scripts/scholar.py
#! /usr/bin/env python
"""
This module provides classes for querying Google Scholar and parsing
returned results. It currently *only* processes the first results
page. It is not a recursive crawler.
"""
# ChangeLog
# ---------
#
# 2.10 Merged a fix for the "TypError: quote_from_bytes()" problem on
# Python 3.x from hinnefe2.
#
# 2.9 Fixed Unicode problem in certain queries. Thanks to smidm for
# this contribution.
#
# 2.8 Improved quotation-mark handling for multi-word phrases in
# queries. Also, log URLs %-decoded in debugging output, for
# easier interpretation.
#
# 2.7 Ability to extract content excerpts as reported in search results.
# Also a fix to -s|--some and -n|--none: these did not yet support
# passing lists of phrases. This now works correctly if you provide
# separate phrases via commas.
#
# 2.6 Ability to disable inclusion of patents and citations. This
# has the same effect as unchecking the two patents/citations
# checkboxes in the Scholar UI, which are checked by default.
# Accordingly, the command-line options are --no-patents and
# --no-citations.
#
# 2.5: Ability to parse global result attributes. This right now means
# only the total number of results as reported by Scholar at the
# top of the results pages (e.g. "About 31 results"). Such
# global result attributes end up in the new attrs member of the
# used ScholarQuery class. To render those attributes, you need
# to use the new --txt-globals flag.
#
# Rendering global results is currently not supported for CSV
# (as they don't fit the one-line-per-article pattern). For
# grepping, you can separate the global results from the
# per-article ones by looking for a line prefix of "[G]":
#
# $ scholar.py --txt-globals -a "Einstein"
# [G] Results 11900
#
# Title Can quantum-mechanical description of physical reality be considered complete?
# URL http://journals.aps.org/pr/abstract/10.1103/PhysRev.47.777
# Year 1935
# Citations 12804
# Versions 80
# Cluster ID 8174092782678430881
# Citations list http://scholar.google.com/scholar?cites=8174092782678430881&as_sdt=2005&sciodt=0,5&hl=en
# Versions list http://scholar.google.com/scholar?cluster=8174092782678430881&hl=en&as_sdt=0,5
#
# 2.4: Bugfixes:
#
# - Correctly handle Unicode characters when reporting results
# in text format.
#
# - Correctly parse citation-only (i.e. linkless) results in
# Google Scholar results.
#
# 2.3: Additional features:
#
# - Direct extraction of first PDF version of an article
#
# - Ability to pull up an article cluster's results directly.
#
# This is based on work from @aliparsai on GitHub -- thanks!
#
# - Suppress missing search results (so far shown as "None" in
# the textual output form.
#
# 2.2: Added a logging option that reports full HTML contents, for
# debugging, as well as incrementally more detailed logging via
# -d up to -dddd.
#
# 2.1: Additional features:
#
# - Improved cookie support: the new --cookie-file options
# allows the reuse of a cookie across invocations of the tool;
# this allows higher query rates than would otherwise result
# when invoking scholar.py repeatedly.
#
# - Workaround: remove the num= URL-encoded argument from parsed
# URLs. For some reason, Google Scholar decides to propagate
# the value from the original query into the URLs embedded in
# the results.
#
# 2.0: Thorough overhaul of design, with substantial improvements:
#
# - Full support for advanced search arguments provided by
# Google Scholar
#
# - Support for retrieval of external citation formats, such as
# BibTeX or EndNote
#
# - Simple logging framework to track activity during execution
#
# 1.7: Python 3 and BeautifulSoup 4 compatibility, as well as printing
# of usage info when no options are given. Thanks to Pablo
# Oliveira (https://github.com/pablooliveira)!
#
# Also a bunch of pylinting and code cleanups.
#
# 1.6: Cookie support, from Matej Smid (https://github.com/palmstrom).
#
# 1.5: A few changes:
#
# - Tweak suggested by Tobias Isenberg: use unicode during CSV
# formatting.
#
# - The option -c|--count now understands numbers up to 100 as
# well. Likewise suggested by Tobias.
#
# - By default, text rendering mode is now active. This avoids
# confusion when playing with the script, as it used to report
# nothing when the user didn't select an explicit output mode.
#
# 1.4: Updates to reflect changes in Scholar's page rendering,
# contributed by Amanda Hay at Tufts -- thanks!
#
# 1.3: Updates to reflect changes in Scholar's page rendering.
#
# 1.2: Minor tweaks, mostly thanks to helpful feedback from Dan Bolser.
# Thanks Dan!
#
# 1.1: Made author field explicit, added --author option.
#
# Don't complain about missing docstrings: pylint: disable-msg=C0111
#
# Copyright 2010--2014 Christian Kreibich. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following
# disclaimer in the documentation and/or other materials provided
# with the distribution.
#
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT,
# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
# IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
import optparse
import os
import sys
import re
try:
# Try importing for Python 3
# pylint: disable-msg=F0401
# pylint: disable-msg=E0611
from urllib.request import HTTPCookieProcessor, Request, build_opener
from urllib.parse import quote, unquote
from http.cookiejar import MozillaCookieJar
except ImportError:
# Fallback for Python 2
from urllib2 import Request, build_opener, HTTPCookieProcessor
from urllib import quote, unquote
from cookielib import MozillaCookieJar
# Import BeautifulSoup -- try 4 first, fall back to older
try:
from bs4 import BeautifulSoup
except ImportError:
try:
from BeautifulSoup import BeautifulSoup
except ImportError:
print('We need BeautifulSoup, sorry...')
