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# ``twisted`.`internet`.`utils`.`_BackRelay``

class documentation

`class _BackRelay(protocol.ProcessProtocol): (source)`

Constructor: `_BackRelay(deferred, errortoo)`

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Trivial protocol for communicating with a process and turning its output into the result of a `Deferred`.

Method | `__init__` | Undocumented
Method | `errReceivedIsBad` | Undocumented
Method | `errReceivedIsGood` | Undocumented
Method | `outReceived` | Some data was received from stdout.
Method | `processEnded` | Called when the child process exits and all file descriptors associated with it have been closed.
Instance Variable | `deferred` | A `Deferred` which will be called back with all of stdout and, if `errortoo` is true, all of stderr as well (mixed together in one string). If `errortoo` is false and any bytes are received over stderr, this will fire with an ...
Instance Variable | `onProcessEnded` | If `errortoo` is false and bytes are received over stderr, this attribute will refer to a `Deferred` which will be called back when the process ends. This `Deferred` is also associated with the `_UnexpectedErrorOutput`...
Instance Variable | `s` | Undocumented

Inherited from `ProcessProtocol`:

Method | `childConnectionLost` | Called when a file descriptor associated with the child process is closed.
Method | `childDataReceived` | Called when data arrives from the child process.
Method | `errConnectionLost` | This will be called when stderr is closed.
Method | `errReceived` | Some data was received from stderr.
Method | `inConnectionLost` | This will be called when stdin is closed.
Method | `outConnectionLost` | This will be called when stdout is closed.
Method | `processExited` | This will be called when the subprocess exits.
Instance Variable | `transport` | Undocumented

Inherited from `BaseProtocol` (via `ProcessProtocol`):

Method | `connectionMade` | Called when a connection is made.
Method | `makeConnection` | Make a connection to a transport and a server.
Instance Variable | `connected` | Undocumented

def __init__(self, deferred, errortoo=0): (source)

Undocumented

def errReceivedIsBad(self, text): (source)

Undocumented

def errReceivedIsGood(self, text): (source)

Undocumented

def outReceived(self, text): (source)
overrides `twisted.internet.protocol.ProcessProtocol.outReceived`

Some data was received from stdout.

def processEnded(self, reason): (source)
from `twisted.internet.interfaces.IProcessProtocol`
overrides `twisted.internet.protocol.ProcessProtocol.processEnded`

Called when the child process exits and all file descriptors associated with it have been closed.

Parameters
reason:`twisted.python.failure.Failure` | Undocumented

deferred = (source)

A `Deferred` which will be called back with all of stdout and, if `errortoo` is true, all of stderr as well (mixed together in one string). If `errortoo` is false and any bytes are received over stderr, this will fire with an `_UnexpectedErrorOutput` instance and the attribute will be set to `None`.

onProcessEnded = (source)

If `errortoo` is false and bytes are received over stderr, this attribute will refer to a `Deferred` which will be called back when the process ends. This `Deferred` is also associated with the `_UnexpectedErrorOutput` which `deferred` fires with earlier in this case so that users can determine when the process has actually ended, in addition to knowing when bytes have been received via stderr.

s = (source)

Undocumented