fix(frontend-canister): allow overwriting default HTTP headers (#2689)

Change to use HashMap instead of Vec to aggregate HTTP Headers, and also cast all HTTP Header keys lowercase. This change required an updating asset canister wasm.

Author: Marcin Nowak-Liebiediew

CHANGELOG.md

@@ -4,6 +4,22 @@
 
 ## DFX
 
+### fix(frontend-canister): Allow overwriting default HTTP Headers for assets in frontend canister 
+
+Allows to overwrite `Content-Type`, `Content-Encoding`, and `Cache-Control` HTTP headers with custom values via `.ic-assets.json5` config file. Example `.ic-assets.json5` file:
+```json5
+[
+    {
+        "match": "web-gz.data.gz",
+        "headers": {
+            "Content-Type": "application/octet-stream",
+            "Content-Encoding": "gzip"
+        }
+    }
+]
+```
+This change will trigger the update process for frontend canister (new module hash: `2ff0513123f11c57716d889ca487083fac7d94a4c9434d5879f8d0342ad9d759`). 
+
 ### fix: Save SNS canister IDs
 
 SNS canister IDs were not being parsed reliably.  Now the candid file is being specified explicitly, which resolves the issue in at least some cases.
@@ -501,6 +517,10 @@ Updated ic-ref to 0.0.1-1fba03ee
 - Module hash: b944b1e5533064d12e951621d5045d5291bcfd8cf9d60c28fef02c8fdb68e783
 - https://github.com/dfinity/cycles-wallet/commit/fa86dd3a65b2509ca1e0c2bb9d7d4c5be95de378
 
+### Frontend canister:
+- Module hash: 2ff0513123f11c57716d889ca487083fac7d94a4c9434d5879f8d0342ad9d759
+- https://github.com/dfinity/sdk/pull/2689
+
 # 0.11.2
 
 ## DFX

e2e/tests-dfx/assetscanister.bash

@@ -506,3 +506,36 @@ CHERRIES" "$stdout"
     assert_match "HTTP/1.1 404 Not Found"
 
 }
+
+@test "asset configuration via .ic-assets.json5 - overwriting default headers" {
+    install_asset assetscanister
+
+    dfx_start
+
+    touch src/e2e_project_frontend/assets/thing.json
+
+    echo '[
+      {
+        "match": "thing.json",
+        "cache": { "max_age": 2000 },
+        "headers": {
+          "Content-Encoding": "my-encoding",
+          "Content-Type": "x-type",
+          "Cache-Control": "custom",
+          "etag": "my-etag"
+        }
+      }
+    ]' > src/e2e_project_frontend/assets/.ic-assets.json5
+
+    dfx deploy
+
+    ID=$(dfx canister id e2e_project_frontend)
+    PORT=$(get_webserver_port)
+
+    assert_command curl --head "http://localhost:$PORT/thing.json?canisterId=$ID"
+    assert_match "cache-control: custom"
+    assert_match "content-encoding: my-encoding"
+    assert_match "content-type: x-type"
+    assert_not_match "etag: my-etag"
+    assert_match "etag: \"[a-z0-9]{64}\""
+}

src/canisters/frontend/ic-certified-assets/src/state_machine.rs

@@ -709,19 +709,19 @@ fn build_ok(
     callback: Func,
     etags: Vec<Hash>,
 ) -> HttpResponse {
-    let mut headers = vec![("Content-Type".to_string(), asset.content_type.to_string())];
+    let mut headers = HashMap::from([("content-type".to_string(), asset.content_type.to_string())]);
     if enc_name != "identity" {
-        headers.push(("Content-Encoding".to_string(), enc_name.to_string()));
+        headers.insert("content-encoding".to_string(), enc_name.to_string());
     }
     if let Some(head) = certificate_header {
-        headers.push(head);
+        headers.insert(head.0, head.1);
     }
     if let Some(max_age) = asset.max_age {
-        headers.push(("Cache-Control".to_string(), format!("max-age={}", max_age)));
+        headers.insert("cache-control".to_string(), format!("max-age={}", max_age));
     }
     if let Some(arg_headers) = asset.headers.as_ref() {
         for (k, v) in arg_headers {
-            headers.push((k.to_owned(), v.to_owned()));
+            headers.insert(k.to_owned().to_lowercase(), v.to_owned());
         }
     }
 
@@ -731,16 +731,16 @@ fn build_ok(
     let (status_code, body) = if etags.contains(&enc.sha256) {
         (304, RcBytes::default())
     } else {
-        headers.push((
-            "ETag".to_string(),
+        headers.insert(
+            "etag".to_string(),
             format!("\"{}\"", hex::encode(enc.sha256)),
-        ));
+        );
         (200, enc.content_chunks[chunk_index].clone())
     };
 
     HttpResponse {
         status_code,
-        headers,
+        headers: headers.into_iter().collect::<_>(),
         body,
         streaming_strategy,
     }