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Referrer key missing form os.environ dictionary?

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  Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 15:45 +0300
    Re: Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 16:14 +0300
    Re: Referrer key missing form os.environ dictionary? Chris “Kwpolska” Warrick <kwpolska@gmail.com> - 2013-09-25 16:01 +0200
      Re: Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 17:04 +0300
        Re: Referrer key missing form os.environ dictionary? John Gordon <gordon@panix.com> - 2013-09-25 14:26 +0000
          Re: Referrer key missing form os.environ dictionary? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-25 15:04 +0000
            Re: Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 18:16 +0300
              Re: Referrer key missing form os.environ dictionary? Tim Chase <python.list@tim.thechases.com> - 2013-09-25 10:42 -0500
              Re: Referrer key missing form os.environ dictionary? Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-25 21:17 +0000
          Re: Referrer key missing form os.environ dictionary? Ned Batchelder <ned@nedbatchelder.com> - 2013-09-25 11:09 -0400
        Re: Referrer key missing form os.environ dictionary? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-25 14:52 +0000
          Re: Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 18:02 +0300
            Re: Referrer key missing form os.environ dictionary? Xaxa Urtiz <urtizvereaxaxa@gmail.com> - 2013-09-25 08:09 -0700
            Re: Referrer key missing form os.environ dictionary? Tim Chase <python.list@tim.thechases.com> - 2013-09-25 10:14 -0500
              Re: Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 18:35 +0300
          Re: Referrer key missing form os.environ dictionary? Grant Edwards <invalid@invalid.invalid> - 2013-09-25 15:18 +0000
            Re: Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 18:41 +0300
              Re: Referrer key missing form os.environ dictionary? John Gordon <gordon@panix.com> - 2013-09-25 16:27 +0000
              Re: Referrer key missing form os.environ dictionary? Grant Edwards <invalid@invalid.invalid> - 2013-09-25 18:37 +0000
            Re: Referrer key missing form os.environ dictionary? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-26 00:11 +0000
              Re: Referrer key missing form os.environ dictionary? Terry Reedy <tjreedy@udel.edu> - 2013-09-25 21:32 -0400
              Re: Referrer key missing form os.environ dictionary? Chris Angelico <rosuav@gmail.com> - 2013-09-26 13:25 +1000
                Re: Referrer key missing form os.environ dictionary? Grant Edwards <invalid@invalid.invalid> - 2013-09-26 14:16 +0000
              Re: Referrer key missing form os.environ dictionary? Robert Kern <robert.kern@gmail.com> - 2013-09-26 11:15 +0100
              Re: Referrer key missing form os.environ dictionary? Grant Edwards <invalid@invalid.invalid> - 2013-09-26 14:11 +0000
                Re: Referrer key missing form os.environ dictionary? Chris Angelico <rosuav@gmail.com> - 2013-09-27 01:17 +1000
                  Re: Referrer key missing form os.environ dictionary? Grant Edwards <invalid@invalid.invalid> - 2013-09-26 23:27 +0000
                    Re: Referrer key missing form os.environ dictionary? Chris Angelico <rosuav@gmail.com> - 2013-09-27 16:01 +1000
      Re: Referrer key missing form os.environ dictionary? Νίκος <nikos.gr33k@gmail.com> - 2013-09-25 17:07 +0300
        Re: Referrer key missing form os.environ dictionary? Robert Kern <robert.kern@gmail.com> - 2013-09-25 15:26 +0100
        Re: Referrer key missing form os.environ dictionary? John Gordon <gordon@panix.com> - 2013-09-25 14:30 +0000
        Re: Referrer key missing form os.environ dictionary? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-25 14:46 +0000
        Re: Referrer key missing form os.environ dictionary? Piet van Oostrum <piet@vanoostrum.org> - 2013-09-25 15:59 -0400
    Re: Referrer key missing form os.environ dictionary? John Gordon <gordon@panix.com> - 2013-09-25 14:18 +0000
      Re: Referrer key missing form os.environ dictionary? Tim Chase <python.list@tim.thechases.com> - 2013-09-25 09:58 -0500

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#54728 — Referrer key missing form os.environ dictionary?

Hello, i decided am ong other os.environ variables to also grab the 
'HTTP_REFERER' fiel but when i try to run my script i was seeing a 
KeyError complaining that 'HTTP_REFERER' didnt exist.