sys.exit(1)
# Support unicode in both Python 2 and 3. In Python 3, unicode is str.
if sys.version_info[0] == 3:
unicode = str # pylint: disable-msg=W0622
encode = lambda s: unicode(s) # pylint: disable-msg=C0103
else:
def encode(s):
if isinstance(s, basestring):
return s.encode('utf-8') # pylint: disable-msg=C0103
else:
return str(s)
class Error(Exception):
"""Base class for any Scholar error."""
class FormatError(Error):
"""A query argument or setting was formatted incorrectly."""
class QueryArgumentError(Error):
"""A query did not have a suitable set of arguments."""
class ScholarConf(object):
"""Helper class for global settings."""
VERSION = '2.10'
LOG_LEVEL = 1
MAX_PAGE_RESULTS = 20 # Current maximum for per-page results
SCHOLAR_SITE = 'http://scholar.google.com'
# USER_AGENT = 'Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.9.2.9) Gecko/20100913 Firefox/3.6.9'
# Let's update at this point (3/14):
USER_AGENT = 'Mozilla/5.0 (X11; Linux x86_64; rv:27.0) Gecko/20100101 Firefox/27.0'
# If set, we will use this file to read/save cookies to enable
# cookie use across sessions.
COOKIE_JAR_FILE = None
class ScholarUtils(object):
"""A wrapper for various utensils that come in handy."""
LOG_LEVELS = {'error': 1,
'warn': 2,
'info': 3,
'debug': 4}
@staticmethod
def ensure_int(arg, msg=None):
try:
return int(arg)
except ValueError:
raise FormatError(msg)
@staticmethod
def log(level, msg):
if level not in ScholarUtils.LOG_LEVELS.keys():
return
if ScholarUtils.LOG_LEVELS[level] > ScholarConf.LOG_LEVEL:
return
sys.stderr.write('[%5s] %s' % (level.upper(), msg + '\n'))
sys.stderr.flush()
class ScholarArticle(object):
"""
A class representing articles listed on Google Scholar. The class
provides basic dictionary-like behavior.
"""
def __init__(self):
# The triplets for each keyword correspond to (1) the actual
# value, (2) a user-suitable label for the item, and (3) an
# ordering index:
self.attrs = {
'title': [None, 'Title', 0],
'url': [None, 'URL', 1],
'year': [None, 'Year', 2],
'num_citations': [0, 'Citations', 3],
'num_versions': [0, 'Versions', 4],
'cluster_id': [None, 'Cluster ID', 5],
'url_pdf': [None, 'PDF link', 6],
'url_citations': [None, 'Citations list', 7],
'url_versions': [None, 'Versions list', 8],
'url_citation': [None, 'Citation link', 9],
'excerpt': [None, 'Excerpt', 10],
}
# The citation data in one of the standard export formats,
# e.g. BibTeX.
self.citation_data = None
def __getitem__(self, key):
if key in self.attrs:
return self.attrs[key][0]
return None
def __len__(self):
return len(self.attrs)
def __setitem__(self, key, item):
if key in self.attrs:
self.attrs[key][0] = item
else:
self.attrs[key] = [item, key, len(self.attrs)]
def __delitem__(self, key):
if key in self.attrs:
del self.attrs[key]
def set_citation_data(self, citation_data):
self.citation_data = citation_data
def as_txt(self):
# Get items sorted in specified order:
items = sorted(list(self.attrs.values()), key=lambda item: item[2])
# Find largest label length:
max_label_len = max([len(str(item[1])) for item in items])
fmt = '%%%ds %%s' % max_label_len
res = []
for item in items:
if item[0] is not None:
res.append(fmt % (item[1], item[0]))
return '\n'.join(res)
def as_csv(self, header=False, sep='|'):
# Get keys sorted in specified order:
keys = [pair[0] for pair in \
sorted([(key, val[2]) for key, val in list(self.attrs.items())],
key=lambda pair: pair[1])]
res = []
if header:
res.append(sep.join(keys))
res.append(sep.join([unicode(self.attrs[key][0]) for key in keys]))
return '\n'.join(res)
def as_citation(self):
"""
Reports the article in a standard citation format. This works only
if you have configured the querier to retrieve a particular
citation export format. (See ScholarSettings.)
"""
return self.citation_data or ''
class ScholarArticleParser(object):
"""
ScholarArticleParser can parse HTML document strings obtained from
Google Scholar. This is a base class; concrete implementations
adapting to tweaks made by Google over time follow below.
"""
def __init__(self, site=None):
self.soup = None
self.article = None
self.site = site or ScholarConf.SCHOLAR_SITE
self.year_re = re.compile(r'\b(?:20|19)\d{2}\b')
def handle_article(self, art):
"""
The parser invokes this callback on each article parsed
successfully. In this base class, the callback does nothing.
"""
def handle_num_results(self, num_results):
"""
The parser invokes this callback if it determines the overall
number of results, as reported on the parsed results page. The
base class implementation does nothing.
"""
def parse(self, html):
"""
This method initiates parsing of HTML content, cleans resulting
content as needed, and notifies the parser instance of
resulting instances via the handle_article callback.
"""
self.soup = BeautifulSoup(html)
# This parses any global, non-itemized attributes from the page.
self._parse_globals()
# Now parse out listed articles:
for div in self.soup.findAll(ScholarArticleParser._tag_results_checker):
self._parse_article(div)
self._clean_article()
if self.article['title']:
self.handle_article(self.article)
def _clean_article(self):
"""
This gets invoked after we have parsed an article, to do any
needed cleanup/polishing before we hand off the resulting
article.
"""
if self.article['title']:
self.article['title'] = self.article['title'].strip()
def _parse_globals(self):
tag = self.soup.find(name='div', attrs={'id': 'gs_ab_md'})
if tag is not None:
raw_text = tag.findAll(text=True)
# raw text is a list because the body contains <b> etc
if raw_text is not None and len(raw_text) > 0:
try:
num_results = raw_text[0].split()[1]
# num_results may now contain commas to separate
# thousands, strip:
num_results = num_results.replace(',', '')
num_results = int(num_results)
self.handle_num_results(num_results)
except (IndexError, ValueError):
pass
def _parse_article(self, div):
self.article = ScholarArticle()
for tag in div:
if not hasattr(tag, 'name'):
continue
if tag.name == 'div' and self._tag_has_class(tag, 'gs_rt') and \
tag.h3 and tag.h3.a:
self.article['title'] = ''.join(tag.h3.a.findAll(text=True))
self.article['url'] = self._path2url(tag.h3.a['href'])
if self.article['url'].endswith('.pdf'):
self.article['url_pdf'] = self.article['url']
if tag.name == 'font':
for tag2 in tag:
if not hasattr(tag2, 'name'):
continue
if tag2.name == 'span' and \
self._tag_has_class(tag2, 'gs_fl'):
self._parse_links(tag2)
def _parse_links(self, span):
for tag in span:
if not hasattr(tag, 'name'):
continue
if tag.name != 'a' or tag.get('href') is None:
continue
if tag.get('href').startswith('/scholar?cites'):
if hasattr(tag, 'string') and tag.string.startswith('Cited by'):
self.article['num_citations'] = \
self._as_int(tag.string.split()[-1])
# Weird Google Scholar behavior here: if the original
# search query came with a number-of-results limit,
# then this limit gets propagated to the URLs embedded
# in the results page as well. Same applies to
# versions URL in next if-block.
self.article['url_citations'] = \
self._strip_url_arg('num', self._path2url(tag.get('href')))
# We can also extract the cluster ID from the versions
# URL. Note that we know that the string contains "?",
# from the above if-statement.
args = self.article['url_citations'].split('?', 1)[1]
for arg in args.split('&'):
if arg.startswith('cites='):
self.article['cluster_id'] = arg[6:]
if tag.get('href').startswith('/scholar?cluster'):
if hasattr(tag, 'string') and tag.string.startswith('All '):
self.article['num_versions'] = \
self._as_int(tag.string.split()[1])
self.article['url_versions'] = \
self._strip_url_arg('num', self._path2url(tag.get('href')))
if tag.getText().startswith('Import'):
self.article['url_citation'] = self._path2url(tag.get('href'))
@staticmethod
def _tag_has_class(tag, klass):
"""
This predicate function checks whether a BeatifulSoup Tag instance
has a class attribute.
"""
res = tag.get('class') or []
if type(res) != list:
# BeautifulSoup 3 can return e.g. 'gs_md_wp gs_ttss',
# so split -- conveniently produces a list in any case
res = res.split()
return klass in res
@staticmethod
def _tag_results_checker(tag):
return tag.name == 'div' \
and ScholarArticleParser._tag_has_class(tag, 'gs_r')
@staticmethod
def _as_int(obj):
try:
return int(obj)
except ValueError:
return None
def _path2url(self, path):
"""Helper, returns full URL in case path isn't one."""
if path.startswith('http://'):
return path
if not path.startswith('/'):
path = '/' + path
return self.site + path
def _strip_url_arg(self, arg, url):
"""Helper, removes a URL-encoded argument, if present."""
parts = url.split('?', 1)
if len(parts) != 2:
return url
res = []
for part in parts[1].split('&'):
if not part.startswith(arg + '='):
res.append(part)
return parts[0] + '?' + '&'.join(res)
class ScholarArticleParser120201(ScholarArticleParser):
"""
This class reflects update to the Scholar results page layout that
Google recently.
