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* Update all non-major dependencies * Prettier Signed-off-by: Michael Telatynski <7t3chguy@gmail.com> --------- Signed-off-by: Michael Telatynski <7t3chguy@gmail.com> Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com> Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>
71 lines
2.4 KiB
Markdown
71 lines
2.4 KiB
Markdown
# Browser Storage Notes
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## Overview
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Browsers examined: Firefox 67, Chrome 75
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The examination below applies to the default, non-persistent storage policy.
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## Quota Measurement
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Browsers appear to enforce and measure the quota in terms of space on disk, not
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data stored, so you may be able to store more data than the simple sum of all
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input data depending on how compressible your data is.
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## Quota Limit
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Specs and documentation suggest we should consistently receive
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`QuotaExceededError` when we're near space limits, but the reality is a bit
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blurrier.
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When we are low on disk space overall or near the group limit / origin quota:
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- Chrome
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- Log database may fail to start with AbortError
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- IndexedDB fails to start for crypto: AbortError in connect from
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indexeddb-store-worker
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- When near the quota, QuotaExceededError is used more consistently
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- Firefox
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- The first error will be QuotaExceededError
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- Future write attempts will fail with various errors when space is low,
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including nonsense like "InvalidStateError: A mutation operation was
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attempted on a database that did not allow mutations."
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- Once you start getting errors, the DB is effectively wedged in read-only
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mode
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- Can revive access if you reopen the DB
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## Cache Eviction
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While the Storage Standard says all storage for an origin group should be
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limited by a single quota, in practice, browsers appear to handle `localStorage`
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separately from the others, so it has a separate quota limit and isn't evicted
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when low on space.
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- Chrome, Firefox
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- IndexedDB for origin deleted
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- Local Storage remains in place
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## Persistent Storage
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Storage Standard offers a `navigator.storage.persist` API that can be used to
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request persistent storage that won't be deleted by the browser because of low
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space.
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- Chrome
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- Chrome 75 seems to grant this without any prompt based on [interaction
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criteria](https://developers.google.com/web/updates/2016/06/persistent-storage)
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- Firefox
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- Firefox 67 shows a prompt to grant
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- Reverting persistent seems to require revoking permission _and_ clearing
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site data
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## Storage Estimation
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Storage Standard offers a `navigator.storage.estimate` API to get some clue of
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how much space remains.
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- Chrome, Firefox
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- Can run this at any time to request an estimate of space remaining
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- Firefox
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- Returns `0` for `usage` if a site is persisted
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