Cam Proudlock
7bda8e6d60
The branch stored scopejson, desiredstate and params as sa.JSON, the only JSON columns in the product. MySQL 5.6 has no JSON type - it arrived in 5.7 - and the migration failed there with a bare syntax error near the word JSON. They are TEXT now, through a JSONText type decorator, so the seventeen call sites still assign and read dicts. The convention elsewhere is already TEXT: guides.blocksjson, geenforce.manifestjson. Spec regenerated: 331 paths, 477 operations across 22 surfaces.
45 lines
1.7 KiB
Python
45 lines
1.7 KiB
Python
"""JSON stored in a TEXT column.
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MySQL 5.6 has no JSON type - it arrived in 5.7 - and a site is still running
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5.6, where `sa.JSON()` fails at migration time with a bare syntax error near the
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word JSON. Every other JSON-bearing column in this product is already TEXT for
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that reason: guides' `blocksjson`, GE-Enforce's `manifestjson`.
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This keeps the Python side identical. A model attribute still holds a dict or a
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list, still assigns and reads like one; only the storage changes. The
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alternative - json.dumps and json.loads at seventeen call sites - is the same
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thing written out seventeen times, with seventeen chances to forget one.
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Note the SQLite behaviour is deliberately the same as MySQL's. Tests run on
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SQLite and production does not, so a type that behaved differently across the
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two would hide exactly the failure this exists to prevent.
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"""
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import json
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from sqlalchemy import Text
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from sqlalchemy.types import TypeDecorator
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class JSONText(TypeDecorator):
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"""A dict or list on the Python side, TEXT in the database."""
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impl = Text
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cache_ok = True
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def process_bind_param(self, value, dialect):
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if value is None:
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return None
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return json.dumps(value, separators=(',', ':'))
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def process_result_value(self, value, dialect):
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if value is None or value == '':
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return None
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try:
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return json.loads(value)
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except (TypeError, ValueError):
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# A row written before this column was JSON, or hand-edited. Hand
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# back the raw text rather than raising: a policy that cannot be
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# parsed should be visible and fixable, not an exception on read.
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return value
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