Struct reqwest::ClientBuilder

pub struct ClientBuilder { /* private fields */ }

A ClientBuilder can be used to create a Client with custom configuration.

Implementations

impl ClientBuilder

pub fn new() -> ClientBuilder

Constructs a new ClientBuilder.

This is the same as Client::builder().

pub fn build(self) -> Result<Client>

Returns a Client that uses this ClientBuilder configuration.

Errors

This method fails if a TLS backend cannot be initialized, or the resolver cannot load the system configuration.

pub fn user_agent<V>(self, value: V) -> ClientBuilder

where V: TryInto<HeaderValue>, V::Error: Into<Error>,

Sets the User-Agent header to be used by this client.

Example

// Name your user agent after your app?
static APP_USER_AGENT: &str = concat!(
    env!("CARGO_PKG_NAME"),
    "/",
    env!("CARGO_PKG_VERSION"),
);

let client = reqwest::Client::builder()
    .user_agent(APP_USER_AGENT)
    .build()?;
let res = client.get("https://www.rust-lang.org").send().await?;

pub fn default_headers(self, headers: HeaderMap) -> ClientBuilder

Sets the default headers for every request.

Example

use reqwest::header;
let mut headers = header::HeaderMap::new();
headers.insert("X-MY-HEADER", header::HeaderValue::from_static("value"));

// Consider marking security-sensitive headers with `set_sensitive`.
let mut auth_value = header::HeaderValue::from_static("secret");
auth_value.set_sensitive(true);
headers.insert(header::AUTHORIZATION, auth_value);

// get a client builder
let client = reqwest::Client::builder()
    .default_headers(headers)
    .build()?;
let res = client.get("https://www.rust-lang.org").send().await?;

Override the default headers:

use reqwest::header;
let mut headers = header::HeaderMap::new();
headers.insert("X-MY-HEADER", header::HeaderValue::from_static("value"));

// get a client builder
let client = reqwest::Client::builder()
    .default_headers(headers)
    .build()?;
let res = client
    .get("https://www.rust-lang.org")
    .header("X-MY-HEADER", "new_value")
    .send()
    .await?;

pub fn no_gzip(self) -> ClientBuilder

Disable auto response body gzip decompression.

This method exists even if the optional gzip feature is not enabled. This can be used to ensure a Client doesn’t use gzip decompression even if another dependency were to enable the optional gzip feature.

pub fn no_brotli(self) -> ClientBuilder

Disable auto response body brotli decompression.

This method exists even if the optional brotli feature is not enabled. This can be used to ensure a Client doesn’t use brotli decompression even if another dependency were to enable the optional brotli feature.

pub fn no_deflate(self) -> ClientBuilder

Disable auto response body deflate decompression.

This method exists even if the optional deflate feature is not enabled. This can be used to ensure a Client doesn’t use deflate decompression even if another dependency were to enable the optional deflate feature.

pub fn redirect(self, policy: Policy) -> ClientBuilder

Set a RedirectPolicy for this client.

Default will follow redirects up to a maximum of 10.

pub fn referer(self, enable: bool) -> ClientBuilder

Enable or disable automatic setting of the Referer header.

Default is true.

pub fn proxy(self, proxy: Proxy) -> ClientBuilder

Add a Proxy to the list of proxies the Client will use.

Note

Adding a proxy will disable the automatic usage of the “system” proxy.

pub fn no_proxy(self) -> ClientBuilder

Clear all Proxies, so Client will use no proxy anymore.

Note

To add a proxy exclusion list, use crate::proxy::Proxy::no_proxy() on all desired proxies instead.

This also disables the automatic usage of the “system” proxy.

pub fn timeout(self, timeout: Duration) -> ClientBuilder

Enables a request timeout.

The timeout is applied from when the request starts connecting until the response body has finished.

Default is no timeout.

pub fn connect_timeout(self, timeout: Duration) -> ClientBuilder

Set a timeout for only the connect phase of a Client.

Default is None.

Note

This requires the futures be executed in a tokio runtime with a tokio timer enabled.

pub fn connection_verbose(self, verbose: bool) -> ClientBuilder

Set whether connections should emit verbose logs.