So, to see what existed in the os.environ dictionary i issues a print( 
os.environ ) to see all available keys and their values:

environ({'SERVER_PORT': '80', 'REQUEST_URI': '/', 
'HTTP_ACCEPT_ENCODING': 'gzip,deflate,sdch', 'SERVER_ADDR': 
'84.200.17.58', 'DOCUMENT_ROOT': '/home/nikos/public_html', 
'HTTP_CONNECTION': 'keep-alive', 'SCRIPT_FILENAME': 
'/home/nikos/public_html/cgi-bin/metrites.py', 'SERVER_NAME': 
'superhost.gr', 'REMOTE_PORT': '58896', 'HTTP_ACCEPT': 
'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8', 
'HTTP_USER_AGENT': 'Mozilla/5.0 (Windows NT 6.2; WOW64) 
AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.2 
Safari/537.36', 'HTTP_ACCEPT_LANGUAGE': 'en-US,en;q=0.8,el;q=0.6', 
'GATEWAY_INTERFACE': 'CGI/1.1', 'HTTP_HOST': 'superhost.gr', 
'REDIRECT_URL': '/index.html', 'SERVER_PROTOCOL': 'HTTP/1.1', 
'SERVER_SIGNATURE': '
Apache/2.2.25 (Unix) mod_ssl/2.2.25 OpenSSL/1.0.0-fips 
mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server 
at superhost.gr Port 80
\n', 'HTTP_DNT': '1', 'REQUEST_METHOD': 'GET', 'QUERY_STRING': 
'file=/home/nikos/public_html/index.html', 'PATH': 
'/sbin:/usr/sbin:/bin:/usr/bin', 'HTTP_COOKIE': 'cf_use_ob=0; 
__cfduid=da37079bb377f13e9c50224189ab46ac71379783691866; 
__utma=210786583.1207352568.1379497319.1380099225.1380108255.32; 
__utmc=210786583; 
__utmz=210786583.1379497319.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)', 
'REMOTE_ADDR': '176.92.73.41', 'REDIRECT_QUERY_STRING': 
'file=/home/nikos/public_html/index.html', 'SERVER_SOFTWARE': 
'Apache/2.2.25 (Unix) mod_ssl/2.2.25 OpenSSL/1.0.0-fips 
mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635', 
'SERVER_ADMIN': 'webmaster@superhost.gr', 'SCRIPT_NAME': 
'/cgi-bin/metrites.py', 'REDIRECT_STATUS': '200'})


i dont see anywhere a refferer key so to catch it in a variable sting 
like this:

referrer = os.environ['HTTP_REFERER']

Do i miss something? its a suprise to me that the environ dictioanry has 
almost anythign but a referrer key.

I need your help please.

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#54729

Στις 25/9/2013 3:45 μμ, ο/η Νίκος έγραψε:
> Hello, i decided am ong other os.environ variables to also grab the
> 'HTTP_REFERER' fiel but when i try to run my script i was seeing a
> KeyError complaining that 'HTTP_REFERER' didnt exist.
>
> So, to see what existed in the os.environ dictionary i issues a print(
> os.environ ) to see all available keys and their values:
>
> environ({'SERVER_PORT': '80', 'REQUEST_URI': '/',
> 'HTTP_ACCEPT_ENCODING': 'gzip,deflate,sdch', 'SERVER_ADDR':
> '84.200.17.58', 'DOCUMENT_ROOT': '/home/nikos/public_html',
> 'HTTP_CONNECTION': 'keep-alive', 'SCRIPT_FILENAME':
> '/home/nikos/public_html/cgi-bin/metrites.py', 'SERVER_NAME':
> 'superhost.gr', 'REMOTE_PORT': '58896', 'HTTP_ACCEPT':
> 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
> 'HTTP_USER_AGENT': 'Mozilla/5.0 (Windows NT 6.2; WOW64)
> AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.2
> Safari/537.36', 'HTTP_ACCEPT_LANGUAGE': 'en-US,en;q=0.8,el;q=0.6',
> 'GATEWAY_INTERFACE': 'CGI/1.1', 'HTTP_HOST': 'superhost.gr',
> 'REDIRECT_URL': '/index.html', 'SERVER_PROTOCOL': 'HTTP/1.1',
> 'SERVER_SIGNATURE': '
> Apache/2.2.25 (Unix) mod_ssl/2.2.25 OpenSSL/1.0.0-fips
> mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server
> at superhost.gr Port 80
> \n', 'HTTP_DNT': '1', 'REQUEST_METHOD': 'GET', 'QUERY_STRING':
> 'file=/home/nikos/public_html/index.html', 'PATH':
> '/sbin:/usr/sbin:/bin:/usr/bin', 'HTTP_COOKIE': 'cf_use_ob=0;
> __cfduid=da37079bb377f13e9c50224189ab46ac71379783691866;
> __utma=210786583.1207352568.1379497319.1380099225.1380108255.32;
> __utmc=210786583;
> __utmz=210786583.1379497319.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)',
> 'REMOTE_ADDR': '176.92.73.41', 'REDIRECT_QUERY_STRING':
> 'file=/home/nikos/public_html/index.html', 'SERVER_SOFTWARE':
> 'Apache/2.2.25 (Unix) mod_ssl/2.2.25 OpenSSL/1.0.0-fips
> mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635',
> 'SERVER_ADMIN': 'webmaster@superhost.gr', 'SCRIPT_NAME':
> '/cgi-bin/metrites.py', 'REDIRECT_STATUS': '200'})
>
>
> i dont see anywhere a refferer key so to catch it in a variable sting
> like this:
>
> referrer = os.environ['HTTP_REFERER']
>
> Do i miss something? its a suprise to me that the environ dictioanry has
> almost anythign but a referrer key.
>
> I need your help please.

