# actix_web::http::header::IF_RANGE - Rust
API documentation for the Rust `IF_RANGE` constant in crate `actix_web`.
Keywords: rust, rustlang, rust-lang, IF_RANGE

# Constant actix_web::http::header::IF_RANGE [−] [src]

    pub const IF_RANGE: HeaderName = HeaderName{inner: Repr::Standard(StandardHeader::IfRange),}

Makes a request conditional based on range.

The If-Range HTTP request header makes a range request conditional: if the condition is fulfilled, the range request will be issued and the server sends back a 206 Partial Content answer with the appropriate body. If the condition is not fulfilled, the full resource is sent back, with a 200 OK status.

This header can be used either with a Last-Modified validator, or with an ETag, but not with both.

The most common use case is to resume a download, to guarantee that the stored resource has not been modified since the last fragment has been received.

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