pyobjc-dev

[Pyobjc-dev] NSError.localizedDescription() and Application Bundles

[Jean-Pierre <cho...@fr...>]

Hello,

I am having problems to get the localized error message from an  
NSError object.

The following code runs fine when launched as a simple script in the  
Terminal:

from Foundation import *
url = NSURL.URLWithString_("http://invalid")
request = NSURLRequest.requestWithURL_(url)
(data, response, error)=  
NSURLConnection.sendSynchronousRequest_returningResponse_error_(request)
NSLog("error:%@", error.localizedDescription())
print unicode(error.localizedDescription())

But fails with an UnicodeError Exception: <type  
'exceptions.UnicodeEncodeError'>: 'ascii' codec can't encode character  
u'\u2019' in position 3: ordinal not in range(128)
when ran from a Cocoa-Python Application project from Xcode.
The error string has indeed an non ascii character in its fourth  
position ("can’t find host"), but the type of the  
error.localizedDescription() object is objc.pyobjc_unicode so it  
shouldn't be a problem.

Am I doing something wrong ?

Thanks,

  - Jean-Pierre.

Re: [Pyobjc-dev] NSError.localizedDescription() and Application Bundles

[James R E. <Jam...@lr...>]

Hi Jean-Pierre,

The problem you're having is actually at the print statement at the  
very end.  The problem is that your sys.stdout.defaultencoding is  
usually set to US-ASCII rather than UTF8.  Unfortunately, the pythonic  
way of changing this encoding is via the site-config file, which you  
can't very well distribute with your python application.  You can  
either restrict yourself to NSLog, which does properly output UTF-8  
encoded unicode text, or you can manually encode your output via:

	print error.localizedDescription().encode('utf8')

This approach is better suited if you can bury that deep inside your  
own logging-like mechanism, since you don't want a single missed  
".encode('utf8')" to introduce a unicode bug to your code.

If anyone has any alternative suggestions, btw, I'd love to hear  
them.  Unicode in python is often a source of headaches.

Cheers!
James

Le 11 juil. 09 à 11:18, Jean-Pierre a écrit :

> Hello,
>
> I am having problems to get the localized error message from an
> NSError object.
>
> The following code runs fine when launched as a simple script in the
> Terminal:
>
> from Foundation import *
> url = NSURL.URLWithString_("http://invalid")
> request = NSURLRequest.requestWithURL_(url)
> (data, response, error)=
> NSURLConnection 
> .sendSynchronousRequest_returningResponse_error_(request)
> NSLog("error:%@", error.localizedDescription())
> print unicode(error.localizedDescription())
>
> But fails with an UnicodeError Exception: <type
> 'exceptions.UnicodeEncodeError'>: 'ascii' codec can't encode character
> u'\u2019' in position 3: ordinal not in range(128)
> when ran from a Cocoa-Python Application project from Xcode.
> The error string has indeed an non ascii character in its fourth
> position ("can’t find host"), but the type of the
> error.localizedDescription() object is objc.pyobjc_unicode so it
> shouldn't be a problem.
>
> Am I doing something wrong ?
>
> Thanks,
>
>  - Jean-Pierre.
>
> ------------------------------------------------------------------------------
> Enter the BlackBerry Developer Challenge
> This is your chance to win up to $100,000 in prizes! For a limited  
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> vendors submitting new applications to BlackBerry App World(TM) will  
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> the opportunity to enter the BlackBerry Developer Challenge. See  
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Re: [Pyobjc-dev] NSError.localizedDescription() and Application Bundles

[Jean-Pierre <cho...@fr...>]

Hi James,

Le 11 juil. 09 à 12:45, James R Eagan a écrit :

> Hi Jean-Pierre,
>
> The problem you're having is actually at the print statement at the  
> very end.  The problem is that your sys.stdout.defaultencoding is  
> usually set to US-ASCII rather than UTF8.  Unfortunately, the  
> pythonic way of changing this encoding is via the site-config file,  
> which you can't very well distribute with your python application.   
> You can either restrict yourself to NSLog, which does properly  
> output UTF-8 encoded unicode text, or you can manually encode your  
> output via:
>
> 	print error.localizedDescription().encode('utf8')
>
> This approach is better suited if you can bury that deep inside your  
> own logging-like mechanism, since you don't want a single missed  
> ".encode('utf8')" to introduce a unicode bug to your code.


I first thought my problem was solved, until I tried to concatenate an  
utf8 string to the error message returned by the NSURLConnection  
object, and I still have an UnicodeEncodeError exception.
The problem seems to be that the localizedDescription() function  
returns an ascii string containing utf-8 characters, instead of an  
unicode one.
The following code fails for localized error messages containing non  
ascii characters, returned by the system:

from Foundation import *
url = NSURL.URLWithString_("http://invalid")
request = NSURLRequest.requestWithURL_(url)
(data, response, error)=  
NSURLConnection.sendSynchronousRequest_returningResponse_error_(request)
print u"error: " + error.localizedDescription().encode('utf-8')

This also fails using the Terminal.

I didn't dig yet into the PyObjc bridge, but could it be a problem in  
the declared encoding for the NSError.localizedDescription() function ?

Thanks,

  - Jean-Pierre.

