Is it possible to know how many requests finished in ASINetworkQueue?
Question is very straight forward.. Please see below example..
Example
Suppose there are number of ASIHttpRequests in ASINetworkQueue and if all requests are running and in between I am cancelling all operations in ASINetworkQueue then how do I know that how many requests are finished before cancel ?
Please help me to solve this question or just tell me that it is possible or not to count this?
Thanks in advance..
Let networkQueue be the object of your networkQueue. You may use
[networkQueue requestsCount];
It returns the number of operations pending in Network queue and on completion of each operations it subtracts the requestCount property. Thus by subtracting it From total requests you added in network queue , you may get the number of completed requests of networkQueue
If you are using NSOperationQueue then following code can be used for getting count and to cancel all operations (requests) in the queue.
if([self.serviceQueue operationCount])
{
[self.serviceQueue cancelAllOperations];
self.serviceQueue = nil;
}
Its a very old thread but I am posting for future considerations. Please let me know if any one is facing any other issue.
Related
I am relatively new to MS-MQ Development and I was wondering if any of you guru's out there know an answer to the following:
In the concept of queues, there is something called "peaking", whereby; you can look at the message on the queue BUT NOT take it off the queue. This is different to performing a GET call.
Does anyone know how to do this?
Thanks in Advance.
Well, it's not much different than recieving a message from a queue.
var queue = new MessageQueue([path to queue]);
var msg = queue.Peek();
It is also possible to iterate over the messages in the queue by using
var msg = queue.Peek(TimeSpan.FromSeconds(10), PeekAction.Next);
and you can also peek by different Id's
PeekByCorrelationId
PeekByLookupId
PeekById
Check out the examples in the documentation on MSDN for each of these methods as they can get you started quite easily.
http://msdn.microsoft.com/en-us/library/829zyck7.aspx
I have xml http://weather.yahooapis.com/forecastrss?w=20070458&u=c and I want that when xml is updated my data also gets updated.
Thanks.
As you can see this XML has ttl node, which tells that Time To Live is 60 seconds. So, you can periodically (once in a minute, according to the TTL value) check this URL and stay up to date.
Read this tutorial for xmlparser and NSXMLParser Class Reference. I think it will be helpful to you.
You can poll on it.
static void timerHandler(CFRunLoopTimerRef timer, void *info)
{
//request the xml here and compare it with the previous one
}
- (void)weatherMonitor
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
CFRunLoopTimerContext context = {0, self, NULL, NULL, NULL};
CFRunLoopTimerRef timer = CFRunLoopTimerCreate(kCFAllocatorDefault, CFAbsoluteTimeGetCurrent(), 1, 0, 0, timerHandler, &context);//use your own time interval
CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, kCFRunLoopDefaultMode);
CFRelease(timer);
CFRunLoopRun();
[pool drain];
}
Run weatherMonitor in a background thread.
You have 2 options:
Implement Easy APNS which will notify your app about any changes.
And you may deliver xml data directly along the notification
message, or you may launch a request to pull up xml as soon as you
get notified.
Set a timer in your app that will launch requests to check for xml
updates each 1-10-60 minutes, whatever.
Both have pros and cons, depending on your requirements and abilities. One thing is clear: you CANNOT receive data from exterior without sending requests, other than implementing Push Notifications. Implementing Easy APNS will provide your app with data even if the application is not running. On the other side, with the timer, will be the fastest/easiest way. You decide. Cheers!
I am trying to download files from remote, and I now can monitor every single files download success status
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
But any way to monitor the whole process of downloading? How should I know all downloads are finished?
And I tried start download request with
[afhttpClient enqueueBatchOfHTTPRequestOperations:operationArray
progressBlock:progressBlock
completionBlock:completionBlock];
seems not work, so what the difference between above code and start download request with [operation start] in a loop?
#mattt (if you can see this)
You most probably have an NSArray of URL objects that you use to download images. What you need to do is to create an integer value equal to the count of your URL objects. Each time you successfully download an image or absolutely fail to download it (for instance after few timeouts or upon receiving 404 HTTP status code) you need to decrement that integer (note that it should be an atomic property, since blocks are being executed on different threads). Once the count reaches zero - all requests are finished. You can also use that integer to update a progress bar or simply notify user that "#/15 images are downloaded". Let me know if you need any other clarifications.
And unfortunately I have not worked with AFHTTPClient, so I can't tell you the difference between the two operations precisely, but contextually, first one executes all the requests almost at the same time asynchronously and the latter one uses consecutive approach, where second request will only be launched upon completion of the first one.
You can create NSOperationQueue and put all AFHTTPRequestOperation into it.
