/
base.py
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/
base.py
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import asyncio
import csv
import hashlib
import re
import sys
import time
import urllib
import pint
from datasette import __version__
from datasette.database import QueryInterrupted
from datasette.utils.asgi import Request
from datasette.utils import (
add_cors_headers,
await_me_maybe,
EscapeHtmlWriter,
InvalidSql,
LimitedWriter,
call_with_supported_arguments,
tilde_decode,
path_from_row_pks,
path_with_added_args,
path_with_removed_args,
path_with_format,
sqlite3,
HASH_LENGTH,
)
from datasette.utils.asgi import (
AsgiStream,
Forbidden,
NotFound,
Response,
BadRequest,
)
ureg = pint.UnitRegistry()
class DatasetteError(Exception):
def __init__(
self,
message,
title=None,
error_dict=None,
status=500,
template=None,
message_is_html=False,
):
self.message = message
self.title = title
self.error_dict = error_dict or {}
self.status = status
self.message_is_html = message_is_html
class BaseView:
ds = None
has_json_alternate = True
def __init__(self, datasette):
self.ds = datasette
async def head(self, *args, **kwargs):
response = await self.get(*args, **kwargs)
response.body = b""
return response
async def check_permission(self, request, action, resource=None):
ok = await self.ds.permission_allowed(
request.actor,
action,
resource=resource,
default=True,
)
if not ok:
raise Forbidden(action)
def database_color(self, database):
return "ff0000"
async def options(self, request, *args, **kwargs):
return Response.text("Method not allowed", status=405)
async def post(self, request, *args, **kwargs):
return Response.text("Method not allowed", status=405)
async def put(self, request, *args, **kwargs):
return Response.text("Method not allowed", status=405)
async def patch(self, request, *args, **kwargs):
return Response.text("Method not allowed", status=405)
async def delete(self, request, *args, **kwargs):
return Response.text("Method not allowed", status=405)
async def dispatch_request(self, request):
if self.ds:
await self.ds.refresh_schemas()
handler = getattr(self, request.method.lower(), None)
return await handler(request)
async def render(self, templates, request, context=None):
context = context or {}
template = self.ds.jinja_env.select_template(templates)
template_context = {
**context,
**{
"database_color": self.database_color,
"select_templates": [
f"{'*' if template_name == template.name else ''}{template_name}"
for template_name in templates
],
},
}
headers = {}
if self.has_json_alternate:
alternate_url_json = self.ds.absolute_url(
request,
self.ds.urls.path(path_with_format(request=request, format="json")),
)
template_context["alternate_url_json"] = alternate_url_json
headers.update(
{
"Link": '{}; rel="alternate"; type="application/json+datasette"'.format(
alternate_url_json
)
}
)
return Response.html(
await self.ds.render_template(
template,
template_context,
request=request,
view_name=self.name,
),
headers=headers,
)
@classmethod
def as_view(cls, *class_args, **class_kwargs):
async def view(request, send):
self = view.view_class(*class_args, **class_kwargs)
return await self.dispatch_request(request)
view.view_class = cls
view.__doc__ = cls.__doc__
view.__module__ = cls.__module__
view.__name__ = cls.__name__
return view
class DataView(BaseView):
name = ""
async def options(self, request, *args, **kwargs):
r = Response.text("ok")
if self.ds.cors:
add_cors_headers(r.headers)
return r
def redirect(self, request, path, forward_querystring=True, remove_args=None):
if request.query_string and "?" not in path and forward_querystring:
path = f"{path}?{request.query_string}"
if remove_args:
path = path_with_removed_args(request, remove_args, path=path)
r = Response.redirect(path)
r.headers["Link"] = f"<{path}>; rel=preload"
if self.ds.cors:
add_cors_headers(r.headers)
return r
async def data(self, request):
raise NotImplementedError
def get_templates(self, database, table=None):
assert NotImplemented
async def as_csv(self, request, database):
kwargs = {}
stream = request.args.get("_stream")
# Do not calculate facets or counts:
extra_parameters = [
"{}=1".format(key)
for key in ("_nofacet", "_nocount")
if not request.args.get(key)
]
if extra_parameters:
# Replace request object with a new one with modified scope
if not request.query_string:
new_query_string = "&".join(extra_parameters)
else:
new_query_string = (
request.query_string + "&" + "&".join(extra_parameters)
)
new_scope = dict(
request.scope, query_string=new_query_string.encode("latin-1")
)
receive = request.receive
request = Request(new_scope, receive)
if stream:
# Some quick soundness checks
if not self.ds.setting("allow_csv_stream"):
raise BadRequest("CSV streaming is disabled")