"""
def _parse_article(self, div):
self.article = ScholarArticle()
for tag in div:
if not hasattr(tag, 'name'):
continue
if tag.name == 'h3' and self._tag_has_class(tag, 'gs_rt') and tag.a:
self.article['title'] = ''.join(tag.a.findAll(text=True))
self.article['url'] = self._path2url(tag.a['href'])
if self.article['url'].endswith('.pdf'):
self.article['url_pdf'] = self.article['url']
if tag.name == 'div' and self._tag_has_class(tag, 'gs_a'):
year = self.year_re.findall(tag.text)
self.article['year'] = year[0] if len(year) > 0 else None
if tag.name == 'div' and self._tag_has_class(tag, 'gs_fl'):
self._parse_links(tag)
class ScholarArticleParser120726(ScholarArticleParser):
"""
This class reflects update to the Scholar results page layout that
Google made 07/26/12.
"""
def _parse_article(self, div):
self.article = ScholarArticle()
for tag in div:
if not hasattr(tag, 'name'):
continue
if str(tag).lower().find('.pdf'):
if tag.find('div', {'class': 'gs_ttss'}):
self._parse_links(tag.find('div', {'class': 'gs_ttss'}))
if tag.name == 'div' and self._tag_has_class(tag, 'gs_ri'):
# There are (at least) two formats here. In the first
# one, we have a link, e.g.:
#
# <h3 class="gs_rt">
# <a href="http://dl.acm.org/citation.cfm?id=972384" class="yC0">
# <b>Honeycomb</b>: creating intrusion detection signatures using
# honeypots
# </a>
# </h3>
#
# In the other, there's no actual link -- it's what
# Scholar renders as "CITATION" in the HTML:
#
# <h3 class="gs_rt">
# <span class="gs_ctu">
# <span class="gs_ct1">[CITATION]</span>
# <span class="gs_ct2">[C]</span>
# </span>
# <b>Honeycomb</b> automated ids signature creation using honeypots
# </h3>
#
# We now distinguish the two.
try:
atag = tag.h3.a
self.article['title'] = ''.join(atag.findAll(text=True))
self.article['url'] = self._path2url(atag['href'])
if self.article['url'].endswith('.pdf'):
self.article['url_pdf'] = self.article['url']
except:
# Remove a few spans that have unneeded content (e.g. [CITATION])
for span in tag.h3.findAll(name='span'):
span.clear()
self.article['title'] = ''.join(tag.h3.findAll(text=True))
if tag.find('div', {'class': 'gs_a'}):
year = self.year_re.findall(tag.find('div', {'class': 'gs_a'}).text)
self.article['year'] = year[0] if len(year) > 0 else None
if tag.find('div', {'class': 'gs_fl'}):
self._parse_links(tag.find('div', {'class': 'gs_fl'}))
if tag.find('div', {'class': 'gs_rs'}):
# These are the content excerpts rendered into the results.
raw_text = tag.find('div', {'class': 'gs_rs'}).findAll(text=True)
if len(raw_text) > 0:
raw_text = ''.join(raw_text)
raw_text = raw_text.replace('\n', '')
self.article['excerpt'] = raw_text
class ScholarQuery(object):
"""
The base class for any kind of results query we send to Scholar.
"""
def __init__(self):
self.url = None
# The number of results requested from Scholar -- not the
# total number of results it reports (the latter gets stored
# in attrs, see below).
self.num_results = ScholarConf.MAX_PAGE_RESULTS
# Queries may have global result attributes, similar to
# per-article attributes in ScholarArticle. The exact set of
# attributes may differ by query type, but they all share the
# basic data structure:
self.attrs = {}
def set_num_page_results(self, num_page_results):
msg = 'maximum number of results on page must be numeric'
self.num_results = ScholarUtils.ensure_int(num_page_results, msg)
def get_url(self):
"""
Returns a complete, submittable URL string for this particular
query instance. The URL and its arguments will vary depending
on the query.
"""
return None
def _add_attribute_type(self, key, label, default_value=None):
"""
Adds a new type of attribute to the list of attributes
understood by this query. Meant to be used by the constructors
in derived classes.
"""
if len(self.attrs) == 0:
self.attrs[key] = [default_value, label, 0]
return
idx = max([item[2] for item in self.attrs.values()]) + 1
self.attrs[key] = [default_value, label, idx]
def __getitem__(self, key):
"""Getter for attribute value. Returns None if no such key."""
if key in self.attrs:
return self.attrs[key][0]
return None
def __setitem__(self, key, item):
"""Setter for attribute value. Does nothing if no such key."""
if key in self.attrs:
self.attrs[key][0] = item
def _parenthesize_phrases(self, query):
"""
Turns a query string containing comma-separated phrases into a
space-separated list of tokens, quoted if containing
whitespace. For example, input
'some words, foo, bar'
becomes
'"some words" foo bar'
This comes in handy during the composition of certain queries.
