Network connection lost reported by iOS clients.

[rolivieri]

Description of the problem will be added below.

[rolivieri]

Long story short, 1) if the body of an HTTP request from an iOS client to a Kitura-based server app has a semi-large amount of data (e.g. ~600kb), 2) and the body of that HTTP request is not consumed (i.e. read) at all on the Kitura-based server, 3) and a response is sent to the iOS client, 4) then a network connect lost or a network timed out error is reported by the iOS application. Now if the body of the http request is consumed and, only after that, a response is sent to the iOS app, then no errors are reported on the iOS side.

I can now reproduce this easily and have code to demonstrate this issue if needed. The question now seems to be: What changes are needed in Kitura so that a response can be sent to a client without having to consume the body of the http request? Not being able to send a response without having to consume the body of the request is having a negative impact on the MCA Server SDK and also on any Kitura-based application that needs to send a response without having to consume the HTTP request body (~ >600kb).

[irar2]

I can't reproduce the problem. I sent an almost 2MB picture with wrong token, and got an error from the server, but no connection lost/network timeout. Could you please provide more information how to reproduce this?

[rolivieri]

@irar2 - The easiest way to reproduce this problem is to clone the following branch: git clone -b ro-test2 https://github.com/IBM-Swift/BluePic.git. Once you've cloned the repo, compile both, the iOS app (BluePic-iOS) and the server side code (BluePic-Server). Dome that, add breakpoints to the iOS app in the following file: BluePic/DataManagers/BluemixDataManager.swift. You may want add breakpoints to the rotest() method, specifically lines 518, 534, 535. Also, make sure you reset your iOS simulator so that it is at known state. Now, launch the BluePic server (.build/debug/Server) and then launch/run the iOS app. Sign in using your Facebook account. Done that, then try to upload a picture from the camera roll in the simulator. This action will take you to the rotest() method and your breakpoints should be hit. Using the debugger in Xcode, step through lines 535 - 541. You should see that on the server side things seem to be fine but on the client (iOS side) you should see that the error variable is NOT nil and response object is nil.

Once you have reproduced the problem, you can also take the following steps. Go to the following file on the server side: BluePic-Server/ Sources/Server/Routes.swift. Uncomment lines 43 and 44 and rebuild the server:

let rawUserData = try? BodyParser.readBodyData(with: request)
print("rawUserData: \(rawUserData)")

Now, try to upload an image again using the iOS app. Now that you are consuming the request body the error should not occur. In other words, the error object should now be nil and the response object should NOT be nil. You can play with uncommenting and commenting out lines 43 and 44 in the Routes.swift file to reproduce the problem. Let me know if you have any other questions.

[irar2]

@rolivieri Please validate

[rolivieri]

@irar2 Tested the fix and it is working! Thanks for your help.