Merge pull request #517 from pact-foundation/fix/pact-js-issue-1058

fix: only split known multi-value HTTP headers on commas

Author: rholshausen

rust/pact_matching/src/headers.rs

@@ -101,7 +101,14 @@ pub(crate) fn match_header_value(
   } else if PARAMETERISED_HEADERS.contains(&key.to_lowercase().as_str()) {
     match_parameter_header(expected, actual, key, "header", index, single_value)
   } else {
-    MatchingRule::Equality.match_value(expected, actual, false, false)
+    // Normalize whitespace around commas for comparison, since RFC 7230 allows optional whitespace
+    // after commas in header values. This ensures "a,b" matches "a, b".
+    let normalize_comma_whitespace = |s: &str| -> String {
+      s.split(',').map(|v| v.trim()).collect::<Vec<_>>().join(",")
+    };
+    let normalized_expected = normalize_comma_whitespace(expected);
+    let normalized_actual = normalize_comma_whitespace(actual);
+    MatchingRule::Equality.match_value(normalized_expected.as_str(), normalized_actual.as_str(), false, false)
       .map_err(|err| {
         if single_value {
           vec![format!("{}", err)]

rust/pact_models/src/headers.rs

@@ -26,12 +26,12 @@ pub static MULTI_VALUE_HEADERS: [&str; 12] = [
 ];
 
 /// Tries to parse the header value into multiple values, taking into account headers that should
-/// not be split.
+/// not be split. Only known multi-value headers (per RFC 7230/9110) are split on commas.
 pub fn parse_header(name: &str, value: &str) -> Vec<String> {
-  if SINGLE_VALUE_HEADERS.contains(&name.to_lowercase().as_str()) {
-    vec![ value.trim().to_string() ]
-  } else {
+  if MULTI_VALUE_HEADERS.contains(&name.to_lowercase().as_str()) {
     value.split(',').map(|v| v.trim().to_string()).collect()
+  } else {
+    vec![ value.trim().to_string() ]
   }
 }
 
@@ -70,4 +70,17 @@ mod tests {
     let parsed = parse_header("User-Agent", "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) QtWebEngine/6.6.3 Chrome/112.0.5615.213 Safari/537.36");
     expect!(parsed).to(be_equal_to(vec!["Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) QtWebEngine/6.6.3 Chrome/112.0.5615.213 Safari/537.36"]));
   }
+
+  /// Verifies that custom headers containing JSON (with commas) are not split into multiple values.
+  /// See: https://github.com/pact-foundation/pact-reference/commit/6a985b9d0e512973a18943d3eaacae564a773c74
+  /// This test covers the original bug from Pact JS.
+  #[test]
+  fn parse_custom_header_should_not_split_unknown_headers() {
+    // JSON header value containing commas
+    let header_name = "x-custom-json";
+    let header_value = "{\"foo\":\"bar,baz\",\"arr\":[1,2,3]}";
+    let parsed = parse_header(header_name, header_value);
+    // Should not split into multiple values
+    expect!(parsed).to(be_equal_to(vec![header_value.to_string()]));
+  }
 }

rust/pact_models/src/json_utils.rs

@@ -596,7 +596,7 @@ mod tests {
     let result = headers_from_json(&headers);
     expect!(result.unwrap()).to(be_equal_to(hashmap! {
       "A".to_string() => vec!["B".to_string()],
-      "B".to_string() => vec!["A".to_string(), "B".to_string(), "C".to_string()],
+      "B".to_string() => vec!["A, B, C".to_string()],
       "C".to_string() => vec!["B".to_string()],
       "Date".to_string() => vec!["Sun, 12 Mar 2023 01:21:35 GMT".to_string()]
     }));