Fix Driver.onCompleted callback #298
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Setting this callback will now trigger connectivity verification. Provided callback function will be invoked if verification succeeds. When `onCompleted` callback is not set no verification will happen. This is achieved using getter/setter on `onCompleted` property. This callback has previously been broken when session was decoupled from connection. Removed `Driver.onCompleted` and `Driver.onError` from README. These callbacks were introduced specifically for neo4j-browser that needs to verify connectivity and be notified about broken WebSockets. So they were always a "special" not fully thought through part of driver's public API. It is preferable to do connectivity verification by running a dummy query like `RETURN 1`. Note that it's not always required.
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ali-ince
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Oct 4, 2017
| return this._onCompleted; | ||
| } | ||
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| set onCompleted(callback) { |
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Setting an event handler invoking actual verification confused me a bit. What happens if verification fails? Maybe an explicit method verifyConnectivity() returning a promise would be a better option, can be elaborated for upcoming versions?
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Failed verification will result in Driver.onCompleted not being invoked. Instead Driver.onError will be invoked. I agree, these callbacks are not ideal and rather ugly. That's why they are removed from README. Users can verify connectivity by running a dummy query like RETURN 1. So this fix is only for backwards compatibility.
ali-ince
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Oct 4, 2017
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Setting this callback will now trigger connectivity verification. Provided callback function will be invoked if verification succeeds. When
onCompletedcallback is not set no verification will happen. This is achieved using getter/setter ononCompletedproperty.This callback has previously been broken when session was decoupled from connection.
Removed
Driver.onCompletedandDriver.onErrorfrom README. These callbacks were introduced specifically for neo4j-browser that needs to verify connectivity and be notified about broken WebSockets. So they were always a "special" not fully thought through part of driver's public API. It is preferable to do connectivity verification by running a dummy query likeRETURN 1. Note that it's not always required.Fixes #234