A generator for making request to OpenAlex API Returns one record at a time.
Details
For the case without group_by, setting `verbose = TRUE` when you call `oar()` for the first time will give the total number of records in the message. With group_by, unfortunately we don't have a way to know the total until we query until exhausted.
Examples
if (require("coro")) {
# Example 1: basic usage getting one record at a time
query_url <- "https://api.openalex.org/works?filter=cites%3AW1160808132"
oar <- oa_generate(query_url, verbose = TRUE)
p1 <- oar() # record 1
p2 <- oar() # record 2
p3 <- oar() # record 3
head(p1)
head(p3)
# Example 2: using `coro::loop()` to iterate through the generator
query_url <- "https://api.openalex.org/works?filter=cited_by%3AW1847168837"
oar <- oa_generate(query_url)
coro::loop(for (x in oar) {
print(x$id)
})
# Example 3: save records in blocks of 100
query_url <- "https://api.openalex.org/works?filter=cites%3AW1160808132"
oar <- oa_generate(query_url)
n <- 100
recs <- vector("list", n)
i <- 0
coro::loop(for (x in oar) {
j <- i %% n + 1
recs[[j]] <- x
if (j == n) {
# saveRDS(recs, sprintf("rec-%s.rds", i %/% n))
recs <- vector("list", n) # reset recs
}
i <- i + 1
})
head(x)
j
# 398 works total, so j = 98 makes sense.
# You can also manually call the generator until exhausted
# using `while (!coro::is_exhausted(record_i))`.
# More details at https://coro.r-lib.org/articles/generator.html.
}
#> Loading required package: coro
#> Getting record 1 of 490 records...
#> Getting record 2 of 490 records...
#> Getting record 3 of 490 records...
#> [1] "https://openalex.org/W4248184440"
#> [1] "https://openalex.org/W1521059904"
#> [1] "https://openalex.org/W2063977404"
#> [1] "https://openalex.org/W1987736762"
#> [1] "https://openalex.org/W2127626512"
#> [1] "https://openalex.org/W2135732400"
#> [1] 90