Tests passed.

src/server.cpp

@@ -143,6 +143,11 @@ void Server::setup_routes() {
         handle_get_hash(req, res);
     });
 
+    // Check if object exists by hash or label:tag
+    server_.Get("/exists/(.*)", [this](const httplib::Request& req, httplib::Response& res) {
+        handle_exists(req, res);
+    });
+
     // Get directory listing
     server_.Get("/dir", [this](const httplib::Request& req, httplib::Response& res) {
         handle_get_directory(req, res);
@@ -529,4 +534,48 @@ void Server::handle_append_tag(const httplib::Request& req, httplib::Response& r
     res.set_content(response.dump(), "application/json");
 }
 
+void Server::handle_exists(const httplib::Request& req, httplib::Response& res) {
+    const auto& key = req.matches[1].str();
+    std::string hash_str = key;
+
+    // Check if the key is a label:tag format
+    dbEntry entry;
+    if (db_->get(key, entry)) {
+        // Got it from label:tag, use the hash
+        hash_str = entry.hash;
+    }
+
+    // If we couldn't determine a hash
+    if (hash_str.empty()) {
+        nlohmann::json response = {{"result", "success"}, {"exists", false}};
+        res.set_content(response.dump(), "application/json");
+        return;
+    }
+
+    // Try to interpret the key as a hash directly
+    uint64_t hash_value;
+    try {
+        hash_value = std::stoull(hash_str);
+    } catch (const std::invalid_argument& e) {
+        nlohmann::json response = {{"result", "success"}, {"exists", false}};
+        res.set_content(response.dump(), "application/json");
+        return;
+    }
+
+    std::stringstream oss;
+    oss << hash_value;
+    if (oss.str() != hash_str) {
+        nlohmann::json response = {{"result", "success"}, {"exists", false}};
+        res.set_content(response.dump(), "application/json");
+        return;
+    }
+
+    // Hash is valid, check if the file exists
+    std::filesystem::path file_path = config_.object_store_path / oss.str();
+    bool exists = std::filesystem::exists(file_path) && std::filesystem::is_regular_file(file_path);
+
+    nlohmann::json response = {{"result", "success"}, {"exists", exists}};
+    res.set_content(response.dump(), "application/json");
+}
+
 } // namespace simple_object_storage