Struct WinHttpPacResolver 

pub struct WinHttpPacResolver { /* private fields */ }

Available on Windows and crate feature pac-windows-native and crate feature pac only.

PAC/WPAD via WinHttpGetProxyForUrlEx. Reuse one session; the cache it does not bound is described on resolve.

Pac / WpadAutoDetect: native fetch. PacInline: pac-boa. Direct/Manual: resolve_config. resolve_config answers a hostless URL Direct, except PacInline: that one is Error::PacNotSupported whether or not the URL has a host. resolve does not short-circuit it — see its doc. PacPolicy does not apply — real DNS/local IP.

Implementations

impl WinHttpPacResolver

pub fn new() -> Result<Self, Error>

Open a session with the default DEFAULT_WINHTTP_PAC_TIMEOUT budget.

Errors

Error::Io when WinHttpOpen, WinHttpSetTimeouts or WinHttpSetStatusCallback fails.

pub fn with_timeout(timeout: Duration) -> Result<Self, Error>

Open a session; zero timeout → Error::PacTimeout (not “unlimited”).

Errors

Error::Io (WinHttpOpen / SetTimeouts / SetStatusCallback) or Error::PacTimeout when timeout is zero.

pub fn timeout(&self) -> Duration

The per-resolution budget.

pub fn resolve( &self, url: &Url, source: &WinHttpPacSource, ) -> Result<Vec<ProxyStep>, Error>

Resolve url via source. Full FindProxyForURL chain → ProxySteps (HTTP/HTTPS/SOCKS4; fProxy == FALSE → Direct; FTP skipped; repeats collapse, as in parse_find_proxy_result, so the chain can be shorter than the entry count WinHTTP reported).

ERROR_WINHTTP_AUTODETECTION_FAILED → [Direct], but only from a source that asked for auto-detect. Download / script failure — and that same code from a URL-only source, where there was nothing to discover — stays an error.

A hostless URL (mailto:, data:) is resolved rather than short-circuited: this is the engine door, the native counterpart of pac::evaluate, and FindProxyForURL sees it with an empty host. Answering Direct without asking belongs to resolve_config, which was handed a whole configuration to decide from rather than a source the caller had already chosen.

Asking twice can be answered once. What WinHTTP caches is the autoproxy URL and the script — a repeat resolution re-runs that script rather than fetching it again, and a WPAD miss is remembered for as long as the session lives. The call that would bypass the cache is deliberately not made: it hands the user’s credentials to whatever WPAD found. Nothing here flushes it, and neither does dropping the resolver: WinHttpGetProxyForUrlEx “always executes out-of-process”, and with that service active Microsoft’s AutoProxy Cache topic puts the cached URL and script “available to the whole computer” — typically until the machine’s IP address changes, which no caller controls. Unlike ProxyConfig the result carries no capture time to say which fetch it came from.

A PacTimeout cancels the resolution without finishing it: the abandoned operation goes on draining behind this session, and a retry issued at once can spend its own budget waiting behind that rather than on the script. Widen the timeout or wait before retrying.

Errors

Error::PacTimeout, Error::PacEvaluation (ERROR_WINHTTP_BAD_AUTO_PROXY_SCRIPT), Error::PacInvalidResult, Error::Io (incl. undownloadable PAC URL).

pub fn resolve_config( &self, config: &ProxyConfig, url: &Url, ) -> Result<Vec<ProxyStep>, Error>

Like resolve_with_pac but WinHTTP fetches the script. Direct/Manual → resolve; hostless → Direct except PacInline → Error::PacNotSupported.

WpadAutoDetect may re-read the live registry for PAC URL / static fallback — not a pure function of config alone.

Errors

Error::PacNotSupported for PacInline, plus resolve’s errors — and, for the Direct/Manual arm this hands over, resolve’s, which is where Error::ProxyEntryUnusable comes from.

Trait Implementations

impl Debug for WinHttpPacResolver

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.