I also tried this:

referer = os.environ.get('HTTP_REFERER', 'UnknownRef')

but that doesn't return anythign either.

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#54731

On Wed, Sep 25, 2013 at 2:45 PM, Νίκος <nikos.gr33k@gmail.com> wrote:
> Hello, i decided am ong other os.environ variables to also grab the
> 'HTTP_REFERER' fiel but when i try to run my script i was seeing a KeyError
> complaining that 'HTTP_REFERER' didnt exist.
>
> So, to see what existed in the os.environ dictionary i issues a print(
> os.environ ) to see all available keys and their values:

The Referer header is not mandatory by any means.  Your client
probably does not send it.

-- 
Chris “Kwpolska” Warrick <http://kwpolska.tk>
PGP: 5EAAEA16
stop html mail | always bottom-post | only UTF-8 makes sense

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#54732

Στις 25/9/2013 5:01 μμ, ο/η Chris “Kwpolska” Warrick έγραψε:
> On Wed, Sep 25, 2013 at 2:45 PM, Νίκος <nikos.gr33k@gmail.com> wrote:
>> Hello, i decided am ong other os.environ variables to also grab the
>> 'HTTP_REFERER' fiel but when i try to run my script i was seeing a KeyError
>> complaining that 'HTTP_REFERER' didnt exist.
>>
>> So, to see what existed in the os.environ dictionary i issues a print(
>> os.environ ) to see all available keys and their values:
>
> The Referer header is not mandatory by any means.  Your client
> probably does not send it.
>
I would like to check for its existence and retrieve it if possible, if 
its not there then default to the string "UnKnown Ref".

I try to do this with:

referer = os.environ.get('HTTP_REFERER', 'UnknownRef')

but that doesn't return anything either.

Can you verify that its the correct way to grab the referral string?

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#54735

In <l1uqi7$qi5$1@dont-email.me> =?UTF-8?B?zp3Or866zr/Pgg==?= <nikos.gr33k@gmail.com> writes:

> referer = os.environ.get('HTTP_REFERER', 'UnknownRef')

> but that doesn't return anything either.

When you say it "doesn't return anything", what exactly do you mean?  Does
it return None?  Does it raise KeyError?  Something else?

In any case, I'm surprised that doesn't work.  That should be the correct
way to do it.

You could try this:

    try:
        referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
    except KeyError:
        referer = None

    if not referer:
        referer = 'UnknownRef'

-- 
John Gordon                   A is for Amy, who fell down the stairs
gordon@panix.com              B is for Basil, assaulted by bears
                                -- Edward Gorey, "The Gashlycrumb Tinies"

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#54742

On Wed, 25 Sep 2013 14:26:23 +0000, John Gordon wrote:

> You could try this:
> 
>     try:
>         referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
>     except KeyError:
>         referer = None
>     if not referer:
>         referer = 'UnknownRef'

The get method will not raise KeyError. If the key is missing, 
'UnknownRef' will be returned instead.

So when Nikos reports that os.environ.get('HTTP_REFERER', 'UnknownRef') 
"doesn't return anything", he is mistaken. It returns 'UnknownRef'.


