R: Read HTML or XML.

read_xml {xml2} | R Documentation

## Read HTML or XML.

### Description

Read HTML or XML.

### Usage

    read_xml(x, encoding = "", ..., as_html = FALSE, options = "NOBLANKS")

    read_html(x, encoding = "", ..., options = c("RECOVER", "NOERROR", "NOBLANKS"))

    ## S3 method for class 'character'
    read_xml(x, encoding = "", ..., as_html = FALSE, options = "NOBLANKS")

    ## S3 method for class 'raw'
    read_xml(
      x,
      encoding = "",
      base_url = "",
      ...,
      as_html = FALSE,
      options = "NOBLANKS"
    )

    ## S3 method for class 'connection'
    read_xml(
      x,
      encoding = "",
      n = 64 * 1024,
      verbose = FALSE,
      ...,
      base_url = "",
      as_html = FALSE,
      options = "NOBLANKS"
    )

### Arguments

`x` | A string, a connection, or a raw vector. A string can be either a path, a url or literal xml. Urls will be converted into connections either using `base::url` or, if installed, `curl::curl`. Local paths ending in `.gz`, `.bz2`, `.xz`, `.zip` will be automatically uncompressed. If a connection, the complete connection is read into a raw vector before being parsed.
`encoding` | Specify a default encoding for the document. Unless otherwise specified XML documents are assumed to be in UTF-8 or UTF-16. If the document is not UTF-8/16, and lacks an explicit encoding directive, this allows you to supply a default.
`...` | Additional arguments passed on to methods.
`as_html` | Optionally parse an xml file as if it's html.
`options` | Set parsing options for the libxml2 parser. Zero or more of RECOVER recover on errors NOENT substitute entities DTDLOAD load the external subset DTDATTR default DTD attributes DTDVALID validate with the DTD NOERROR suppress error reports NOWARNING suppress warning reports PEDANTIC pedantic error reporting NOBLANKS remove blank nodes SAX1 use the SAX1 interface internally XINCLUDE Implement XInclude substitition NONET Forbid network access NODICT Do not reuse the context dictionary NSCLEAN remove redundant namespaces declarations NOCDATA merge CDATA as text nodes NOXINCNODE do not generate XINCLUDE START/END nodes COMPACT compact small text nodes; no modification of the tree allowed afterwards (will possibly crash if you try to modify the tree) OLD10 parse using XML-1.0 before update 5 NOBASEFIX do not fixup XINCLUDE xml:base uris HUGE relax any hardcoded limit from the parser OLDSAX parse using SAX2 interface before 2.7.0 IGNORE_ENC ignore internal document encoding hint BIG_LINES Store big lines numbers in text PSVI field
`base_url` | When loading from a connection, raw vector or literal html/xml, this allows you to specify a base url for the document. Base urls are used to turn relative urls into absolute urls.
`n` | If `file` is a connection, the number of bytes to read per iteration. Defaults to 64kb.
`verbose` | When reading from a slow connection, this prints some output on every iteration so you know its working.

### Value

An XML document. HTML is normalised to valid XML - this may not be exactly the same transformation performed by the browser, but it's a reasonable approximation.

### Setting the "user agent" header

When performing web scraping tasks it is both good practice — and often required — to set the user agent request header to a specific value. Sometimes this value is assigned to emulate a browser in order to have content render in a certain way (e.g. `Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Firefox/52.0` to emulate more recent Windows browsers). Most often, this value should be set to provide the web resource owner information on who you are and the intent of your actions like this Google scraping bot user agent identifier: `Googlebot/2.1 (+http://www.google.com/bot.html)`.

You can set the HTTP user agent for URL-based requests using `httr::set_config()` and `httr::user_agent()`:

`httr::set_config(httr::user_agent("me@example.com; +https://example.com/info.html"))`

`httr::set_config()` changes the configuration globally, `httr::with_config()` can be used to change configuration temporarily.

### Examples

    # Literal xml/html is useful for small examples
    read_xml("<foo><bar /></foo>")
    read_html("<html><title>Hi<title></html>")
    read_html("<html><title>Hi")

    # From a local path
    read_html(system.file("extdata", "r-project.html", package = "xml2"))

    ## Not run:
    # From a url
    cd <- read_xml(xml2_example("cd_catalog.xml"))
    me <- read_html("http://had.co.nz")

    ## End(Not run)

[Package xml2 version 1.3.0 Index]