1
0
mirror of https://github.com/gsi-upm/sitc synced 2024-11-05 07:31:41 +00:00
sitc/lod/helpers.py
2020-02-20 11:28:55 +01:00

136 lines
4.0 KiB
Python

'''
Helper functions and ipython magic for the SPARQL exercises.
The tests in the notebooks rely on the `LAST_QUERY` variable, which is updated by the `%%sparql` magic after every query.
This variable contains the full query used (`LAST_QUERY["query"]`), the endpoint it was sent to (`LAST_QUERY["endpoint"]`), and a dictionary with the response of the endpoint (`LAST_QUERY["results"]`).
For convenience, the results are also given as tuples (`LAST_QUERY["tuples"]`), and as a dictionary of of `{column:[values]}` (`LAST_QUERY["columns"]`).
'''
from IPython.core.magic import (register_line_magic, register_cell_magic,
register_line_cell_magic)
from IPython.display import HTML, display, Image, display_javascript
from urllib.request import Request, urlopen
from urllib.parse import quote_plus, urlencode
from urllib.error import HTTPError
import json
import sys
js = "IPython.CodeCell.options_default.highlight_modes['magic_sparql'] = {'reg':[/^%%sparql/]};"
display_javascript(js, raw=True)
def send_query(query, endpoint):
FORMATS = ",".join(["application/sparql-results+json",
"text/javascript",
"application/json"])
data = {'query': query}
# b = quote_plus(query)
r = Request(endpoint,
data=urlencode(data).encode('utf-8'),
headers={'content-type': 'application/x-www-form-urlencoded',
'accept': FORMATS},
method='POST')
res = urlopen(r)
data = res.read().decode('utf-8')
if res.getcode() == 200:
try:
return json.loads(data)
except Exception:
print('Got: ', data, file=sys.stderr)
raise
raise Exception('Error getting results: {}'.format(data))
def tabulate(tuples, header=None):
if not header:
header, tuples = tuples[0], tuples[1:]
header = '<tr>{}<tr>'.format(''.join('<th>{}</th>'.format(h) for h in header))
rows = []
for row in tuples:
inner = ''.join('<td>{}</td>'.format(c) for c in row)
rows.append('<tr>{}</tr>'.format(inner))
body = ''.join(rows)
table = '<table><thead>{header}</thead><tbody>{body}</tbody></table>'.format(body=body,
header=header)
return table
LAST_QUERY = {}
def solution():
return LAST_QUERY
def query(query, endpoint=None, print_table=False):
global LAST_QUERY
endpoint = endpoint or "http://fuseki.gsi.upm.es/sitc/"
results = send_query(query, endpoint)
tuples = to_table(results)
columns = {}
header, values = tuples[0], tuples[1:]
for ix, h in enumerate(header):
columns[h] = []
for row in values:
columns[h].append(row[ix])
LAST_QUERY.update({
'query': query,
'endpoint': query,
'results': results,
'tuples': values,
'columns': columns
})
if not print_table:
return tuples
return HTML(tabulate(tuples))
def to_table(results):
table = []
header = results['head']['vars']
table.append(header)
for result in results["results"]["bindings"]:
table.append(tuple(result.get(h, {}).get('value', "") for h in header))
return table
@register_cell_magic
def sparql(line, cell):
'''
Sparql magic command for ipython. It can be used in a cell like this:
```
%%sparql
... Your SPARQL query ...
```
by default, it will use the DBpedia endpoint, but you can use a different endpoint like this:
```
%%sparql http://my-sparql-endpoint...
... Your SPARQL query ...
```
'''
try:
return query(cell, endpoint=line, print_table=True)
except HTTPError as ex:
error_message = ex.read().decode('utf-8')
print('Error {}. Reason: {}'.format(ex.status, ex.reason))
print(error_message, file=sys.stderr)
def show_photos(values):
for value in values:
if 'http://' in value:
display(Image(url=value))