Enabling this option will emit log messages at the TRACE level for read and write operations on connections.

pub fn pool_idle_timeout<D>(self, val: D) -> ClientBuilder

where D: Into<Option<Duration>>,

Set an optional timeout for idle sockets being kept-alive.

Pass None to disable timeout.

Default is 90 seconds.

pub fn pool_max_idle_per_host(self, max: usize) -> ClientBuilder

Sets the maximum idle connection per host allowed in the pool.

pub fn http1_title_case_headers(self) -> ClientBuilder

Send headers as title case instead of lowercase.

pub fn http1_allow_obsolete_multiline_headers_in_responses( self, value: bool ) -> ClientBuilder

Set whether HTTP/1 connections will accept obsolete line folding for header values.

Newline codepoints (\r and \n) will be transformed to spaces when parsing.

pub fn http1_only(self) -> ClientBuilder

Only use HTTP/1.

pub fn http09_responses(self) -> ClientBuilder

Allow HTTP/0.9 responses

pub fn http2_prior_knowledge(self) -> ClientBuilder

Only use HTTP/2.

pub fn http2_initial_stream_window_size( self, sz: impl Into<Option<u32>> ) -> ClientBuilder

Sets the SETTINGS_INITIAL_WINDOW_SIZE option for HTTP2 stream-level flow control.

Default is currently 65,535 but may change internally to optimize for common uses.

pub fn http2_initial_connection_window_size( self, sz: impl Into<Option<u32>> ) -> ClientBuilder

Sets the max connection-level flow control for HTTP2

Default is currently 65,535 but may change internally to optimize for common uses.

pub fn http2_adaptive_window(self, enabled: bool) -> ClientBuilder

Sets whether to use an adaptive flow control.

Enabling this will override the limits set in http2_initial_stream_window_size and http2_initial_connection_window_size.

pub fn http2_max_frame_size(self, sz: impl Into<Option<u32>>) -> ClientBuilder

Sets the maximum frame size to use for HTTP2.

Default is currently 16,384 but may change internally to optimize for common uses.

pub fn http2_keep_alive_interval( self, interval: impl Into<Option<Duration>> ) -> ClientBuilder

Sets an interval for HTTP2 Ping frames should be sent to keep a connection alive.

Pass None to disable HTTP2 keep-alive. Default is currently disabled.

pub fn http2_keep_alive_timeout(self, timeout: Duration) -> ClientBuilder

Sets a timeout for receiving an acknowledgement of the keep-alive ping.

If the ping is not acknowledged within the timeout, the connection will be closed. Does nothing if http2_keep_alive_interval is disabled. Default is currently disabled.

pub fn http2_keep_alive_while_idle(self, enabled: bool) -> ClientBuilder

Sets whether HTTP2 keep-alive should apply while the connection is idle.

If disabled, keep-alive pings are only sent while there are open request/responses streams. If enabled, pings are also sent when no streams are active. Does nothing if http2_keep_alive_interval is disabled. Default is false.

pub fn tcp_nodelay(self, enabled: bool) -> ClientBuilder

Set whether sockets have TCP_NODELAY enabled.

Default is true.

pub fn local_address<T>(self, addr: T) -> ClientBuilder

where T: Into<Option<IpAddr>>,

Bind to a local IP Address.

Example

use std::net::IpAddr;
let local_addr = IpAddr::from([12, 4, 1, 8]);
let client = reqwest::Client::builder()
    .local_address(local_addr)
    .build().unwrap();

pub fn tcp_keepalive<D>(self, val: D) -> ClientBuilder

where D: Into<Option<Duration>>,

Set that all sockets have SO_KEEPALIVE set with the supplied duration.

If None, the option will not be set.

pub fn add_root_certificate(self, cert: Certificate) -> ClientBuilder

Add a custom root certificate.

This can be used to connect to a server that has a self-signed certificate for example.

Optional

This requires the optional default-tls, native-tls, or rustls-tls(-...) feature to be enabled.

pub fn tls_built_in_root_certs( self, tls_built_in_root_certs: bool ) -> ClientBuilder

Controls the use of built-in/preloaded certificates during certificate validation.

Defaults to true – built-in system certs will be used.

Optional

This requires the optional default-tls, native-tls, or rustls-tls(-...) feature to be enabled.

pub fn identity(self, identity: Identity) -> ClientBuilder

Sets the identity to be used for client certificate authentication.

