From e03c3623025d1f59d73321d9905541a8f2ffbeae Mon Sep 17 00:00:00 2001
From: "xinhui.li" <xinhui.li@salesforce.com>
Date: Sat, 4 Mar 2023 20:44:07 -0800
Subject: [PATCH] try if trust-dns-resolver works or not

---
 examples/http_headers/Cargo.toml |  3 +++
 examples/http_headers/src/lib.rs | 46 ++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/examples/http_headers/Cargo.toml b/examples/http_headers/Cargo.toml
index 02afd242..91310af1 100644
--- a/examples/http_headers/Cargo.toml
+++ b/examples/http_headers/Cargo.toml
@@ -13,6 +13,9 @@ crate-type = ["cdylib"]
 [dependencies]
 log = "0.4"
 proxy-wasm = { path = "../../" }
+trust-dns-resolver = "0.22.0"
+tokio = "1.26.0"
+hostname = "^0.3"
 
 [profile.release]
 lto = true
diff --git a/examples/http_headers/src/lib.rs b/examples/http_headers/src/lib.rs
index 315a7b88..38099de6 100644
--- a/examples/http_headers/src/lib.rs
+++ b/examples/http_headers/src/lib.rs
@@ -12,6 +12,37 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::net::*;
+use trust_dns_resolver::Resolver;
+use trust_dns_resolver::config::*;
+
+use std::{
+    net::*,
+    str::FromStr,
+    sync::{Arc, Mutex as StdMutex},
+};
+
+use tokio::runtime::Runtime;
+
+use trust_dns_proto::{
+    op::{NoopMessageFinalizer, Query},
+    rr::{DNSClass, Name, RData, Record, RecordType},
+    xfer::{DnsExchange, DnsMultiplexer, DnsResponse},
+    TokioTime,
+};
+use trust_dns_resolver::{
+    caching_client::CachingClient,
+    config::LookupIpStrategy,
+    error::ResolveError,
+    lookup::{Lookup, LookupFuture},
+    lookup_ip::LookupIpFuture,
+    Hosts,
+};
+use trust_dns_server::{
+    authority::{Authority, Catalog},
+    store::in_memory::InMemoryAuthority,
+};
+
 use log::info;
 use proxy_wasm::traits::*;
 use proxy_wasm::types::*;
@@ -43,10 +74,25 @@ impl Context for HttpHeaders {}
 
 impl HttpContext for HttpHeaders {
     fn on_http_request_headers(&mut self, _: usize, _: bool) -> Action {
+        
+        let lookup = LookupFuture::lookup(
+            vec![Name::from_str("www.example.com.").unwrap()],
+            RecordType::A,
+            Default::default(),
+            CachingClient::new(0, client, false),
+        );
+    
+        let io_loop = Runtime::new().unwrap();
+        let lookup = io_loop.block_on(lookup).unwrap();
+
+        self.set_http_request_header("wasm-request-header-xh", lookup);
+        
         for (name, value) in &self.get_http_request_headers() {
             info!("#{} -> {}: {}", self.context_id, name, value);
         }
 
+        
+
         match self.get_http_request_header(":path") {
             Some(path) if path == "/hello" => {
                 self.send_http_response(