
+            }
+
+// Make a fake root object containing our value under the key of ''.
+// Return the result of stringifying the value.
+
+            return str('', {'': value});
+        };
+    }
+
+
+// If the JSON object does not yet have a parse method, give it one.
+
+    if (typeof JSON.parse !== 'function') {
+        JSON.parse = function (text, reviver) {
+
+// The parse method takes a text and an optional reviver function, and returns
+// a JavaScript value if the text is a valid JSON text.
+
+            var j;
+
+            function walk(holder, key) {
+
+// The walk method is used to recursively walk the resulting structure so
+// that modifications can be made.
+
+                var k, v, value = holder[key];
+                if (value && typeof value === 'object') {
+                    for (k in value) {
+                        if (Object.hasOwnProperty.call(value, k)) {
+                            v = walk(value, k);
+                            if (v !== undefined) {
+                                value[k] = v;
+                            } else {
+                                delete value[k];
+                            }
+                        }
+                    }
+                }
+                return reviver.call(holder, key, value);
+            }
+
+
+// Parsing happens in four stages. In the first stage, we replace certain
+// Unicode characters with escape sequences. JavaScript handles many characters
+// incorrectly, either silently deleting them, or treating them as line endings.
+
+            cx.lastIndex = 0;
+            if (cx.test(text)) {
+                text = text.replace(cx, function (a) {
+                    return '\\u' +
+                        ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
+                });
+            }
+
+// In the second stage, we run the text against regular expressions that look
+// for non-JSON patterns. We are especially concerned with '()' and 'new'
+// because they can cause invocation, and '=' because it can cause mutation.
+// But just to be safe, we want to reject all unexpected forms.
+
+// We split the second stage into 4 regexp operations in order to work around
+// crippling inefficiencies in IE's and Safari's regexp engines. First we
+// replace the JSON backslash pairs with '@' (a non-JSON character). Second, we
+// replace all simple value tokens with ']' characters. Third, we delete all
+// open brackets that follow a colon or comma or that begin the text. Finally,
+// we look to see that the remaining characters are only whitespace or ']' or
+// ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.
+
+            if (/^[\],:{}\s]*$/.
+test(text.replace(/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g, '@').
+replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').
+replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {
+
+// In the third stage we use the eval function to compile the text into a
+// JavaScript structure. The '{' operator is subject to a syntactic ambiguity
+// in JavaScript: it can begin a block or an object literal. We wrap the text
+// in parens to eliminate the ambiguity.
+
+                j = eval('(' + text + ')');
+
+// In the optional fourth stage, we recursively walk the new structure, passing
+// each name/value pair to a reviver function for possible transformation.
+
+                return typeof reviver === 'function' ?
+                    walk({'': j}, '') : j;
+            }
+
+// If the text is not JSON parseable, then a SyntaxError is thrown.
+
+            throw new SyntaxError('JSON.parse');
+        };
+    }
+})();

--- a/static-files/wiki.css	Thu Feb 12 19:32:36 2009 -0800
+++ b/static-files/wiki.css	Thu Feb 12 20:06:17 2009 -0800
@@ -27,11 +27,11 @@
     margin: 0 auto;
 }
 
-#local-changes {
+#recent-changes {
     display: none;
 }
 
-#local-changes div {
+#recent-changes div {
     cursor: pointer;
 }
 
@@ -71,7 +71,6 @@
 
 .changeset.diffed {
     background: #ffe6e6;
-    color: #000000;
 }
 
 #content {

--- a/static-files/wiki.html	Thu Feb 12 19:32:36 2009 -0800
+++ b/static-files/wiki.html	Thu Feb 12 20:06:17 2009 -0800
@@ -19,8 +19,8 @@
     <img src="http://www.yahoo.com/favicon.ico">
     <img src="http://openid.net/favicon.ico">
   </div>
-  <div id="local-changes">
-    <h1>Local Changes</h1>
+  <div id="recent-changes">
+    <h1>Recent Changes</h1>
   </div>
 </div>
 <div id="content"></div>
@@ -28,6 +28,7 @@
 <script src="jquery.js"></script>
 <script src="jquery.timeago.js"></script>
 <script src="jsdiff.js"></script>
+<script src="json2.js"></script>
 <script src="wikicreole.js"></script>
 <script src="wiki.js"></script>
 </html>

