I'm wondering if someone could point me in the right direction for this problem. A bit of introduction:
In an app we maintan we just rewrote our network layer to remove support for OS 4. We're using the cleaner ConnectionFactory provided in OS 5. Please note the issues we're encountering are device-only, not simulator related.
There are two ways or app has connectivity, a data thread that polls specific urls and stores data, and a "generic web view" (a BrowserField).
So far it seems there's no problems with the data thread connectivity, it properly builds the urls based off transport type and downloads the data correctly. In the BrowserField we have a different problem. There's an OS 6 curve causing problems (no other OS 6 device though) when we open the BrowserField with a URL there's a chance it will show a "Could not select proper transport descriptor" message - the most common culprit is WAP2.
I guess we're a bit baffled that BlackBerry doesn't seem to handle the transport descriptor choosing as well as we had hoped. Does anyone have any recommendations?
Due to its length, I've posted our connection utility class on gist: https://gist.github.com/3490101
The most common connection form, used by the data thread, is the getUrlAsString(String etag) function, which does a GET and caches the response based off the etag/url.
To build URLs for our BrowserField we use the buildURLTransport(String url) function, which gets a connection on the url, determines the transport information, and returns the built URL.
TL;DR: There's an oddity in a BrowserField we can't seem to debug, we'd appreciate a new set of eyes: we think there's something wrong in the above posted gist in the buildURLTransport(String url) function.
Thanks a tonne in advance.
Be careful with your code because getUrlAsString isn't thread safe. I didn't understand why you keep reference to the ConnectionFactory sometimes why you don't for other.
I aslo didn't understand why do you need method buildUrlTransport. Why don't use BrowserFieldConfig together with ConnectionFactory for BrowserField as here.
So I would instantiate one ConnectionFactory, configure it with your specific parameters and use it everywhere. In case of preferences change I would recreate ConnectionFactory and update BrowserFieldConfig. Sure this code should be thread safe.
Also be more consistent - sometimes you use quick connection check, sometimes you don't.
Related
This is for a visualisation project on what data gets recorded about us from our phones.
The idea would be to log as much detail as is reasonable to an internal location (probably) on the phone for later analysis, e.g. HTTP requests. It doesn’t need to be secret at all – the subject will be aware they are participating – and it doesn’t have to be 100% automatic; if the phone owner needs to perform some action regularly that’s okay too, although they need to be able to use their phone approximately normally throughout the day.
I can’t find any Apple APIs that look suitable, but that’s hardly surprising. I can find some approaches that would potentially work on OSX (tcpdump, netstat), so perhaps a jailbroken iOS device would support one of those?
Alternatively, running a custom proxy server would open up a bunch more options, but is there any way to get a mobile device to reliably route through a proxy server?
It appears this question provides a viable proxy-server-based approach:
https://apple.stackexchange.com/questions/81102/proxy-settings-for-iphone-3g-connection
Basically, it seems it is possible to route all requests through a proxy server, even over cellular.
I have weird issue running the last version of Raknet on iOS with Unity3D: I get CONNECTION_ATTEMPT_FAILED when trying to connect to the server.
Now let's me detail the issue:
he exact same Library connects fine when used in an ObjectiveC application, so the issue seems to be Unity3D related.
I already managed to pinpoint my issue to be located in Raknet reliability layer:
Apparently, during the last step of the connection process (when the connection handshake as been completed) the reliability layer of the server thinks that the ID_CONNECTION_REQUEST packet received from the client is an acknowledgment instead of a message. Therefore it doesn't answer. Ultimately after a few tries, (and a 10s timeout) the client fails with the CONNECTION_ATTEMPT_FAILED error.
Does anybody there as an idea? I will update the question when I manage to get more info.
Update
We are using Unity3D 5.1.1f1
We managed to find a workaround! See answer for more information. As the workaround doesn't tell us much about what really happened, I would gladly hear some C++/XCode/Unity/iOS/AppleLLVM6.1 experts around here explain what really happened.
The issue was that the Raknet header wasn't properly generated by the iOS client. Namely we were sending ACK messages in place of simple packets. The rest of the message was considered as garbage by the server and the packet was dropped. The client kept trying to send the corrupted handshake packet a few times before timeouting.
This doesn't tell us why, doesn't it? Apparently the serialize method of the class DatagramHeaderFormat wasn't called as it should have been when running Raknet in Unity (iOS). Something else (and I don't know what) was linked in place of this method and was filling the BitStream with a corrupted header.
I am quite sure that the serialize method wasn't called because printf calls from inside weren't displayed in the console.
We renamed DatagramHeaderFormat::serialize into DatagramHeaderFormat::serializeHeader and... voila, it works.
Now I only want to understand what did the compiler (and why).
We're writing an application which uses our http api, and occasionally it will encounter errors, failed connections, timeouts, etc.
We'd like to, at least in beta, be able to capture these incidents, and forward them to ourselves somehow. Since obviously many of these issues could be due to the actual connection being down, this would need to queue these incidents and send them when a connection is available.
