Done:

"Cargo.toml":
Hide FTP support under new feature flag.

"operator.rs", "scheme.rs, src/services/mod.rs":
Added conditional compilation for ftp services.

"src/services/ftp/backend.rs":
Removed any unnecessary helper functions that only use
once.
Removed username and password store to avoid data breach.
Combine port and endpoint into one.
Built a FTP command stream inside Builder's build() function
and persist this stream inside Backend.
Changed tls to enable_secure. Developer can use enable_secure() function
to enable tls connection.
Modified read() function to avoid putting all stream content into memory.
Fixed stat() function, when path argument is empty, stat() function will
return the stat of root directory.

"src/services/ftp/dir_stream.rs"
Added more metadata in DirEntry.

"src/services/ftp/err.rs":
Removed any unnecessary error functions.

"src/services/ftp/mod.rs":
Remove empty line.

"tests/behavior/behavior.rs":
Added feature for ftp.

Resolve conflict.

.env.example

@@ -40,6 +40,4 @@ OPENDAL_FTP_TEST=false
 OPENDAL_FTP_ENDPOINT=<endpoint>
 OPENDAL_FTP_ROOT=/path/to/dir
 OPENDAL_FTP_USER=<user>
-OPENDAL_FTP_PASSWORD=<password>
-
-
+OPENDAL_FTP_PASSWORD=<password>

Cargo.toml

@@ -35,6 +35,8 @@ layers-tracing = ["tracing"]
 services-hdfs = ["hdrs"]
 # Enable services http support
 services-http = ["radix_trie"]
+# Enable services ftp support
+services-ftp = ["suppaftp"]
 
 [lib]
 bench = false
@@ -89,7 +91,7 @@ thiserror = "1.0"
 time = "0.3"
 tokio = { version = "1.20", features = ["fs"] }
 tracing = { version = "0.1", optional = true }
-suppaftp = {version = "^4.4.0", features = ["secure"]}
+suppaftp = {version = "4.4", features = ["secure"], optional = true}
 
 [dev-dependencies]
 cfg-if = "1.0"

examples/ftp.rs

@@ -33,11 +33,9 @@ async fn main() -> Result<()> {
 
 Available Environment Values:
     - OPENDAL_FTP_ENDPOINT=endpoint     # required  
-    - OPENDAL_FTP_Port=port      # default with 21
-    - OPENDAL_FTP_ROOT=/path/to/dir/   # if not set, will be seen as "/ftp"
+    - OPENDAL_FTP_ROOT=/path/to/dir/   # if not set, will be seen as "/"
     - OPENDAL_FTP_USER=user    # default with empty string ""
-    - OPENDAL_FTP_PWD=password    # default with empty string ""
-    - OPENDAL_FTP_TLS=bool    # default with false
+    - OPENDAL_FTP_PASSWORD=password    # default with empty string ""
     "#
     );
 
@@ -47,11 +45,10 @@ Available Environment Values:
     // Set the root for ftp, all operations will happen under this root.
 
     // NOTE: the root must be absolute path.
-    builder.endpoint(&env::var("OPENDAL_FTP_ENDPOINT").unwrap_or_else(|_| "127.0.0.1".to_string()));
+    builder
+        .endpoint(&env::var("OPENDAL_FTP_ENDPOINT").unwrap_or_else(|_| "127.0.0.1:21".to_string()));
     builder.user(&env::var("OPENDAL_FTP_USER").unwrap_or_else(|_| "".to_string()));
-    builder.password(&env::var("OPENDAL_FTP_PWD").unwrap_or_else(|_| "".to_string()));
-    builder.port(&env::var("OPENDAL_FTP_PORT").unwrap_or_else(|_| "21".to_string()));
-    builder.tls(&env::var("OPENDAL_FTP_TLS").unwrap_or_else(|_| "false".to_string()));
+    builder.password(&env::var("OPENDAL_FTP_PASSWORD").unwrap_or_else(|_| "".to_string()));
 
     // Use `Operator` normally.
     let op: Operator = Operator::new(builder.build()?);
@@ -78,8 +75,8 @@ Available Environment Values:
     op.object(&path).write("write test").await?;
     info!("write to file successful!",);
 
-    info!("try to read file: {}", &path);
-    let content = op.object(&path).read().await?;
+    info!("try to read file content between 5-10: {}", &path);
+    let content = op.object(&path).range_read(5..10).await?;
     info!(
         "read file successful, content: {}",
         String::from_utf8_lossy(&content)

src/operator.rs

@@ -131,9 +131,9 @@ impl Operator {
             Scheme::Hdfs => services::hdfs::Backend::from_iter(it)?.into(),
             #[cfg(feature = "services-http")]
             Scheme::Http => services::http::Backend::from_iter(it)?.into(),
-            Scheme::Ipfs => services::ipfs::Backend::from_iter(it)?.into(),
             #[cfg(feature = "services-ftp")]
             Scheme::Ftp => services::ftp::Backend::from_iter(it)?.into(),
+            Scheme::Ipfs => services::ipfs::Backend::from_iter(it)?.into(),
             Scheme::Memory => services::memory::Builder::default().build()?.into(),
             Scheme::Gcs => services::gcs::Backend::from_iter(it)?.into(),
             Scheme::S3 => services::s3::Backend::from_iter(it)?.into(),

src/scheme.rs

@@ -109,6 +109,7 @@ impl FromStr for Scheme {
             #[cfg(feature = "services-ftp")]
             "ftp" => Ok(Scheme::Ftp),
             "ipfs" => Ok(Scheme::Ipfs),
+            "gcs" => Ok(Scheme::Gcs),
             "memory" => Ok(Scheme::Memory),
             "obs" => Ok(Scheme::Obs),
             "s3" => Ok(Scheme::S3),