library(rdav)r<-wd_connect("https://example.com/remote.php/dav/files/myname/","myname")wd_download(r,"data/data.csv","localdata/data.csv")data<-read.table("localdata/data.csv")png("data_plot.png")plot(data)dev.off()wd_upload(r,"data_plot.png","data_plot.png")

ocs_create_share_mail(r,"data_plot.png","yourname@example.com",note ="Please check the plotted data.")

3.1 Establishing theconnection

To interact with theWebDAV server, you have to create aconnection viawd_connect by supplying the URL, usernameand password.

In an interactive R session, you may omit the password when callingwd_connect. Then R will ask you to type the password.

# no password given, R will ask.r<-wd_connect(url ="https://cloud.example.com/remote.php/dav/files/myname",username ="myname")

When usingWebDAV in a script, you have to pass the passwordtowd_connect. It is not good practice, to write thepassword literally in your script

# Don"t do this! You would reveal your super secret password to others when# sharing your script.r<-wd_connect(url ="https://cloud.example.com/remote.php/dav/files/myname/",username ="myname",password ="12345")

Better use your system”s credential store (i. e. the password will bestored encrypted in your user account). You may use the packagekeyringto access the system”s credential store.

You once have to set a key / password combination on your computer bycalling:

keyring::key_set("mycloud","myusername")

You will be asked for the password and then the credentials arestored on your system.

In your scripts you can then usekeyring::get_key("mycloud","myusername") to pass the storedpassword towd_connect:

r<-wd_connect(url ="https://cloud.example.com/remote.php/dav/files/myname",username ="myname",password = keyring::get_key("mycloud","myusername"))

3.2 Downloading anduploading data

To download a file, you have to give the path of the filename on theserver, as well as the path to the location where you want to store thefile on your computer.

wd_download(r,"data/data.csv","localdata/data_new.csv")

Instead of giving the full path of the target file, you can use onlythe directory name. Then the file will be stored in that folder with thesame name as it has on the server.

wd_download(r,"data/data.csv","localdata")

You can download full directories. All the data within the directory,including subdirectories will be downloaded.

wd_download(r,"data","localdata")

For uploading data from your computer, you have to usewd_upload in a similar way aswd_download:

wd_upload(r,"localdata/data.csv","data/data_new.csv")wd_upload(r,"localdata/data.csv","data")wd_upload(r,"localdata","data")

Notice:

• If you upload / download files into a directory, the targetdirectory has to exist already.
• If you upload / download a directory, then the target directory willbe created, if it does not exist. However, the parent directory have toexist already.

3.3 Copy, move, deletefiles on the server

You can copy, move, delete files or directory on the server andcreate new directories.

By default existing files will be overwritten when using copy andmove operation, unless you specify the parameteroverwrite=FALSE. Notice: Some WebDAV servers may behavedifferently and won’t overwrite files. In these case you have to deletefiles first.

wd_copy(r,"actual.csv","backup.csv")wd_move(r,"backup.csv","backup-2024-02-27.csv")wd_move(r,"backup.csv","backup-2024-02-27.csv",overwrite =FALSE)wd_delete(r,"obsolete.csv")

You can create new directories.

wd_mkdir(r,"data/soil/new")

Notice that parent directories have to exist. If not, you have tocreate them first

wd_mkdir(r,"data/soil")wd_mkdir(r,"data/soil/new")

3.4 Get informationsabout files and directories

You can get the list of files and subfolders as a character vector byusingwd_dir. Using the parameterfull_names = TRUE will give you the files with relativepaths.

To get more information about files, you can use the optionas_df = TRUE. You will then get a data.frame withadditional columns like size, last modification date andcontenttype.

wd_dir(r)# get content of main folderwd_dir(r,"example")wd_dir(r,"example",full_names =TRUE)wd_dir(r,"example",as_df =TRUE)

4.1 Handling base andshare URLs

BaseWebDAV entry point URLs for Nextcloud based servers areof the form<hostname>/<optional_subfolder>/remote.php/dav/files/<username>.Public share URLs of are of the form<hostname>/<optional_subfolder>/s/<token>where the token is used as username for authentication. TheWebDAV entry point for public shares is of the form<hostname>/<optional_subfolder>/public.php/dav/files/<username>.The package provides some functions to deal with these URLs:

• ncl_baseurl(hostname, username) creates the base urlfrom host and user name.
• ncl_shareurl(hostname, username) creates the base urlfor public shares from host and username (token).
• ncl_shareurl_from_publicurl(url) creates the base urlfor public shares from the public share url.
• ncl_username_from_from_url extracts the username fromthe base urls.

This simplifies the connection to Nextcloud based servers:

url<-ncl_baseurl("example.com","johndoe")r<-wd_connect(url)shareurl<-ncl_shareurl_from_publicurl("https://example.com/s/aXaejfaheDde")rs<-wd_connect(shareurl)

4.2 Managing shares

OnNextcloud based servers one can manage shares via theOCS API.

The package provides functions for

• getting infos about shares
• create, modify and delete shares

r<-wd_connect(url)# list all sharesocs_child_shares(r)# list the shares of a specific file or folderocs_shares(r,"folder_to_share")# create an e-mail sharesh<-ocs_create_share_mail(r,"folder_to_share","jackdoe@example.com")# modify the share by adding a password and notifying the userocs_modify_share(r, sh$id,password ="super_secret")ocs_send_mail(r, sh$id,password ="super_secret")# delete the shareocs_delete_share(r, sh$id)

4.3 Find users you wantto share with

You can search yourNextcloud based server for other usersor groups on that server as well as remote (e.g. federated shares ore-mail shares that are known to your server).

r<-wd_connect(url)ocs_find_users(r,"Doe, John")

5.1 Don’t put passwordsin your code

You should avoid putting passwords in your code. See the example inthe sections above how to use system credential store.

5.2 Use applicationpasswords instead of account passwords

Some cloud services offer you the possibility to create additionalapplication passwords. If you use an application password withrdav, and the password gets somehow disclosed, you can justdelete the application password and create a new one. You don’t have tochange then your account’s password.

5.3 Use passwordprotected public shares instead of main account

Instead accessing the full account, you may create a subfolder andshare it via a public link, adding a password. You can give the sharefull read / write and edit rights, so you can manage the content of thefolder as you were logged in with your main account.

If someone gets access to your share, only the data in this foldercan then be manipulated.

5.4 When sharing data,use different shares for writing and reading

If you want to share data with other people, create public shares.Don’t give them your account credentials.

You may create separated shares for reading and writing data ifappropriate.

• make a folderyour_upload and create a write-only shareto receive data from other users
• make a folderyour_download and create a read-onlyshare to make data available to other users

Then you can check the uploaded files and move them to the downloadfolder, or process uploaded files and save results you want to share tothe download folder.

This will prevent that someone who gained access to the share todistribute unwanted or illegal content. Even if unwanted or illegalcontent might get uploaded, no one else can download it.