robotparser doesn't support request rate and crawl delay parameters

[XapaJIaMnu]

BPO	16099
Nosy	@rhettinger, @orsenthil, @tiran, @berkerpeksag, @hynek
Files	robotparser.patch: patch for robotparser.py robotparser.patch: same patch for python3X robotparser.patch: Changes + test cases + documentation robotparser_reformatted.patch: Changes, test cases, documentation, reformatted robotparser_v2.patch: V2 with fixes robotparser_v3.patch: V3 crawl delay and request rate patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/berkerpeksag'
closed_at = <Date 2015-10-08.09:34:21.553>
created_at = <Date 2012-10-01.12:58:25.141>
labels = ['easy', 'type-feature', 'library']
title = "robotparser doesn't support request rate and crawl delay parameters"
updated_at = <Date 2015-10-08.09:34:21.551>
user = 'https://bugs.python.org/XapaJIaMnu'

bugs.python.org fields:

activity = <Date 2015-10-08.09:34:21.551>
actor = 'berker.peksag'
assignee = 'berker.peksag'
closed = True
closed_date = <Date 2015-10-08.09:34:21.553>
closer = 'berker.peksag'
components = ['Library (Lib)']
creation = <Date 2012-10-01.12:58:25.141>
creator = 'XapaJIaMnu'
dependencies = []
files = ['27373', '27374', '27476', '27477', '33071', '35377']
hgrepos = []
issue_num = 16099
keywords = ['patch', 'easy', 'needs review']
message_count = 17.0
messages = ['171711', '171712', '171715', '171719', '172327', '172338', '205567', '205641', '205755', '205761', '208721', '219212', '223099', '225916', '252483', '252521', '252525']
nosy_count = 7.0
nosy_names = ['rhettinger', 'orsenthil', 'christian.heimes', 'python-dev', 'berker.peksag', 'hynek', 'XapaJIaMnu']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue16099'
versions = ['Python 3.6']

[XapaJIaMnu]

Robotparser doesn't support two quite important optional parameters from the robots.txt file. I have implemented those in the following way:
(Robotparser should be initialized in the usual way:
rp = robotparser.RobotFileParser()
rp.set_url(..)
rp.read
)

crawl_delay(useragent) - Returns time in seconds that you need to wait for crawling
if none is specified, or doesn't apply to this user agent, returns -1
request_rate(useragent) - Returns a list in the form [request,seconds].
if none is specified, or doesn't apply to this user agent, returns -1

[tiran]

Thanks for the patch. New features must be implemented in Python 3.4. Python 2.7 is in feature freeze mode and therefore doesn't get new features.

[XapaJIaMnu]

Okay, sorry didn't know that (:
Here's the same patch (Same functionality) for python3

Feedback is welcome, as always (:

[tiran]

We have a team that mentors new contributors. If you are interested to get your patch into Python 3.4, please read http://pythonmentors.com/ . The people are really friendly and will help you with every step of the process.

[XapaJIaMnu]

Okay, here's a proper patch with documentation entry and test cases.
Please review and comment

[XapaJIaMnu]

Reformatted patch

[XapaJIaMnu]

Hey,
it has been more than an year since the last activity.
Is there anything else I should do in order for someone of the python devs team to review my changes and perhaps give some feedback?

Nick

[berkerpeksag]

I left a few comments on Rietveld.

[XapaJIaMnu]

Thank you for the review!
I have addressed your comments and release a v2 of the patch:
Highlights:
No longer crashes when provided with malformed crawl-delay/robots.txt parameter.
Returns None when parameter is missing or syntax is invalid.
Simplified several functions.
Extended tests.

http://bugs.python.org/review/16099/diff/6206/Doc/library/urllib.robotparser.rst
File Doc/library/urllib.robotparser.rst (right):

http://bugs.python.org/review/16099/diff/6206/Doc/library/urllib.robotparser....
Doc/library/urllib.robotparser.rst:56: .. method:: crawl_delay(useragent)
On 2013/12/09 03:30:54, berkerpeksag wrote:

Is crawl_delay used for search engines? Google recommends you to set crawl speed
via Google Webmaster Tools instead.

See https://support.google.com/webmasters/answer/48620?hl=en.

Crawl delay and request rate parameters are targeted to custom crawlers that many people/companies write for specific tasks. The Google webmaster tools is targeted only to google's crawler and typically web admins have different rates for google/yahoo/bing and all other user agents.

http://bugs.python.org/review/16099/diff/6206/Lib/urllib/robotparser.py
File Lib/urllib/robotparser.py (right):

http://bugs.python.org/review/16099/diff/6206/Lib/urllib/robotparser.py#newco...
Lib/urllib/robotparser.py:168: for entry in self.entries:
On 2013/12/09 03:30:54, berkerpeksag wrote:

Is there a better way to calculate this? (perhaps O(1)?)

I have followed the model of what was written beforehand. A 0(1) implementation (probably based on dictionaries) would require a complete rewrite of this library, as all previously implemented functions employ the:
for entry in self.entries:
if entry.applies_to(useragent):

logic. I don't think this matters particularly here, as those two functions in particular need only be called once per domain and robots.txt seldom contains more than 3 entries. This is why I have just followed the design laid out by the original developer.

Thanks

Nick

[XapaJIaMnu]

Oh... Sorry for the spam, could you please verify my documentation link syntax. I'm not entirely sure I got it right.

[XapaJIaMnu]

Hey,

Just a reminder friendly reminder that there hasn't been any activity for a month and I have released a v2, pending for review (: