Enum ProxyMode 

pub enum ProxyMode {
    None,
    Environment,
    Explicit(String),
    System,
}

How requests reach the network.

Threat model. A direct connection is the strongest case: this crate resolves the name, checks every address and connects to exactly those addresses. Through a proxy it cannot: the proxy resolves the destination name itself, so the address a connection reaches cannot be checked or pinned here. The guarantee through a proxy is therefore name- and literal-based, and weaker than a direct connection. ProxyMode::None stays the default for that reason.

With a proxy:

• The proxy endpoint is trusted (it is user or administrator configuration, often on a private address such as http://10.0.0.5:3128). It gets no address-class denial. Only http and https proxies are accepted.
• Every destination is still vetted: IP literals (and localhost) by class, hostnames by the name rules (localhost, *.localhost, *.local, *.internal and single-label names are refused unless an allow_if rule lists the host), cloud metadata names, and the first-party host pin. deny_ranges and deny_if apply to literals only, because a hostname’s address is not known. A hostname that resolves to a private address at the proxy is not caught.
• Every redirect hop is vetted the same way.
• Hosts that match NO_PROXY connect directly and get the full direct-connection check.
• ClientConfig::proxy_bypass_first_party skips the proxy for a first-party client.

The proxy is trusted: it sees destinations and can forward anywhere. Credentials in a proxy URL never appear in Debug output or errors.

Variants

None

No proxy. Environment proxy variables are ignored. This is the default.

Environment

ALL_PROXY, HTTPS_PROXY, HTTP_PROXY (first set, either case) and NO_PROXY.

Explicit(String)

A proxy URL such as http://proxy.corp:3128 or socks5://127.0.0.1:1080.

System

The proxy the operating system is configured with for the current user.

Windows: the static proxy and bypass list of the system proxy settings, followed exactly or not at all. One http or https proxy for both schemes with a bypass list of plain hosts (host, *.example.com) is used. Anything else (different routes per scheme, <local>, a scheme-limited or inner-wildcard bypass entry, a proxy auto-config script, automatic detection) is HttpError::SystemProxyUnsupported and nothing is sent; catch it and use the mode the app used before. When nothing is configured, and on other systems, this is ProxyMode::Environment.

Trait Implementations

impl Clone for ProxyMode

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ProxyMode

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

Formats the value using the given formatter.

impl Default for ProxyMode

fn default() -> Self

Returns the “default value” for a type.