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PONSOperationQueue with synchronous NSURLConnection
 

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    <p>Building on an <a href="https://stackoverflow.com/questions/20224811/nsoperationqueue-trouble-understanding-the-order">earlier</a> question: I have an <code>NSOperationQueue</code> that looks like this:</p> <pre><code>NSBlockOperation *block1 = [NSBlockOperation blockOperationWithBlock:^{ [someObject someSelector]; }]; NSBlockOperation *block2= [NSBlockOperation blockOperationWithBlock:^{ [someObject anotherSelector]; }]; [block2 addDependency:block1]; [queue addOperation:block1]; [queue addOperation:block2]; </code></pre> <p>Now, inside <code>someSelector</code> I have:</p> <pre><code>returnData = [requesterObj getDataWithURL:(NSString*)url]; </code></pre> <p>where <code>getDataWithURL</code> contains something like:</p> <pre><code>NSURL *requestUrl = [NSURL URLWithString:strUrl]; NSMutableURLRequest *request = [NSMutableURLRequest requestUrl cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:timeout]; NSError *requestError; NSURLResponse *urlResponse = nil; NSData *urlData = [NSURLConnection sendSynchronousRequest:request returningResponse:&amp;urlResponse error:&amp;requestError]; </code></pre> <p>Now, when I add breakpoints, it appears that the second block is being called before the <code>NSURLConnection</code> from the first block finishes. Presumably because the call to <code>getDataWithURL</code>, is itself asyncronous. What's the best way to make sure that the first block doesn't complete before that request returns. Should I try using an <code>NSInvocation</code> to put the data inside <code>returnData</code>?</p>
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    1. COThis should be solved by setting the dependencies correctly. In the posted code you are **starting** block operations without setting dependencies! So what do you mean with _Assume also that I have set up dependencies..._ ? Can you post the relevant code where you set them?
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    2. CONo, dependencies are set correctly. The problem is that `NSBlockOperation` has no way of knowing that async request is not yet completed – it assumes that all stuff is finished after the block ends.
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