R: Download File from the Internet

download.file {base}

R Documentation

Download File from the Internet

Description

This function can be used to download a file from the Internet.

Usage

download.file(url, destfile, method, quiet = FALSE, mode="w",
              cacheOK = TRUE)

Arguments

`url`	A character string naming the URL of a resource to be downloaded.
`destfile`	A character string with the name where the downloaded file is saved. Tilde-expansion is performed.
`method`	Method to be used for downloading files. Currently download methods `"internal"`, `"wget"` and `"lynx"` are available. The default is to choose the first of these which `"internal"`. The method can also be set through the option `"download.file.method"`: see `options()`.
`quiet`	If `TRUE`, suppress status messages (if any).
`mode`	character. The mode with which to write the file. Useful values are `"w"`, `"wb"` (binary), `"a"` (append) and `"ab"`. Only used for the `"internal"` method.
`cacheOK`	logical. Is a server-side cached value acceptable? Implemented for the `"internal"` and `"wget"` methods.

Details

The function download.file can be used to download a single file as described by url from the internet and store it in destfile. The url must start with a scheme such as "http://", "ftp://" or "file://".

cacheOK = FALSE is useful for "http://" URLs, and will attempt to get a copy directly from the site rather than from an intermediate cache. (Not all platforms support it.) It is used by CRAN.packages.

The remaining details apply to method "internal" only.

The timeout for many parts of the transder can be set by the option timeout which defaults to 60 seconds.

The level of detail provided during transfer can be set by the quiet argument and the internet.info option. The details depend on the platform and scheme, but setting internet.info to 0 gives all available details, including all server responses. Using 2 (the default) gives only serious messages, and 3 or more suppresses all messages.

Proxies can be specified via environment variables. Setting "no_proxy" stops any proxy being tried. Otherwise the setting of "http_proxy" or "ftp_proxy" (or failing that, the all upper-case version) is consulted and if non-empty used as a proxy site. For FTP transfers, the username and password on the proxy can be specified by "ftp_proxy_user" and "ftp_proxy_password".

Method "wget" can be used with proxy firewalls which require user/password authentication if proper values are stored in the configuration file for wget.

Note

Methods "wget" and "lynx" are for historical compatibility. They will block all other activity on the R process.