Fix to use STU_ROOT_DIR environment variable

README.md

@@ -45,11 +45,14 @@ Or refer to the `***-help.png` screenshots in the [./img directory](./img).
 
 ### Config
 
-Config is loaded from `~/.stu/config.toml`. If the file does not exist, it will be created automatically at startup.
+Config is loaded from `$STU_ROOT_DIR/config.toml`.
+
+- If `STU_ROOT_DIR` environment variable is not set, `~/.stu` is used by default.
+- If the file does not exist, it will be created automatically at startup.
 
 The values that can be set are as follows:
 
-- `download_dir`: _string_ - Directory to save when downloading objects (_default_: `~/.stu/download`)
+- `download_dir`: _string_ - Directory to save when downloading objects (_default_: `$STU_ROOT_DIR/download`)
 
 ## Screenshots
 

src/config.rs

@@ -1,9 +1,11 @@
-use std::path::PathBuf;
+use std::{env, path::PathBuf};
 
 use serde_derive::{Deserialize, Serialize};
 
 use crate::error::{AppError, Result};
 
+const STU_ROOT_DIR_ENV_VAR: &str = "STU_ROOT_DIR";
+
 const APP_BASE_DIR: &str = ".stu";
 const CONFIG_FILE_NAME: &str = "config.toml";
 const ERROR_LOG_FILE_NAME: &str = "error.log";
@@ -47,8 +49,14 @@ impl Config {
     }
 
     fn get_app_base_dir() -> Result<PathBuf> {
-        dirs::home_dir()
-            .map(|home| home.join(APP_BASE_DIR))
-            .ok_or_else(|| AppError::msg("Failed to load home directory"))
+        match env::var(STU_ROOT_DIR_ENV_VAR) {
+            Ok(dir) => Ok(PathBuf::from(dir)),
+            Err(_) => {
+                // default
+                dirs::home_dir()
+                    .map(|home| home.join(APP_BASE_DIR))
+                    .ok_or_else(|| AppError::msg("Failed to load home directory"))
+            }
+        }
     }
 }