"""
if query.find(',') < 0:
return query
phrases = []
for phrase in query.split(','):
phrase = phrase.strip()
if phrase.find(' ') > 0:
phrase = '"' + phrase + '"'
phrases.append(phrase)
return ' '.join(phrases)
class ClusterScholarQuery(ScholarQuery):
"""
This version just pulls up an article cluster whose ID we already
know about.
"""
SCHOLAR_CLUSTER_URL = ScholarConf.SCHOLAR_SITE + '/scholar?' \
+ 'cluster=%(cluster)s' \
+ '&num=%(num)s'
def __init__(self, cluster=None):
ScholarQuery.__init__(self)
self._add_attribute_type('num_results', 'Results', 0)
self.cluster = None
self.set_cluster(cluster)
def set_cluster(self, cluster):
"""
Sets search to a Google Scholar results cluster ID.
"""
msg = 'cluster ID must be numeric'
self.cluster = ScholarUtils.ensure_int(cluster, msg)
def get_url(self):
if self.cluster is None:
raise QueryArgumentError('cluster query needs cluster ID')
urlargs = {'cluster': self.cluster,
'num': self.num_results or ScholarConf.MAX_PAGE_RESULTS}
for key, val in urlargs.items():
urlargs[key] = quote(encode(val))
return self.SCHOLAR_CLUSTER_URL % urlargs
class SearchScholarQuery(ScholarQuery):
"""
This version represents the search query parameters the user can
configure on the Scholar website, in the advanced search options.
"""
SCHOLAR_QUERY_URL = ScholarConf.SCHOLAR_SITE + '/scholar?' \
+ 'as_q=%(words)s' \
+ '&as_epq=%(phrase)s' \
+ '&as_oq=%(words_some)s' \
+ '&as_eq=%(words_none)s' \
+ '&as_occt=%(scope)s' \
+ '&as_sauthors=%(authors)s' \
+ '&as_publication=%(pub)s' \
+ '&as_ylo=%(ylo)s' \
+ '&as_yhi=%(yhi)s' \
+ '&as_sdt=%(patents)s%%2C5' \
+ '&as_vis=%(citations)s' \
+ '&btnG=&hl=en' \
+ '&num=%(num)s'
def __init__(self):
ScholarQuery.__init__(self)
self._add_attribute_type('num_results', 'Results', 0)
self.words = None # The default search behavior
self.words_some = None # At least one of those words
self.words_none = None # None of these words
self.phrase = None
self.scope_title = False # If True, search in title only
self.author = None
self.pub = None
self.timeframe = [None, None]
self.include_patents = True
self.include_citations = True
def set_words(self, words):
"""Sets words that *all* must be found in the result."""
self.words = words
def set_words_some(self, words):
"""Sets words of which *at least one* must be found in result."""
self.words_some = words
def set_words_none(self, words):
"""Sets words of which *none* must be found in the result."""
self.words_none = words
def set_phrase(self, phrase):
"""Sets phrase that must be found in the result exactly."""
self.phrase = phrase
def set_scope(self, title_only):
"""
Sets Boolean indicating whether to search entire article or title
only.
"""
self.scope_title = title_only
def set_author(self, author):
"""Sets names that must be on the result's author list."""
self.author = author
def set_pub(self, pub):
"""Sets the publication in which the result must be found."""
self.pub = pub
def set_timeframe(self, start=None, end=None):
"""
Sets timeframe (in years as integer) in which result must have
appeared. It's fine to specify just start or end, or both.
"""
if start:
start = ScholarUtils.ensure_int(start)
if end:
end = ScholarUtils.ensure_int(end)
self.timeframe = [start, end]
def set_include_citations(self, yesorno):
self.include_citations = yesorno
def set_include_patents(self, yesorno):
self.include_patents = yesorno
def get_url(self):
if self.words is None and self.words_some is None \
and self.words_none is None and self.phrase is None \
and self.author is None and self.pub is None \
and self.timeframe[0] is None and self.timeframe[1] is None:
raise QueryArgumentError('search query needs more parameters')
# If we have some-words or none-words lists, we need to
# process them so GS understands them. For simple
# space-separeted word lists, there's nothing to do. For lists
# of phrases we have to ensure quotations around the phrases,
# separating them by whitespace.
words_some = None
words_none = None
if self.words_some:
words_some = self._parenthesize_phrases(self.words_some)
if self.words_none:
words_none = self._parenthesize_phrases(self.words_none)
urlargs = {'words': self.words or '',
'words_some': words_some or '',
'words_none': words_none or '',
'phrase': self.phrase or '',
'scope': 'title' if self.scope_title else 'any',
'authors': self.author or '',
'pub': self.pub or '',
'ylo': self.timeframe[0] or '',
'yhi': self.timeframe[1] or '',
'patents': '0' if self.include_patents else '1',
'citations': '0' if self.include_citations else '1',
'num': self.num_results or ScholarConf.MAX_PAGE_RESULTS}
for key, val in urlargs.items():
urlargs[key] = quote(encode(val))
return self.SCHOLAR_QUERY_URL % urlargs
class ScholarSettings(object):
"""
This class lets you adjust the Scholar settings for your
session. It's intended to mirror the features tunable in the
Scholar Settings pane, but right now it's a bit basic.
