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renderers.py
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renderers.py

# Copyright (C) 2015-2016 The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU Affero General Public License version 3, or any later version
# See top-level LICENSE file for more information
import re
import yaml
import json
from docutils.core import publish_parts
from docutils.writers.html4css1 import Writer, HTMLTranslator
from inspect import cleandoc
from jinja2 import Markup
from flask import request, Response, render_template
from flask import g
from pygments import highlight
from pygments.lexers import guess_lexer
from pygments.formatters import HtmlFormatter
from swh.web.ui import utils
class SWHFilterEnricher():
"""Global filter on fields.
"""
@classmethod
def filter_by_fields(cls, data):
"""Extract a request parameter 'fields' if it exists to permit the
filtering on the data dict's keys.
If such field is not provided, returns the data as is.
"""
fields = request.args.get('fields')
if fields:
fields = set(fields.split(','))
data = utils.filter_field_keys(data, fields)
return data
class SWHComputeLinkHeader:
"""Add link header to response.
Mixin intended to be used for example in SWHMultiResponse
"""
@classmethod
def compute_link_header(cls, rv, options):
"""Add Link header in returned value results.
Expects rv to be a dict with 'results' and 'headers' key:
'results': the returned value expected to be shown
'headers': dictionary with link-next and link-prev
Args:
rv (dict): with keys:
- 'headers': potential headers with 'link-next'
and 'link-prev' keys
- 'results': containing the result to return
Returns:
tuple rv, options:
If link-headers are present, rv is the returned value
present in the 'results' key. Also, options is updated
with headers 'Link' containing the 'link-next' and
'link-prev' headers.
Otherwise, rv, options stays the same as the input.
"""
link_headers = []
if 'headers' not in rv:
return options
rv_headers = rv['headers']
if 'link-next' in rv_headers:
link_headers.append('<%s>; rel="next"' % (
rv_headers['link-next']))
if 'link-prev' in rv_headers:
link_headers.append('<%s>; rel="previous"' % (
rv_headers['link-prev']))
if link_headers:
link_header_str = ','.join(link_headers)
headers = options.get('headers', {})
headers.update({
'Link': link_header_str
})
options['headers'] = headers
return options
return options
class SWHTransformProcessor:
"""Transform an eventual returned value with multiple layer of
information with only what's necessary.
If the returned value rv contains the 'results' key, this is the
associated value which is returned.
Otherwise, return the initial dict without the potential 'headers'
key.
"""
@classmethod
def transform(cls, rv):
if 'results' in rv:
return rv['results']
if 'headers' in rv:
rv.pop('headers')
return rv
class SWHMultiResponse(Response, SWHFilterEnricher,
SWHComputeLinkHeader, SWHTransformProcessor):
"""
A Flask Response subclass.
Override force_type to transform dict/list responses into callable Flask
response objects whose mimetype matches the request's Accept header: HTML
template render, YAML dump or default to a JSON dump.
"""
@classmethod
def make_response_from_mimetype(cls, rv, options={}):
if not (isinstance(rv, list) or isinstance(rv, dict)):
return rv
def wants_html(best_match):
return best_match == 'text/html' and \
request.accept_mimetypes[best_match] > \
request.accept_mimetypes['application/json']
def wants_yaml(best_match):
return best_match == 'application/yaml' and \
request.accept_mimetypes[best_match] > \
request.accept_mimetypes['application/json']
rv = cls.filter_by_fields(rv)
acc_mime = ['application/json', 'application/yaml', 'text/html']
best_match = request.accept_mimetypes.best_match(acc_mime)
options = cls.compute_link_header(rv, options)
rv = cls.transform(rv)
if wants_html(best_match):
data = json.dumps(rv, sort_keys=True,
indent=4, separators=(',', ': '))
env = g.get('doc_env', {})
env['response_data'] = data
env['request'] = request
rv = Response(render_template('apidoc.html', **env),
content_type='text/html',
**options)
elif wants_yaml(best_match):
rv = Response(
yaml.dump(rv),
content_type='application/yaml',
**options)
else:
# jsonify is unhappy with lists in Flask 0.10.1, use json.dumps
rv = Response(
json.dumps(rv),
content_type='application/json',
**options)
return rv
@classmethod
def force_type(cls, rv, environ=None):
if isinstance(rv, dict) or isinstance(rv, list):
rv = cls.make_response_from_mimetype(rv)
return super().force_type(rv, environ)
def error_response(error_code, error):
"""Private function to create a custom error response.
"""
error_opts = {'status': error_code}
error_data = {'error': str(error)}
return SWHMultiResponse.make_response_from_mimetype(error_data,
options=error_opts)
def urlize_api_links(content):
"""Utility function for decorating api links in browsable api."""
return re.sub(r'"(/api/.*|/browse/.*)"', r'"<a href="\1">\1</a>"', content)
class NoHeaderHTMLTranslator(HTMLTranslator):
"""
Docutils translator subclass to customize the generation of HTML
from reST-formatted docstrings
"""
def __init__(self, document):
super().__init__(document)
self.body_prefix = []
self.body_suffix = []
def visit_bullet_list(self, node):
self.context.append((self.compact_simple, self.compact_p))
self.compact_p = None
self.compact_simple = self.is_compactable(node)
self.body.append(self.starttag(node, 'ul', CLASS='docstring'))
DOCSTRING_WRITER = Writer()
DOCSTRING_WRITER.translator_class = NoHeaderHTMLTranslator
def safe_docstring_display(docstring):
"""
Utility function to htmlize reST-formatted documentation in browsable
api.
"""
docstring = cleandoc(docstring)
return publish_parts(docstring, writer=DOCSTRING_WRITER)['html_body']
def revision_id_from_url(url):
"""Utility function to obtain a revision's ID from its browsing URL."""
return re.sub(r'/browse/revision/([0-9a-f]{40}|[0-9a-f]{64})/.*',
r'\1', url)
def highlight_source(source_code_as_text):
"""Leverage pygments to guess and highlight source code.
Args
source_code_as_text (str): source code in plain text
Returns:
Highlighted text if possible or plain text otherwise
"""
try:
maybe_lexer = guess_lexer(source_code_as_text)
if maybe_lexer:
r = highlight(
source_code_as_text, maybe_lexer,
HtmlFormatter(linenos=True,
lineanchors='l',
anchorlinenos=True))
else:
r = '<pre>%s</pre>' % source_code_as_text
except:
r = '<pre>%s</pre>' % source_code_as_text
return Markup(r)

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