I tried googling for an answer for this but to no avail, came across a bunch of solutions which catch exceptions, but not just random "incidents" (could really just be a string we log somewhere, we'd just include all the details in it).
Short of writing my own coredata (or something) backed queue, I'm at a loss at what a solution for this could be.
Does anyone know of any libs/services which could help with this?
You might want to look into Testflight, or less general purpose, Parse. Not quite sure, but maybe HockeyKit offers a solution for this, too.
You can take a look at Bugfender, it's a product we have built to solve this problem. We have found that while developing an app there are a lot of issues that are not crashes, so we decided to make our own product to help us on this.
It's easy to integrate and you can get the devices logs. Our service works offline and online, we have spent a lot of time to make it reliable and easy to use.
Compared to other products, you don't need any crash to get the logs, you choose when you want them.
I read some of the similar posts on this site that deal with what seems to be the same issue and the responses didn't really seem to clarify things for me.
My application works fine in the simulator. I believe I'm on Bold 9000 with OS 4.6. The app is signed.
My app makes an HTTP call via 3G to fetch an XML result. type is application/xhtml+xml.
In the device, it gives no error. it makes no visual sign of error. I tell the try catch to print the results to the screen and I get nothing.
HttpConnection was taken right out of the demos and works fine in sim.
Since it gives no error, I begin to reflect back on things I recall reading back when the project began. deviceside=true? Something like that?
My request is simply HttpConnection connection = (HttpConnection)Connector.open(url);
where url is just a standard url, no get vars.
Based on the amount of time I see the connection arrows in the corner of the screen, I assume the app is launching the initial communication to my server, then either getting a bad result, or it gets results and the persistent store is not functioning as expected.
I have no idea where to begin with this. Posting code would be ridiculous since it would be basically my whole app.
I guess my question is if anyone knows of any major differences with device versus simulator that could cause something like http connection or persistent store to fail?
A build setting? An OS restriction? Any standard procedure I may have just not known about that everyone should do before beginning device testing?
Thanks
Just providing the URL will not work. You will have to append some info after the URL to determine the transport method your HTTP connection will use. For instance http://example.com;deviceside=true will use DirectTCP (you might also have to supply APN information but that's saved on the device for my phone). http://example.com;interface=wifi will use wi-fi. On OS 5 there's a ConnectionFactory class that makes this a lot easier. Here's a link that goes into more detail.
This was a tough one for me!
As Jonathan said you have to put some parameters in the url to make it work on the device. You shouldn't do it by hand but use the ConnectionFactory instead.
As you may thing this would just make it work but it doesn't!
The real problem is that not the url has been altered because it has ;interface=wifi;deviceside=true in it (in my case). Depending on the webserver accepting your request this could broke the code.
A solution I tried and that works is try to happend a fake parameter like
&foo=true -> &foo=true;deviceside=true
This will result as a standard parameter for the webserver but your device would use it to driver your connection.
On the simulator this work without this extra code because behind it there is a BIS server for you. On the device (as in my case) there isn't because I'm using a development device unregistered and without SIM (just wifi).
Another point is that the HttpConnection class doesn't handle HTTP 302 Redirect and if you get one you have to handle it manually.
It's probably an issue with the APN not being specified. See my answer for this question for details:
video streaming over http in blackberry
I would make this a comment, but I think I don't have enough rep yet for that... So I'll just answer and hope this doesn't get hosed for just pasting in some links.
I've been working on this exact sort of networking issue on our app this past week, and it is indeed tricky as some others have pointed out. Here are two links which really helped us out using HTTP on different devices, especially older devices which do not provide ConnectionFactory.
http://supportforums.blackberry.com/t5/Java-Development/Connecting-your-BlackBerry-http-and-socket-connections-to-the/td-p/206242
The first one has some code examples, including demonstration of querying the system's ServiceBook and CoverageInfo classes to make a decision about what kind of connection will work.
I have a simple application, which should send a single byte to a serial port once a minute. But sometimes, from some strange reason, it freezes somewhere in the WriteFile() function. Both sw and hw flow controls are turned off. I've googled some stuff about pending read operations performed from another threads, but I believe this is not a problem, because my app has single thread. Also, handle from CreateFile looks valid, so the port should not be used by any other applications. Have anybody suffered this?
If you google for the words writefile hangs, you'll find a number of discussions on this problem. Some leads are buffer overruns, sizing your buffer correctly, a defective COM port, clearing the status on error... Seems like there are plenty of things to try.
Another thing I would suggest is to use a communications library instead of calling the API directly, something like Async Professional (http://sourceforge.net/projects/tpapro/). Even if they add some overhead to your application, they might simplify your work and avoid a number of potential pitfalls...
Well, I'm using this library: http://lhdelphi.ic.cz/uploader/storage/ComDrv32.pas in Delphi 7, on Windows XP, but the component inside is just a wrapper around some Win API calls, CreateFile, WriteFile, etc.
Have you tried setting CommPortDriver.CheckLineStatus to true ("to prevent hangs when not device connected or device is OFF")? The source for the comdrv32.pas library contains that suggestion.
You can also try ComPort, which was neglected for some time but is now actively developed again.