"""
CITFORM_NONE = 0
CITFORM_REFWORKS = 1
CITFORM_REFMAN = 2
CITFORM_ENDNOTE = 3
CITFORM_BIBTEX = 4
def __init__(self):
self.citform = 0 # Citation format, default none
self.per_page_results = ScholarConf.MAX_PAGE_RESULTS
self._is_configured = False
def set_citation_format(self, citform):
citform = ScholarUtils.ensure_int(citform)
if citform < 0 or citform > self.CITFORM_BIBTEX:
raise FormatError('citation format invalid, is "%s"' \
% citform)
self.citform = citform
self._is_configured = True
def set_per_page_results(self, per_page_results):
msg = 'page results must be integer'
self.per_page_results = ScholarUtils.ensure_int(per_page_results, msg)
self.per_page_results = min(self.per_page_results,
ScholarConf.MAX_PAGE_RESULTS)
self._is_configured = True
def is_configured(self):
return self._is_configured
class ScholarQuerier(object):
"""
ScholarQuerier instances can conduct a search on Google Scholar
with subsequent parsing of the resulting HTML content. The
articles found are collected in the articles member, a list of
ScholarArticle instances.
"""
# Default URLs for visiting and submitting Settings pane, as of 3/14
GET_SETTINGS_URL = ScholarConf.SCHOLAR_SITE + '/scholar_settings?' \
+ 'sciifh=1&hl=en&as_sdt=0,5'
SET_SETTINGS_URL = ScholarConf.SCHOLAR_SITE + '/scholar_setprefs?' \
+ 'q=' \
+ '&scisig=%(scisig)s' \
+ '&inststart=0' \
+ '&as_sdt=1,5' \
+ '&as_sdtp=' \
+ '&num=%(num)s' \
+ '&scis=%(scis)s' \
+ '%(scisf)s' \
+ '&hl=en&lang=all&instq=&inst=569367360547434339&save='
# Older URLs:
# ScholarConf.SCHOLAR_SITE + '/scholar?q=%s&hl=en&btnG=Search&as_sdt=2001&as_sdtp=on
class Parser(ScholarArticleParser120726):
def __init__(self, querier):
ScholarArticleParser120726.__init__(self)
self.querier = querier
def handle_num_results(self, num_results):
if self.querier is not None and self.querier.query is not None:
self.querier.query['num_results'] = num_results
def handle_article(self, art):
self.querier.add_article(art)
def __init__(self):
self.articles = []
self.query = None
self.cjar = MozillaCookieJar()
# If we have a cookie file, load it:
if ScholarConf.COOKIE_JAR_FILE and \
os.path.exists(ScholarConf.COOKIE_JAR_FILE):
try:
self.cjar.load(ScholarConf.COOKIE_JAR_FILE,
ignore_discard=True)
ScholarUtils.log('info', 'loaded cookies file')
except Exception as msg:
ScholarUtils.log('warn', 'could not load cookies file: %s' % msg)
self.cjar = MozillaCookieJar() # Just to be safe
self.opener = build_opener(HTTPCookieProcessor(self.cjar))
self.settings = None # Last settings object, if any
def apply_settings(self, settings):
"""
Applies settings as provided by a ScholarSettings instance.
"""
if settings is None or not settings.is_configured():
return True
self.settings = settings
# This is a bit of work. We need to actually retrieve the
# contents of the Settings pane HTML in order to extract
# hidden fields before we can compose the query for updating
# the settings.
html = self._get_http_response(url=self.GET_SETTINGS_URL,
log_msg='dump of settings form HTML',
err_msg='requesting settings failed')
if html is None:
return False
# Now parse the required stuff out of the form. We require the
# "scisig" token to make the upload of our settings acceptable
# to Google.
soup = BeautifulSoup(html)
tag = soup.find(name='form', attrs={'id': 'gs_settings_form'})
if tag is None:
ScholarUtils.log('info', 'parsing settings failed: no form')
return False
tag = tag.find('input', attrs={'type':'hidden', 'name':'scisig'})
if tag is None:
ScholarUtils.log('info', 'parsing settings failed: scisig')
return False
urlargs = {'scisig': tag['value'],
'num': settings.per_page_results,
'scis': 'no',
'scisf': ''}
if settings.citform != 0:
urlargs['scis'] = 'yes'
urlargs['scisf'] = '&scisf=%d' % settings.citform
html = self._get_http_response(url=self.SET_SETTINGS_URL % urlargs,
log_msg='dump of settings result HTML',
err_msg='applying setttings failed')
if html is None:
return False
ScholarUtils.log('info', 'settings applied')
return True
def send_query(self, query):
"""
This method initiates a search query (a ScholarQuery instance)
with subsequent parsing of the response.