-- 
Steven

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#54746

Στις 25/9/2013 6:04 μμ, ο/η Steven D'Aprano έγραψε:
> On Wed, 25 Sep 2013 14:26:23 +0000, John Gordon wrote:
>
>> You could try this:
>>
>>      try:
>>          referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
>>      except KeyError:
>>          referer = None
>>      if not referer:
>>          referer = 'UnknownRef'
>
> The get method will not raise KeyError. If the key is missing,
> 'UnknownRef' will be returned instead.
>
> So when Nikos reports that os.environ.get('HTTP_REFERER', 'UnknownRef')
> "doesn't return anything", he is mistaken. It returns 'UnknownRef'.
>
>
Not actually Steven,

the referer key works well but it was the simlutaneous "host" issues 
that was giving me false understanding. now it works ok?

So you say if the key is missign the get method wotn return an error but 
the default string instead. That is nice to hear.

But answer me plz this:

how caom the http_referer thing works ok now but when i just print all 
the key listing of .os.environ ket the http_referer key isnt inside?

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#54749

On 2013-09-25 18:16, Νίκος wrote:
> how caom the http_referer thing works ok now but when i just print
> all the key listing of .os.environ ket the http_referer key isnt
> inside?

Well, first off, it's entirely possible (based on reading that
paragraph) that you typed something wrong.

That said, it depends on whether you're looking in your local
environment, or the CGI environment provided by the server.  As a
simple example of what the server-side has/puts in your environment,
you can use this CGI script:


#!/usr/bin/env python
import cgitb; cgitb.enable()
import cgi
import os
import sys
print "Content-Type: text/html\n\n"
print """
<html>
 <head>
  <title>Test CGI</title>
  <style>dt{font-weight: bold;}</style>
 </head>
 <body>
 <dl>"""
for k,v in sorted(os.environ.items()):
    print "<dt>%s</dt>" % cgi.escape(k)
    print "<dd>%s</dd>" % cgi.escape(v)
print """
 </dl>
 </body>
</html>"""

Note that, if you go directly to the page, you shouldn't have a
refer[r]er header, while if you arrive at it from some previous page,
you might (modulo the aforementioned chicanery that plugins can
induce)

-tkc

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#54758

On Wed, 25 Sep 2013 18:16:39 +0300, Νίκος wrote:

> how caom the http_referer thing works ok now but when i just print all
> the key listing of .os.environ ket the http_referer key isnt inside?

That you do not understand this is caused by your failure to understand 
the HTTP protocol. You have been told before, this NG is not networking 
and / or tcp/ip and / or internet protocols 101.

Please go and learn about the network protocols you're trying to interact 
with before you start writing code that interacts with them. The issue 
you are raising here is not a python issue, it is a network protocols 
issue that has nothing whatsoever to do with python.

-- 
Denis McMahon, denismfmcmahon@gmail.com

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#54743

On 9/25/13 10:26 AM, John Gordon wrote:
> You could try this:
>
>      try:
>          referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
>      except KeyError:
>          referer = None
>
>      if not referer:
>          referer = 'UnknownRef'
There's no need for the "except KeyError" clause.  dict.get never raises 
KeyError, this code will assign 'UnknownRef' in the case the environment 
variable is missing.

--Ned.

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#54739

On Wed, 25 Sep 2013 17:04:55 +0300, Νίκος wrote:

> I would like to check for its existence and retrieve it if possible, if
> its not there then default to the string "UnKnown Ref".
> 
> I try to do this with:
> 
> referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
> 
> but that doesn't return anything either.
> 
> Can you verify that its the correct way to grab the referral string?


The Referer is not an environment variable. How would your shell know 
what URL you were just browsing?

Have you googled for HTTP Referer? Do you understand what it is?


-- 
Steven

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#54741

Στις 25/9/2013 5:52 μμ, ο/η Steven D'Aprano έγραψε:
> On Wed, 25 Sep 2013 17:04:55 +0300, Νίκος wrote:
>
>> I would like to check for its existence and retrieve it if possible, if
>> its not there then default to the string "UnKnown Ref".
>>
>> I try to do this with:
>>
>> referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
>>
>> but that doesn't return anything either.
>>
>> Can you verify that its the correct way to grab the referral string?
>
>
> The Referer is not an environment variable. How would your shell know
> what URL you were just browsing?
>
> Have you googled for HTTP Referer? Do you understand what it is?
>
>
Yes Steven googleign for 2 hours now.

You were rigth about the carret it was a synatx error above which i 
missed and i was breakign my head to the wall to understand what was wot 
with the 'host' variable. why python doestn detect the exact synxtax 
error and ispoitnign to me to another line making me think the error is 
elsewhere?