if request.args.get("_next"):
raise BadRequest("_next not allowed for CSV streaming")
kwargs["_size"] = "max"
# Fetch the first page
try:
response_or_template_contexts = await self.data(request)
if isinstance(response_or_template_contexts, Response):
return response_or_template_contexts
elif len(response_or_template_contexts) == 4:
data, _, _, _ = response_or_template_contexts
else:
data, _, _ = response_or_template_contexts
except (sqlite3.OperationalError, InvalidSql) as e:
raise DatasetteError(str(e), title="Invalid SQL", status=400)
except sqlite3.OperationalError as e:
raise DatasetteError(str(e))
except DatasetteError:
raise
# Convert rows and columns to CSV
headings = data["columns"]
# if there are expanded_columns we need to add additional headings
expanded_columns = set(data.get("expanded_columns") or [])
if expanded_columns:
headings = []
for column in data["columns"]:
headings.append(column)
if column in expanded_columns:
headings.append(f"{column}_label")
content_type = "text/plain; charset=utf-8"
preamble = ""
postamble = ""
trace = request.args.get("_trace")
if trace:
content_type = "text/html; charset=utf-8"
preamble = (
"<html><head><title>CSV debug</title></head>"
'<body><textarea style="width: 90%; height: 70vh">'
)
postamble = "</textarea></body></html>"
async def stream_fn(r):
nonlocal data, trace
limited_writer = LimitedWriter(r, self.ds.setting("max_csv_mb"))
if trace:
await limited_writer.write(preamble)
writer = csv.writer(EscapeHtmlWriter(limited_writer))
else:
writer = csv.writer(limited_writer)
first = True
next = None
while first or (next and stream):
try:
kwargs = {}
if next:
kwargs["_next"] = next
if not first:
data, _, _ = await self.data(request, **kwargs)
if first:
if request.args.get("_header") != "off":
await writer.writerow(headings)
first = False
next = data.get("next")
for row in data["rows"]:
if any(isinstance(r, bytes) for r in row):
new_row = []
for column, cell in zip(headings, row):
if isinstance(cell, bytes):
# If this is a table page, use .urls.row_blob()
if data.get("table"):
pks = data.get("primary_keys") or []
cell = self.ds.absolute_url(
request,
self.ds.urls.row_blob(
database,
data["table"],
path_from_row_pks(row, pks, not pks),
column,
),
)
else:
# Otherwise generate URL for this query
url = self.ds.absolute_url(
request,
path_with_format(
request=request,
format="blob",
extra_qs={
"_blob_column": column,
"_blob_hash": hashlib.sha256(
cell
).hexdigest(),
},
replace_format="csv",
),
)
cell = url.replace("&_nocount=1", "").replace(
"&_nofacet=1", ""
)
new_row.append(cell)
row = new_row
if not expanded_columns:
# Simple path
await writer.writerow(row)
else:
# Look for {"value": "label": } dicts and expand
new_row = []
for heading, cell in zip(data["columns"], row):
if heading in expanded_columns:
if cell is None:
new_row.extend(("", ""))
else:
assert isinstance(cell, dict)
new_row.append(cell["value"])
new_row.append(cell["label"])
else:
new_row.append(cell)
await writer.writerow(new_row)
except Exception as e:
sys.stderr.write("Caught this error: {}\n".format(e))
sys.stderr.flush()
await r.write(str(e))
return
await limited_writer.write(postamble)
headers = {}
if self.ds.cors:
add_cors_headers(headers)
if request.args.get("_dl", None):
if not trace:
content_type = "text/csv; charset=utf-8"
disposition = 'attachment; filename="{}.csv"'.format(
request.url_vars.get("table", database)
)
headers["content-disposition"] = disposition
return AsgiStream(stream_fn, headers=headers, content_type=content_type)
async def get(self, request):
database_route = tilde_decode(request.url_vars["database"])
try:
db = self.ds.get_database(route=database_route)
except KeyError:
raise NotFound("Database not found: {}".format(database_route))
database = db.name
_format = request.url_vars["format"]
data_kwargs = {}
if _format == "csv":
return await self.as_csv(request, database_route)
if _format is None:
# HTML views default to expanding all foreign key labels
data_kwargs["default_labels"] = True
extra_template_data = {}
start = time.perf_counter()
status_code = None
templates = []
try:
response_or_template_contexts = await self.data(request, **data_kwargs)
if isinstance(response_or_template_contexts, Response):
return response_or_template_contexts
# If it has four items, it includes an HTTP status code
if len(response_or_template_contexts) == 4:
(
data,
extra_template_data,
templates,
status_code,
) = response_or_template_contexts
else:
data, extra_template_data, templates = response_or_template_contexts
except QueryInterrupted:
raise DatasetteError(
"""
SQL query took too long. The time limit is controlled by the
<a href="https://docs.datasette.io/en/stable/settings.html#sql-time-limit-ms">sql_time_limit_ms</a>
configuration option.
