api: add SFTP download helper

backend/sftp_store.py

@@ -1,113 +1,39 @@
 import os
 import posixpath
-from dataclasses import dataclass
-from typing import Optional
-
 import paramiko
 
 
-@dataclass
-class SFTPConfig:
-    host: str
-    port: int
-    user: str
-    password: str
-    root: str
-
-
-def _cfg() -> SFTPConfig:
-    host = os.getenv("SFTP_HOST", "").strip()
-    port = int(os.getenv("SFTP_PORT", "2222"))
-    user = os.getenv("SFTP_USER", "").strip()
-    password = os.getenv("SFTP_PASS", "")
-    root = os.getenv("SFTP_ROOT", "/inserio").strip() or "/inserio"
-
-    if not host or not user or not password:
-        raise RuntimeError("Missing SFTP_HOST/SFTP_USER/SFTP_PASS")
-
-    # normalize root to POSIX
-    if not root.startswith("/"):
-        root = "/" + root
-    return SFTPConfig(host=host, port=port, user=user, password=password, root=root)
-
-
-class SFTPStore:
-    def __init__(self, cfg: Optional[SFTPConfig] = None):
-        self.cfg = cfg or _cfg()
-
-    def _connect(self):
-        t = paramiko.Transport((self.cfg.host, self.cfg.port))
-        t.connect(username=self.cfg.user, password=self.cfg.password)
-        sftp = paramiko.SFTPClient.from_transport(t)
-        return t, sftp
-
-    def _abs(self, rel: str) -> str:
-        rel = rel.lstrip("/")
-        return posixpath.join(self.cfg.root, rel)
-
-    def mkdir_p(self, remote_dir_rel: str) -> None:
-        t, sftp = self._connect()
-        try:
-            path = self._abs(remote_dir_rel).rstrip("/")
-            parts = path.split("/")
-            cur = ""
-            for part in parts:
-                if not part:
-                    continue
-                cur = cur + "/" + part
-                try:
-                    sftp.stat(cur)
-                except FileNotFoundError:
-                    sftp.mkdir(cur)
-        finally:
-            sftp.close()
-            t.close()
-
-    def put_bytes(self, remote_path_rel: str, data: bytes) -> None:
-        remote_abs = self._abs(remote_path_rel)
-        remote_dir = posixpath.dirname(remote_abs)
-
-        t, sftp = self._connect()
-        try:
-            # mkdir -p
-            parts = remote_dir.split("/")
-            cur = ""
-            for part in parts:
-                if not part:
-                    continue
-                cur = cur + "/" + part
-                try:
-                    sftp.stat(cur)
-                except FileNotFoundError:
-                    sftp.mkdir(cur)
-
-            tmp = remote_abs + ".tmp"
-            with sftp.file(tmp, "wb") as f:
-                f.write(data)
-                f.flush()
-            sftp.rename(tmp, remote_abs)
-        finally:
-            sftp.close()
-            t.close()
-
-    def get_bytes(self, remote_path_rel: str) -> bytes:
-        remote_abs = self._abs(remote_path_rel)
-        t, sftp = self._connect()
+def _env(name: str) -> str:
+    v = (os.getenv(name) or "").strip()
+    if not v:
+        raise RuntimeError(f"Missing env var: {name}")
+    return v
+
+
+def download_bytes(remote_path: str) -> bytes:
+    """
+    Downloads a file from SFTP_ROOT + remote_path.
+    remote_path should be relative like 'pdfs/<id>.pdf' (no leading slash).
+    """
+    host = _env("SFTP_HOST")
+    port = int(_env("SFTP_PORT"))
+    user = _env("SFTP_USER")
+    pw = _env("SFTP_PASS")
+    root = (_env("SFTP_ROOT").rstrip("/") or "/")
+
+    rp = remote_path.lstrip("/")
+
+    transport = paramiko.Transport((host, port))
+    transport.connect(username=user, password=pw)
+    sftp = paramiko.SFTPClient.from_transport(transport)
+
+    try:
+        sftp.chdir(root)
+        full = posixpath.join(".", rp)
+        with sftp.open(full, "rb") as f:
+            return f.read()
+    finally:
         try:
-            with sftp.file(remote_abs, "rb") as f:
-                return f.read()
-        finally:
             sftp.close()
-            t.close()
-
-    def exists(self, remote_path_rel: str) -> bool:
-        remote_abs = self._abs(remote_path_rel)
-        t, sftp = self._connect()
-        try:
-            sftp.stat(remote_abs)
-            return True
-        except FileNotFoundError:
-            return False
         finally:
-            sftp.close()
-            t.close()
+            transport.close()