This indeed works now:

ref = os.environ.get('HTTP_REFERER', 'Άγνωστο Ref')

but iam wondering why this doesnt work also:

ref = os.environ('HTTP_REFERER')

Shouldnt both work?

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#54744

Le mercredi 25 septembre 2013 17:02:45 UTC+2, Ferrous Cranus a écrit :
> Στις 25/9/2013 5:52 μμ, ο/η Steven D'Aprano έγραψε:
> 
> > On Wed, 25 Sep 2013 17:04:55 +0300, Νίκος wrote:
> 
> >
> 
> >> I would like to check for its existence and retrieve it if possible, if
> 
> >> its not there then default to the string "UnKnown Ref".
> 
> >>
> 
> >> I try to do this with:
> 
> >>
> 
> >> referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
> 
> >>
> 
> >> but that doesn't return anything either.
> 
> >>
> 
> >> Can you verify that its the correct way to grab the referral string?
> 
> >
> 
> >
> 
> > The Referer is not an environment variable. How would your shell know
> 
> > what URL you were just browsing?
> 
> >
> 
> > Have you googled for HTTP Referer? Do you understand what it is?
> 
> >
> 
> >
> 
> Yes Steven googleign for 2 hours now.
> 
> 
> 
> You were rigth about the carret it was a synatx error above which i 
> 
> missed and i was breakign my head to the wall to understand what was wot 
> 
> with the 'host' variable. why python doestn detect the exact synxtax 
> 
> error and ispoitnign to me to another line making me think the error is 
> 
> elsewhere?
> 
> 
> 
> This indeed works now:
> 
> 
> 
> ref = os.environ.get('HTTP_REFERER', 'Άγνωστο Ref')
> 
> 
> 
> but iam wondering why this doesnt work also:
> 
> 
> 
> ref = os.environ('HTTP_REFERER')
> 
> 
> 
> Shouldnt both work?

http://www.tutorialspoint.com/python/dictionary_get.htm

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#54745

On 2013-09-25 18:02, Νίκος wrote:
> This indeed works now:
> 
> ref = os.environ.get('HTTP_REFERER', 'Άγνωστο Ref')
> 
> but iam wondering why this doesnt work also:
> 
> ref = os.environ('HTTP_REFERER')
> 
> Shouldnt both work?

No...that calls os.environ.  You likely *mean*

  ref = os.environ['HTTP_REFERER']

using square brackets.  However, as previously noted by multiple
respondents, this header is not guaranteed to be sent by the browser
for a variety of reasons, so it may not be in the environment
dictionary at all. Thus you are likely to get KeyError exceptions if
you don't use .get() unless you wrap it in a check:

  if "HTTP_REFERER" in os.environ:
    ref = os.environ["HTTP_REFERER"]
  else:
    deal_with_this_situation()

-tkc

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#54748

Στις 25/9/2013 6:14 μμ, ο/η Tim Chase έγραψε:
> On 2013-09-25 18:02, Νίκος wrote:
>> This indeed works now:
>>
>> ref = os.environ.get('HTTP_REFERER', 'Άγνωστο Ref')
>>
>> but iam wondering why this doesnt work also:
>>
>> ref = os.environ('HTTP_REFERER')
>>
>> Shouldnt both work?
>
> No...that calls os.environ.  You likely *mean*
>
>    ref = os.environ['HTTP_REFERER']
>
> using square brackets.  However, as previously noted by multiple
> respondents, this header is not guaranteed to be sent by the browser
> for a variety of reasons, so it may not be in the environment
> dictionary at all. Thus you are likely to get KeyError exceptions if
> you don't use .get() unless you wrap it in a check:
>
>    if "HTTP_REFERER" in os.environ:
>      ref = os.environ["HTTP_REFERER"]
>    else:
>      deal_with_this_situation()

Thank you very much for the clarification.
I just wanted to know the differecne between the 2 ways of using the 
HTTP_REFERER.

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#54747

On 2013-09-25, Steven D'Aprano <steve+comp.lang.python@pearwood.info> wrote:
> On Wed, 25 Sep 2013 17:04:55 +0300, ?????????? wrote:
>
>> I would like to check for its existence and retrieve it if possible, if
>> its not there then default to the string "UnKnown Ref".
>> 
>> I try to do this with:
>> 
>> referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
>> 
>> but that doesn't return anything either.