Optional

This requires the optional native-tls or rustls-tls(-...) feature to be enabled.

pub fn danger_accept_invalid_certs( self, accept_invalid_certs: bool ) -> ClientBuilder

Controls the use of certificate validation.

Defaults to false.

Warning

You should think very carefully before using this method. If invalid certificates are trusted, any certificate for any site will be trusted for use. This includes expired certificates. This introduces significant vulnerabilities, and should only be used as a last resort.

Optional

This requires the optional default-tls, native-tls, or rustls-tls(-...) feature to be enabled.

pub fn tls_sni(self, tls_sni: bool) -> ClientBuilder

Controls the use of TLS server name indication.

Defaults to true.

Optional

This requires the optional default-tls, native-tls, or rustls-tls(-...) feature to be enabled.

pub fn min_tls_version(self, version: Version) -> ClientBuilder

Set the minimum required TLS version for connections.

By default the TLS backend’s own default is used.

Errors

A value of tls::Version::TLS_1_3 will cause an error with the native-tls/default-tls backend. This does not mean the version isn’t supported, just that it can’t be set as a minimum due to technical limitations.

Optional

This requires the optional default-tls, native-tls, or rustls-tls(-...) feature to be enabled.

pub fn max_tls_version(self, version: Version) -> ClientBuilder

Set the maximum allowed TLS version for connections.

By default there’s no maximum.

Errors

A value of tls::Version::TLS_1_3 will cause an error with the native-tls/default-tls backend. This does not mean the version isn’t supported, just that it can’t be set as a maximum due to technical limitations.

Optional

This requires the optional default-tls, native-tls, or rustls-tls(-...) feature to be enabled.

pub fn use_rustls_tls(self) -> ClientBuilder

Force using the Rustls TLS backend.

Since multiple TLS backends can be optionally enabled, this option will force the rustls backend to be used for this Client.

Optional

This requires the optional rustls-tls(-...) feature to be enabled.

pub fn use_preconfigured_tls(self, tls: impl Any) -> ClientBuilder

Use a preconfigured TLS backend.

If the passed Any argument is not a TLS backend that reqwest understands, the ClientBuilder will error when calling build.

Advanced

This is an advanced option, and can be somewhat brittle. Usage requires keeping the preconfigured TLS argument version in sync with reqwest, since version mismatches will result in an “unknown” TLS backend.

If possible, it’s preferable to use the methods on ClientBuilder to configure reqwest’s TLS.

Optional

This requires one of the optional features native-tls or rustls-tls(-...) to be enabled.

pub fn no_trust_dns(self) -> ClientBuilder

Disables the trust-dns async resolver.

This method exists even if the optional trust-dns feature is not enabled. This can be used to ensure a Client doesn’t use the trust-dns async resolver even if another dependency were to enable the optional trust-dns feature.

pub fn https_only(self, enabled: bool) -> ClientBuilder

Restrict the Client to be used with HTTPS only requests.

Defaults to false.

pub fn resolve(self, domain: &str, addr: SocketAddr) -> ClientBuilder

Override DNS resolution for specific domains to a particular IP address.

Warning

Since the DNS protocol has no notion of ports, if you wish to send traffic to a particular port you must include this port in the URL itself, any port in the overridden addr will be ignored and traffic sent to the conventional port for the given scheme (e.g. 80 for http).

pub fn resolve_to_addrs( self, domain: &str, addrs: &[SocketAddr] ) -> ClientBuilder

Override DNS resolution for specific domains to particular IP addresses.

Warning

Since the DNS protocol has no notion of ports, if you wish to send traffic to a particular port you must include this port in the URL itself, any port in the overridden addresses will be ignored and traffic sent to the conventional port for the given scheme (e.g. 80 for http).

pub fn dns_resolver<R: Resolve + 'static>( self, resolver: Arc<R> ) -> ClientBuilder

Override the DNS resolver implementation.

Pass an Arc wrapping a trait object implementing Resolve. Overrides for specific names passed to resolve and resolve_to_addrs will still be applied on top of this resolver.

Trait Implementations

impl Debug for ClientBuilder

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

Formats the value using the given formatter.

impl Default for ClientBuilder

fn default() -> Self

Returns the “default value” for a type.