Re: Help With NSURLConnection Authentication

FROM : Topaness
DATE : Wed Oct 06 22:04:44 2004

Rudi,

Thank you for your quick responses. Once again you'll have to forgive
me, I'm still quite new to Cocoa/Objective-C.

I have receivedData defined in the header file, I should have pasted
that code as well (I've included it this time at the bottom of the
message). I don't have a defined runLoop, the original code I included
was everything from the NSConTest.m file in my project. Do I actually
need to manually define a runLoop for this? I would think since it
works with pages not requiring authentication that this shouldn't be an
issue.

What happens when I run the program with break points on each of the
delegate functions is that it starts on awakeFromNib and runs through
to the "receivedData=[[NSMutableData data] retain];" line. Normally,
when I'm operating on a URL that does not require authentication,
continuing or stepping into this will take me to the breakpoint of the
next function, which is didReceiveResponse, and then goes through each
of the other functions as appropriate. When operating on this URL
however which requires authentication, when I click continue or step
into on the receivedData line, it then jumps to the closing } for
awakeFromNib, however the awakeFromNib thread does not close. The
program doesn't become unresponsive, I can enter text into a edit box I
have.

I checked tcpdump as you suggested. Safari and my app are definately
not doing the same things. My app appears to stop sending and
requesting info much earlier. Though I'm not yet sure where. I'm
installing ethereal at the moment and will try to better figure out
where its all breaking.

I would suspect at this point though that its something improper I've
done with my code. I realize it isn't normal to have this much stuff in
awakeFromNib, however I was trying to create the simplest app possible,
so I could get the bare functions I wanted to use working without
anything else in the way. From what you mentioned it sounds as though I
may need to add more and learn more Cocoa/Objective-C before I can use
NSURLConnection. I'm used to figuring things out from looking at code
and just jumping in, but i've yet to find any complete demo apps that
use NSURLConnection for authentication.

Again, thank you for your response.

Here is my code for NSConTest.h. I tried adding in definitions for all
of the delegate functions like didReceiveAuthenticationChallenge: but
that doesn't seem to have fixed it.

/* NSConTest */

#import <Cocoa/Cocoa.h>

@interface NSConTest : NSObject
{
   IBOutlet id TextOut;
   IBOutlet NSMutableData *receivedData;
   IBOutlet NSURLDownload *theDownload;
}
@end

With extra stuff added:

/* NSConTest */

#import <Cocoa/Cocoa.h>

@interface NSConTest : NSObject
{
   IBOutlet id TextOut;
   IBOutlet NSMutableData *receivedData;
   IBOutlet NSURLDownload *theDownload;
}
- (void)connection:(NSURLConnection *)connection
didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge
*)challenge;
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData
*)data;
- (void)connection:(NSURLConnection *)connection
didFailWithError:(NSError *)error;
- (void)connection:(NSURLConnection *)connection
didReceiveResponse:(NSURLResponse *)response;
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;
@end





On Oct 6, 2004, at 10:57 AM, Rudi Sherry wrote:

> Sorry, my last post was not a quality post.  I didn't read your post
> carefully -- you said this works with other sites, so obviously you
> have a runLoop and receivedData is working (although I would still
> initialize receivedData first just in case didReceiveData: is being
> called within initWithRequest:delegate: ).
>
> When you say it hits the NSMutableData line "and then finishes", do
> you mean the URLConnection says that it's done, that is, it calls
> connectionDidFinishLoading: ?  Or do you mean the application becomes
> unresponsive?
>
> You might try tcpdump to find out whether you're getting a response
> from the server but the Cocoa code is not giving it to you.  I know of
> at least one case where NSURLConnection times out even though the
> server is responding.  This happens on a synchronous HEAD request to
> particular kinds of servers (I think it's Apache servers but it might
> be Netscape servers).  NSURLConnection sends a "Connection:
> Keep-Alive" (ignoring my specifically-added header of "Connection:
> close"), and tcpdump shows that the server immediately responds with
> the headers and a Content-Length and a Keep-Alive with timeout 15
> seconds... but NSURLConnection sits there for 15 seconds then times
> out, never having given me a response.  My theory is that it's looking
> at the Content-Length and assumes content will follow -- but for a
> response to a HEAD request it won't.  Your request is undoubtedly a
> GET, but you never know.
>
> One final stab in the dark: I've seen some issues where a method is in
> the implementation but not the interface -- compiles and links ok --
> but outside classes don't find it -- do you have
> didReceiveAuthenticationChallenge: in your interface?
>
>
>
> On Oct 6, 2004, at 8:16 AM, Rudi Sherry wrote:
>

>> First, I think you need to initialized receivedData *before* you call
>> initWithRequest (I assume it's an instance variable of NSConTest),
>> since initWithRequest starts the connection and you may start
>> receving data before you get to the next line.  If receivedData is
>> uninitialized then didReceiveData: could be getting an exception with
>> results I'm not sure (maybe what you're seeing).
>>
>> I assume you put breakpoints at all the delegate functions to see if
>> anything is triggering there and nothing is?
>>
>> Also, I assume you're in an application that has a RunLoop going
>> because NSURLConnection needs a RunLoop in order to function -- that
>> is, if you're not within some kind of application run loop
>> NSURLConnection gets no time and the delegates never hit.  Any sample
>> application has that, so I imagine you're OK there.
>>
>> That's all I can think of,
>> Rudi
>>
>> On Oct 6, 2004, at 7:38 AM, Topaness wrote:
>>