And of course that's bolloks:

   Python 2.7.5 (default, Aug 29 2013, 15:13:35) 
   [GCC 4.6.3] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import os
   >>> os.environ.get('HTTP_REFERER','UnkownRef')
   'UnkownRef'
   >>> 

   Python 3.2.5 (default, Aug 29 2013, 15:19:46) 
   [GCC 4.6.3] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import os
   >>> os.environ.get('HTTP_REFERER','UnkownRef')
   'UnkownRef'
   >>> 

>> Can you verify that its the correct way to grab the referral string?

It is.

> The Referer is not an environment variable.

It is when you're writing a CGI app.

> How would your shell know what URL you were just browsing?

Because the HTTP server sets those environment variables before
invoking the CGI app.

-- 
Grant Edwards               grant.b.edwards        Yow! Boy, am I glad it's
                                  at               only 1971...
                              gmail.com            

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#54750

Στις 25/9/2013 6:18 μμ, ο/η Grant Edwards έγραψε:
> On 2013-09-25, Steven D'Aprano <steve+comp.lang.python@pearwood.info> wrote:
>> On Wed, 25 Sep 2013 17:04:55 +0300, ?????????? wrote:
>>
>>> I would like to check for its existence and retrieve it if possible, if
>>> its not there then default to the string "UnKnown Ref".
>>>
>>> I try to do this with:
>>>
>>> referer = os.environ.get('HTTP_REFERER', 'UnknownRef')
>>>
>>> but that doesn't return anything either.
>
> And of course that's bolloks:
>
>     Python 2.7.5 (default, Aug 29 2013, 15:13:35)
>     [GCC 4.6.3] on linux2
>     Type "help", "copyright", "credits" or "license" for more information.
>     >>> import os
>     >>> os.environ.get('HTTP_REFERER','UnkownRef')
>     'UnkownRef'
>     >>>
>
>     Python 3.2.5 (default, Aug 29 2013, 15:19:46)
>     [GCC 4.6.3] on linux2
>     Type "help", "copyright", "credits" or "license" for more information.
>     >>> import os
>     >>> os.environ.get('HTTP_REFERER','UnkownRef')
>     'UnkownRef'
>     >>>
>
>>> Can you verify that its the correct way to grab the referral string?
>
> It is.
>
>> The Referer is not an environment variable.
>
> It is when you're writing a CGI app.
>
>> How would your shell know what URL you were just browsing?
>
> Because the HTTP server sets those environment variables before
> invoking the CGI app.
>
So you mean that even if i run it via shell this stement will  also work 
because it happens to be in the same enviroment with the HTTP server?

No need to run it via web browser and check the Apache's error log?

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#54751

In <l1v07g$tej$2@dont-email.me> =?UTF-8?B?zp3Or866zr/Pgg==?= <nikos.gr33k@gmail.com> writes:

> So you mean that even if i run it via shell this stement will  also work 
> because it happens to be in the same enviroment with the HTTP server?

No.  Each process has its own environment.  Your shell's environment
knows nothing about the web server's environment.

-- 
John Gordon                   A is for Amy, who fell down the stairs
gordon@panix.com              B is for Basil, assaulted by bears
                                -- Edward Gorey, "The Gashlycrumb Tinies"

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#54753

On 2013-09-25, ?????????? <nikos.gr33k@gmail.com> wrote:
> ???????? 25/9/2013 6:18 ????, ??/?? Grant Edwards ????????????:

>>> The Referer is not an environment variable.
>>
>> It is when you're writing a CGI app.
>>
>>> How would your shell know what URL you were just browsing?
>>
>> Because the HTTP server sets those environment variables before
>> invoking the CGI app.
>
> So you mean that even if i run it via shell this stement will also
> work

If the shell was started by the HTTP server, yes.  If you logged in
normally, no.

> because it happens to be in the same enviroment with the HTTP server?

The shell will only have that environment if the shell was run by the
HTTP server.

> No need to run it via web browser and check the Apache's error log?

You can set the environemnt variables appropriately in the shell and
then invoke a CGI application directly for testing purposes.

-- 
Grant Edwards               grant.b.edwards        Yow! I was born in a
                                  at               Hostess Cupcake factory
                              gmail.com            before the sexual
                                                   revolution!

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#54767

On Wed, 25 Sep 2013 15:18:41 +0000, Grant Edwards wrote:

>> The Referer is not an environment variable.
> 
> It is when you're writing a CGI app.
> 
>> How would your shell know what URL you were just browsing?
> 
> Because the HTTP server sets those environment variables before invoking
> the CGI app.


I stand corrected.


That's a pretty shitty design though, isn't it? Communicating via 
environment variables. What is this, 1998? :-)

Mind you, I'm not sure what other alternatives exist.


-- 
Steven

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