Question

The package looks like this:

• main.py
• HTTPQuery.py
• SmartDownload.py

in main.py I run from SmartDownload import DownloadFile.

in Smartdownload.py I run from HTTPQuery import Is_ServerSupportHTTPRange

in HTTPQuery I run from SmartDownload import DownloadFile

It seems that I get stuck in a loop, because this is the error:

Traceback (most recent call last):
  File "C:\Scripts\mp3grabber\main.py", line 13, in <module>
    import HTTPQuery
  File "C:\Scripts\mp3grabber\HTTPQuery.py", line 6, in <module>
    from SmartDownload import DownloadFile
  File "C:\Scripts\mp3grabber\SmartDownload.py", line 3, in <module>
    from HTTPQuery import Is_ServerSupportHTTPRange
ImportError: cannot import name Is_ServerSupportHTTPRange

But I must import second file’s functions into the third file and vice-versa.

What can I do?

Answer 1

As you suggest, there is a circular dependency between HTTPQuery and SmartDownload. The easy fix is to move the import into the functions that require it, e.g.

# SmartDownload.py
def download(url):
    from HTTPQuery import Is_ServerSupportHTTPRange
    ...

A better solution might be to reorganize your modules. If there is no reasonable way to remove HTTPQuery‘s dependence on SmartDownload or vice versa, consider merging them into one module.