pub struct ClientBuilder { /* private fields */ }
Expand description

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

Example

use std::time::Duration;

let client = reqwest::blocking::Client::builder()
    .timeout(Duration::from_secs(10))
    .build()?;

Implementations§

Constructs a new ClientBuilder.

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

Returns a Client that uses this ClientBuilder configuration.

Errors

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

Panics

This method panics if called from within an async runtime. See docs on reqwest::blocking for details.

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

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"));
headers.insert(header::AUTHORIZATION, header::HeaderValue::from_static("secret"));

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

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::blocking::Client::builder()
    .default_headers(headers)
    .build()?;
let res = client
    .get("https://www.rust-lang.org")
    .header("X-MY-HEADER", "new_value")
    .send()?;
Available on crate feature cookies only.

Enable a persistent cookie store for the client.

Cookies received in responses will be preserved and included in additional requests.

By default, no cookie store is used.

Optional

This requires the optional cookies feature to be enabled.

Available on crate feature cookies only.

Set the persistent cookie store for the client.

Cookies received in responses will be passed to this store, and additional requests will query this store for cookies.

By default, no cookie store is used.

Optional

This requires the optional cookies feature to be enabled.

Available on crate feature gzip only.

Enable auto gzip decompression by checking the Content-Encoding response header.

If auto gzip decompresson is turned on:

  • When sending a request and if the request’s headers do not already contain an Accept-Encoding and Range values, the Accept-Encoding header is set to gzip. The request body is not automatically compressed.
  • When receiving a response, if it’s headers contain a Content-Encoding value that equals to gzip, both values Content-Encoding and Content-Length are removed from the headers’ set. The response body is automatically decompressed.

If the gzip feature is turned on, the default option is enabled.

Optional

This requires the optional gzip feature to be enabled

Available on crate feature brotli only.

Enable auto brotli decompression by checking the Content-Encoding response header.

If auto brotli decompression is turned on:

  • When sending a request and if the request’s headers do not already contain an Accept-Encoding and Range values, the Accept-Encoding header is set to br. The request body is not automatically compressed.
  • When receiving a response, if it’s headers contain a Content-Encoding value that equals to br, both values Content-Encoding and Content-Length are removed from the headers’ set. The response body is automatically decompressed.

If the brotli feature is turned on, the default option is enabled.

Optional

This requires the optional brotli feature to be enabled

Available on crate feature deflate only.

Enable auto deflate decompression by checking the Content-Encoding response header.

If auto deflate decompresson is turned on:

  • When sending a request and if the request’s headers do not already contain an Accept-Encoding and Range values, the Accept-Encoding header is set to deflate. The request body is not automatically compressed.
  • When receiving a response, if it’s headers contain a Content-Encoding value that equals to deflate, both values Content-Encoding and Content-Length are removed from the headers’ set. The response body is automatically decompressed.

If the deflate feature is turned on, the default option is enabled.

Optional

This requires the optional deflate feature to be enabled

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.

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.

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.

Set a redirect::Policy for this client.

Default will follow redirects up to a maximum of 10.

Enable or disable automatic setting of the Referer header.

Default is true.

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.

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.

Set a timeout for connect, read and write operations of a Client.

Default is 30 seconds.

Pass None to disable timeout.

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

Default is None.

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.

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

Pass None to disable timeout.

Default is 90 seconds.

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

Send headers as title case instead of lowercase.

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.

Only use HTTP/1.

Allow HTTP/0.9 responses

Only use HTTP/2.

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.

Sets the max connection-level flow control for HTTP2

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

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.

Sets the maximum frame size to use for HTTP2.

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

Set whether sockets have TCP_NODELAY enabled.

Default is true.

Bind to a local IP Address.

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

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

If None, the option will not be set.

Available on crate features default-tls or native-tls or rustls-tls only.

Add a custom root certificate.

This allows connecting to a server that has a self-signed certificate for example. This does not replace the existing trusted store.

Example
// read a local binary DER encoded certificate
let der = std::fs::read("my-cert.der")?;

// create a certificate
let cert = reqwest::Certificate::from_der(&der)?;

// get a client builder
let client = reqwest::blocking::Client::builder()
    .add_root_certificate(cert)
    .build()?;
Optional

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

Available on crate features default-tls or native-tls or rustls-tls only.

Controls the use of built-in system 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.

Available on crate features native-tls or rustls-tls only.

Sets the identity to be used for client certificate authentication.

Optional

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

Available on crate feature native-tls only.

Controls the use of hostname verification.

Defaults to false.

Warning

You should think very carefully before you use this method. If hostname verification is not used, any valid certificate for any site will be trusted for use from any other. This introduces a significant vulnerability to man-in-the-middle attacks.

Optional

This requires the optional native-tls feature to be enabled.

Available on crate features default-tls or native-tls or rustls-tls only.

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.

Available on crate features default-tls or native-tls or rustls-tls only.

Controls the use of TLS server name indication.

Defaults to true.

Available on crate features default-tls or native-tls or rustls-tls only.

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.

Available on crate features default-tls or native-tls or rustls-tls only.

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.

Available on crate feature native-tls only.

Force using the native TLS backend.

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

Optional

This requires the optional native-tls feature to be enabled.

Available on crate feature rustls-tls only.

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.

Available on crate features native-tls or rustls-tls only.

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.

Available on crate feature trust-dns only.

Enables the trust-dns async resolver instead of a default threadpool using getaddrinfo.

If the trust-dns feature is turned on, the default option is enabled.

Optional

This requires the optional trust-dns feature to be enabled

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.

Restrict the Client to be used with HTTPS only requests.

Defaults to false.

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).

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).

Trait Implementations§

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