Re: [Pyobjc-dev] NSError.localizedDescription() and Application Bundles

[Ronald O. <ron...@ma...>]

On 14 Jul, 2009, at 9:53, Jean-Pierre wrote:

> Hi James,
>
> Le 11 juil. 09 à 12:45, James R Eagan a écrit :
>
>> Hi Jean-Pierre,
>>
>> The problem you're having is actually at the print statement at the  
>> very end.  The problem is that your sys.stdout.defaultencoding is  
>> usually set to US-ASCII rather than UTF8.  Unfortunately, the  
>> pythonic way of changing this encoding is via the site-config file,  
>> which you can't very well distribute with your python application.   
>> You can either restrict yourself to NSLog, which does properly  
>> output UTF-8 encoded unicode text, or you can manually encode your  
>> output via:
>>
>> 	print error.localizedDescription().encode('utf8')
>>
>> This approach is better suited if you can bury that deep inside  
>> your own logging-like mechanism, since you don't want a single  
>> missed ".encode('utf8')" to introduce a unicode bug to your code.
>
>
> I first thought my problem was solved, until I tried to concatenate  
> an utf8 string to the error message returned by the NSURLConnection  
> object, and I still have an UnicodeEncodeError exception.
> The problem seems to be that the localizedDescription() function  
> returns an ascii string containing utf-8 characters, instead of an  
> unicode one.
> The following code fails for localized error messages containing non  
> ascii characters, returned by the system:
>
> from Foundation import *
> url = NSURL.URLWithString_("http://invalid")
> request = NSURLRequest.requestWithURL_(url)
> (data, response, error)=  
> NSURLConnection.sendSynchronousRequest_returningResponse_error_ 
> (request)
> print u"error: " + error.localizedDescription().encode('utf-8')
>
> This also fails using the Terminal.
>
> I didn't dig yet into the PyObjc bridge, but could it be a problem  
> in the declared encoding for the NSError.localizedDescription()  
> function ?

The bridge is fine. There are three ways to fix the error:

1) Copy a sitecustomize.py file into your application bundle (if you  
use an Xcode project to build the application you can just add the  
file to the project, using py2app adding the file to the directory  
containing setup.py should be enough). That file should contain the  
following code:

     import sys
     sys.setdefaultencoding('utf-8')

2) Explicitly encode unicode strings to UTF-8 before printing them,  
your print statement would end up as:

      print (u"error:" + error.localizedDescription()).encode('utf-8')

3) Use NSLog instead of print to print debug information:


       NSLog("error: %@", error.localizedDescription())

NOTE: all code was typed in Mail.app, I haven't actually tested the  
code.

The problem you run into is that the python interpreter needs to  
convert a unicode string (either Python's unicode or NSString) to a  
sequence of bytes when you print it. The interpreter uses the default  
encoding for that. On the command-line the default encoding is  
'utf-8', but for some reason the default encoding in an app bundle is  
'ascii'. The latter encoding is a problem for you because the  
localizedDescription contains some characters that are not pure ASCII  
(most likely some fancy accent).

Ronald

>
> Thanks,
>
>  - Jean-Pierre.
> ------------------------------------------------------------------------------
> Enter the BlackBerry Developer Challenge
> This is your chance to win up to $100,000 in prizes! For a limited  
> time,
> vendors submitting new applications to BlackBerry App World(TM) will  
> have
> the opportunity to enter the BlackBerry Developer Challenge. See  
> full prize
> details at: http://p.sf.net/sfu/Challenge_______________________________________________
> Pyobjc-dev mailing list
> Pyo...@li...
> https://lists.sourceforge.net/lists/listinfo/pyobjc-dev

Re: [Pyobjc-dev] NSError.localizedDescription() and Application Bundles

[Ronald O. <ron...@ma...>]

The attached version of app delegate should work. You should not use  
"decode('utf-8')" on unicode strings that you use with Cocoa API's.

Ronald

On 14 Jul, 2009, at 15:34, Jean-Pierre wrote:

> Le 14 juil. 09 à 13:52, Ronald Oussoren a écrit :
>
>> If you want to display the message in a window you should be able  
>> use it as is, that is use aTextField.setStringValue_ 
>> (error.localizedDescription()) should work just fine.
>
> That's what I am trying to do indeed.
>
>> If that doesn't work: could you please create a small program that  
>> shows the problem (that is, a complete Xcode project)?
>>
>> Ronald
>
> Here you are, a small Xcode 3 project with just a Text Label  
> displaying the error message from an NSURLConnection failure.
>
> - Jean-Pierre.
>
> <Localized.zip>
>
>

Re: [Pyobjc-dev] NSError.localizedDescription() and Application Bundles

[Jean-Pierre <cho...@fr...>]

Le 14 juil. 09 à 15:45, Ronald Oussoren a écrit :

> The attached version of app delegate should work. You should not use  
> "decode('utf-8')" on unicode strings that you use with Cocoa API's.
>
> Ronald

Ok, I missed the fact that I had to convert the string only to print  
it to stdout, everything works fine now.
Thanks.

Best regards,

  - Jean-Pierre.

Re: [Pyobjc-dev] NSError.localizedDescription() and Application Bundles

[Jean-Pierre <cho...@fr...>]

Le 14 juil. 09 à 13:52, Ronald Oussoren a écrit :

> If you want to display the message in a window you should be able  
> use it as is, that is use  
> aTextField.setStringValue_(error.localizedDescription()) should work  
> just fine.

That's what I am trying to do indeed.

> If that doesn't work: could you please create a small program that  
> shows the problem (that is, a complete Xcode project)?
>
> Ronald

Here you are, a small Xcode 3 project with just a Text Label  
displaying the error message from an NSURLConnection failure.

  - Jean-Pierre.