103 lines
3.2 KiB
Python
103 lines
3.2 KiB
Python
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#!/usr/bin/env python
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# coding: utf-8
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"""
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Helpers to implement a JSON API with Bottle.
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"""
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import json
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import re
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import bottle
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FILTER_RE = re.compile(r"filter\[([A-z0-9_]+)\]")
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@bottle.hook('after_request')
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def enable_cors():
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"""
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Add CORS headers at each request.
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"""
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# The str() call is required as we import unicode_literal and WSGI
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# headers list should have plain str type.
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bottle.response.headers[str('Access-Control-Allow-Origin')] = str('*')
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bottle.response.headers[str('Access-Control-Allow-Methods')] = str(
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'PUT, GET, POST, DELETE, OPTIONS, PATCH'
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)
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bottle.response.headers[str('Access-Control-Allow-Headers')] = str(
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'Origin, Accept, Content-Type, X-Requested-With, X-CSRF-Token'
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)
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def JsonApiError(error_code, error_str):
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"""
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Return an HTTP error with a JSON payload.
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:param error_code: HTTP error code to return.
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:param error_str: Error as a string.
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:returns: Set correct response parameters and returns JSON-serialized error
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content.
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"""
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bottle.response.status = error_code
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bottle.response.content_type = "application/json"
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return json.dumps(dict(detail=error_str, status=error_code))
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def JsonApiParseQuery(query, model, default_sorting=None):
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"""
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Implementing JSON API spec for filtering, sorting and paginating results.
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:param query: A Bottle query dict.
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:param model: Database model used in this query.
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:param default_sorting: Optional field to sort on if no sort options are
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passed through parameters.
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:return: A tuple of filters, page number, page size (items per page) and
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sorting to apply.
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"""
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# Handle filtering according to JSON API spec
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filters = []
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for param in query:
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filter_match = FILTER_RE.match(param)
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if not filter_match:
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continue
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field = getattr(model, filter_match.group(1))
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value = query[filter_match.group(0)]
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filters.append(field == value)
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# Handle pagination according to JSON API spec
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page_number, page_size = 0, None
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try:
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if 'page[size]' in query:
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page_size = int(query['page[size]'])
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assert page_size > 0
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if 'page[number]' in query:
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page_number = int(query['page[number]'])
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assert page_number >= 0
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except (AssertionError, ValueError):
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raise ValueError("Invalid pagination provided.")
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# Handle sorting according to JSON API spec
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sorting = []
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if 'sort' in query:
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for index in query['sort'].split(','):
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try:
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sort_field = getattr(model, index.lstrip('-'))
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except AttributeError:
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raise ValueError(
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"Invalid sorting key provided: {}.".format(index)
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)
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if index.startswith('-'):
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sort_field = sort_field.desc()
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sorting.append(sort_field)
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# Default sorting options
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if not sorting and default_sorting:
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try:
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sorting.append(getattr(model, default_sorting))
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except AttributeError:
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raise ValueError(
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"Invalid default sorting key provided: {}.".format(
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default_sorting
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)
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)
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return filters, page_number, page_size, sorting
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