webdav to ical export

caldav-export.py

@@ -0,0 +1,110 @@
+import argparse
+import os
+import re
+from pathlib import Path
+
+import yaml
+from caldav import DAVClient
+from icalendar import Calendar
+
+
+def safe_filename(name):
+    return re.sub(r"[^a-zA-Z0-9._-]+", "_", name)
+
+
+def export_calendar(url, username, password, output):
+    client = DAVClient(
+        url=url,
+        username=username,
+        password=password,
+    )
+
+    principal = client.principal()
+
+    calendars = principal.calendars()
+
+    target = None
+    for cal in calendars:
+        if cal.name == output["calendar"]:
+            target = cal
+            break
+
+    if target is None:
+        raise RuntimeError(
+            f"Calendar '{output['calendar']}' not found for {username}"
+        )
+
+    print(f"Exporting {username}/{target.name}")
+
+    result = Calendar()
+    result.add("prodid", "-//CalDAV Export//")
+    result.add("version", "2.0")
+
+    objects = target.objects()
+
+    print(f"  {len(objects)} objects")
+
+    for obj in objects:
+        cal = Calendar.from_ical(obj.data)
+
+        for component in cal.walk():
+            if component.name != "VCALENDAR":
+                result.add_component(component)
+
+    return result
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("config")
+    parser.add_argument(
+        "-o",
+        "--output",
+        default="/srv/http/ics",
+    )
+    args = parser.parse_args()
+
+    with open(args.config) as f:
+        config = yaml.safe_load(f)
+
+    output_dir = Path(args.output)
+    output_dir.mkdir(parents=True, exist_ok=True)
+
+    combined = Calendar()
+    combined.add("prodid", "-//CalDAV Export Combined//")
+    combined.add("version", "2.0")
+
+    for entry in config["calendars"]:
+        username = entry["username"]
+        password = entry["password"]
+
+        cal = export_calendar(
+            entry["url"],
+            username,
+            password,
+            entry,
+        )
+
+        filename = output_dir / f"{safe_filename(entry['calendar'])}.ics"
+
+        with open(filename, "wb") as f:
+            f.write(cal.to_ical())
+
+        print(f"  -> {filename}")
+
+        for component in cal.walk():
+            if component.name != "VCALENDAR":
+                combined.add_component(component)
+
+    combined_file = output_dir / "all-calendars.ics"
+
+    with open(combined_file, "wb") as f:
+        f.write(combined.to_ical())
+
+    print()
+    print(f"Combined export: {combined_file}")
+
+
+if __name__ == "__main__":
+    main()
+

flake.nix

@@ -110,6 +110,12 @@
                 group = "nginx";
                 mode = "0440";
               };
+              caldav-export-config = {
+                file = ./secrets/caldav-export-config.age;
+                owner = "nobody";
+                group = "nobody";
+                mode = "0400";
+              };
             };
           }
           ./hosts/www

hosts/www/dav2ical.nix

@@ -0,0 +1,37 @@
+{ config, pkgs, ... }:
+
+let
+  outputDir = "/srv/http/ical";
+  script = pkgs.writeScript "caldav-export.py" ''
+    #!${pkgs.python3}/bin/python3
+
+    ${builtins.readFile ./caldav-export.py}
+  '';
+  pythonEnv = pkgs.python3.withPackages (ps: with ps; [
+    caldav
+    icalendar
+    pyyaml
+  ]);
+in
+{
+  systemd = {
+    services.caldav-export = {
+      description = "Export CalDAV calendars to ICS";
+      serviceConfig = {
+        Type = "oneshot";
+        ExecStart = "${pythonEnv}/bin/python ${script} ${config.age.secrets.caldav-export-config.path} -o ${outputDir}";
+      };
+    };
+    timers.caldav-export = {
+      description = "Daily CalDAV export";
+      wantedBy = [
+        "timers.target"
+      ];
+      timerConfig = {
+        OnCalendar = "daily";
+        Persistent = true;
+      };
+    };
+  };
+}
+

hosts/www/default.nix

@@ -7,6 +7,7 @@
     ./openssh.nix
     ../../services/prometheus-node.nix
     ./nginx.nix
+    ./dav2ical.nix
   ];
 
   networking = {

secrets/secrets.nix

@@ -65,4 +65,5 @@ in
   ];
   "www-staging-htpasswd.age".publicKeys = xengi ++ [ _www ];
   "radicale_htpasswd.age".publicKeys = xengi ++ [ _dav ];
+  "caldav-export-config.age".publicKeys = xengi ++ [ _dav ];
 }