feat: header in http processor

fastn-core/src/http.rs

@@ -908,7 +908,7 @@
 }
 
 #[cfg(test)]
 mod test {
     use actix_web::body::MessageBody;
     use pretty_assertions::assert_eq;
 
@@ -1016,3 +1016,14 @@
         Ok(())
     }
 }
+
+static HEADER_KEY_PATTERN: once_cell::sync::Lazy<regex::Regex> =
+    once_cell::sync::Lazy::new(|| regex::Regex::new(r"\$header-(\w+)\$").unwrap());
+
+pub(crate) fn match_header_key(header_key: &str) -> Option<String> {
+    if let Some(captures) = HEADER_KEY_PATTERN.captures(header_key) {
+        return captures.get(1).map(|c| c.as_str().to_string());
+    }
+
+    None
+}

fastn-core/src/library2022/processor/http.rs

@@ -84,7 +84,7 @@ pub async fn process(
                 .get_value(header.line_number, value.as_str())?
                 .to_json_string(doc, true)?
             {
-                if let Some(key) = header.key.strip_prefix("header-") {
+                if let Some(key) = fastn_core::http::match_header_key(header.key.as_str()) {
                     conf.insert(key.to_string(), value);
                     continue;
                 }
@@ -96,7 +96,7 @@ pub async fn process(
                     .append_pair(header.key.as_str(), value.trim_matches('"'));
             }
         } else {
-            if let Some(key) = header.key.strip_prefix("header-") {
+            if let Some(key) = fastn_core::http::match_header_key(header.key.as_str()) {
                 conf.insert(key.to_string(), value);
                 continue;
             }

ftd/src/ast/kind.rs

@@ -622,7 +622,9 @@ impl VariableValue {
             })
             .map(|header| {
                 let key = header.get_key();
-                let header_key = if ftd::ast::utils::is_variable_mutable(key.as_str()) {
+                let header_key = if ftd::ast::utils::is_variable_mutable(key.as_str())
+                    && !ftd::ast::utils::is_header_key(key.as_str())
+                {
                     key.trim_start_matches(ftd::ast::utils::REFERENCE)
                 } else {
                     key.as_str()

ftd/src/ast/utils.rs

@@ -74,6 +74,10 @@ pub(crate) fn get_css_and_fields_from_headers(
     Ok((css, fields))
 }
 
+pub(crate) fn is_header_key(key: &str) -> bool {
+    key.starts_with(HEADER_KEY_START) && key.ends_with('$')
+}
+
 pub const REFERENCE: &str = "$";
 pub const CLONE: &str = "*$";
 pub const LOOP: &str = "$loop$";
@@ -82,3 +86,4 @@ pub const IN: &str = " in ";
 pub const IF: &str = "if";
 pub const FOR: &str = "for";
 pub const PROCESSOR: &str = "$processor$";
+pub const HEADER_KEY_START: &str = "$header-";