fix: add object notification filtering

Author: garrensmith

docs/buckets/object-notifications.md

@@ -104,6 +104,24 @@ An example notification payload is:
 }
 ```
 
+## Filtering
+
+Object notifications support adding a SQL-like filter to only receive
+notifications that match the filter. The filter is configured in the Tigris
+Dashboard. The filtering can be used to send specific events or object keys that
+match a given prefix. The filtering uses the SQL-like syntax defined in given
+prefix. The filtering uses the SQL-like syntax defined in
+[Metadata Querying](/docs/objects/query-metadata.md).
+
+An example to only receive notifications for a key with a prefix of `images/`:
+
+For example, if you only want to receive notifications for objects in the
+"images" folder, you would use this filter:
+
+```sql
+WHERE key REGEXP "^images"
+```
+
 ## Pricing
 
 See [Pricing](/docs/pricing/index.md) for how object notifications are charged.

docs/objects/query-metadata.md

@@ -10,7 +10,7 @@ The `X-Tigris-Query` field query can be thought of as the `WHERE` clause in a
 SQL query. For instance, to find all objects with a `Content-Type` of
 `text/javascript`, set the header as follows:
 
-- `X-Tigris-Query`: `` `Content-Type` = "text/javascript" ``
+- `X-Tigris-Query`: `` WHERE `Content-Type` = "text/javascript" ``
 
 ## Queryable Fields
 
@@ -20,6 +20,9 @@ Tigris supports querying against the following fields:
 2. `` `Content-Length` ``: The size of the object.
 3. `` `Last-Modified` ``: The date and time the object was last modified in
    [RFC3339](https://www.ietf.org/rfc/rfc3339.txt) format.
+4. `` `key` ``: The key of the object.
+5. `` `Event-Type` ``: The type of the event, this is only supported in
+   [Object Notifications](/docs/buckets/object-notifications.md).
 
 ## SQL Operations
 
@@ -31,6 +34,16 @@ Query supports following comparison operators:
 4. `>=` and `<=`: Greater than or equal and less than or equal
 5. `AND`: Combine multiple conditions in a query.
 
+## In Memory Operations
+
+Tigris supports `IN`, `NOT IN`, and `REGEXP` operators for filtering results.
+Since these operations are performed in memory, they must be combined with SQL
+operations mentioned above. For example:
+
+1. `` WHERE `Content-Type` = "text/plain" AND key REGEXP ".*\.txt$"  ``
+2. `` WHERE `Content-Length` > 1024 AND `Content-Type` IN ("text/javascript", "text/css")  ``.
+3. `` WHERE `Content-Length` != 65536 AND `Content-Type` NOT IN ("text/plain", "text/html")  ``.
+
 ## Order by
 
 You can sort the list using `ORDER BY`. For example, to retrieve all items
@@ -42,11 +55,11 @@ smaller than `64KB` ordered by `Content-Type`:
 
 Example queries that can be performed:
 
-1. `` `Content-Type` = "text/plain" ``
-2. `` `Content-Type` >= "text/c" AND `Content-Type` < "text/j" ``
-3. `` `Content-Length` > 0 ORDER BY `Content-Length` ASC ``
-4. `` `Content-Length` != 65536 AND `Content-Type` = "text/plain" ``
-5. `` `Last-Modified` > "2024-06-23T10:38:46Z" ``
+1. `` WHERE `Content-Type` = "text/plain"  ``
+2. `` WHERE `Content-Type` >= "text/c" AND `Content-Type` < "text/j"  ``
+3. `` WHERE `Content-Length` > 0 ORDER BY `Content-Length` ASC  ``
+4. `` WHERE `Content-Length` != 65536 AND `Content-Type` = "text/plain"  ``
+5. `` WHERE `Last-Modified` > "2024-06-23T10:38:46Z"  ``
 
 ## Next steps