http_open:http

/home/swipl/lib/swipl/library/http/http_open.pl

library
- http

http_open(+URL, -Stream, +Options) is det

Open the data at the HTTP server as a Prolog stream. URL is either an atom specifying a URL or a list representing a broken-down URL as specified below. After this predicate succeeds the data can be read from Stream. After completion this stream must be closed using the built-in Prolog predicate close/1. Options provides additional options:

authenticate(+Boolean)

If false (default true), do not try to automatically authenticate the client if a 401 (Unauthorized) status code is received.

authorization(+Term)

Send authorization. See also http_set_authorization/2. Supported schemes:

basic(+User, +Password): HTTP Basic authentication.
bearer(+Token): HTTP Bearer authentication.
digest(+User, +Password): HTTP Digest authentication. This option is only provided if the plugin library(http/http_digest) is also loaded.

unix_socket(+Path)

Connect to the given Unix domain socket. In this scenario the host name and port or ignored. If the server replies with a redirect message and the host differs from the original host as normal TCP connection is used to handle the redirect. This option is inspired by curl(1)'s option `--unix-socket`.

connection(+Connection)

Specify the Connection header. Default is close. The alternative is Keep-alive. This maintains a pool of available connections as determined by keep_connection/1. The library(http/websockets) uses Keep-alive, Upgrade. Keep-alive connections can be closed explicitly using http_close_keep_alive/1. Keep-alive connections may significantly improve repetitive requests on the same server, especially if the IP route is long, HTTPS is used or the connection uses a proxy.

final_url(-FinalURL)

Unify FinalURL with the final destination. This differs from the original URL if the returned head of the original indicates an HTTP redirect (codes 301, 302 or 303). Without a redirect, FinalURL is the same as URL if URL is an atom, or a URL constructed from the parts.

header(Name, -AtomValue)

If provided, AtomValue is unified with the value of the indicated field in the reply header. Name is matched case-insensitive and the underscore (_) matches the hyphen (-). Multiple of these options may be provided to extract multiple header fields. If the header is not available AtomValue is unified to the empty atom ('').

headers(-List)

If provided, List is unified with a list of Name(Value) pairs corresponding to fields in the reply header. Name and Value follow the same conventions used by the header(Name,Value) option. See also raw_headers(-List) which provides the entire HTTP reply header in unparsed representation.

method(+Method)

One of get (default), head, delete, post, put or patch. The head message can be used in combination with the header(Name, Value) option to access information on the resource without actually fetching the resource itself. The returned stream must be closed immediately.

If post(Data) is provided, the default is post.

size(-Size)

Size is unified with the integer value of Content-Length in the reply header.

version(-Version)

Version is a pair Major-Minor, where Major and Minor are integers representing the HTTP version in the reply header.

range(+Range)

Ask for partial content. Range is a term Unit(From,To), where From is an integer and To is either an integer or the atom end. HTTP 1.1 only supports Unit = bytes. E.g., to ask for bytes 1000-1999, use the option range(bytes(1000,1999))

raw_encoding(+Encoding)

Do not install a decoding filter for Encoding. For example, using raw_encoding('applocation/gzip') the system will not decompress the stream if it is compressed using gzip.