Python - gphoto2 如何找出函数的作用？

Question

I am playing around with gphoto2 and I found that camera object has a public function file_get_info() . I would like to know:

1. what this function does
2. how to call it

But so far I have failed to find any information about it.

---

This is what I do:

import gphoto2 as gp

portInfoList = gp.PortInfoList()
portInfoList.load()
abilitiesList = gp.CameraAbilitiesList()
abilitiesList.load()
cams = abilitiesList.detect(portInfoList)

for name, addr in cams:
    print("%s at port %s"%(name, addr))
    idx = portInfoList.lookup_path(addr)
    camera = gp.Camera()
    camera.set_port_info(portInfoList[idx])
    camera.init()
camera.file_get_info()

This is what I get:

TypeError: Camera_file_get_info expected at least 2 arguments, got 0

---

What is even more frustrating is that no matter how hard I google I cannot find anything about the Camera_file_get_info function.

Am I approaching this wrong?

Answer 1

The file_get_info method on a Camera object is a more Pythonic version of the libgphoto2 function gp_camera_file_get_info . This would be a better term for web searching.

There are several ways to get the information you're looking for. Like other Python modules you can use pydoc:

pydoc3 gphoto2.Camera.file_get_info

Help on method_descriptor in gphoto2.Camera:

gphoto2.Camera.file_get_info = file_get_info(...)
    file_get_info(char const * folder, char const * file, Context context)

    Retrieves information about a file.  

    Parameters
    ----------
    * `camera` :  
        a Camera  
    * `folder` :  
        a folder  
    * `file` :  
        the name of the file  
    * `info` :  
    * `context` :  
        a GPContext  

    Returns
    -------
    a gphoto2 error code

    See also gphoto2.gp_camera_file_get_info

This is taken from the "C" documentation, so the parameter list is a bit confusing - info is a parameter in the C version but not in Python. The two parameters you need are folder and file - these tell the function which file you want information about.

You might prefer to use the C documentation directly: http://www.gphoto.org/doc/api/gphoto2-camera_8h.html#adda54321b1947b711d345936041f80c7 This includes a link to the info structure.

Finally, the list-files.py example program included in python-gphoto2 shows a use of file_get_info .