7. September 2011

Debian – apt-get install perl problem

I wanted to install new package on Debian. But what a funny message:

E: Could not perform immediate configuration on 'perl-modules'. 
Please see man 5 apt.conf under APT::Immediate-Configure for details. (2)

How to solve it?

Type:

apt-get install perl -o APT::Immediate-Configure=0

27. August 2011

Try to create aux.h file on Windows 7

Try it 🙂

I was playing with one package from Linux. I grab source code of package using Cygwin. This source code contained one funny file: aux.h.

Windows version of Vim refused to open this file with error message: Permission denied.

Even Notepad refused to open this file.

Finally Visual Studio gave me interesting hint about this aux.h file name:

 

I tried to zip this file by 7Zip and extract it back. Result was that 7Zip decompressed file as _aux.h.

Interesting issue. 🙂

5. March 2011

IE 6 Countdown

IE 6 is one of the biggest blocker of innovation in web technologies. IE 6 is eating hours and hours of developer’s time.

Some goverments stubbornly require support of this “ancient” application.

Christian Heilmann has been talking about this problem for several years.

Usage of IE 6 is falling. 12% in February. You can watch the departure of IE 6 from computer stage at: ie6countdown.com

31. January 2011

Amazon S3 – Authenticating REST – bug in documentation

Document Amazon S3 – Authenticating REST says that you should generate authentication signature using following code:

"Authorization: AWS " + AWSAccessKeyId + ":"
   + base64(hmac-sha1(VERB + "\n"
   + CONTENT-MD5 + "\n"
   + CONTENT-TYPE + "\n"
   + DATE + "\n"
   + CanonicalizedAmzHeaders + "\n"
   + CanonicalizedResource))

In documentation you can find following instructions:
The string to be signed is formed by appending the REST verb, content-md5 value, content-type value, date value, canonicalized x-amz headers, and the resource; all separated by newlines.

I followed instructions, but server always responded in the same stubborn fashion:

Code: SignatureDoesNotMatch
Message: The request signature we calculated does not match the signature you provided. Check your key and signing method.

The problem was that my request didn’t contain any AmzHeader and therefore CanonicalizedAmzHeaders was empty string followed by new line. That’s wrong.

If CanonizalizedAmzHeaders is empty string then there MUST NOT be new line!

Correct string for signing in case when AmzHeader is empty:

"Authorization: AWS " + AWSAccessKeyId + ":"
   + base64(hmac-sha1(VERB + "\n"
   + CONTENT-MD5 + "\n"
   + CONTENT-TYPE + "\n"
   + DATE + "\n"
   + CanonicalizedResource))

26. January 2011

IntelliJ Idea – Windows – Git – The remote end hung up

I was trying to clone git repository. I had brand new Windows with Cygwin version of git. Intellij Idea displayed nice helpful error message:

fatal: The remote end hung up unexpectedly

I found article at grublesmurf.org that pointed me to solution.

Problem was that Cygwin was using directory c:\cygwin\home\georgik\.ssh, but Intellij Idea was trying to read c:\Users\georgik\.ssh. I moved .ssh directory to c:\Users\georgik and set HOME variable to %USERPROFILE%.It is also worthy to modify /etc/passwd in cygwin to match that directory.