>>> I'm new to Cocoa development and am having trouble with the
>>> authentication features of NSURLConncetion. Admittedly I've not done
>>> that much with Objective-C or Xcode yet, but i've read through a
>>> couple tutorials including the "Developing Cocoa Objective-C
>>> Applications: A Tutorial" and wrote some small apps. Most of my
>>> experience lies in Perl and Ruby for Windows and Linux development
>>> but i'm trying to make the move to OSX, so please forgive me for any
>>> simple mistakes.
>>>
>>> The application connects to a site
>>> (http://rpc.bloglines.com/listsubs) and uses basic http
>>> authentication to login. The site then sends its response in the
>>> form of an XML file. This is what is supposed to happen anyway. The
>>> problem is that while all of this code works fine with other sites
>>> that don't use authentication, it doesn't work here. I can access
>>> the URL and login just fine from Safari, so its nothing with my
>>> connection. What I find odd is that according to the log i'm not
>>> even receiving a response. The log says the session started, and it
>>> still responds, but after stepping through the code in debug mode,
>>> it looks like it hits the "receivedData=[[NSMutableData data]
>>> retain];" line and then finishes. I've been trying to figure this
>>> out for about a week now, and have done more searches than I can
>>> count. It's becoming rather frustrating and I'm close to giving up
>>> on Objective-C.
>>>
>>> I have included the code below. Most(all) of the code is example
>>> code from the Apple docs (hopefully this isn't a violation, i looked
>>> through the FAQ and guidelines and didn't see anything about this,
>>> and the code did not contain any copyright info). I cannot find any
>>> example code elsewhere or enough documentation to go beyond this
>>> yet. If anyone can offer any help or knows of any place or even
>>> books that have more comprehensive info on the NSURLConnection and
>>> using authentication with it it would be greatly appreciated.
>>> Thanks.
>>>
>>> #import "NSConTest.h"
>>>
>>> @implementation NSConTest
>>> - (void)awakeFromNib
>>> {    
>>>     NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL
>>> URLWithString:@"http://rpc.bloglines.com/listsubs/"]
>>>                         cachePolicy:NSURLRequestReloadIgnoringCacheData
>>>                         timeoutInterval:60.0];
>>>     NSURLConnection *theConnection=[[NSURLConnection alloc]
>>> initWithRequest:theRequest delegate:self];
>>>     if (theConnection) {
>>>         receivedData=[[NSMutableData data] retain];
>>>     } else {
>>>         NSLog(@"Connection could not be made");
>>>     }
>>> }
>>>
>>> - (void)connection:(NSURLConnection *)connection
>>> didReceiveData:(NSData *)data
>>> {
>>>    [receivedData appendData:data];
>>>
>>> }
>>>
>>> - (void)connection:(NSURLConnection *)connection
>>> didFailWithError:(NSError *)error
>>> {
>>>    // release the connection, and the data object
>>>    [connection release];
>>>    [receivedData release];
>>>
>>>    NSLog(@"Connection failed! Error - %@ %@",
>>>          [error localizedDescription],
>>>          [[error userInfo]
>>> objectForKey:NSErrorFailingURLStringKey]);
>>> }
>>>
>>> - (void)connection:(NSURLConnection *)connection
>>> didReceiveResponse:(NSURLResponse *)response
>>> {
>>>     NSLog(@"Got response");
>>>    [receivedData setLength:0];
>>> }
>>>
>>> - (void)connectionDidFinishLoading:(NSURLConnection *)connection
>>> {
>>>    // do something with the data
>>>    NSLog(@"Succeeded! Received %d bytes of data",[receivedData
>>> length]);
>>>     
>>>     NSString *urlData;
>>>     if (nil != receivedData) {
>>>         urlData = [[[NSString alloc] initWithData:receivedData
>>> encoding:NSUTF8StringEncoding] autorelease];
>>>     }
>>>     [TextOut replaceCharactersInRange: NSMakeRange(0,0)
>>> withString:urlData];
>>>     
>>>    // release the connection, and the data object
>>>    [connection release];
>>>    [receivedData release];
>>> }
>>>
>>> -(void)connection:(NSURLConnection *)connection
>>> didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge
>>> *)challenge
>>> {
>>>    NSLog(@"Auth Request");
>>>    if ([challenge previousFailureCount] == 0) {
>>>        NSURLCredential *newCredential;
>>>        newCredential=[NSURLCredential credentialWithUser:(NSString
>>> *)@"<email_removed>"
>>>                                                  password:(NSString
>>> *)@"yeyinde99"
>>>                                             
>>> persistence:NSURLCredentialPersistenceForSession];
>>>        [[challenge sender] useCredential:newCredential
>>>                forAuthenticationChallenge:challenge];
>>>    } else {
>>>        [[challenge sender] cancelAuthenticationChallenge:challenge];
>>>        // inform the user that the user name and password
>>>        // in the preferences are incorrect
>>>        //[self showPreferencesCredentialsAreIncorrectPanel:self];
>>>    }
>>> }
>>> @end
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