HTTP headers are not checked case insensitively

[sopgreg]

Testing exchange with a third party AS2 software, we noticed that this extension does not check the HTTP headers case insensitively within GenericMessageInfo. So, exchange with any third party software sending headers like AS2-From or AS2-To is not supported, unless the headers are sent in lowercase.

ReadUserMessageInfo:

log.debug("Get the general message info of the User Message from msgCtx");
GenericMessageInfo generalInfo = (GenericMessageInfo) procCtx.getProperty(Constants.CTX_AS2_GENERAL_DATA);
        
// Check that at least the party ids of the sender and receiver are included in the message
final String fromId = generalInfo.getFromPartyId();
final String toId = generalInfo.getToPartyId();        
if (Utils.isNullOrEmpty(fromId) || Utils.isNullOrEmpty(toId)) {
   log.error("Received message does not contain AS2-To and/or AS2-From header(s)!"); // <---- ERROR is logged here

A potential fix (verified to work) is to put the HTTP headers into a TreeMap with a case insensitive comparator:

    public GenericMessageInfo(final Map<String, String> httpHeaders) {
        // If there are no HTTP headers, no information is avaible and an "empty" object is created
        if (Utils.isNullOrEmpty(httpHeaders))
            return;

        Map<String, String> caseInsensitiveHeaders = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
        caseInsensitiveHeaders.putAll(httpHeaders);

        messageId = caseInsensitiveHeaders.get(MESSAGE_ID_HEADER);
        refToMessageId = caseInsensitiveHeaders.get(REF_TO_MESSAGE_ID_HEADER);
        try {
        	timestamp = new MimeDateParser(caseInsensitiveHeaders.get(TIMESTAMP_HEADER)).parse();
        } catch (NullPointerException | ParseException notaDate) {
            timestamp = null;
        }
        subject = caseInsensitiveHeaders.get(SUBJECT_HEADER);
        fromPartyId = caseInsensitiveHeaders.get(SENDER_ID_HEADER);
        toPartyId = caseInsensitiveHeaders.get(RECEIVER_ID_HEADER);
        originalRecipient = caseInsensitiveHeaders.get(ORIGINAL_RECIPIENT);
        finalRecipient = caseInsensitiveHeaders.get(FINAL_RECIPIENT);
    }