File Storage

Current implementation only supports local file storage: Base64 image saving and Multipart file upload, with delete functionality. Does not cover S3/OSS or Nginx configuration.

• Directory partitioned by month: YYYY-MM
• File naming: day-dd + Global ID (GID) + extension
• Path configuration:
  • Static image directory: APPCOFIG.server.static_dir
  • General upload directory: APPCOFIG.server.upload_dir (default: data/upload)
  • Return URL prefix: APPCOFIG.server.domainname

---

Path Conventions

• Base64 Image
  • Physical path: {static_dir}/{YYYY-MM}/{dd}_{GID}.png
  • Returns: (url_path, no_domain_path)
• Multipart Upload
  • Physical path: {upload_dir}/{YYYY-MM}/{dd}-{GID}.{ext}
  • Returns: {domainname}/{YYYY-MM}/{file}

---

Reference Implementation

use axum::extract::Multipart;
use tokio::{fs, io::AsyncWriteExt};

// Base64 Image Save
pub async fn save_base64_img(base64_data: &str) -> Result<(String, String)> {
    let server_config = APPCOFIG.server.clone();
    let now = chrono::Local::now();
    let file_path_t = format!("{}/{}", server_config.static_dir, &now.format("%Y-%m"));
    fs::create_dir_all(&file_path_t).await?;
    let fid = GID().await;
    let file_name = format!("{}_{}{}", now.format("%d"), fid, ".png");
    let file_path = format!("{}/{}", file_path_t, &file_name);

    let decoded_data = general_purpose::STANDARD.decode(base64_data)?;
    let mut file = fs::File::create(file_path).await?;
    file.write_all(&decoded_data).await?;

    let url_path = format!("{}/{}/{}/{}", server_config.domainname, "static", &now.format("%Y-%m"), &file_name);
    let no_domain_path = format!("{}/{}/{}", "static", &now.format("%Y-%m"), &file_name);
    Ok((url_path, no_domain_path))
}

Configuration

From APPCOFIG.server:

• upload_dir: Local upload directory (default: data/upload)
• static_dir: Local static image directory
• domainname: URL prefix for returned paths

Notes

• Content-Type whitelist: currently jpeg/png/gif, extendable as needed
• Size limits: check bytes.len() to limit single file size
• File uniqueness: uses GID to avoid conflicts
• Old file cleanup: pass old URL via field.file_name()