"""
self.clear_articles()
self.query = query
print query.get_url()
html = self._get_http_response(url=query.get_url(),
log_msg='dump of query response HTML',
err_msg='results retrieval failed')
if html is None:
return
self.parse(html)
def get_citation_data(self, article):
"""
Given an article, retrieves citation link. Note, this requires that
you adjusted the settings to tell Google Scholar to actually
provide this information, *prior* to retrieving the article.
"""
if article['url_citation'] is None:
return False
if article.citation_data is not None:
return True
ScholarUtils.log('info', 'retrieving citation export data')
data = self._get_http_response(url=article['url_citation'],
log_msg='citation data response',
err_msg='requesting citation data failed')
if data is None:
return False
article.set_citation_data(data)
return True
def parse(self, html):
"""
This method allows parsing of provided HTML content.
"""
parser = self.Parser(self)
parser.parse(html)
def add_article(self, art):
self.get_citation_data(art)
self.articles.append(art)
def clear_articles(self):
"""Clears any existing articles stored from previous queries."""
self.articles = []
def save_cookies(self):
"""
This stores the latest cookies we're using to disk, for reuse in a
later session.
"""
if ScholarConf.COOKIE_JAR_FILE is None:
return False
try:
self.cjar.save(ScholarConf.COOKIE_JAR_FILE,
ignore_discard=True)
ScholarUtils.log('info', 'saved cookies file')
return True
except Exception as msg:
ScholarUtils.log('warn', 'could not save cookies file: %s' % msg)
return False
def _get_http_response(self, url, log_msg=None, err_msg=None):
"""
Helper method, sends HTTP request and returns response payload.
"""
if log_msg is None:
log_msg = 'HTTP response data follow'
if err_msg is None:
err_msg = 'request failed'
try:
ScholarUtils.log('info', 'requesting %s' % unquote(url))
req = Request(url=url, headers={'User-Agent': ScholarConf.USER_AGENT})
hdl = self.opener.open(req)
html = hdl.read()
ScholarUtils.log('debug', log_msg)
ScholarUtils.log('debug', '>>>>' + '-'*68)
ScholarUtils.log('debug', 'url: %s' % hdl.geturl())
ScholarUtils.log('debug', 'result: %s' % hdl.getcode())
ScholarUtils.log('debug', 'headers:\n' + str(hdl.info()))
ScholarUtils.log('debug', 'data:\n' + html.decode('utf-8')) # For Python 3
ScholarUtils.log('debug', '<<<<' + '-'*68)
return html
except Exception as err:
ScholarUtils.log('info', err_msg + ': %s' % err)
return None
def txt(querier, with_globals):
if with_globals:
# If we have any articles, check their attribute labels to get
# the maximum length -- makes for nicer alignment.
max_label_len = 0
if len(querier.articles) > 0:
items = sorted(list(querier.articles[0].attrs.values()),
key=lambda item: item[2])
max_label_len = max([len(str(item[1])) for item in items])
# Get items sorted in specified order:
items = sorted(list(querier.query.attrs.values()), key=lambda item: item[2])
# Find largest label length:
max_label_len = max([len(str(item[1])) for item in items] + [max_label_len])
fmt = '[G] %%%ds %%s' % max(0, max_label_len-4)
for item in items:
if item[0] is not None:
print(fmt % (item[1], item[0]))
if len(items) > 0:
print
articles = querier.articles
for art in articles:
print(encode(art.as_txt()) + '\n')
def csv(querier, header=False, sep='|'):
articles = querier.articles
for art in articles:
result = art.as_csv(header=header, sep=sep)
print(encode(result))
header = False
def citation_export(querier):
articles = querier.articles
for art in articles:
print(art.as_citation() + '\n')
def main():
usage = """scholar.py [options] <query string>
A command-line interface to Google Scholar.
Examples:
# Retrieve one article written by Einstein on quantum theory:
scholar.py -c 1 --author "albert einstein" --phrase "quantum theory"
# Retrieve a BibTeX entry for that quantum theory paper:
scholar.py -c 1 -C 17749203648027613321 --citation bt
# Retrieve five articles written by Einstein after 1970 where the title
# does not contain the words "quantum" and "theory":
scholar.py -c 5 -a "albert einstein" -t --none "quantum theory" --after 1970"""
fmt = optparse.IndentedHelpFormatter(max_help_position=50, width=100)
parser = optparse.OptionParser(usage=usage, formatter=fmt)
group = optparse.OptionGroup(parser, 'Query arguments',
'These options define search query arguments and parameters.')