To observe the "operations" by using KVO. When the count go to zero, that is the time to say all operations completed.
If what you want is a constant progress update for each operation with bytes downloaded and total expected then I can highly recommend Peter Steinberger's AFDownloadRequestOperation.
This class derives from AFHTTPRequestOperation and adds a progressiveDownloadProgressBlock per-operation rather than just a per-operation-completion progress at the operation queue level, which is what I think you're looking for. Another great bonus is that it makes resumable/partial downloads much more accessible than in the core AFNetworking implementation.
it's this easy to use (example from the GitHub project's README.md):
[pdfRequest setProgressiveDownloadProgressBlock:^(NSInteger bytesRead,
long long totalBytesRead, long long totalBytesExpected,
long long totalBytesReadForFile, long long totalBytesExpectedToReadForFile)
{
self.downloadProgress = totalBytesReadForFile/(float)totalBytesExpectedToReadForFile;
}];
I use this in a few enterprise iOS projects to download multi-gigabyte files and I can tell you that it works great with the 1.0.1 release of AFNetworking.
Hope that helps…
I am working with network request - response in Objective-C. There is something with asynchronous model that I don't understand.
In summary, I have a view that will show my statuses from 2 social networks: Twitter and Facebook. When I clicked refresh, it will call a model manager. That model manager will call 2 service helpers to request for latest items. When 2 service helpers receive data, it will pass back to model manager and this model will add all data into a sorted array.
What I don't understand here is that : when response from social networks come back, how many threads will handle the response. From my understanding about multithreading and networking (in Java), there must have 2 threads handle 2 responses and those 2 threads will execute the code to add the responses to the array. So, it can have race condition and the program can go wrong right? Is it the correct working model of iphone objective-C? Or they do it in a different way that it will never have race condition and we don't have to care about locking, synchronize?
Here is my example code:
ModelManager.m
- (void)updateMyItems:(NSArray *)items {
self.helpers = [self authenticatedHelpersForAction:NCHelperActionGetMyItems];
for (id<NCHelper> helper in self.helpers) {
[helper updateMyItems:items]; // NETWORK request here
}
}
- (void)helper:(id <NCHelper>)helper didReturnItems:(NSArray *)items {
[self helperDidFinishGettingMyItems:items callback:#selector(model:didGetMyItems:)];
break;
}
}
// some private attributes
int *_currentSocialNetworkItemsCount = 0; // to count the number of items of a social network
- (void)helperDidFinishGettingMyItems:(NSArray *)items {
for (Item *item in items) {
_currentSocialNetworkItemsCount ++;
}
NSLog(#"count: %d", _currentSocialNetworkItemsCount);
_currentSocialNetworkItemsCount = 0;
}
I want to ask if there is a case that the method helperDidFinishGettingMyItems is called concurrently. That means, for example, faceboook returns 10 items, twitter returns 10 items, will the output of count will ever be larger than 10?
And if there is only one single thread, how can the thread finishes parsing 1 response and jump to the other response because, IMO, thread is only executed sequently, block of code by block of code
Yes, there is probably a thread per network request. The trick is to handle the response on the main thread. You should have something like this:
- (void)helper:(id <NCHelper>)helper didReturnItems:(NSArray *)items;
{
[self performSelectorOnMainThread:#selector(helperDidFinishGettingMyItems:)
withObject:items
waitUntilDone:NO];
}
Putting the response back onto the main thread will avoid a whole bunch of multithreading problems.
Also, the output of count will never be larger than 10. It's just that multiple threads may be running helperDidFinishGettingMyItems: at the same time. They won't automatically combine the two arrays.
The counter could possibly be more than 10, because multiple threads could be increasing that ivar at the same time.
I am trying to create class that will handle multiple downloads at same time (I need to download a lot of small files) and I have problems with "disappearing" connections.
I have function addDonwload that adds url to list of urls to download, and checks if there is free download slot available. If there is one it starts download immediately. When one of downloads finishes, I pick first url form list and start new download.
