fix: Multipart chunk content type (apollographql/apollo-ios-dev#572)

Author: calvincestari

Sources/Apollo/MultipartResponseDeferParser.swift

@@ -23,7 +23,7 @@ struct MultipartResponseDeferParser: MultipartResponseSpecificationParser {
   }
 
   private enum DataLine {
-    case contentHeader(type: String)
+    case contentHeader(directives: [String])
     case json(object: JSONObject)
     case unknown
 
@@ -32,14 +32,8 @@ struct MultipartResponseDeferParser: MultipartResponseSpecificationParser {
     }
 
     private static func parse(_ dataLine: String) -> DataLine {
-      var contentTypeHeader: StaticString { "content-type:" }
-
-      if dataLine.starts(with: contentTypeHeader.description) {
-        let contentType = (dataLine
-          .components(separatedBy: ":").last ?? dataLine
-        ).trimmingCharacters(in: .whitespaces)
-
-        return .contentHeader(type: contentType)
+      if let directives = dataLine.parseContentTypeDirectives() {
+        return .contentHeader(directives: directives)
       }
 
       if
@@ -58,9 +52,9 @@ struct MultipartResponseDeferParser: MultipartResponseSpecificationParser {
   static func parse(_ chunk: String) -> Result<Data?, any Error> {
     for dataLine in chunk.components(separatedBy: Self.dataLineSeparator.description) {
       switch DataLine(dataLine.trimmingCharacters(in: .newlines)) {
-      case let .contentHeader(type):
-        guard type == "application/json" else {
-          return .failure(ParsingError.unsupportedContentType(type: type))
+      case let .contentHeader(directives):
+        guard directives.contains("application/json") else {
+          return .failure(ParsingError.unsupportedContentType(type: directives.joined(separator: ";")))
         }
 
       case let .json(object):

Sources/Apollo/MultipartResponseParsingInterceptor.swift

@@ -182,4 +182,16 @@ extension String {
 
     return nil
   }
+
+  func parseContentTypeDirectives() -> [String]? {
+    var lowercasedContentTypeHeader: StaticString { "content-type:" }
+
+    guard lowercased().starts(with: lowercasedContentTypeHeader.description) else {
+      return nil
+    }
+
+    return dropFirst(lowercasedContentTypeHeader.description.count)
+      .components(separatedBy: ";")
+      .map({ $0.trimmingCharacters(in: .whitespaces) })
+  }
 }

Sources/Apollo/MultipartResponseSubscriptionParser.swift

@@ -30,7 +30,7 @@ struct MultipartResponseSubscriptionParser: MultipartResponseSpecificationParser
 
   private enum DataLine {
     case heartbeat
-    case contentHeader(type: String)
+    case contentHeader(directives: [String])
     case json(object: JSONObject)
     case unknown
 
@@ -46,12 +46,8 @@ struct MultipartResponseSubscriptionParser: MultipartResponseSpecificationParser
         return .heartbeat
       }
 
-      if dataLine.lowercased().starts(with: contentTypeHeader.description) {
-        let contentType = (dataLine
-          .components(separatedBy: ":").last ?? dataLine
-        ).trimmingCharacters(in: .whitespaces)
-
-        return .contentHeader(type: contentType)
+      if let directives = dataLine.parseContentTypeDirectives() {
+        return .contentHeader(directives: directives)
       }
 
       if
@@ -74,9 +70,9 @@ struct MultipartResponseSubscriptionParser: MultipartResponseSpecificationParser
         // Periodically sent by the router - noop
         break
 
-      case let .contentHeader(type):
-        guard type == "application/json" else {
-          return .failure(ParsingError.unsupportedContentType(type: type))
+      case let .contentHeader(directives):
+        guard directives.contains("application/json") else {
+          return .failure(ParsingError.unsupportedContentType(type: directives.joined(separator: ";")))
         }
 
       case let .json(object):