No longer serve Expires header; it is not needed.

[remoteglot] / www / serve-analysis.js

diff --git a/www/serve-analysis.js b/www/serve-analysis.js
index 10a3e55545d18b9a5af7cc6143c5899a93ea0f5b..edb4a18a9db7b6a933d77771f244806995525304 100644 (file)
--- a/www/serve-analysis.js
+++ b/www/serve-analysis.js
@@ -14,6 +14,10 @@ var delta = require('./js/json_delta.js');
 var JSON_FILENAME = '/srv/analysis.sesse.net/www/analysis.json';
 var HISTORY_TO_KEEP = 5;
 
+// If set to 1, we are already processing a JSON update and should not
+// start a new one. If set to 2, we are _also_ having one in the queue.
+var json_lock = 0;
+
 // The current contents of the file to hand out, and its last modified time.
 var json = undefined;
 
@@ -69,6 +73,7 @@ var replace_json = function(new_json_contents, mtime) {
                        new_json.gzip = buffer;
                        json = new_json;
                        diff_json = new_diff_json;
+                       json_lock = 0;
 
                        // Finally, wake up any sleeping clients.
                        possibly_wakeup_clients();
@@ -101,6 +106,17 @@ var reread_file = function(event, filename) {
        if (filename != path.basename(JSON_FILENAME)) {
                return;
        }
+       if (json_lock >= 2) {
+               return;
+       }
+       if (json_lock == 1) {
+               // Already processing; wait a bit.
+               json_lock = 2;
+               setTimeout(function() { json_lock = 1; reread_file(event, filename); }, 100);
+               return;
+       }
+       json_lock = 1;
+
        console.log("Rereading " + JSON_FILENAME);
        fs.open(JSON_FILENAME, 'r+', function(err, fd) {
                if (err) throw err;
@@ -167,7 +183,6 @@ var send_json = function(response, ims, accept_gzip, num_viewers) {
                'X-Remoteglot-Last-Modified': this_json.last_modified,
                'X-Remoteglot-Num-Viewers': num_viewers,
                'Access-Control-Expose-Headers': 'X-Remoteglot-Last-Modified, X-Remoteglot-Num-Viewers',
-               'Expires': 'Mon, 01 Jan 1970 00:00:00 UTC',
                'Vary': 'Accept-Encoding',
        };