[CXF-8279] Attachment inputstream starts with -1 for slow connections

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Bug
• Affects Version/s: 3.2.8
• Component/s: Core
• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Bhathiya Jayasekara
• Created: 08/May/20 07:29
• Updated: 10/May/20 15:00
• Resolved: 10/May/20 15:00

Description

When a file is uploaded with a slow connection (only), using my CXF REST API, I get Couldn't find MIME boundary error. So I debugged the CXF core code to find out why. Now I'm looking at this code[1].

    private static boolean readTillFirstBoundary(PushbackInputStream pbs, byte[] bp) throws IOException {

        // work around a bug in PushBackInputStream where the buffer isn't
        // initialized
        // and available always returns 0.
        int value = pbs.read();
        pbs.unread(value);
        while (value != -1) {
            value = pbs.read();

When the client to server connection is very slow, the first read() of the input stream almost always is -1. That results Couldn't find MIME boundary error at the later on the flow.

If I change the code (just to debug) to skip the first byte when it's -1, like below, it works smoothly. See the 3 lines shown with "<<<<<<<". That means the data I expect is available after -1.

    private static boolean readTillFirstBoundary(PushbackInputStream pbs, byte[] bp) throws IOException {

        // work around a bug in PushBackInputStream where the buffer isn't
        // initialized
        // and available always returns 0.
        int value = pbs.read();
        if (value == -1) {                <<<<<< if the first byte is -1,
            value = pbs.read();           <<<<<< ignore that and read the  
        }                                 <<<<<< next byte
        pbs.unread(value);
        while (value != -1) {
            value = pbs.read();

Another important thing is this happens only for non-localhost and https connections.

Any idea what could be the reason for giving -1 for the first read always when the connection is slow?

[1] https://github.com/apache/cxf/blob/cxf-3.2.8/core/src/main/java/org/apache/cxf/attachment/AttachmentDeserializer.java#L264