I use NSURLConnection for downloading, here is some code
- (bool) TryDownload:(downloadInfo*)info
{
int index;
#synchronized(_asyncConnection)
{
index = [_asyncConnection indexOfObject:nullObject];
if(index != NSNotFound)
{
NSLog(#"downloading %# at index %i", info.url, index);
activeInfo[index] = info;
NSURLRequest *request = [NSURLRequest requestWithURL:info.url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:15];
[_asyncConnection replaceObjectAtIndex:index withObject:[[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:TRUE]];
//[[_asyncConnection objectAtIndex:i] scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
return true;
}
}
return false;
}
- (void)connectionDidFinishLoading:(NSURLConnection*)connection
{
[self performSelectorOnMainThread:#selector(DownloadFinished:) withObject:connection waitUntilDone:false];
}
- (void)DownloadFinished:(id)connection
{
NSInteger index = NSNotFound;
#synchronized(_asyncConnection)
{
index = [_asyncConnection indexOfObject:(NSURLConnection*)connection];
}
[(id)activeInfo[index].delegate performSelectorInBackground:#selector(backgroundDownloadSucceededWithData:) withObject:_data[index]];
[_data[index] release];
[activeInfo[index].delegate release];
#synchronized(_asyncConnection)
{
[[_asyncConnection objectAtIndex:index] release];
[_asyncConnection replaceObjectAtIndex:index withObject:nullObject];
}
#synchronized(downloadQueue)
{
[downloadQueue removeObject:activeInfo[index]];
[self NextDownload];
}
}
- (void)NextDownload
{
NSLog(#"files remaining: %i", downloadQueue.count);
if(downloadQueue.count > 0)
{
if([self TryDownload:[downloadQueue objectAtIndex:0]])
{
[downloadQueue removeObjectAtIndex:0];
}
}
}
_asyncConnection is my array of download slots (NSURLConnections)
downloadQueue is list of urls to download
What happens is, at the beginning everything works ok, but after few downloads my connections start to disappear. Download starts but connection:didReceiveResponse: never gets called. There is one thing in output console that I don't understand I that might help a bit. Normaly there is something like
2010-01-24 21:44:17.504 appName[3057:207]
before my NSLog messages. I guess that number in square brackets is some kind of app:thread id? everything works ok while there is same number, but after some time, "NSLog(#"downloading %# at index %i", info.url, index);" messages starts having different that second number. And when that happens, I stop receiving any callbacks for that urlconnection.
This has been driving me nuts as I have strict deadlines and I can't find problem. I don't have many experiences with iphone dev and multithreaded apps. I have been trying different approaches so my code is kinda messy, but I hope you will see what I am trying to do here :)
btw is anyone of you know about existing class/lib I could use that would be helpful as well. I want parallel downloads with ability o dynamically add new files to download (so initializing downloader at the beginning with all urls is not helpful for me)
You've got a bunch of serious memory issues, and thread synchronization issues in this code.
Rather than go into them all, I'll ask the following question: You are doing this on a background thread of some kind? Why? IIRC NSURLConnection already does it's downloads on a background thread and calls your delegate on the thread that the NSURLConnection was created upon (e.g., your main thread ideally).
Suggest you step back, re-read NSURLConnection documentation and then remove your background threading code and all the complexity you've injected into this unnecessarily.
Further Suggestion: Instead of trying to maintain parallel positioning in two arrays (and some sketchy code in the above relating to that), make one array and have an object that contains both the NSURLConnection AND the object representing the result. Then you can just release the connection instance var when the connection is done. And the parent object (and thus the data) when you are done with the data.
I recommend that you take a look at this:
http://allseeing-i.com/ASIHTTPRequest/
It's a pretty sophisticated set of classes with liberal licensing terms (free too).
It may provide a lot of the functionality that you are wanting.
This snippet can be the source of the bug, you release the object pointed to by the activeInfo[index].delegate pointer right after issuing async method call on that object.
[(id)activeInfo[index].delegate performSelectorInBackground:#selector(backgroundDownloadSucceededWithData:) withObject:_data[index]];
[_data[index] release];
[activeInfo[index].delegate release];
Do you use connection:didFailWithError: ? There may be a timeout that prevents the successful download completion.
Try to get rid of the #synchronized blocks and see what happens.
The string inside the square brackets seems to be thread identifier as you guessed. So maybe you get locked in the #synchronized. Actually, I don't see a reason for switching thread - all the problematic code should run in the main thread (performSelectorOnMainThread)...
Anyhow, there is no need to use both the #synchronized and the performSelectorOnMainThread.
BTW, I didn't see the NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; line. Where do you initiate the connection?
As for the parallel downloads - I think that you can download more than one file in a time with the same code that you use here. Just create a separate connection for each download.
Consider just keeping a download queue along with a count of active connections, popping items off the top of the queue when downloads complete and a slot becomes free. You can then fire off NSURLConnection objects asynchronously and process events on the main thread.
If you find that your parallel approach prohibits doing all of the processing on the main thread, consider having intermediary manager objects between your main thread download code and NSURLConnection. Using that approach, you'd instantiate your manager and get it to use NSURLConnection synchronously on a background thread. That manager then completely deals with the downloading and passes the result back to its main thread delegate using a performSelectorOnMainThread:withObject: call. Each download is then just a case of creating a new manager object when you've a slot free and setting it going.