group.add_option('-a', '--author', metavar='AUTHORS', default=None,
help='Author name(s)')
group.add_option('-A', '--all', metavar='WORDS', default=None, dest='allw',
help='Results must contain all of these words')
group.add_option('-s', '--some', metavar='WORDS', default=None,
help='Results must contain at least one of these words. Pass arguments in form -s "foo bar baz" for simple words, and -s "a phrase, another phrase" for phrases')
group.add_option('-n', '--none', metavar='WORDS', default=None,
help='Results must contain none of these words. See -s|--some re. formatting')
group.add_option('-p', '--phrase', metavar='PHRASE', default=None,
help='Results must contain exact phrase')
group.add_option('-t', '--title-only', action='store_true', default=False,
help='Search title only')
group.add_option('-P', '--pub', metavar='PUBLICATIONS', default=None,
help='Results must have appeared in this publication')
group.add_option('--after', metavar='YEAR', default=None,
help='Results must have appeared in or after given year')
group.add_option('--before', metavar='YEAR', default=None,
help='Results must have appeared in or before given year')
group.add_option('--no-patents', action='store_true', default=False,
help='Do not include patents in results')
group.add_option('--no-citations', action='store_true', default=False,
help='Do not include citations in results')
group.add_option('-C', '--cluster-id', metavar='CLUSTER_ID', default=None,
help='Do not search, just use articles in given cluster ID')
group.add_option('-c', '--count', type='int', default=None,
help='Maximum number of results')
parser.add_option_group(group)
group = optparse.OptionGroup(parser, 'Output format',
'These options control the appearance of the results.')
group.add_option('--txt', action='store_true',
help='Print article data in text format (default)')
group.add_option('--txt-globals', action='store_true',
help='Like --txt, but first print global results too')
group.add_option('--csv', action='store_true',
help='Print article data in CSV form (separator is "|")')
group.add_option('--csv-header', action='store_true',
help='Like --csv, but print header with column names')
group.add_option('--citation', metavar='FORMAT', default=None,
help='Print article details in standard citation format. Argument Must be one of "bt" (BibTeX), "en" (EndNote), "rm" (RefMan), or "rw" (RefWorks).')
parser.add_option_group(group)
group = optparse.OptionGroup(parser, 'Miscellaneous')
group.add_option('--cookie-file', metavar='FILE', default=None,
help='File to use for cookie storage. If given, will read any existing cookies if found at startup, and save resulting cookies in the end.')
group.add_option('-d', '--debug', action='count', default=0,
help='Enable verbose logging to stderr. Repeated options increase detail of debug output.')
group.add_option('-v', '--version', action='store_true', default=False,
help='Show version information')
parser.add_option_group(group)
options, _ = parser.parse_args()
# Show help if we have neither keyword search nor author name
if len(sys.argv) == 1:
parser.print_help()
return 1
if options.debug > 0:
options.debug = min(options.debug, ScholarUtils.LOG_LEVELS['debug'])
ScholarConf.LOG_LEVEL = options.debug
ScholarUtils.log('info', 'using log level %d' % ScholarConf.LOG_LEVEL)
if options.version:
print('This is scholar.py %s.' % ScholarConf.VERSION)
return 0
if options.cookie_file:
ScholarConf.COOKIE_JAR_FILE = options.cookie_file
# Sanity-check the options: if they include a cluster ID query, it
# makes no sense to have search arguments:
if options.cluster_id is not None:
if options.author or options.allw or options.some or options.none \
or options.phrase or options.title_only or options.pub \
or options.after or options.before:
print('Cluster ID queries do not allow additional search arguments.')
return 1
querier = ScholarQuerier()
settings = ScholarSettings()
if options.citation == 'bt':
settings.set_citation_format(ScholarSettings.CITFORM_BIBTEX)
elif options.citation == 'en':
settings.set_citation_format(ScholarSettings.CITFORM_ENDNOTE)
elif options.citation == 'rm':
settings.set_citation_format(ScholarSettings.CITFORM_REFMAN)
elif options.citation == 'rw':
settings.set_citation_format(ScholarSettings.CITFORM_REFWORKS)
elif options.citation is not None:
print('Invalid citation link format, must be one of "bt", "en", "rm", or "rw".')
return 1
querier.apply_settings(settings)
if options.cluster_id:
query = ClusterScholarQuery(cluster=options.cluster_id)
else:
query = SearchScholarQuery()
if options.author:
query.set_author(options.author)
if options.allw:
query.set_words(options.allw)
if options.some:
query.set_words_some(options.some)
if options.none:
query.set_words_none(options.none)
if options.phrase:
query.set_phrase(options.phrase)
if options.title_only:
query.set_scope(True)
if options.pub:
query.set_pub(options.pub)
if options.after or options.before:
query.set_timeframe(options.after, options.before)
if options.no_patents:
query.set_include_patents(False)
if options.no_citations:
query.set_include_citations(False)
if options.count is not None:
options.count = min(options.count, ScholarConf.MAX_PAGE_RESULTS)
query.set_num_page_results(options.count)
querier.send_query(query)
if options.csv:
csv(querier)
elif options.csv_header:
csv(querier, header=True)
elif options.citation is not None:
citation_export(querier)
else:
txt(querier, with_globals=options.txt_globals)
if options.cookie_file:
querier.save_cookies()
return 0
if __name__ == "__main__":
sys.exit(main())