Fixes #68

dekobon · dekobon · commit 08814b9b05d9 · 2022-12-14T16:45:12.000-08:00
This commit changes the behavior of the gateway so that by
default when a listing is requested on an empty bucket
a message saying no files are available is displayed. For the
previous behavior (which was returning a 404), it can be enabled
by setting the the following environment variable:
FOUR_O_FOUR_ON_EMPTY_BUCKET=true

Signed-off-by: Elijah Zupancic &lt;e.zupancic@f5.com&gt;
diff --git a/common/etc/nginx/include/listing.xsl b/common/etc/nginx/include/listing.xsl
@@ -15,11 +15,13 @@
 
     </xsl:template>
 
+    <!-- When FOUR_O_FOUR_ON_EMPTY_BUCKET is disabled (the default setting),
+         the following template will be executed when the bucket is empty. -->
     <xsl:template name="no_contents">
         <html>
-            <head><title>Not Found</title></head>
+            <head><title>No Files Available for Listing</title></head>
             <body>
-                <h1>Not Found</h1>
+                <h1>No Files Available for Listing</h1>
             </body>
         </html>
     </xsl:template>
diff --git a/common/etc/nginx/include/s3gateway.js b/common/etc/nginx/include/s3gateway.js
@@ -34,7 +34,7 @@ const DEBUG = _parseBoolean(process.env['S3_DEBUG']);
 const ALLOW_LISTING = _parseBoolean(process.env['ALLOW_DIRECTORY_LIST']);
 const PROVIDE_INDEX_PAGE = _parseBoolean(process.env['PROVIDE_INDEX_PAGE']);
 const APPEND_SLASH = _parseBoolean(process.env['APPEND_SLASH_FOR_POSSIBLE_DIRECTORY']);
-
+const FOUR_O_FOUR_ON_EMPTY_BUCKET = _parseBoolean(process.env['FOUR_O_FOUR_ON_EMPTY_BUCKET']);
 const S3_STYLE = process.env['S3_STYLE'];
 
 const ADDITIONAL_HEADER_PREFIXES_TO_STRIP = _parseArray(process.env['HEADER_PREFIXES_TO_STRIP']);
@@ -501,9 +501,10 @@ function signatureV2(r, bucket, credentials) {
 }
 
 /**
- * Processes the directory listing output as returned from S3 and corrupts the
- * XML output by inserting 'junk' into causing nginx to return a 404 for empty
- * directory listings.
+ * Processes the directory listing output as returned from S3. If
+ * FOUR_O_FOUR_ON_EMPTY_BUCKET is enabled, this function will corrupt the
+ * XML output by inserting the string 'junk' into the output thereby causing
+ * nginx to return a 404 for empty directory listings.
  *
  * If anyone finds a better way to do this, please submit a PR.
  *
@@ -512,20 +513,24 @@ function signatureV2(r, bucket, credentials) {
  * @param flags contains field that indicates that a chunk is last
  */
 function filterListResponse(r, data, flags) {
-    let indexIsEmpty = _parseBoolean(r.variables.indexIsEmpty);
+    if (FOUR_O_FOUR_ON_EMPTY_BUCKET) {
+        let indexIsEmpty = _parseBoolean(r.variables.indexIsEmpty);
 
-    if (indexIsEmpty && data.indexOf('<Contents') >= 0) {
-        r.variables.indexIsEmpty = false;
-        indexIsEmpty = false;
-    }
+        if (indexIsEmpty && data.indexOf('<Contents') >= 0) {
+            r.variables.indexIsEmpty = false;
+            indexIsEmpty = false;
+        }
 
-    if (indexIsEmpty && data.indexOf('<CommonPrefixes') >= 0) {
-        r.variables.indexIsEmpty = false;
-        indexIsEmpty = false;
-    }
+        if (indexIsEmpty && data.indexOf('<CommonPrefixes') >= 0) {
+            r.variables.indexIsEmpty = false;
+            indexIsEmpty = false;
+        }
 
-    if (flags.last && indexIsEmpty) {
-        r.sendBuffer('junk', flags);
+        if (flags.last && indexIsEmpty) {
+            r.sendBuffer('junk', flags);
+        } else {
+            r.sendBuffer(data, flags);
+        }
     } else {
         r.sendBuffer(data, flags);
     }
diff --git a/common/etc/nginx/nginx.conf b/common/etc/nginx/nginx.conf
@@ -26,6 +26,7 @@ env PROXY_CACHE_VALID_OK;
 env PROXY_CACHE_VALID_NOTFOUND;
 env PROXY_CACHE_VALID_FORBIDDEN;
 env HEADER_PREFIXES_TO_STRIP;
+env FOUR_O_FOUR_ON_EMPTY_BUCKET;
 
 events {
     worker_connections  1024;
