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Parse a response from read_page()

Source: R/parse.R
page_text.Rd

page_text() decodes the body to a UTF-8 string, page_json() parses it as JSON with jsonlite::fromJSON(), and page_html() parses it as HTML with xml2::read_html().

Usage

page_text(resp, encoding = NULL, check = TRUE)

page_json(resp, ..., check = TRUE)

page_html(resp, encoding = NULL, check = TRUE)

Arguments

resp

A response from read_page(), or a URL, which is then read with read_page()'s defaults: page_html(url) stands in for rvest::read_html(url). To read through a browser_session(), call read_page() yourself and pass its response.

encoding

The body's charset, overriding the one in the response's content-type.

check

Whether an HTTP status outside 200–299 is an error.

...

Passed on to jsonlite::fromJSON().

Value

page_text(): a character string, in UTF-8. page_json(): what jsonlite::fromJSON() returns. page_html(): an xml_document, whose relative links resolve against resp$url, the URL after any redirects.

Errors are classed under safeconduct_error: safeconduct_http_error for a status outside 200–299, carrying status and url, and safeconduct_parse_error for a body that cannot be decoded, or HTML where JSON was asked for.

Details

The charset is taken from the response's content-type. Without one, page_text() and page_json() assume UTF-8 (JSON is UTF-8 by definition), while page_html() leaves it to the page's own <meta charset>, falling back to UTF-8 only when there is none. ISO-8859-1 is read as windows-1252, as browsers do. A body that is not valid in its charset is an error, not silently patched.

A status check catches an error page that is sent as one. Some servers redirect a missing page to a "not found" page served with status 200 instead; for a JSON request, page_json() catches that by refusing an HTML body, while for a page, compare resp$url with the URL asked for.

Examples

if (FALSE) { # \dontrun{
r <- read_page("https://results.vancouver.ca/data/arearesults.json")
page_json(r)

r <- read_page("https://www12.statcan.gc.ca/census-recensement/index-fra.cfm")
xml2::xml_text(xml2::xml_find_first(page_html(r), "//title"))

# In one step, with read_page()'s defaults.
page_html("https://www12.statcan.gc.ca/census-recensement/index-fra.cfm")
} # }