web.v

1//! The web backend: read-only access to a public Koh mirror.2module remote34import net.http5import net.urllib67pub struct Web {8pub mut:9	base string10	// on_body hears how much of a response has arrived, each time it passes another MiB.11	on_body fn (received u64) = unsafe { nil }12}1314pub fn new_web(base string) !Web {15	return Web{ base: kepr_host(base)! }16}1718// kepr_host normalises a Kepr address: https unless the scheme says otherwise, and scheme, host19// and port only. A path, a query, a fragment or credentials would send the code somewhere else.20pub fn kepr_host(value string) !string {21	for letter in value {22		if letter <= ` ` {23			return error('"${value}" is not a Kepr address — try kepr.uk')24		}25	}26	text := if value.starts_with('http://') || value.starts_with('https://') {27		value28	} else {29		'https://${value}'30	}31	parsed := urllib.parse(text) or { return error('"${value}" is not a Kepr address — try kepr.uk') }32	if parsed.scheme !in ['http', 'https'] || parsed.host == '' || parsed.path.trim_right('/') != '' || parsed.raw_query != '' || parsed.fragment != '' {33		return error('"${value}" is not a Kepr address — try kepr.uk')34	}35	if text.all_after('//').contains('@') {36		return error('"${value}" is not a Kepr address — try kepr.uk')37	}38	// `/api/connect` answers with the bucket's secret key, so plain http is only for a Kepr on39	// this machine: a test, or a local run.40	if parsed.scheme == 'http' && parsed.hostname().to_lower() !in ['127.0.0.1', 'localhost', '::1'] {41		return error('"${value}" needs https — plain http is only for a Kepr on this machine')42	}43	// A hostname is case-insensitive, so the stored form is the lower-case one.44	return '${parsed.scheme}://${parsed.host.to_lower()}'45}4647pub fn (mut w Web) get(key string) !Object {48	on_body := w.on_body49	response := http.fetch(50		url:              w.url(key)51		method:           .get52		enable_http2:     false53		allow_redirect:   false54		on_progress_body: fn [on_body] (_ &http.Request, chunk []u8, received u64, _ u64, _ int) ! {55			if on_body != unsafe { nil } && (received - u64(chunk.len)) >> 20 != received >> 20 {56				on_body(received)57			}58		}59	)!60	if response.status_code == 404 {61		return Object{}62	}63	if response.status_code < 200 || response.status_code >= 300 {64		return error('web GET ${key} failed: ${response.status_code}')65	}66	return Object{67		found: true68		body:  response.body.bytes()69		tag:   response.header.get_custom('etag', http.HeaderQueryConfig{}) or { '' }70	}71}7273pub fn (mut w Web) list(prefix string) ![]string {74	response := http.fetch(75		url:            w.url(prefix)76		method:         .get77		enable_http2:   false78		allow_redirect: false79	)!80	if response.status_code == 404 {81		return []string{}82	}83	if response.status_code < 200 || response.status_code >= 300 {84		return error('web GET ${prefix} failed: ${response.status_code}')85	}86	mut result := []string{}87	for id in response.body.split_into_lines() {88		if id.trim_space() != '' { result << '${prefix}/${id.trim_space()}' }89	}90	return result91}9293pub fn (mut w Web) put_if_absent(key string, body []u8) !bool {94	return error('${w.repo(key)} is read-only.')95}9697pub fn (mut w Web) put_if_match(key string, body []u8, tag string) !bool {98	return error('${w.repo(key)} is read-only.')99}100101pub fn (mut w Web) delete(key string) ! {102	return error('${w.repo(key)} is read-only.')103}104105fn (w &Web) url(key string) string {106	parts := key.split('/')107	return '${w.base}/${parts[0]}/koh/${parts[1..].join('/')}'108}109110fn (w &Web) repo(key string) string {111	return '${w.base}/${key.all_before('/')}'112}