""",
title="SQL Interrupted",
status=400,
message_is_html=True,
)
except (sqlite3.OperationalError, InvalidSql) as e:
raise DatasetteError(str(e), title="Invalid SQL", status=400)
except sqlite3.OperationalError as e:
raise DatasetteError(str(e))
except DatasetteError:
raise
end = time.perf_counter()
data["query_ms"] = (end - start) * 1000
for key in ("source", "source_url", "license", "license_url"):
value = self.ds.metadata(key)
if value:
data[key] = value
# Special case for .jsono extension - redirect to _shape=objects
if _format == "jsono":
return self.redirect(
request,
path_with_added_args(
request,
{"_shape": "objects"},
path=request.path.rsplit(".jsono", 1)[0] + ".json",
),
forward_querystring=False,
)
if _format in self.ds.renderers.keys():
# Dispatch request to the correct output format renderer
# (CSV is not handled here due to streaming)
result = call_with_supported_arguments(
self.ds.renderers[_format][0],
datasette=self.ds,
columns=data.get("columns") or [],
rows=data.get("rows") or [],
sql=data.get("query", {}).get("sql", None),
query_name=data.get("query_name"),
database=database,
table=data.get("table"),
request=request,
view_name=self.name,
# These will be deprecated in Datasette 1.0:
args=request.args,
data=data,
)
if asyncio.iscoroutine(result):
result = await result
if result is None:
raise NotFound("No data")
if isinstance(result, dict):
r = Response(
body=result.get("body"),
status=result.get("status_code", status_code or 200),
content_type=result.get("content_type", "text/plain"),
headers=result.get("headers"),
)
elif isinstance(result, Response):
r = result
if status_code is not None:
# Over-ride the status code
r.status = status_code
else:
assert False, f"{result} should be dict or Response"
else:
extras = {}
if callable(extra_template_data):
extras = extra_template_data()
if asyncio.iscoroutine(extras):
extras = await extras
else:
extras = extra_template_data
url_labels_extra = {}
if data.get("expandable_columns"):
url_labels_extra = {"_labels": "on"}
renderers = {}
for key, (_, can_render) in self.ds.renderers.items():
it_can_render = call_with_supported_arguments(
can_render,
datasette=self.ds,
columns=data.get("columns") or [],
rows=data.get("rows") or [],
sql=data.get("query", {}).get("sql", None),
query_name=data.get("query_name"),
database=database,
table=data.get("table"),
request=request,
view_name=self.name,
)
it_can_render = await await_me_maybe(it_can_render)
if it_can_render:
renderers[key] = self.ds.urls.path(
path_with_format(
request=request, format=key, extra_qs={**url_labels_extra}
)
)
url_csv_args = {"_size": "max", **url_labels_extra}
url_csv = self.ds.urls.path(
path_with_format(request=request, format="csv", extra_qs=url_csv_args)
)
url_csv_path = url_csv.split("?")[0]
context = {
**data,
**extras,
**{
"renderers": renderers,
"url_csv": url_csv,
"url_csv_path": url_csv_path,
"url_csv_hidden_args": [
(key, value)
for key, value in urllib.parse.parse_qsl(request.query_string)
if key not in ("_labels", "_facet", "_size")
]
+ [("_size", "max")],
"datasette_version": __version__,
"settings": self.ds.settings_dict(),
},
}
if "metadata" not in context:
context["metadata"] = self.ds.metadata
r = await self.render(templates, request=request, context=context)
if status_code is not None:
r.status = status_code
ttl = request.args.get("_ttl", None)
if ttl is None or not ttl.isdigit():
ttl = self.ds.setting("default_cache_ttl")
return self.set_response_headers(r, ttl)
def set_response_headers(self, response, ttl):
# Set far-future cache expiry
if self.ds.cache_headers and response.status == 200:
ttl = int(ttl)
if ttl == 0:
ttl_header = "no-cache"
else:
ttl_header = f"max-age={ttl}"
response.headers["Cache-Control"] = ttl_header
response.headers["Referrer-Policy"] = "no-referrer"
if self.ds.cors:
add_cors_headers(response.headers)
return response