server.py 文件源码

def graphtxn(write=False, create=False, excl=False, on_success=None, on_failure=None):
    def decorator(func):
        def wrapper(self, _, uuid, *args, **kwargs):
            g = self.graph(uuid, readonly=not write, create=create, excl=excl)
            success = None
            try:
                with g.transaction(write=write) as txn:
                    lastID = txn.lastID
                    success = False
                    ret = func(self, g, txn, _, uuid, *args, **kwargs)
                    try:
                        next = getattr(ret, 'next')
                    except AttributeError:
                        ret = [ret] if ret is not None else []
                    finally:
                        if write:
                            txn.flush()
                            self.res.headers.set('X-lg-updates', txn.lastID - lastID)
                        self.res.headers.set('X-lg-maxID', txn.lastID)
                        for x in ret:
                            yield x
                    success = True
                # delay final chunking trailer until txn has been committed
                if write:
                    if 'x-lg-sync' in self.req.headers:
                        g.sync(force=True)
                    yield ''
            except HTTPError:
                raise
            except (IOError, OSError) as e:
                raise HTTPError(507 if e.errno is errno.ENOSPC else 500, str(e))
            except Exception as e:
                info = sys.exc_info()
                log.error('Unhandled exception: %s', traceback.print_exception(*info))
                raise
            finally:
                if success is True:
                    if on_success:
                        on_success(g)
                elif success is False:
                    if on_failure:
                        on_failure(g)
                g.close()
        return wrapper
    return decorator