HELP HTTP_SERVER                       Serve HTTP from pure Pop-11

    uses http_server;

A small, single-threaded HTTP/1.1 server over LIB * UNIX_SOCKETS: one
accept loop, one request per connection (Connection: close).  It
composes with LIB * JSON for API work — see examples/http_hello.p
for a complete service.

http_serve(PORT, HANDLER)
http_serve_n(PORT, HANDLER, COUNT)
    Listen on PORT and call HANDLER(REQUEST) -> RESPONSE for each
    request.  http_serve runs forever; http_serve_n returns after
    COUNT requests (false = forever).  If HANDLER returns false the
    server answers 404; if HANDLER mishaps the server answers 500
    and carries on.

REQUEST is a property:

    req('method')     'GET', 'POST', ... (upper case)
    req('path')       '/hello'  (query string removed)
    req('query')      'name=poplog'  (raw; '' if none)
    req('headers')    property of header values, names lowercased:
                      req('headers')('content-type')
    req('body')       the request body ('' unless Content-Length)

RESPONSE constructors:

    http_response(STATUS, CTYPE, BODY) -> RESP
    http_text(BODY) -> RESP               200 text/plain
    http_json(ITEM) -> RESP               200 application/json,
                                          body via json_generate

Minimal service:

    uses http_server;
    define handler(req) -> resp;
        if req('path') = '/hello' then
            http_text('hello from Pop-11\n') -> resp
        else
            false -> resp               ;;; -> 404
        endif;
    enddefine;
    http_serve(8080, handler);

Limits (v1, by design): single-threaded (one request at a time), no
keep-alive, no TLS (put a reverse proxy in front for production), no
chunked request bodies, query strings are not URL-decoded.

See also: REF * SOCKETS, LIB * JSON, examples/http_hello.p,
tools/tests/test_http_server.p (which exercises a live server with
curl via LIB * SHELL).

--- pop/help/http_server