--- a/static-files/wiki.js	Thu Feb 12 19:32:36 2009 -0800
+++ b/static-files/wiki.js	Thu Feb 12 20:06:17 2009 -0800
@@ -38,6 +38,7 @@
   PART_SEPARATOR: "\n\n",
   creole: null,
   editingElement: null,
+  latestRemoteChangeset: null,
   localChanges: [],
   eventHandlers: {}
 };
@@ -60,10 +61,11 @@
   return partsMarkup.join(App.PART_SEPARATOR);
 };
 
-App.saveChanges = function saveChanges(doFadeIn) {
+App.saveChanges = function saveChanges(isUserChange) {
   var markup = App.getMarkup($(window.document));
   var changeset = {date: new Date(),
-                   content: markup};
+                   content: markup,
+                   parentRemoteChangeset: App.latestRemoteChangeset};
   App.localChanges.push(changeset);
   var changesetElem = $('<div class="changeset selected"></div>');
   function setText() {
@@ -76,7 +78,7 @@
 
       aEvt.preventDefault();
       if (aEvt.shiftKey) {
-        $('#local-changes').find('.changeset').removeClass('diffed');
+        $('#recent-changes').find('.changeset').removeClass('diffed');
         var newerVersion = App.getMarkup($("#content"));
         var diff = $('<div class="diff"></div>');
         var markupDiv = $('<div class="creole-markup"></div>');
@@ -87,19 +89,39 @@
         $("#content").append(markupDiv);
         $(this).addClass('diffed');
       } else {
-        $('#local-changes').find('.changeset').removeClass('selected');
-        $('#local-changes').find('.changeset').removeClass('diffed');
+        $('#recent-changes').find('.changeset').removeClass('selected');
+        $('#recent-changes').find('.changeset').removeClass('diffed');
         $(this).addClass('selected');
         $("#content").empty();
         $("#content").append(App.createParts(changeset.content));
       }
     }
   );
-  $('#local-changes').find('.changeset').removeClass('selected');
-  $('#local-changes').find('.changeset').removeClass('diffed');
-  $('#local-changes').find('h1').after(changesetElem);
-  if (doFadeIn)
-    $('#local-changes').fadeIn();
+  $('#recent-changes').find('.changeset').removeClass('selected');
+  $('#recent-changes').find('.changeset').removeClass('diffed');
+  $('#recent-changes').find('h1').after(changesetElem);
+  if (isUserChange) {
+    $('#recent-changes').fadeIn();
+    var maybeNewChangeset = App.latestRemoteChangeset + 1;
+    var jsonData = JSON.stringify({date: changeset.date.toString(),
+                                   content: changeset.content});
+    jQuery.ajax({url: '/' + maybeNewChangeset,
+                 type: 'PUT',
+                 success: function() {
+                   // TODO: Because we're running asynchronously,
+                   // weird things can happen here, e.g. if the user
+                   // makes another edit while the XHR is being
+                   // processed.
+                   App.latestRemoteChangeset = maybeNewChangeset;
+                 },
+                 error: function(xhr, textStatus, errorThrown) {
+                   // TODO: Do something here.
+                 },
+                 dataType: 'text',
+                 processData: false,
+                 contentType: 'application/json',
+                 data: jsonData});
+  }
 };
 
 App.enterEditMode = function enterEditMode(parts, level, cursorPos) {
@@ -121,7 +143,6 @@
     $(this).replaceWith(App.createParts(markup));
     if (markup != originalMarkup) {
       App.saveChanges(true);
-      $('#login').fadeIn();
     }
   }
 
@@ -193,6 +214,7 @@
     });
 
   function onStatus(status) {
+    App.latestRemoteChangeset = status.max_changeset;
     jQuery.get("/" + status.max_changeset,
                {},
                function(obj) {