René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Documentation suggesting incorrect flags for sftp.open()","articleBody":"__Steps to reproduce:__\r\n\r\nSimply use the code in the README file to read a file from SFTP:\r\n\r\n```python\r\nsftp = session.sftp_init()\r\nwith sftp.open(\u003cremote file to read\u003e, 0, 0) as remote_fh, \\\r\n        open(\u003cfile to write\u003e, 'wb') as local_fh:\r\n    for size, data in remote_fh:\r\n        local_fh.write(data)\r\n```\r\n\r\n__Expected behaviour:__\r\n\r\nData is copied from the remote file to the local file.\r\n\r\n__Actual behaviour:__\r\n\r\nNo data is ever written to `\u003cfile to write\u003e`. The size parameter is set by libssh2 to ``LIBSSH2_ERROR_SFTP_PROTOCOL`` (-31) and the calling `sftp.last_error()` will report ``LIBSSH2_FX_FAILURE`` (4). ``remote_fh.fstat()`` will succeed without issues (reporting correct data).\r\n\r\n__Additional info:__\r\n\r\nVersion ``ssh2-python 0.6.0`` with bundled ``libssh2``.\r\n\r\nThis seems to happen because (at least up to ``libssh2`` 1.8.0) ``0`` and ``LIBSSH2_FXF_READ`` are not synonyms, like it is (in my understanding) incorrectly suggested in the [documentation](https://github.com/ParallelSSH/ssh2-python/blob/master/ssh2/sftp.pyx#L157) and the examples ([sftp_read.py](https://github.com/ParallelSSH/ssh2-python/blob/master/examples/sftp_read.py#L40), for example). This may be tested using ``libssh2`` directly by changing line 251 of the [``sftp.c``](https://github.com/libssh2/libssh2/blob/master/example/sftp.c) example from:\r\n```c\r\nlibssh2_sftp_open(sftp_session, sftppath, LIBSSH2_FXF_READ, 0);\r\n```\r\nto\r\n```c\r\nlibssh2_sftp_open(sftp_session, sftppath, 0, 0);\r\n```\r\nThis will make ``libssh2_sftp_read()`` fail in in the same way described in the actual behaviour.\r\n\r\nI should be able to send a pull request to fix the documentation and examples if needed (and my understanding of the issue is correct).","author":{"url":"https://github.com/gvialetto","@type":"Person","name":"gvialetto"},"datePublished":"2017-11-16T13:35:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/13/ssh2-python/issues/13"}