From f5c87a14fa972b147a6759c83e55e660d9e21eeb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Konstantin=20Ka=CC=88fer?= <github@kkaefer.com>
Date: Tue, 28 Jun 2011 16:47:23 +0200
Subject: [PATCH] pass header information with a .getTile() request

---
 lib/mbtiles.js | 20 ++++++++++++++++----
 lib/utils.js   | 15 +++++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/lib/mbtiles.js b/lib/mbtiles.js
index 6ddd23c..d385df6 100644
--- a/lib/mbtiles.js
+++ b/lib/mbtiles.js
@@ -24,14 +24,19 @@ MBTiles.utils = require('./utils');
 // - callback: Will be called when the resources have been acquired
 //       or acquisition failed.
 function MBTiles(uri, callback) {
+    var mbtiles = this;
     if (typeof callback !== 'function') callback = noop;
     if (typeof uri === 'string') uri = url.parse(uri);
 
     this.filename = uri.pathname;
-    this.db = new sqlite3.cached.Database(uri.pathname, function(err) {
+    this.db = new sqlite3.cached.Database(mbtiles.filename, function(err) {
         if (err) return callback(err);
-        else callback(null, this);
-    }.bind(this));
+        else fs.stat(mbtiles.filename, function(err, stat) {
+            if (err) return callback(err);
+            mbtiles.stat = stat;
+            callback(null, mbtiles);
+        });
+    });
 };
 
 // Finds all mbtiles file in the filepath and returns their tilesource URI.
@@ -279,7 +284,14 @@ MBTiles.prototype.getTile = function(z, x, y, callback) {
         function(err, row) {
             if (!row || (err && err.errno == 1)) callback(new Error('Tile does not exist'));
             else if (err) callback(err);
-            else callback(null, row.tile_data);
+            else {
+                var options = {
+                    'Content-Type': MBTiles.utils.getMimeType(row.tile_data),
+                    'Last-Modified': mbtiles.stat.mtime,
+                    'E-Tag': mbtiles.stat.size + '-' + Number(mbtiles.stat.mtime)
+                };
+                callback(null, row.tile_data, options);
+            }
         });
 };
 
diff --git a/lib/utils.js b/lib/utils.js
index 1f0387c..37146ae 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -20,6 +20,21 @@ utils.table = function(fields) {
     });
 };
 
+utils.getMimeType = function(data) {
+    if (data[0] === 0x89 && data[1] === 0x50 && data[2] === 0x4E &&
+        data[3] === 0x47 && data[4] === 0x0D && data[5] === 0x0A &&
+        data[6] === 0x1A && data[7] === 0x0A) {
+        return 'image/png';
+    } else if (data[0] === 0xFF && data[1] === 0xD8 &&
+        data[data.length - 2] === 0xFF && data[data.length - 1] === 0xD9) {
+        return 'image/jpeg';
+    } else if (data[0] === 0x47 && data[1] === 0x49 && data[2] === 0x46 &&
+        data[3] === 0x38 && (data[4] === 0x39 || data[4] === 0x37) &&
+        data[5] === 0x61) {
+        return 'image/gif';
+    }
+};
+
 function Queue(callback, concurrency) {
     this.callback = callback;
     this.concurrency = concurrency || 10;