Re: NSURLConnection sendSynchronousRequest crash

FROM : Colin Cornaby
DATE : Fri May 30 17:35:30 2008

Strangely enough, I actually was already disabling the cache in my 
NSURLRequest. I changed the disable caching flag to the newer constant 
(NSURLRequestReloadIgnoringLocalCacheData), and now the crash has 
changed...

#0    0x90e684a6 in mach_msg_trap
#1    0x90e6fc9c in mach_msg
#2    0x901a60be in CFRunLoopRunSpecific
#3    0x901a6cf8 in CFRunLoopRunInMode
#4    0x970c5b5e in CFURLConnectionSendSynchronousRequest
#5    0x963d080b in +[NSURLConnection 
sendSynchronousRequest:returningResponse:error:]
#6    0x0001993b in -[BBSHessianProxy callSynchronous:withParameters:] at 
BBSHessianProxy.m:67
#7    0xb0006ca7 in -[SQLDatabase queryString:]
#8    0xb0005cf6 in -[SQLDatabase 
table:objectValueForColumn:row:withSort:withFilter:cacheRow:] at 
SQLDatabase.m:301
#9    0xb00029d4 in -[SQLRow valueForUndefinedKey:] at SQLRow.m:103
#10    0x9634069b in _NSGetUsingKeyValueGetter
#11    0x96340137 in -[NSObject(NSKeyValueCoding) valueForKey:]
#12    0xb0001a8c in -[SQLRelationshipDictionary parseTable] at 
SQLRelationshipDictionary.m:43
#13    0xb00021a9 in -[SQLRelationshipDictionary initWithDatabase:] at 
SQLRelationshipDictionary.m:94
#14    0xb0004cbd in -[SQLDatabase connect] at SQLDatabase.m:130
#15    0xb0004701 in -[SQLDatabase awakeFromNib] at SQLDatabase.m:64
#16    0x9022e955 in -[NSSet makeObjectsPerformSelector:]
#17    0x96627be6 in -[NSIBObjectData 
nibInstantiateWithOwner:topLevelObjects:]
#18    0x9661de12 in loadNib
#19    0x9661d774 in +[NSBundle(NSNibLoading) 
_loadNibFile:nameTable:withZone:ownerBundle:]
#20    0x9661d3b7 in +[NSBundle(NSNibLoading) 
loadNibFile:externalNameTable:withZone:]
#21    0x9661d2f5 in +[NSBundle(NSNibLoading) loadNibNamed:owner:]
#22    0x9661cfa4 in NSApplicationMain
#23    0x00001f60 in main at main.m:13

Here is the code I am using (it's nearly identical to the code of the 
official Hessian Obj-C framework)...

NSMutableURLRequest * request = [[[NSMutableURLRequest alloc] 
initWithURL:[self serviceUrl]
                                                                 
cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                                             
timeoutInterval:60.0] autorelease];
//add all the paramters to the data
[request setHTTPMethod:@"POST"];
NSData *hessianData = [hessianRequest data];
[request setHTTPBody:hessianData];
//force this header field to be text/xml... Tomcat 4 blows up otherwise
[request setValue:@"text/xml" forHTTPHeaderField:@"Content-type"];
NSHTTPURLResponse * returnResponse = nil;

NSError * requestError = nil;
NSData * retData = [NSURLConnection sendSynchronousRequest:request
                                             
returningResponse:&returnResponse
                                                         
error:&requestError];

On May 30, 2008, at 8:12 AM, Jens Alfke wrote:

>
> On 30 May '08, at 12:55 AM, Colin Cornaby wrote:
>

>> I'm using an NSURLConnection to heavily query a server (basically 
>> I'm abstracting a MySQL database, and I have a Hessian server 
>> (basically SOAP) on the other end handling requests.) However, I 
>> keep having sendSyncronousRequest crash on me after periods of 
>> heavy load. The stack trace is:

>
> Make sure you file a bug report. I haven't heard of a crash like 
> this, but almost all of the URL loading code was rewritten in 
> Leopard, so it's somewhat less mature than the Tiger codebase was.
>
> You could try working around this by disabling caching in your 
> NSURLRequests. If you're sending SOAP queries it's probably not 
> appropriate to cache them anyway, right?
>
> —Jens