def get_coauthors(self):
"""Retrieves basic information about co-authors as a list of
namedtuples in the form
(surname, given_name, id, areas, affiliation_id, name, city, country),
where areas is a list of subject area codes joined by "; ".
Note: These information will not be cached and are slow for large
coauthor groups.
"""
# Get number of authors to search for
res = cache_file(url=self.coauthor_link)
data = loads(res.text)['search-results']
N = int(data.get('opensearch:totalResults', 0))
# Store information in namedtuples
fields = 'surname given_name id areas affiliation_id name city country'
coauth = namedtuple('Coauthor', fields)
coauthors = []
# Iterate over search results in chunks of 25 results
count = 0
while count < N:
params = {'start': count, 'count': 25}
res = cache_file(url=self.coauthor_link,
params=params,
accept='json')
data = loads(res.text)['search-results'].get('entry', [])
# Extract information for each coauthor
for entry in data:
aff = entry.get('affiliation-current', {})
try:
areas = [a['$'] for a in entry.get('subject-area', [])]
except TypeError: # Only one subject area given
areas = [entry['subject-area']['$']]
new = coauth(
surname=entry['preferred-name']['surname'],
given_name=entry['preferred-name'].get('given-name'),
id=entry['dc:identifier'].split(':')[-1],
areas='; '.join(areas),
name=aff.get('affiliation-name'),
affiliation_id=aff.get('affiliation-id'),
city=aff.get('affiliation-city'),
country=aff.get('affiliation-country'))
coauthors.append(new)
count += 25
return coauthors
def _parse(res, params, n, api, **kwds):
"""Auxiliary function to download results and parse json."""
cursor = "cursor" in params
if not cursor:
start = params["start"]
if n == 0:
return ""
_json = res.get('search-results', {}).get('entry', [])
# Download the remaining information in chunks
while n > 0:
n -= params["count"]
if cursor:
pointer = res['search-results']['cursor'].get('@next')
params.update({'cursor': pointer})
else:
start += params["count"]
params.update({'start': start})
res = cache_file(url=SEARCH_URL[api], params=params, **kwds).json()
_json.extend(res.get('search-results', {}).get('entry', []))
return _json
def __init__(self,
query,
api,
refresh,
view='STANDARD',
count=200,
max_entries=5000,
cursor=False,
download=True,
**kwds):
"""Class intended as superclass to perform a search query.
Parameters
----------
query : str
A string of the query.
api : str
The name of the Scopus API to be accessed. Allowed values:
AffiliationSearch, AuthorSearch, ScopusSearch.
refresh : bool
Whether to refresh the cached file if it exists or not.
view : str
The view of the file that should be downloaded.
count : int (optional, default=200)
The number of entries to be displayed at once. A smaller number
means more queries with each query having less results.
max_entries : int (optional, default=5000)
Raise error when the number of results is beyond this number.
To skip this check, set `max_entries` to `None`.
cursor : str (optional, default=False)
Whether to use the cursor in order to iterate over all search
results without limit on the number of the results. In contrast
to `start` parameter, the `cursor` parameter does not allow users
to obtain partial results.
download : bool (optional, default=True)
Whether to download results (if they have not been cached) or not.
kwds : key-value parings, optional
Keywords passed on to requests header. Must contain fields
and values specified in the respective API specification.
Raises
------
ScopusQueryError
If the number of search results exceeds max_entries.
ValueError
If the api parameteris an invalid entry.
"""
# Read the file contents if file exists and we are not refreshing,
# otherwise download query anew and cache file
fname = md5(query.encode('utf8')).hexdigest()
qfile = join(get_folder(api, view), fname)
if not refresh and exists(qfile):
with open(qfile, "rb") as f:
self._json = [loads(line) for line in f.readlines()]
self._n = len(self._json)
else:
# Set query parameters
params = {'query': query, 'count': count, 'view': view}
if cursor:
params.update({'cursor': '*'})
else:
params.update({'start': 0})
# Download results
res = cache_file(url=SEARCH_URL[api], params=params, **kwds).json()
n = int(res['search-results'].get('opensearch:totalResults', 0))
self._n = n
if not cursor and n > max_entries: # Stop if there are too many results
text = ('Found {} matches. Set max_entries to a higher '
'number, change your query ({}) or set '
'subscription=True'.format(n, query))
raise ScopusQueryError(text)
if download:
self._json = _parse(res, params, n, api, **kwds)
# Finally write out the file
with open(qfile, 'wb') as f:
for item in self._json:
f.write('{}\n'.format(dumps(item)).encode('utf-8'))
else:
# Assures that properties will not result in an error
self._json = []
self._view = view