R: Attempts to download PDFs from multiple DOI links.

PDFs_collect {metagear}

R Documentation

Attempts to download PDFs from multiple DOI links.

Description

Tries to download a collection of PDF files using multiple digital object identifier (DOI) links. Updates a data frame with the success of these downloads. The function is a wrapper for PDF_download. NOTE: A single DOI may generate multiple PDF files. If running downloader in Windows, having "WindowsProxy = TRUE" will significantly improve download success.

Usage

PDFs_collect(
  aDataFrame,
  DOIcolumn,
  FileNamecolumn,
  directory = getwd(),
  randomize = FALSE,
  seed = NULL,
  buffer = FALSE,
  validatePDF = TRUE,
  quiet = FALSE,
  showSummary = TRUE,
  WindowsProxy = FALSE
)

Arguments

`aDataFrame`	A data frame containing a column of DOIs and a column of individual file names for each downloaded PDF.
`DOIcolumn`	The label of the column containing all the DOI links.
`FileNamecolumn`	The label of the column containing all the strings that will be used to rename the downloaded files.
`directory`	A string of the location (directory) were downloaded PDF files are to be saved. NOTE: helps to have this directory created before initializing the `PDFs_collect` function.
`randomize`	When `TRUE` will attempt to download PDFs in a random order. This may be necessary to ensure that host websites do not have their HTML and files repeatedly accessed.
`seed`	An integer used to enforce repeatability when randomly downloading PDFs.
`buffer`	When `TRUE` will randomly delay the downloads by a few seconds (with a mean 4 seconds and a range of 1 to 20 seconds). Another strategy to avoid quickly and repeatedly accessing host websites.
`validatePDF`	When `TRUE` will only save to files that are valid PDF documents. When `FALSE` will save all candidate files, even if they are not valid PDF formats.
`quiet`	When `FALSE` does not print to console individual download progress and summary.
`showSummary`	When `FALSE` does not print overall summary of download successes and failures.
`WindowsProxy`	When `TRUE` significantly improves download success for computers running Windows; when `FALSE` on a Windows based computer, you may only be able to download 30 to 50 PDFs at a time before a connection error occurs and halts all downloads (e.g., `InternetOpenUrl failed` error).

Value

The data frame with new column containing download-outcome successes.

Examples

## Not run: 

data(example_references_metagear)
someRefs <- effort_initialize(example_references_metagear)  
dir.create("metagear_downloads")      
PDFs_collect(aDataFrame = someRefs, DOIcolumn = "DOI", 
             FileNamecolumn = "STUDY_ID", directory = "metagear_downloads",
			WindowsProxy = TRUE)

## End(Not run)