42 lines
1.3 KiB
Python
42 lines
1.3 KiB
Python
from flask import request
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from app import get_app_url
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from util.pagination import encrypt_page_token, decrypt_page_token
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import urllib
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import logging
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_MAX_RESULTS_PER_PAGE = 50
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def add_pagination(query, url):
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""" Adds optional pagination to the given query by looking for the Docker V2 pagination request
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args.
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"""
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try:
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requested_limit = int(request.args.get('n', _MAX_RESULTS_PER_PAGE))
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except ValueError:
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requested_limit = 0
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limit = max(min(requested_limit, _MAX_RESULTS_PER_PAGE), 1)
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next_page_token = request.args.get('next_page', None)
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# Decrypt the next page token, if any.
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offset = 0
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page_info = decrypt_page_token(next_page_token)
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if page_info is not None:
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# Note: we use offset here instead of ID >= n because one of the V2 queries is a UNION.
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offset = page_info.get('offset', 0)
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query = query.offset(offset)
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query = query.limit(limit + 1)
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url = get_app_url() + url
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results = list(query)
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if len(results) <= limit:
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return None, results
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# Add a link to the next page of results.
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page_info = dict(offset=limit + offset)
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next_page_token = encrypt_page_token(page_info)
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link = url + '?' + urllib.urlencode(dict(n=limit, next_page=next_page_token))
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link = link + '; rel="next"'
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return link, results[0:-1]
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