Import contacts (vCards) into Nextcloud

TL;DR

Export your contacts from Google in vCard version 3 format, split the contacts file and use cadaver to upload all files individually to your address book.

The struggle

Last week, I did a fresh install of Lingeage OS 14.1 on my OnePlus X and decided not to install any GApps. I have been slowly moving away from using Google services and, having found replacements in the form of open-source apps or web interfaces, I felt confident I would be able to use my phone without a Google Play Store or Play Services. (F-Droid is now my sole source of apps.)

To tackle the problem of storing contacts and a calendar that could be synced, I installed a Nextcloud instance on a Raspberry Pi 3. Having installed DAVdroid, I got my phone to sync contacts with Nextcloud, but not all of them: it would stop synchronizing after some 120 contacts, while I had more than 400.

I decided to try a different approach, so I exported the contacts on my phone in vCard format and tried to upload them to Nextcloud using the aptly named application "contacts" for this. However, this also failed unexpectedly. I’m using Nextcloud version 12.0.3 and version 2.0.1 of the contact app, but it refuses to accept vCard version 2.1 (HTTP response code 415: Unsupported media type). This, naturally, is the version Android 6 uses to export contacts.

After some searching, I found out that if you go to contacts.google.com, you can download your contacts in vCards version 3. Problem fixed? Well, not so fast: importing 400+ contacts into Nextcloud using the web interface on a Raspberry Pi 3 with an SD card for storage will take a long time. In fact, it never finished over the course of a couple of hours (!), so I needed yet another approach.

Fortunately, you can approach your Nextcloud instance through the WebDAV protocol using tools such as cadaver:

$ cadaver https://192.168.1.14/nextcloud/remote.php/dav

Storing your credentials in a .netrc file in your home directory will enable cadaver to verify your identity without prompting, making it suitable for scripting:

machine 192.168.1.14
login foo
password correcthorsebatterystaple

cadaver allows you to traverse the directories of the remote file system over WebDAV. To put a single local contacts file (from your working machine) to the remote Raspberry Pi, you could tell it to:

dav:/nextcloud/remote.php/dav/> cd addressbooks/users/{username}/{addressbookname}
dav:/nextcloud/remote.php/dav/addressbooks/users/foo/Contacts/> put /home/foo/all.vcf all.vcf

I had a single vcf file with 400+ contacts in them, but after uploading it this way, only a single contact was being displayed. Apparently, the Nextcloud’s contacts app assumes a single vcf file contains only a single contact. New challenge: we need to split this single vcf file containing multiple contacts into separate files that we can then upload to Nextcloud.

To split the contacts, we can use awk:

BEGIN {
    RS="END:VCARD\r?\n"
    FS="\n"
}
{
    command = "echo -n $(pwgen 20 1).vcf"
    command | getline filename
    close(command)
    print $0 "END:VCARD" > filename
}

This separates the contacts on the record separator END:VCARD and generates a random filename to store the individual contact in. (I also wrote a Java program to do the same thing, which is faster when splitting large files).

Obviously, it would be convenient now if we could upload all these files in one go. cadaver does provides the mput action to do so, but I did not get it to work with wildcards. So instead, I created a file with put commands:

for file in *.vcf; do
    echo "put $(pwd)/$file addressbooks/users/foo/Contacts/$file" >> commands
done

And then provided this as input to cadaver:

$ cadaver http://192.168.1.14/nextcloud/remote.php/dav <<< $(cat commands)

This may take a while (it took around an hour for 400+ contacts), but at least you get to see the progress as each request is made and processed. And voilĂ , all the contacts are displayed correctly in Nextcloud.