Programmatic access to the GESIS Data Catalogue (DBK)"
In gesis: R Client for GESIS Data Catalogue (DBK)

The GESIS Data Catalogue offers a repository of approximately 5,000 datasets.

library(gesis)

We start by listing all available groups of studies:

groups <- get_study_groups()
head(groups, 10)

We see that the Eurobarometer has study group number 0008. Let's looks at all available Eurobarometer waves:

eurobars <- get_datasets("0008")
head(eurobars)

We would now like to download the first three studies. We first need to log in to the Gesis website and then pass the DOIs (unique data set identifiers) to download_dataset:

# username and password stored as environment 
# variables "GESIS_USER" and "GESIS_PASS"
gesis_session <- login()

if(!dir.exists("downloads")) dir.create("downloads")

download_dataset(s = gesis_session, doi = eurobars$doi[1:3], 
                 path = "downloads", filetype = ".dta")

files <- list.files("downloads", full.names = TRUE)

We can also download the codebooks for the same studies:

download_codebook(eurobars$doi[1:3], path = "downloads")

Using the haven package we can now read the data sets:

# library(haven)
df <- read_dta(files[1])
dim(df)

unlink("downloads", recursive = TRUE)

Disclaimer: the gesis package is neither affiliated with, nor endorsed by, the Leibniz Institute for the Social Sciences. I have been unable to find any indication that programmatic access to the website is disallowed under its terms of use (indeed, its guidelines appear to encourage it). That said, I would discourage users from using the gesis package to put undue pressure on their servers by initiating unnecessary (or unnecessarily large) batch downloads.