Issue History

Relative directory in python

It is hard for me to understand the change of directory in runtime util these days I try to read the config file.

The project file tree

	.
	│  readme.md
	│  stmsvc.py
	│  test.py
	│
	├─conf
	│  │  global.config
	│  │  urls.py
	│  │  __init__.py
	│  │
	│  └─__pycache__
	│          urls.cpython-36.pyc
	│          __init__.cpython-36.pyc
	│
	├─input
	│  └─stm
	│          read_json_test.json
	│          table_source_ulrs.csv
	│
	├─output
	│  └─stm
	│          test_json_write.json
	│
	├─stm
	│  │  TemplateOperation.py
	│  │  test.py
	│  │  WebCrawl.py
	│  │  __init__.py
	│  │
	│  └─__pycache__
	│          TemplateOperation.cpython-36.pyc
	│          test.cpython-36.pyc
	│          urls.cpython-36.pyc
	│          __init__.cpython-36.pyc
	│
	├─templates
	│  └─stm
	│          STM_Template.xlsx
	│          stm_template.xltx
	│
	├─utils
	│  │  ReadConfig.py
	│  │  __init__.py
	│  │
	│  └─__pycache__
	│          ReadConfig.cpython-36.pyc
	│          __init__.cpython-36.pyc
	│
	└─__pycache__
	        requests.cpython-36.pyc

The relative directory effect between modules

Modules are in the same folder

stm
 │  TemplateOperation.py
 │  test.py
 │  WebCrawl.py

Under this situation, the module can be called from each other with simply '.' e.g., in the test.py, you can call TemplateOperation module like this: from .TemplateOperation import TemplateOperations

Modules are in different folder

stm
 │  TemplateOperation.py

utils
 │  ReadConfig.py

In this condition, the if TemplateOperation needs to call ReadConfig, additional codes needed:

	if '../' not in sys.path:
		sys.path.insert(0,'../')
	from utils.ReadConfig import DecodeConfig

The relative directory effect during runtime
Reference a file location is totally an independent process from Module dependency

The relative folder level totally rely on the entance file of the runtime To introduce a configure file global.config, consider the following situations:

1. ├─stm
   │  TemplateOperation.py
   │  test.py               <- the runtime entrance
   │  WebCrawl.py
   ├─conf
   │  global.config

Here the code in test will call a method in TemplateOperation module, and the file path defined in this module.
While the relative path was decided by the location of the entrance, so here the relative path should be `../conf/global.config`.

 2. .
    │  stmsvc.py             <- the runtime entrance
    │
    ├─conf
    │  │  global.config
    │
    ├─stm
    │  │  TemplateOperation.py
    │  │  test.py
    │  │  WebCrawl.py

In this situation, I packed the code to call the TemplateOperation in `stm/test.py` as a class's `foo` method,
then call this method via the utmost code in `stmsvc.py` in `root` directory.
This time the relative path still was decided by the location of the entrance, so here the relative path is `./conf/global.config`.

 3. .
    │  stmsvc.py             
    │
    ├─conf
    │  │  global.config
    │
    ├─stm
    │  │  TemplateOperation.py
    │  │  WebCrawl.py
    │  │	   	   
    │  ├─substm
    │  │  │  test.py         <- the runtime entrance

For this time, following the rule, the relative path should be `../../conf/global.config`

Seems there is no better route reference solution under this vary route change situation. Alternative way is to set a GLOBAL variable class to introduce the absolute folder location.

Petersonjoe/pyproject

Issue History

Relative directory in python