#>/dev/diegor by Diego Russo is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
A public web server could be reached by many http requests with no user agent. Apache can avoid this kind of requests. The configuration is very straightforward:
<Directory /path/to/a/directory> SetEnvIfNoCase User-Agent "^-?$" noUserAgent Order Allow,Deny Allow from All Deny from env=noUserAgent </Directory>
In this example Apache ignores all requests without user agent that are directed to /path/to/a/directory
Any comments are appreciate.
I used to manage a server based on linux and once I had this strange message:
#> ip_conntrack: table full, dropping packet
One of the effects of this message is that you aren’t able to make and receive new connections.
To solve that is enough increase ip_conntrack_max value. As first step check the current value typing:
#> cat /proc/sys/net/ipv4/ip_conntrack_max 65536
Now, increase this value typing:
#> echo 131072 > /proc/sys/net/ipv4/ip_conntrack_max
Generally the right value of ip_conntrack_max is set to the total MB of RAM multiplied by 16. If you have 8GB RAM (8192 MB), the value should be 131072.
Django doesn’t permit you because it goes against MVC model, but sometime it’s useful to get output (in view level) depending on specific arguments. For example in my model i have this method:
def get_value(self, arg_to_pass):
if (arg_to_pass.is_type_A):
return self.value_for_A
else:
return self.value_for_B
In your template you’ll type {{ object.get_value }} but you can’t pass argument. You can solve this issue with templatetags.
Create a templatetag like this below:
def callMethod(obj, methodName):
method = getattr(obj, methodName)
if obj.__dict__.has_key("__callArg"):
ret = method(*obj.__callArg)
del obj.__callArg
return ret
return method()
def args(obj, arg):
if not obj.__dict__.has_key("__callArg"):
obj.__callArg = []
obj.__callArg += [arg]
return obj
register.filter("call", callMethod)
register.filter("args", args)
Ok, almost done. Now, in your template, call your method typying:
{{ object|args:arg_to_pass|call:"get_value" }}
Job done! If you have any question, leave a comment! 
Source: sprklab.com
Yesterday I’ve decided to update my site and significant changes are:
Do you like it? Comment!
When you edit a file with vim, it’s useful understand where the line ends especially if there are spaces at the end of the line. Instead checking all lines, you can highlight white spaces. How?
:set list
:set listchars=eol:$,tab:>-,trail:~,extends:>,precedes:<
Very simple and useful tip!
If you have any doubt, advice or something else, comment this post!
Source: Stackoverflow
If you know what cron is, you also know that the minimum time to execute a job is a minute. There is a small tip to execute a cron job every X seconds. For example if you need to run a cron job every 30 seconds (it’s a common case), you can do it adding these lines to crontab:
* * * * * root sh /path/to/myscript.sh * * * * * root sleep 30 && sh /path/to/myscript.sh
Both lines execute the job every minute, but the second one waits 30 seconds using “sleep” command from bash.
If you have any question, comment this post.
For some years this blog has been written only in italian, and as you know, some time ago I decided to switch it in three languages. While I wrote only in italian, I made many HOWTOs (guess the language?!). In below list you can find all my italian howtos (yep, i’ve translated only the title).
If you like one of them, tell me.. so I can translate it for you. If you like, you may translate too
Comment this post with your request or write me an email!
Vim is my favourite text editor, i use it pretty anywhere
I’ll share a useful trick for commenting multiple lines of code:
1) SHIFT-V to select multiple lines;
2) Type “:s/^/#”
Where “^” indicates the beginning of a line and “#” the comment symbol of your choice.
To decomment a block of code:
1) Shift-V
2) Type “:s/^#//”