From 23d30ff6cb0b748f93a41dba9eb905e1c65eac32 Mon Sep 17 00:00:00 2001
From: Yuang Gao <yg2315@nyu.edu>
Date: Sun, 7 Jun 2026 21:30:03 -0700
Subject: [PATCH] feat(services/obs): support if_modified_since and
 if_unmodified_since for read

---
 core/services/obs/src/backend.rs |  2 ++
 core/services/obs/src/core.rs    | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/core/services/obs/src/backend.rs b/core/services/obs/src/backend.rs
index df26deb512c8..3e5b0135bd1d 100644
--- a/core/services/obs/src/backend.rs
+++ b/core/services/obs/src/backend.rs
@@ -216,6 +216,8 @@ impl Builder for ObsBuilder {
 
                             read_with_if_match: true,
                             read_with_if_none_match: true,
+                            read_with_if_modified_since: true,
+                            read_with_if_unmodified_since: true,
 
                             write: true,
                             write_can_empty: true,
diff --git a/core/services/obs/src/core.rs b/core/services/obs/src/core.rs
index 722ef0054d6d..b55c97bfc2a1 100644
--- a/core/services/obs/src/core.rs
+++ b/core/services/obs/src/core.rs
@@ -26,7 +26,9 @@ use http::header::CONTENT_DISPOSITION;
 use http::header::CONTENT_LENGTH;
 use http::header::CONTENT_TYPE;
 use http::header::IF_MATCH;
+use http::header::IF_MODIFIED_SINCE;
 use http::header::IF_NONE_MATCH;
+use http::header::IF_UNMODIFIED_SINCE;
 use opendal_core::raw::*;
 use opendal_core::*;
 use reqsign_core::Signer;
@@ -125,6 +127,14 @@ impl ObsCore {
             req = req.header(IF_NONE_MATCH, if_none_match);
         }
 
+        if let Some(if_modified_since) = args.if_modified_since() {
+            req = req.header(IF_MODIFIED_SINCE, if_modified_since.format_http_date());
+        }
+
+        if let Some(if_unmodified_since) = args.if_unmodified_since() {
+            req = req.header(IF_UNMODIFIED_SINCE, if_unmodified_since.format_http_date());
+        }
+
         let req = req
             .extension(Operation::Read)
             .body(Buffer::new())