Type Alias opendal::operator_futures::FutureRead

pub type FutureRead<F> = OperatorFuture<(OpRead, OpReader), Buffer, F>;

Future that generated by Operator::read_with.

Users can add more options by public functions provided by this struct.

Aliased Type

struct FutureRead<F> { /* private fields */ }

Implementations

impl<F: Future<Output = Result<Buffer>>> FutureRead<F>

pub fn executor(self, executor: Executor) -> Self

Set the executor for this operation.

pub fn range(self, range: impl RangeBounds<u64>) -> Self

Set range for this read request.

If we have a file with size n.

• .. means read bytes in range [0, n) of file.
• 0..1024 and ..1024 means read bytes in range [0, 1024) of file
• 1024.. means read bytes in range [1024, n) of file

let bs = op.read_with("path/to/file").range(0..1024).await?;

pub fn concurrent(self, concurrent: usize) -> Self

Set concurrent for the reader.

OpenDAL by default to write file without concurrent. This is not efficient for cases when users read large chunks of data. By setting concurrent, opendal will read files concurrently on support storage services.

By setting concurrent, opendal will fetch chunks concurrently with the given chunk size.

let r = op.read_with("path/to/file").concurrent(8).await?;

pub fn chunk(self, chunk_size: usize) -> Self

OpenDAL will use services’ preferred chunk size by default. Users can set chunk based on their own needs.

This following example will make opendal read data in 4MiB chunks:

let r = op.read_with("path/to/file").chunk(4 * 1024 * 1024).await?;

pub fn version(self, v: &str) -> Self

Set version for this read request.

This feature can be used to retrieve the data of a specified version of the given path.

If the version doesn’t exist, an error with kind ErrorKind::NotFound will be returned.

let mut bs = op.read_with("path/to/file").version(version).await?;

pub fn if_match(self, v: &str) -> Self

Set if_match for this read request.

This feature can be used to check if the file’s ETag matches the given ETag.

If file exists and it’s etag doesn’t match, an error with kind ErrorKind::ConditionNotMatch will be returned.

use opendal::Operator;
let mut metadata = op.read_with("path/to/file").if_match(etag).await?;

pub fn if_none_match(self, v: &str) -> Self

Set if_none_match for this read request.

This feature can be used to check if the file’s ETag doesn’t match the given ETag.

If file exists and it’s etag match, an error with kind ErrorKind::ConditionNotMatch will be returned.

use opendal::Operator;
let mut metadata = op.read_with("path/to/file").if_none_match(etag).await?;

pub fn if_modified_since(self, v: DateTime<Utc>) -> Self

if_modified_since

Set if_modified_since for this read request.

This feature can be used to check if the file has been modified since the given timestamp.

If file exists and it hasn’t been modified since the specified time, an error with kind ErrorKind::ConditionNotMatch will be returned.

use opendal::Operator;
use chrono::DateTime;
use chrono::Utc;
let mut metadata = op.read_with("path/to/file").if_modified_since(time).await?;

pub fn if_unmodified_since(self, v: DateTime<Utc>) -> Self

Set if_unmodified_since for this read request.

This feature can be used to check if the file hasn’t been modified since the given timestamp.

If file exists and it has been modified since the specified time, an error with kind ErrorKind::ConditionNotMatch will be returned.

use opendal::Operator;
use chrono::DateTime;
use chrono::Utc;
let mut metadata = op.read_with("path/to/file").if_unmodified_since(time).await?;