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Edit docs of bind option of getCurrentContext()

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josieusa 2017-01-10 14:29:04 +01:00
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README.md
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@ -62,16 +62,26 @@ This approach should be compatible with all process managers, including
`strong-pm`. However, we feel that relying on the order of `require` statements `strong-pm`. However, we feel that relying on the order of `require` statements
is error-prone. is error-prone.
### Re-bind for concurrency ### Bind for concurrency
In order to workaround the aforementioned concurrency issue with `when` (and In order to workaround the aforementioned concurrency issue with `when` (and
similar `Promise`-like and other libraries implementing custom queues and/or similar `Promise`-like and other libraries implementing custom queues and/or
connection pools), it's recommended to activate context re-binding inside each connection pools), it's recommended to activate context binding inside each
HTTP request or concurrent `runInContext()` call, by using the `bind` option, as HTTP request or concurrent `runInContext()` call, by using the `bind` option, as
in this example: in this example:
var ctx = LoopBackContext.getCurrentContext({ bind: true }); var ctx = LoopBackContext.getCurrentContext({ bind: true });
With the option enabled, this both creates the context, and binds the access
methods of the context (i.e. `get` and `set`), at once.
**Warning**: this only works if it's **the first expression evaluated** in every
middleware/operation hook/`runInContext()` call etc. that uses
`getCurrentContext`. (It must be the first expression; it may not be enough if
it's at the first line). Explanation: you must bind the context while it's still
correct, i.e. before it gets mixed up between concurrent operations affected by
bugs. Therefore, to be sure, you must bind it before *any* operation.
The `bind` option defaults to `false`. This is only in order to prevent breaking The `bind` option defaults to `false`. This is only in order to prevent breaking
legacy apps; but if your app doesn't have such issue, then you can safely use legacy apps; but if your app doesn't have such issue, then you can safely use
`bind: true` everywhere in your app (e.g. with a `bind: true` everywhere in your app (e.g. with a