Add seafile-download.sh to mirror Seafile desktop client downloads

seafile-download.sh

@@ -0,0 +1,169 @@
+#!/bin/bash
+# Mirror Seafile client downloads from seafile.com/download.
+#
+# The official download page embeds direct OSS download links.
+# This script fetches the page with wget, parses out OSS URLs with Python,
+# downloads new/changed files atomically via wget, and removes stale local
+# files (bounded by TUNASYNC_MAX_DELETE).
+#
+# wget is used (not curl or urllib) because the tunasync Docker bridge
+# network can reach the Seafile AWS origin only via wget.
+set -euo pipefail
+
+WORKDIR="${TUNASYNC_WORKING_DIR:-}"
+UPSTREAM="${TUNASYNC_UPSTREAM_URL:-https://www.seafile.com/download/}"
+MAX_DELETE="${TUNASYNC_MAX_DELETE:-50}"
+
+if [ -z "$WORKDIR" ]; then
+    echo "ERROR: TUNASYNC_WORKING_DIR not set"
+    exit 2
+fi
+
+mkdir -p "$WORKDIR"
+cd "$WORKDIR"
+
+PAGE=$(mktemp -t seafile-page.XXXXXX.html)
+trap 'rm -f "$PAGE"' EXIT
+
+echo "Fetching download page via wget..."
+wget -qO "$PAGE" --timeout=30 --tries=3 "$UPSTREAM" || {
+    echo "ERROR: wget failed to fetch $UPSTREAM"
+    exit 1
+}
+
+python3 - "$WORKDIR" "$MAX_DELETE" "$UPSTREAM" "$PAGE" <<'PY'
+import sys, os, urllib.parse, subprocess
+from html.parser import HTMLParser
+
+WORKDIR    = sys.argv[1]
+MAX_DELETE = int(sys.argv[2])
+UPSTREAM   = sys.argv[3]
+PAGE       = sys.argv[4]
+OSS_PREFIX = "seafile-downloads.oss-cn-shanghai.aliyuncs.com"
+
+with open(PAGE, encoding="utf-8", errors="replace") as f:
+    html = f.read()
+
+class LinkExtractor(HTMLParser):
+    def __init__(self):
+        super().__init__()
+        self.urls = []
+    def handle_starttag(self, tag, attrs):
+        if tag == "a":
+            for k, v in attrs:
+                if k == "href" and v:
+                    self.urls.append(v)
+
+parser = LinkExtractor()
+parser.feed(html)
+
+oss_urls = []
+for u in parser.urls:
+    full = u if u.startswith("http") else "https://www.seafile.com" + (u if u.startswith("/") else "/" + u)
+    if OSS_PREFIX in full and "seafile-server" not in full:
+        oss_urls.append(full)
+
+if not oss_urls:
+    print("ERROR: no OSS download links found on page", file=sys.stderr)
+    sys.exit(1)
+
+print(f"Found {len(oss_urls)} client download(s)", file=sys.stderr)
+
+
+def safe_basename(url):
+    """Derive a safe filename from the URL, rejecting traversal/separators."""
+    raw = url.rstrip("/").rsplit("/", 1)[-1]
+    name = urllib.parse.unquote(raw)
+    if not name or name in (".", "..") or "/" in name or "\\" in name or "\x00" in name:
+        return None
+    return name
+
+
+remote_names = set()
+url_to_name = {}
+for url in oss_urls:
+    name = safe_basename(url)
+    if name is None:
+        print(f"ERROR: refusing to use suspicious filename derived from {url!r}", file=sys.stderr)
+        sys.exit(1)
+    remote_names.add(name)
+    url_to_name[url] = name
+
+
+def remote_size_via_spider(url):
+    """Get Content-Length using wget --spider. Returns int or None."""
+    r = subprocess.run(
+        ["wget", "--spider", "--timeout=30", "--tries=1", "-S", url],
+        capture_output=True, text=True)
+    if r.returncode != 0:
+        return None, r.stderr
+    size = None
+    for line in r.stderr.split("\n"):
+        if "Content-Length:" in line:
+            try:
+                size = int(line.split(":", 1)[1].strip())
+            except ValueError:
+                pass
+    return size, r.stderr
+
+
+# Download each file atomically via wget (curl fails to Seafile AWS IPs
+# from the Docker bridge network; wget works).
+new_files = []
+for url in oss_urls:
+    name = url_to_name[url]
+    target = os.path.join(WORKDIR, name)
+    tmp = target + ".tmp"
+
+    remote_size, stderr = remote_size_via_spider(url)
+    if remote_size is None:
+        # Some CDNs strip Content-Length on chunked or 302 responses; we still
+        # need to know whether the URL itself is reachable.
+        if stderr and "200 OK" not in stderr and "remote file exists" not in stderr.lower():
+            print(f"ERROR: spider {url}: {stderr[-200:]}", file=sys.stderr)
+            sys.exit(1)
+        # Fall through; we'll download and trust wget to validate.
+
+    if (remote_size is not None
+            and os.path.exists(target)
+            and os.path.getsize(target) == remote_size):
+        continue
+
+    print(f"Downloading: {name} ({remote_size} bytes)" if remote_size is not None
+          else f"Downloading: {name}", file=sys.stderr)
+    r = subprocess.run(
+        ["wget", "-q", "--timeout=30", "--tries=3", "-O", tmp, url],
+        capture_output=True, text=True)
+    if r.returncode != 0:
+        print(f"ERROR: download {url}: {r.stderr[-200:]}", file=sys.stderr)
+        if os.path.exists(tmp):
+            os.remove(tmp)
+        sys.exit(1)
+
+    if remote_size is not None:
+        downloaded = os.path.getsize(tmp)
+        if downloaded != remote_size:
+            print(f"ERROR: short read for {name}: got {downloaded}, "
+                  f"expected {remote_size}", file=sys.stderr)
+            os.remove(tmp)
+            sys.exit(1)
+
+    os.replace(tmp, target)
+    new_files.append(name)
+
+# Only delete stale files after all downloads succeeded so a transient
+# upstream issue cannot wipe the mirror.
+local_files = [f for f in os.listdir(WORKDIR)
+               if os.path.isfile(os.path.join(WORKDIR, f))]
+stale = [f for f in local_files if f not in remote_names and not f.endswith(".tmp")]
+if len(stale) > MAX_DELETE:
+    print(f"WARNING: {len(stale)} stale files exceeds MAX_DELETE ({MAX_DELETE})",
+          file=sys.stderr)
+    sys.exit(1)
+for f in stale:
+    fp = os.path.join(WORKDIR, f)
+    print(f"Deleting stale: {f}", file=sys.stderr)
+    os.remove(fp)
+
+print("Done.", file=sys.stderr)
+PY