feat: support set response header if not exists

examples/grpc-web.toml

@@ -70,16 +70,12 @@ plugins = ["grpc-web-static"]
 [plugins.grpc-web-static]
 category = "directory"
 path = "~/tmp/grpc/commonjs-example"
-step = "request"
 
 [servers.grpc-web]
 addr = "127.0.0.1:3000"
 enabled_h2 = true
 global_certificates = true
-locations = [
-    "grpc-web",
-    "grpc-server",
-]
+locations = ["grpc-web", "grpc-server"]
 modules = ["grpc-web"]
 
 [upstreams.grpc-server]

examples/proxy-upstream.toml

@@ -13,7 +13,6 @@ category = "cache"
 headers = ["Accept-Encoding"]
 max_ttl = "1h"
 namespace = "charts"
-step = "request"
 
 [servers.charts]
 addr = "127.0.0.1:3000"

examples/static-serve.toml

@@ -8,7 +8,6 @@ plugins = [
 [plugins.staticServe]
 category = "directory"
 path = "~/github/pingap/dist"
-step = "request"
 
 [servers.staticServe]
 addr = "127.0.0.1:3000"

src/plugin/response_headers.rs

@@ -59,6 +59,13 @@ pub struct ResponseHeaders {
     ///     Example: [("x-old-header", "x-new-header")]
     rename_headers: Vec<(HeaderName, HeaderName)>,
 
+    /// Headers to be set only if they don't already exist in the response
+    /// - Only sets the header if it's not present
+    /// - Does not modify existing header values
+    /// - Format: Vec of (header_name, header_value) pairs
+    ///     Example: [("x-default-header", "default-value")]
+    set_headers_not_exists: Vec<HttpHeader>,
+
     /// Unique identifier for this plugin instance
     /// Generated from the plugin configuration to track changes
     hash_value: String,
@@ -139,13 +146,25 @@ impl TryFrom<&PluginConf> for ResponseHeaders {
                 rename_headers.push((original_name, new_name));
             }
         }
+        let mut set_headers_not_exists = vec![];
+        for item in get_str_slice_conf(value, "set_headers_not_exists").iter() {
+            let header = convert_header(item).map_err(|e| Error::Invalid {
+                category: PluginCategory::ResponseHeaders.to_string(),
+                message: e.to_string(),
+            })?;
+            if let Some(item) = header {
+                set_headers_not_exists.push(item);
+            }
+        }
+
         let params = Self {
             hash_value,
             plugin_step: step,
             add_headers,
             set_headers,
             remove_headers,
             rename_headers,
+            set_headers_not_exists,
         };
 
         if params.plugin_step != PluginStep::Response {
@@ -252,6 +271,17 @@ impl Plugin for ResponseHeaders {
             }
         }
 
+        // Set headers that don't exist (conditional set)
+        for (name, value) in &self.set_headers_not_exists {
+            if !upstream_response.headers.contains_key(name) {
+                if let Some(value) = convert_header_value(value, session, ctx) {
+                    let _ = upstream_response.insert_header(name, value);
+                } else {
+                    let _ = upstream_response.insert_header(name, value);
+                }
+            }
+        }
+
         // Rename headers (move values to new name)
         for (original_name, new_name) in &self.rename_headers {
             if let Some(value) = upstream_response.remove_header(original_name)
@@ -337,6 +367,10 @@ set_headers = [
 ]
 remove_headers = [
     "Content-Type"
+]
+set_headers_not_exists = [
+    "X-Response-Id:abc",
+    "X-Tag:userTag",
 ]
     "###,
             )
@@ -369,7 +403,7 @@ remove_headers = [
             .unwrap();
 
         assert_eq!(
-            r###"ResponseHeader { base: Parts { status: 200, version: HTTP/1.1, headers: {"x-service": "1", "x-service": "2", "x-response-id": "123"} }, header_name_map: None, reason_phrase: None }"###,
+            r###"ResponseHeader { base: Parts { status: 200, version: HTTP/1.1, headers: {"x-service": "1", "x-service": "2", "x-response-id": "123", "x-tag": "userTag"} }, header_name_map: None, reason_phrase: None }"###,
             format!("{upstream_response:?}")
         )
     }

web/src/i18n/en.ts

@@ -422,6 +422,9 @@ export default {
     responseHeadersRenameHeader: "Rename Header",
     responseHeadersRenamePlaceholder:
       "Input the original header name : Input the new header name",
+    responseHeadersSetHeaderNotExists: "Set Header If Not Exists",
+    responseHeadersSetHeaderNotExistsPlaceholder:
+      "Input the header name : Input the header value",
     responseHeadersRemoveHeader: "Remove Header",
     responseHeadersRemoveHeaderPlaceholder: "Input the header name",
     combinedAuthAuthorizations: "Authorizations",

web/src/i18n/zh.ts

@@ -400,6 +400,9 @@ export default {
     responseHeadersRenameHeader: "修改响应头",
     responseHeadersRenamePlaceholder:
       "输入原来的响应头名称 : 输入新的响应头名称",
+    responseHeadersSetHeaderNotExists: "设置响应头(不存在时)",
+    responseHeadersSetHeaderNotExistsPlaceholder:
+      "输入设置响应头的名称 : 输入设置响应头的值",
     responseHeadersRemoveHeader: "删除响应头",
     responseHeadersRemoveHeaderPlaceholder: "输入响应头名称",
     combinedAuthAuthorizations: "认证配置列表",

web/src/pages/Plugins.tsx

@@ -954,6 +954,14 @@ export default function Plugins() {
           span: 6,
           category: ExFormItemCategory.KV_LIST,
         },
+        {
+          name: "set_headers_not_exists",
+          label: pluginI18n("responseHeadersSetHeaderNotExists"),
+          placeholder: pluginI18n("responseHeadersSetHeaderNotExistsPlaceholder"),
+          defaultValue: pluginConfig.set_headers_not_exists as string[],
+          span: 6,
+          category: ExFormItemCategory.KV_LIST,
+        },
       );
       break;
     }