### Virtual Method

# Soup WebsocketExtension process_outgoing_message

#### Declaration [src]

    GBytes*
    process_outgoing_message (
      SoupWebsocketExtension* extension,
      guint8* header,
      GBytes* payload,
      GError** error
    )

#### Description [src]

Process a message before it’s sent.

If the payload isn’t changed the given `payload` is just returned, otherwise Glib.Bytes.unref is called on the given `payload` and a new `GBytes` is returned with the new data.

Extensions using reserved bits of the header will change them in `header`.

#### Parameters

`header`

  Type: `guint8*`

  The message header.

  The argument will be modified by the function.

`payload`

  Type: `GBytes`

  The payload data.

  The called function takes ownership of the data, and is responsible for freeing it.

`error`

  Type: `GError **`

  The return location for a recoverable error.

  The argument can be `NULL`.
  If the return location is not `NULL`, then you must initialize it to a `NULL` `GError*`.
  The argument will left initialized to `NULL` by the virtual function if there are no errors.
  In case of error, the argument will be set to a newly allocated `GError`; the caller will take ownership of the data, and be responsible for freeing it.

#### Return value

Type: `GBytes`

The message payload data, or `NULL` in case of error.

The caller of the function takes ownership of the data, and is responsible for freeing it.